• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
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    • 专利摘要:
    The invention relates to a positioning drive (15) and a method for positioning an output element (16). The positioning drive (15) has a first step drive unit (21) with a first step drive control (22) and a first step motor (23) and a second step drive unit (24) with a second step drive control (25) and a second step motor (26). The two stepping motors (23, 26) and the output element (16) are force-coupled and drive-coupled via a mechanical coupling unit (18). A central unit (31) controls the two stepper drive controls (22, 25) via a control signal (A1) or (A2). The control signals (A1, A2) each specify the stator target field angle and the rotor target field angle, which is set via the assigned stepper drive control (22) or (25). The central unit (31) has a superimposed regulation for the position of the output element (16). It also has a subordinate control or regulation in order to set a tensioning torque for each stepping motor (23, 26). The tensioning torques result from setting an actual load angle on the relevant stepper motor (23, 26).
    公开号:CH712567B1
    申请号:CH01346/17
    申请日:2016-05-11
    公开日:2020-09-30
    发明作者:Palmer Thomas；Eppinger Uwe
    申请人:Egt Eppinger Getriebe Tech Gmbh；
    IPC主号:
    专利说明:

    The invention relates to a positioning drive and a method for positioning an output element. The output element can be driven linearly or rotatively. For example, it can be a translationally or rotationally drivable table or slide for a tool or a tool.
    In many applications, output elements that are moved by a positioning drive can be positioned very precisely, for example tables or slides of machine tools or measuring machines, in order to obtain a correspondingly high level of accuracy when machining or measuring or testing a workpiece. In the manufacture of such a positioning drive, the movement-transmitting mechanism exhibits elasticities, manufacturing tolerances, friction and play or slack. Because of these inadequacies, inaccuracies or errors can occur in the positioning of the output element.
    The game in the mechanical transmission within the positioning drive to the output element can also lead to a delayed movement of the output element if a controlled positioning motor must first overcome the game before its movement is transmitted to the output element. In highly dynamic applications, problems or errors can occur during positioning, such as oscillations or overshooting behavior, which make it necessary to reduce the gain and thus the dynamics of the position control.
    It is therefore desirable to eliminate the play in the kinematic transmission chain from a positioning motor to the output element.
    To solve this problem, it is known to eliminate play in the kinematic transmission chain by means of elastic biasing elements. The disadvantage here is that the pre-tensioning force of a mechanical pre-tensioning element acts at all times, which has a negative impact on the efficiency of the positioning drive. Devices to be able to activate and deactivate such a mechanical preload element are structurally complex and require additional actuators.
    In order to avoid the disadvantages of a mechanical biasing element, it is also known to drive an output element by a positioning drive with two servomotors, which can be acted upon against one another with a torque for bracing the mechanical system. Such a positioning drive is known, for example, from DD 279432 A1. There, two servomotors are operated in a controlled manner with a control loop which has a superimposed position control loop. A speed control loop is subordinate to the position control loop and a current control loop is subordinate to the speed control loop. In servomotors with field-oriented current control, the motor torque can be changed by influencing the torque-generating motor current (armature cross current), which is proportional to the motor current. Accordingly, there is also a setpoint value generator that modifies the setpoint values for the motor currents of the two servomotors in such a way that they each maintain a motor torque directed against one another. As a result, the mechanical system is tensioned and the output element can be positioned precisely and without play.
    Based on this, it can be seen as the object of the present invention to create a positioning drive and a method that can be implemented with simpler means.
    [0008] This object is achieved by a positioning drive with the features of claim 1 and a method with the features of claim 16.
    [0009] The positioning drive according to the invention has a mechanical coupling unit. The mechanical coupling unit has a coupling output which is connected to the output element. The coupling unit also has two coupling inputs coupled to the coupling output. A change in position at one of the coupling inputs thus leads to a change in the position of the output element at the coupling output. There is also preferably a force or moment coupling between the two coupling inputs, which can thus influence one another. In particular, the coupling unit is designed in such a way that a movement at the coupling output - neglecting the existing elasticity - is only possible if all coupling inputs are also moving. Between the coupling inputs and the coupling output there is a step-up or step-down ratio, which can be the same or different. A ratio of 1: 1 between the coupling inputs and the coupling output is also possible.
    [0010] The positioning drive also has a first step drive unit with a first step motor and a first step drive control which controls this first step motor. Correspondingly, a second step drive unit has a second step motor and a second step drive control which controls this second step motor. The two rotors or rotors of the stepper motors are each connected directly to an associated coupling input of the coupling unit.
    [0011] The positioning drive also has a central unit to which a kinematics setpoint and a tension setpoint are specified. The kinematics setpoint can be a position setpoint, a speed setpoint or an acceleration setpoint. A position setpoint is used as the kinematic setpoint for positioning tasks. For applications in which the feed is to be controlled along a path curve, a speed setpoint can also be specified. The kinematics setpoint and the tension setpoint can, for example, be specified depending on the application by a machine control and transmitted to the central unit. In the case of a machine control that does not provide an output for a desired tension value, the central unit can also determine a desired tension value on the basis of a predetermined tension strategy.
    The central unit is set up to determine a first control signal for the first step drive control and a second control signal for the second step drive control as a function of the kinematics setpoint and the tension setpoint. The control signals each indicate in which direction and by what amount or by what number of steps the relevant rotor or rotor of a stepping motor is to be moved. The control signals therefore define changes in position for the rotors or rotors.
    Due to the kinematic coupling of the drive units and the output element, an over-determined position change specification is brought about via the two control signals, which is otherwise avoided in control technology.
    The kinematic overdetermination is usually avoided in that only one servomotor is position-controlled and the other servomotor is torque-controlled. So-called master-slave operation is carried out. The torque-controlled mode of operation of a servomotor (for example a synchronous motor), however, requires field-oriented current control and the possibility of specifying a setpoint value for a torque-generating armature cross-current via a control signal.
    In the invention, no motor current or armature cross-current or any other variable directly determining the motor torque can be specified for the stepper drive controls via the control signal. The control signals are determined by the central unit in such a way that oppositely directed load torques arise in the stepper motors in the two stepper motors when the specified target position is set. If the stepper drive controls use the control signals to control the respective assigned stepper motor and move it by the specified number of steps in the specified direction, a state of tension arises in the coupling unit, so that any play is eliminated.
    Thus, according to the invention, stepper drive units can be used for setting the position of the output element which have no possibility of specifying the torque setpoint. The position of the output element is controlled or regulated by an overdetermined kinematic specification, preferably a superimposed position or speed or acceleration specification, for example in a superimposed control loop. The other degree of freedom that results from the coupling of several drive units (inputs) with one output is used to set a load angle and therefore a tensioning torque in the two stepper motors in order to eliminate the play in the coupling unit. The load angle is the difference between a stator field angle and a rotor field angle.
    [0017] There can also be more than one output element. At least two stepper motor units are assigned to each output element. The coupling unit can accordingly have many coupling inputs and coupling outputs. It is also possible to provide a separate coupling unit for each output element.
    [0018] Two stepper motor units are preferably assigned to each drive element. In principle, it is sufficient to achieve freedom from backlash if the number of stepper motor units is one greater than the number of output elements, provided that all output elements and stepper motor units are kinematically coupled.
    As stepper motors, permanent magnet stepper motors and / or reluctance stepper motors and / or hybrid stepper motors can be used, which are at least 2-phase. To simplify the control or regulation, it is advantageous if only stepper motors of the same type or, more preferably, identical stepper motors are used.
    [0020] The positioning drive can use linear or rotary stepper motors or synchronous motors. It is generally possible to use stepper motors which have a stator element via which the strength and phase position of the stator rotating field can be controlled or regulated, and which also have a movable rotor element or rotor element which can follow the stator rotating field. Servomotors and brushless DC motors are mostly based on the synchronous motor principle (like stepper motors). In contrast to a field-oriented servo current control, according to the invention, however, the operating point at which the armature cross-flow component of the armature current has the largest share is not set in a targeted manner, but an armature longitudinal current component is always also present. In contrast to the operation of brushless direct current motors with electronic commutation, according to the invention, the stator field angle is set as a function of the load angle specification and not a switchover only as a function of the actual rotor field angle.
    The stepper motors can preferably always be operated in microstep mode, whereby the adjustability of the stator field setpoint angle takes place with a high resolution and a high accuracy.
    In one embodiment, the stator field is generated and moved by activating the stator windings. As an alternative to this, it is also possible to provide a permanent magnet arrangement in which the stator field angle is set by a mechanical movement of the permanent magnet arrangement.
    Each control signal can preferably describe a desired stator field angle and / or a desired rotor field angle and optionally also a stator field strength amount for each stepping motor. In some exemplary embodiments, the stator field strength amount can be predefined via a current amplitude predefinition independently of the control signal and, for example, be permanently set.
    [0024] A step signal for the stepping motor is generated from the control signal via the respective stepper drive control, which step signal sets the actual stator field angle according to the specified nominal stator field angle or nominal rotor field angle. A step signal for the stepper motor can be generated from the control signal via the respective stepper drive control by applying a corresponding current to the stator field windings. The control signal indicates the desired stator field angle and the step signal corresponds, for example, to the currents impressed in the stator field windings for the stepping motor and thus to the actual stator field angle.
    The actual stator field angle can - as a function of the dynamics of the current regulation of the stepper drive control - lag behind the nominal stator field angle, so that a phase shift occurs. In some exemplary embodiments, the dynamics can be described approximately as a first-order delay element, the time constant of this delay generally being in a range from one to five milliseconds. For many practical applications, e.g. When positioning inertial masses, this delay can be neglected and the actual stator field angle can be equated to the target stator field angle for the sake of simplicity. In the case of the invention, however, this delay can in principle also be taken into account in that the stepper drive control makes correspondingly leading stator field target angle specifications via the relevant control signal. According to the invention, the rotor and thus the actual rotor field angle do not follow the actual stator field angle (or the desired stator field angle) when there is a state of tension due to the kinematic coupling and the force or moment coupling of the drive units to one another. A load angle is generated in each stepper motor that is dependent on the actual rotor field angle and the actual stator field angle. The sign or magnitude of the load angles of the two stepping motors are directed against one another in such a way that the tension on the output element creates an equilibrium of forces in the target position of the output element.
    Preferably, each stepper drive control is set up to determine a phase current for each stator phase of the assigned stepper motor depending on the received control signal or the stator field setpoint angle described by the control signal. In this case, the current amplitude value for the phase currents of a stepper motor or for the phase currents of all stepper motors can be predetermined and in particular be predetermined as constant. In a preferred embodiment, the current amplitude value is not varied when positioning the output element.
    It is also advantageous if the central unit is set up to specify control signals in the tensioned state in such a way that the output element carries out a sub-step position change with a position change amount that is smaller than the position change amount that the output element outside of the tensioned state by the step drive units can perform. Each step drive unit is preferably set up to carry out full steps and / or half steps and / or micro steps. In the tensioned state, sub-step position changes are possible that are smaller than an executable micro-step of each step drive unit. The sub-step position change in the state of tension could therefore also be referred to as a “nano step”.
    In a preferred embodiment of the invention, the sub-step position change in the tensioned state can be achieved by the force or torque coupling of the drive units. When adjusting the actual stator field angle of only one step drive unit, the other step drive unit will prevent the output element from rotating by the full step amount and instead increase both its own load angle and that of the other step drive unit. With a kinematic translation of the stepper drive units of 1: 1 to each other and the same construction, the output element will move exactly by half a microstep. Only when the other stepper drive unit is also moved a microstep further, the output element is also rotated further by the full amount and the load angles of both stepper drive units decrease again. Thus, the alternating sequence of steps can be used to achieve sub-position changes in the sub-microstep range, which can be referred to as “nanosteps”.
    To perform a sub-step position change, the actual stator field angle for the stepper motors can be changed alternately, in particular alternately by the smallest possible angular amount that the two stepper drive units allow.
    Furthermore, it is also possible to further increase the sub-step position change or the sub-microstep resolution by utilizing the low-pass behavior due to the inertia or the delayed dynamics of the current control loop of the stepper drive controller. In this case, the central unit generates pulse-width-modulated step signals which have the effect that the stepper drive unit moves not only by half a microstep, but even less according to the duty cycle of the pulse-width modulation. The frequency of the pulse width modulation is preferably selected to be sufficiently high, for example at least 10 kHz, which, due to the low-pass behavior of the inertial masses mentioned, ensures that no disruptive oscillations occur on the output element.
    It is also preferred if the stepping motors in the tensioned state each have a load angle which results from the difference between an actual stator field angle and an actual rotor field angle.
    It is preferred if the actual rotor angle of each stepping motor is determined, for example by a measurement with the aid of a sensor, by a calculation method or by an estimate. The actual rotor field angle can be determined from the actual rotor angle and the number of pole pairs of the stepper motor.
    It is also preferred if the load angle, depending on the type of stepping motor, corresponds at most to a maximum load angle. The maximum load angle is specified in such a way that the load torque increases with an increase in the amount of the load angle up to the maximum load angle. The maximum load angle for a permanent magnet stepper motor can be electrically 90 ° or a reluctance stepper motor is electrically 45 °, and for a hybrid stepper motor it can be in the range from electrically 45 ° to 90 °. The position of the maximum load angle also depends on the pole and slot geometry of the stator and rotor.
    In a preferred embodiment, the coupling unit is designed without self-locking.
    It is also advantageous if a sensor unit with at least one position sensor is present. Controls can be implemented using one or more position sensors. For example, the load angle of each stepping motor can be regulated in a subordinate control loop. It is also preferred if a position sensor generates a sensor signal that describes the position of the output element and / or the change in position of the output element. In this way, the position of the output element can be regulated. In particular, this position control is implemented in a higher-level control loop, while all other regulations or controls are implemented in lower-level control or control circuits.
    [0036] Position values can preferably be measured, estimated or calculated using one or more position sensors, in particular for the output element. In addition, the actual rotor field values of the stepper drive units can be measured, estimated or calculated. With the actual rotor field values of the stepper drive units, in particular the actual load angle values can be calculated or estimated. Ignoring the dynamics of the current controller, it can be assumed that the stator field actual values correspond to the stator field setpoint values. In this way, the position or the speed or the acceleration of the output element and the load angle of the step drive units can be regulated.
    If the actual rotor field angle is not measured, a load angle can nevertheless be controlled assuming, for example, a constant gear backlash. The controlling method can be improved if, for example, a gear backlash characteristic curve is detected and recorded.
    The manipulated variables in the controlling and / or regulating positioning drive or method are, in particular, the target stator field angles, which are transmitted to the stepper drive control units in the form of the relevant control signals, for example as clock and / or direction pulses.
    The central unit is preferably set up to process the at least one sensor signal of the at least one position sensor of the sensor unit and to generate additional virtual signals using predefined models and / or data and / or information that can improve the control or regulation. For example, a Luenberger observer, a Kalman filter, a gear ratio map or the like can be used for this purpose. Elasticities and transmission errors, as well as friction effects in kinematic couplings can also be taken into account. Furthermore, the dynamics of the current control loop or dynamic properties of the controlled system can be taken into account or compensated. A combination of several of the options mentioned can also be used.
    It is also possible to use identification methods, for example, to determine or estimate the current load conditions - such as the masses to be moved or the inertia of masses - and to adapt the control or regulation to them. This allows adaptive processes or learning processes or facilities to be carried out. There is also the possibility of measuring or determining disturbances and determining them by means of model-supported devices or methods, for example with the help of disturbance observers. In this way, for example, disturbance variable compensations can be implemented and the positioning behavior of the positioning drive can be improved.
    [0041] Advantageous embodiments of the invention emerge from the dependent claims, the description and the drawing. In the following, preferred exemplary embodiments of the invention are explained in detail with reference to the accompanying drawings. 1 shows a block diagram of a first embodiment of a positioning drive with two stepper drive units and a central unit, FIG. 2 shows a block diagram of an embodiment of the central unit of the positioning drive from FIG. 1, FIG. 2a shows a block diagram of an embodiment of a position control loop and a tensioning specification block of the central unit from FIG. 2, FIG. 2b shows a block diagram of an exemplary embodiment of a method block for regulating a load angle, FIG. 3 shows a schematic illustration of a stepping motor of a stepper drive unit from FIG. 1, FIG. 4 shows a schematic basic illustration for producing a state of tension, FIGS. 5 to 7 each a block diagram of a further exemplary embodiment of a positioning drive; and FIGS. 8 and 9 each show a schematic, exemplary time profile for the actual stator field angle of the two stepping motors and an actual rotor field angle resulting therefrom el for the two stepper motors.
    Fig. 1 shows an embodiment of a positioning drive 15 in the form of a block diagram. The positioning drive 15 is used to move or position an output element 16. The output element 16 can, for example, be a table or a slide for positioning or for regulating the movement or the advance of a tool or a workpiece. The output element 16 can be driven in a rotary or translatory manner.
    The output element 16 is connected to a coupling output 17 of a mechanical coupling unit 18. The coupling unit 18 is designed, for example, as a transmission, e.g. as a straight gear drive or another gear drive. It has a first coupling input 19 and a second coupling input 20. Each coupling input 19, 20 is force-coupled to the coupling output 17. In addition, in the exemplary embodiment the two coupling inputs 19, 20 are also force-coupled to one another. As a result, a movement at the coupling output 17 independently of one of the two coupling inputs 19, 20 is not possible.
    The positioning drive 15 has a first step drive unit 21 with a first step drive control 22 and a first step motor 23. The first step drive controller 22 generates a first step signal ST1 for the first step motor 23. The first step motor 23 has a stator 23S and a rotor 23R. The rotor 23R is connected to the first coupling input 19.
    Analogous to the first step drive unit 21, there is also a second step drive unit 24 with a second step drive control 25 and a second step motor 26. The second step drive controller 25 generates a second step signal ST2 for the second step motor 26. The second step motor 26 has a stator 26S and a rotor 26R which is connected to the second coupling input 20.
    The positioning drive 15 also has a sensor unit 27 which, for example, has at least one position sensor. In the exemplary embodiment, a first position sensor 28 is present which generates a first position signal P1 which describes the position and / or the change in position of the output element 16. For example, the first position sensor 28 can be implemented by an angle sensor or another position sensor, which measures the current, absolute position of the output element 16 and generates a corresponding first position signal P1.
    In the exemplary embodiment described here, the sensor unit 27 also has a second position sensor 29 and a third position sensor 30. The second and third position sensors 29, 30 are each assigned to a rotor 23R or 26R of a stepping motor and detect its rotational position. The second or third position sensor 29, 30 can, for example, be designed as an encoder and generate a second position signal P2 and a third position signal P3, which each describe the actual rotor angle φR23, ist and φR26, ist of the associated rotor 23R or 26R. The second and third position sensors 29, 30 are optional and serve to execute a subordinate control for a respective load angle λ23 of the first stepping motor 23 and a load angle λ26 of the second stepping motor 26. The load angle λ23 or. λ26 of each stepping motor 23 or 26 results from the difference between an actual stator field angle ρSi, ist and the actual rotor field angle ρRi, ist. For the index i, the value i = 23 relates to the first stepper motor 23 and the index i = 26 to the second stepper motor 26. The actual stator field angle ρSi, actual becomes from the known nominal stator field angle ρSi, setpoint and the actual rotor field angle ρR1, is from the rotor position information Position signals P2 and P3 determined. With the aid of the first position sensor 28, a superimposed regulation for the position of the output element 16 is carried out.
    In the embodiment described here, position signals from position sensors are used. Alternatively, it is also possible to estimate or calculate the position. For example, a defined starting situation can be established as part of an initialization, e.g. by moving against a stop. Based on this initial situation, the changes in the stator field or step pulses can be counted. The respective position can then be calculated based on the information of the transfer factors and the number of pole pairs of the stepping motors 23, 26. This method can optionally be further improved in that gear backlash characteristics or transmission characteristics of the kinematic path and, if applicable, elasticities in the kinematic transmission path are determined and taken into account.
    The at least one position signal and the three position signals P1, P2, P3 of the sensor unit 27 according to the example are transmitted to a central unit 31. The central unit 31 also receives a kinematics setpoint, which is formed here by a position setpoint PS, as well as a tension setpoint VS. The desired position value PS defines the desired position of the output element 16 and the desired tension value VS describes a mechanical tension that is to be applied to the coupling inputs 19, 20 of the coupling unit 18 by the two step drive units 21, 24. As a result of the bracing, play in the mechanical transmission between the coupling inputs 19, 20 and the coupling output 17 and consequently in the kinematic chain between the two rotors 23R, 26R and the output element 16 can be eliminated. Once the state of tension has been established, any existing play is at least reduced and ideally completely eliminated.
    In contrast to the exemplary embodiment described here, a movement specification for the output element 16, for example a speed and / or an acceleration and / or a jolt, can also be used as the kinematics setpoint. In this way, for example, a feed movement can be controlled or regulated.
    The specification of a desired tension value is optional. In the central unit 31, a desired tensioning value and thus a tensioning torque can be determined on the basis of a predetermined tensioning strategy or on the basis of empirical values or a characteristic diagram or on the basis of other parameters such as the speed of the output element. It is also possible not to specify a desired tension value for the central unit 31, but rather to specify a fuzzy setpoint such as “off”, “weak”, “strong” or the like. The desired tension value can also be determined in the central unit 31 on the basis of such fuzzy setpoint values, as described.
    The positioning drive 15 has two degrees of freedom through the use of two stepper drive units 21, 24, by means of which, on the one hand, the output element 16 can be positioned and, on the other hand, the state of tension can be established. In the tensioned state, the stepper motors 23, 26 of the stepper drive units 21, 24 each have a load angle λiauf, as a result of which they generate a motor torque Mier. According to the example, the engine torques Mls are of equal magnitude and have different directions (FIG. 4).
    Depending on the kinematics setpoint and the tension setpoint VS, the central unit 31 determines a first control signal A1 for the first stepper drive unit 21 and a second control signal A2 for the second stepper drive unit 24. The control signals A1, A2 each give a position change for the assigned stepper motor 23 or 26 at. The relevant control signal A1, A2 for positioning the output element 16 indicates in which direction the stator field 23S or 26S is to be rotated and by what amount or by what number of steps the rotation is to take place. The relevant control signal A1, A2 can also specify a variable that characterizes the stator field strength, such as the current amplitude IDi, for example. However, their amount is preferably constant and is not changed during the positioning of the output element 16.
    According to the invention, a bracing situation can be established via the kinematic coupling unit 18 and the control signals A1, A2 and the stator field variables specified thereby. This is because the rotor fields cannot follow the stator fields in the tensioned state. As a result, a load angle λ builds up with each stepping motor 23, 26. The control signals A1, A2 can increase the load angle λ of the stepper motors 23, 26 by making opposite directions of rotation specifications for the relevant stator fields or move the output element by making rotational direction specifications for the stator fields in the same direction. The central unit 31 is set up to output suitable opposite or same direction or also superimpositions of opposite and same direction drive signals A1, A2, so that both the superimposed position control and the subordinate tension control or tension control are carried out. The control signals thus indicate which load angle λ1 is to be set on the stepper motors 23, 26 in order to achieve the desired stressed state.
    The stepper drive controls 22, 25 do not have any inputs via which the motor torque or a motor current defining the motor torque, in particular armature cross current, can be specified. The stepper drive controls 22, 25 only have inputs at which the amount of a rotary movement of a stator field (that is, the stator field setpoint angle ρi, setpoint) and / or its direction of rotation and / or its field strength are specified. The field strength is proportional to the current setpoint amplitude ID1, soll. The nominal currents Iki, soll are calculated for the phases k = 1 to n from the nominal current amplitude IDi, soll and the nominal stator field angle ρSi, soll.
    The stepper motors 23, 26 preferably have a number of pole pairs of at least 25.
    The respective stepper drive control 22 or 25 is set up to set the actual currents Ik1, ist for the different phases k of the assigned stepper motor 23 or 26 on the basis of the setpoint currents Iki, should. Depending on the number of phases, each nominal current Ik1, soll is calculated for one phase as follows: for a stepper motor with n = 2 phases and for a stepper motor with n> 2 phases.with: Iki, soll: target current for phase k IDi, soll: current amplitude target value; ρSi, soll: nominal stator field angle of stator i; i: index for the stepper motors 23, 26 k: index for the phases (k = 1, 2, ... n)
    [0058] The following applies:
    The current control loop including the winding inductances and the winding resistances can be described using a first-order delay element. The actual currents Iki, ist for the phases result from:
    The time constant τ is small and therefore equation (1d) can be simplified to:
    In Fig. 3, two currents I1, I2 for the individual phases of a stator 23S, 26S are schematically illustrated. The actual stator field angle ρsi, ist for the relevant stator 23S, 26S can be set via the phase currents Ik.
    In Fig. 2, the central unit 31 is greatly simplified and illustrated symbolically with its functions. The position signals P1, P2, P3 are transmitted to the central unit 31 according to the example, as already explained in connection with FIG. 1. The central unit 31 has a superimposed position control loop 40. In the position control loop 40, the position of the output element 16 is controlled superimposed. For this purpose, in particular the first position signal P1 is transmitted to the position control loop 40.
    The central unit 31 also has a tensioning specification block 41 which selects a tensioning strategy based on the tensioning setpoint VS and optionally one or more position signals P1, P2, P3 and transmits it to a subsequent method block 42. In order to select the bracing strategy, the triggering signals A1, A2 and / or the kinematic setpoint or other available signals or values can also or alternatively be transmitted to the bracing specification block 41. For example, as a bracing strategy at a high speed of the stepper motors 23, 26 or when the output element 16 moves quickly, the bracing can be reduced or completely eliminated if the freedom from play of the coupling unit 18 is not important during the rapid adjustment. For example, one or more of the following possibilities come into consideration as a bracing strategy: the desired bracing value VS is specified and is retained unchanged, with which a desired value for the bracing torque MV, soll is calculated once; - Depending on the tension setpoint VS and at least one further parameter, such as a position signal P1, P2, P3, a modified tension setpoint VS 'and therefore continuously a setpoint for the tensioning torque MV, soll is calculated, based on which a load angle setpoint λi, soll for each stepper motor 23, 26 is passed on to method block 42; For example, the speed and / or the acceleration of at least one stepping motor 23, 26 or the output element 16 can be used as a parameter for calculating the modified tension setpoint VS 'or the setpoint for the tensioning torque MV setpoint.
    Depending on the selected bracing strategy in bracing specification block 41, a set motor torque Mi, setpoint for each stepping motor 23, 26 and therefore a setpoint load angle λi, setpoint is determined. In the exemplary embodiment, the motor setpoint torque M1, setpoint, is described by a load setpoint angle λi, setpoint.
    The relationship between the target engine torque and the target load angle can be specified as a function of the engine type, for example by means of a characteristic field, a function or a table. The desired load angle λi, soll defines the respective desired motor torque Mi, soll, which is generated by the relevant stepping motor 23 or 26. The following relationship applies: The actual load angle λi, ist corresponds to the difference between the actual rotor field angle ρRi, ist minus the actual stator field angle ρSi, ist, with: λi, is: the actual load angle of the stepper motor i; ρRi, is: actual rotor field angle of stepping motor i; psi, is: Actual stator field angle of the stepper motor i.
    Depending on the number of pole pairs of the stepper motor 23, 26, the following relationship exists between the actual rotor field angle ρRi, ist (electrical rotor field angle) and the mechanical actual rotor angle φRi, ist: with: ρR1, ist: the actual rotor field angle of the stepper motor i; φRi, is: mechanical actual rotor angle of the stepper motor i; pzi: number of pole pairs of the stepper motor i.
    A corresponding relationship applies to the actual stator field angle ρSi, ist (electrical stator actual angle) and the mechanical actual stator angle φSi, is: with: ρSi, is: the actual stator field angle of the stepping motor i; φSi, is: actual stator angle of stepping motor i; pzi: number of pole pairs of the stepper motor i.
    A manufacturing or assembly-dependent angular offset φS1, 0 for the stator and / or a manufacturing or assembly-dependent angular offset φRi, 0 for the stator is neglected in equations (3) and (4).
    The angle offsets can be eliminated in terms of control technology. They can be determined by an initialization process, for example a reference run, or by using absolute angle encoders.
    The respective mechanical actual rotor angle φRi, ist can be measured, calculated or estimated. In the present case, the mechanical actual rotor angle for the first stepping motor 23 is described by the second position signal P2 and the actual rotor angle of the stepping motor 26 is described by the third position signal P3. The respective actual electrical rotor field angle can thus be determined according to equation (3).
    The desired stator field angle ρSi, soll is known because it was output via the relevant output signal A1 or A2 and therefore the actual stator angle φSi is also known because it was determined in the previous control cycle and is therefore used to calculate the actual stator field angle ρSi according to the equation (4) can be used. The actual load angle λi, actual can thus be determined and compared with a setpoint load angle λi, setpoint, which is transmitted to method block 42 from bracing specification block 41. Accordingly, the method block 42 can use a controller to determine a rate of change on the basis of the deviation between the target load angle λi, soll and the actual load angle λi, ist, which is superimposed with the rate of change over time for the target rotor field angle ρRi, soll, whereby the corresponding tensioning torque Mi, ist is set (Fig. 2 B) .
    The central unit 31 also has an output block 43. In the output block 43, the control signals A1, A2 for the stepper drive units 21, 24 are finally determined.
    In FIG. 2b, a part of the method block 42 and the output block 43 is illustrated, which is used to generate and output the first control signal A1. Corresponding to this, there are further parts of the method block 42 and of the output block 43, which are used to determine and output the second control signal A2.
    A proportional controller for load angle control is used as a controller in method block 42, for example. In method block 42, the desired stator field angle ρSi, setpoint is supplied, which roughly corresponds to the actual stator field angle ρSi, actual. By calculating the difference with the actual rotor field angle ρRi, actual, the respective actual load angle λ1, actual is obtained. The control deviation between the desired load angle and the actual load angle is transmitted to the load angle controller 44. This generates at its output a first lateral nominal change rate d1i, soll, which is superimposed with the nominal change rate for the rotor field nominal angle ρRi, soll of the position control loop 40 (see FIG. 2). This results in a desired rate of change over time for the desired stator field angle ρSi, soll, which is transmitted by the output block 43.
    The control of the load angle is carried out in a subordinate control loop. For example, the superimposed position control loop 40 can regulate the respective actual rotor angle and thus the position of the output element 16, while the subordinate control for the load angle λibzw. regulates the stator field angle psi.
    P controllers, PI controllers, PID controllers or the like can be used to implement the regulation. A stable overall system can be achieved by setting the controller for the higher-level or lower-level control loop.
    In general, with the controllers used, care must be taken that the stepper motors are not overloaded. It is therefore advantageous if the controllers have manipulated variable limits such as speed limits or acceleration limits. This is because, in comparison to servomotors, stepper motors are usually not capable of overloading, since the current amplitude is usually kept constant and the torque cannot be increased any further after the maximum load angle has been exceeded.
    In Fig. 2a, the position control loop 40 and the bracing specification block 41 of the central unit 31 is illustrated schematically on the basis of an embodiment.
    The position setpoint value PS and the first position signal P1 are fed to the position control loop 40 and the difference is formed therefrom and fed to a position controller 45. The position controller outputs a first target speed w1soll. A difference between the first setpoint speed w1soll and a second setpoint speed w2soll is then formed and fed to a speed controller 46, which outputs a change in setpoint speed dwsoll for the output element 16. The setpoint speed change dwsoll is integrated in an integrator 47 and the second setpoint speed w2soll is formed therefrom. This second target speed w2soll is then transmitted to a first kinematic model 48 and a second kinematic model 49. These map the possibly existing translations in the coupling unit 18, as well as characterizing parameters of the stepping motors, such as the respective number of pole pairs. The rate of change dρRi, setpoint of the rotor field setpoint angle ρRi, setpoint for the respective stepping motor 23 or 26 is determined, outputted and transmitted to method block 42 at the outputs.
    As illustrated in FIG. 2a, the second setpoint speed w2soll output by the integrator is used here as the actual speed. This signal is free of measurement noise and enables high loop amplifications in the speed controller 46. The controllers 45, 46 are each followed by a control variable limiter in order to maintain the necessary acceleration or speed limit. Overloading the stepper motors and getting out of step are avoided. The manipulated variable limiters can execute a respective manipulated variable limitation to constant values or variably depending on the parameters and, so to speak, depending on the situation.
    In the output block 43 (FIG. 2b) of the central unit 31, a clock pulse TI and a direction pulse RI are generated from the rates of change dρS1, Sollder stator field setpoint angle ρSi, soll, which were determined in method block 42. For this purpose, the nominal rate of change dρSi, soll of the relevant stator field nominal angle ρSi, soll is evaluated. The direction pulse RI results from a sign tuning unit 60. The amount of the nominal rate of change of the nominal stator field angle is determined by an amount forming unit 61, possibly multiplied by a proportional factor, then fed via a limiting unit 62 to a clock generator 63 which outputs the clock pulses TI. The direction pulse RI, the clock pulse TI and, if applicable, the current amplitude setpoint IDi, should correspondingly give the relevant control signal A1 or A2.
    The relevant control signal A1 or A2 is fed to a counter 64 which determines the absolute number of steps of the relevant stepper motor 23, 26 therefrom. From this, the relevant target stator field angle ρSi, soll can be determined in a calculation unit 65 and transmitted to method block 42.
    In the tensioning specification block 41, the desired load angles λi, setpoint for the stepping motors 23, 26 are determined (FIG. 2a). In a function block 70, the desired tension torque MV, soll is determined from the desired tension value VS and then further processed separately for the two stepping motors 23, 26 in a respective calculation path, which are basically structured in the same way. Each calculation path has a limitation block 71, a first normalization block 72 and a second normalization block 73. The respective engine torque is limited to a maximum torque in the limitation block. This can ensure that a maximum load angle is not exceeded. Then the output signal of the limitation block 71 is normalized in the first normalization block 72 to the maximum torque and finally normalized in the second normalization block 73 to the maximum load angle and output as the load target angle λ1, setpoint. The maximum torque can be determined as a function of the current amplitude setpoint ID1, setpoint, of torque constants, of the current angular velocity or speed and the operating voltage.
    Optionally, an additional torque Mai, soll corresponding to a desired acceleration value can be added to the desired tensioning torque MV, soll for each calculation section in front of the respective limiting block 71, in order to apply a specific acceleration torque to the respective stepping motor 23 or 26.
    The state of tension in the coupling unit 18 during the positioning or when the output element 16 is reached is illustrated schematically in FIG. By means of a first actual load angle λ23, ist on the first stepping motor 23 and a second actual load angle λ26, ist on the second stepping motor 26, correspondingly oppositely directed tensioning torques M23 or M26 is generated. Due to these two tensioning moments M23, M26, the output element 16 is not moved, but is held or moved in the position, which in turn is predetermined by the superimposed position control, while eliminating the play in the coupling unit 18.
    The desired load angle λi, soll is limited to a maximum load angle λmax, depending on the type of stepping motor. This ensures that the desired load angle λi, setpoint is in a range in which the magnitude of the load or engine torque Mim, increases with an increasing amount of the actual load angle value λi, ist (FIG. 4). With permanent magnet stepper motors, the load angle is limited to 90 ° and with reluctance stepper motors to 45 °, while with hybrid stepper motors the maximum load angle can be in the range from 45 ° to 90 °. In the case of larger load angles in terms of magnitude, the motor torque of the stepping motors 23, 26 would decrease again.
    If the positioning drive 15 does not have any position sensors 29, 30 for determining the position of the respective rotor 23R, 26R, a control method can also be used instead of a regulation for the motor torques Mia. The central unit 31 can have an initialization block 50 for this purpose. A defined starting situation is first established via the initialization block 50. For this purpose, e.g. the output element 16 can be moved into a defined zero position, in the case of rotationally driven output elements, preferably once in each direction of rotation. This is carried out individually and separately in particular for both stepper drive units 21, 24. The zero position is detected by sensors, for example by means of the first position sensor 28. The initialization detects and stores a relationship between the rotational movement of each rotor 23S, 26S and the output element 16. Translation errors can also be corrected in the mechanical coupling unit 18. A target load angle λ1, setpoint can now be set on the basis of an original rotational position of the rotors 23R, 26R by a predetermined number of rotational steps. Otherwise the control method corresponds to the regulation described above.
    If the second position signal P2 and the third position signal P3 are not available, these two position signals in the backlash-free state can also be estimated or determined in the coupling unit 18 using the first position signal P1 and depending on the respective translation. The second position signal P2 results from a multiplication of the translation i17,23 between the coupling output 17 and the first stepping motor 23 multiplied by the first position signal P1. The third position signal P3 results in an analogous manner from the multiplication between the ratio i17, 26 between the coupling output 17 and the second stepping motor 26 multiplied by the first position signal P1. The virtual sensor signals PV2 and PV3 then result in each case multiplied by the relevant number of pole pairs.
    If the first position signal P1 is also not available, this can also be estimated or determined. Assuming that the current amplitudes are approximately the same and that the same stepper motors are used, the output element 16 will approximately assume a central position, so that: with: PZ23: number of pole pairs of the first stepper motor 23; PZ26: number of pole pairs of the second stepping motor 26; i17,23: translation between coupling output 17 and first stepper motor 23; i17,26: ratio between coupling output 17 and second stepper motor 26.
    Ultimately, pure control without position signal feedback can thus be achieved. However, it can also be advantageous to use the first position signal P1 and only to determine the virtual position signals PV2, PV3. The first position signal P1 or the virtual first position signal PV1 can be used for this:
    The possibility of being able to calculate the first position signal P1 alternatively or redundantly in several ways can also be used to detect a sensor error and / or to detect a blockage of the drive. This can be relevant especially when using stepper motors, since the stepper motors 23, 26 are not tolerant of overload. Appropriate measures can be initiated accordingly. E.g. In the event of a sensor error when determining the position of the output element 16, it is possible to switch to an emergency control in which the virtual first position signal PV1 is used instead of the first position signal P1. If at least one stepper motor 23, 26 is overloaded, an emergency stop and / or an error signal can be output.
    If the sensor signal block 51 is not present, the position signals P1, P2, P3 are used for the regulation within the central unit 31 instead of the virtual sensor signals PV1, PV2, PV3.
    With the aid of the positioning drive 15, a sub-step position change can also be achieved in the tensioned state. This is particularly relevant when a constant bracing torque Mv is specified and the desired load angle should remain constant, in particular in the desired or target position of the output element 16. The load angle control can be switched off.
    A sub-step position change is illustrated schematically in FIG. Outside of the tensioned state, each stepping motor 23, 26 can execute the smallest possible rotary step DS. In the tensioned state, a sub-step position change SUB can also be brought about by the stator fields of the two stepping motors 23, 26 being rotated alternately by a rotational step DS in the same direction, offset in time. As long as only one of the two stator fields is moved by one rotary step DS, the rotor angle of the two stepper motors cannot follow completely. Due to the kinematic coupling, the load angle increases in both stepping motors, so that each rotor position and thus also the output element position only moves by one sub-step position change SUB. This can correspond to half a step, for example, if the kinematic translations between the two stepping motors 23, 26 and the coupling output 17 are of the same size and the stepping motors are designed identically and continue to have the same current amplitude.
    When adjusting the actual stator field angle of only one step drive unit, the other step drive unit will prevent the output element 16 from rotating by the full step amount and instead increase both its own load angle and that of the other step drive unit. Only when the other stepper drive unit is also moved a microstep further (in that the actual stator field angle is rotated further) is the output element 16 rotated further by the full amount and the load angle of both stepper drive units decreases again. Sub-micro-step resolutions, which are illustrated here as a sub-step position change SUB, can thus be achieved by alternating step sequences.
    If the two stator angles are now sequentially moved in the same direction of rotation by one rotary step DS each, the rotor angle of the two stepper motors and therefore the output element 16 can be moved with the sub-step position change, which corresponds to half the rotary step DS, for example. This is the case when the transmission ratios from the first coupling input 19 to the coupling output 17 and from the second coupling output 20 to the coupling output 17 are equal. Different gear ratios would cause sub-step position changes of different magnitudes depending on whether the stator field of the stepping motor 23 or of the stepping motor 26 is moved by a rotary step DS.
    Another possibility for generating a sub-step position change is illustrated schematically in FIG. While the current amplitude value ID for generating the stator fields has not been changed in all previous exemplary embodiments, in the method illustrated in FIG. 9, for example, the current amplitude value IDi for generating the stator field for the first stepping motor 23 is set smaller.
    If the current amplitude of the stepper drive units 21, 24 is different, a stator field step of the weaker stepper drive unit causes a smaller load angle increase in the other stepper drive unit than in itself. As a result, the output element 16 is not moved by half a microstep, but rather less. In such an embodiment, the stepper drive units 21, 24 have different effects on the coupling output 17 of the coupling unit 18, which can be further reinforced by non-linearities in the torque-load angle curve of the stepper drive units 21, 24. In this way, step sequences with amounts of different magnitudes can also be formed at the coupling output 17.
    First, as in the method for changing the sub-step position described in connection with FIG. 8, the stator field of the first stepping motor 23 is moved by a rotary step DS (first point in time t1). To carry out the subsequent sub-step position change, the current amplitude value ID is increased to generate the first stator field (second point in time t2). The next sub-step position change SUB at a third point in time t3 is achieved in that the current amplitude value ID of the first stator field is reduced again to its initial value and at the same time the second stator field is moved by a rotary step DS. This process sequence can be carried out sequentially to carry out sub-step position changes.
    Furthermore, it is possible to increase the sub-microstep resolution even further by specifically utilizing the low-pass behavior due to the inertia or the delayed dynamics of the current control loops of the stepper drive controls 22, 25. In this case, the central unit 31 generates pulse-width-modulated step signals, which cause the respective stepping motor 23, 26 to move by a proportion of the microstep that corresponds to the pulse duty factor. The frequency of the pulse width modulation must be sufficiently large in order not to generate any oscillations on the output element 16 due to the low-pass behavior.
    A further exemplary embodiment for the positioning drive 15 is illustrated in FIG. 7. In contrast to the embodiment described above, the positioning drive 15 according to FIG. 7 has an additional output element 54. The position of this additional output element 43 is also detected via a first position sensor 28, analogously to output element 16. The coupling unit 18 has an additional coupling output 55 to which the additional output element 54 is connected. In addition to the first coupling input 19 and the second coupling input 20, the coupling unit 18 has a third coupling input 56 to which a third step drive unit 57 is connected. As can be seen in FIG. 7, all coupling inputs 19, 20, 56 are force-coupled to one another. The clamping of the coupling unit 18 in relation to the first output element 16 is effected with the aid of the first step drive unit 21 and the second step drive unit 24, while the clamping of the additional output element 54 is effected by the second step drive unit 24 and the third step drive unit 57. Because of the additional stepper motor unit, there is a third degree of freedom in control. The distribution of the bracing torques to achieve an equilibrium of forces or moments in the braced state as a whole can be e.g. can be specified via an additional parameter XP. Alternatively, a further position specification can also be issued via the additional parameter XP, so that independent position specifications can be made for the two output elements. In addition, the embodiment corresponds in its structure and its mode of operation to the previously described embodiments and possible modifications of the method and the positioning drive 15, as was explained in connection with FIGS. 1-4 and 8 and 9.
    Since all inputs and outputs of the coupling unit 18 are force or torque coupled to one another, due to the one redundant drive unit (there is one drive unit more than coupling outputs), its additional setting property can be used to build up the tension in the kinematic chain. The control technology activation is more complex, however. For example, a bracing of five output elements with six drive units would also be conceivable. However, each output element 17, 55 preferably has two separate drive units 21, 24 assigned to it, analogous to the illustration in FIG. 1. This arrangement can also be provided several times if several output elements 17, 55 are present.
    In FIGS. 5 and 6, variants for the coupling unit 18 and the type of output element 16 are illustrated. In the exemplary embodiments in FIGS. 1 and 7, the coupling inputs were coupled to the coupling output of the coupling unit 18 via a gear transmission and in particular a spur gear transmission. In the exemplary embodiment according to FIG. 5, the output element 16 is formed by a toothed rack which is mounted such that it can move in translation and meshes with two toothed wheels which each form a coupling input 19 and 20, respectively.
    In Fig. 6, a further modified embodiment of the coupling unit 18 is illustrated, both the first coupling input 19 and the second coupling input 20 are each formed by a rotating spindle, with a spindle nut sitting on each rotating spindle. The spindles are arranged parallel to one another in a direction in which the output element 16 is translationally movable. The output element 16 is connected to the two spindle nuts with the aid of a coupling element, so that it can be moved in translation together with the spindle nuts.
    The manner of the mechanical coupling between the coupling inputs 19, 20 and the coupling output 17 can be varied in the most varied of ways. The coupling unit 18 preferably does not have any self-locking in either direction between the two coupling inputs 19, 20 and the coupling output 17.
    In Fig. 2a, the connection of additional moments May, is illustrated schematically. These additional torques can be dependent on the second target speed w2sollbzw. the setpoint speed change dwsoll are calculated. The calculation can take place, for example, as a function of frictional torque components and acceleration torque components. One or more of the following variables are taken into account: the friction factor for viscose friction based on the relevant stepper motor 23, 26; - The mass moment of inertia of the relevant gear stage between the respective stepping motor 23, 26 and the coupling output 17; - The respective mass moment of inertia of the rotor of the relevant stepping motor 23, 26; - The static friction torque for the relevant stepping motor 23, 26; - The measurement and moment of inertia of the load in relation to the respective stepper motor 23, 26; - The mass moment of inertia of the output element 16 in relation to the respective stepper motor 23, 26.
    The following equation can be used here. with: with: MRi: frictional torque component w2soll: second target speed i17, i: ratio between the coupling output 17 and the stepper motor 23 or 26 Ki: friction factor for the stepper motor 23 or 26 wRi, is: the actual speed of the rotor of the stepper motor 23 or 26 MH, l: moment of static friction for stepper motor 23 or 26 dwsoll, i: change in setpoint speed for stepper motor 23 or 26 JR, 1: moment of inertia of rotor of stepper motor 23 or 26 JG17, i: moment of inertia of coupling unit 18 from coupling output 17 to Stepping motor 23 or 26 JR16, 1: moment of inertia of the output element related to the relevant stepping motor 23 or 26 JL, 1: moment of inertia of the load related to the relevant stepping motor 23 or 26
    The factor 0.5 in equation (9) indicates that each stepping motor 23, 26 only has to absorb half of the acceleration of the drive-related mass moments of inertia.
    The invention relates to a positioning drive 15 and a method for positioning an output element 16. The positioning drive 15 has a first step drive unit 21 with a first step drive controller 22 and a first step motor 23 and a second step drive unit 24 with a second step drive controller 25 and a second step motor 26 on. The two stepping motors 23, 26 and the output element 16 are force-coupled and drive-coupled via a mechanical coupling unit 18, the coupling unit 18 having play. A central unit 31 controls the two stepper drive controls 22, 25 via a control signal A1 and A2, respectively. The control signals A1, A2 each specify the desired stator field angle in such a way that the output element is positioned and a load angle is set in the two stepper motors 23, 26, which cause a bracing torque that is set via the associated stepper drive control 22 and 25. The central unit 31 has a superimposed regulation for the position of the output element 16. It also has a subordinate control or regulation in order to set opposing motor torques M23, M26 for each stepping motor 23, 26.
    List of reference symbols:
    15 positioning drive 16 output element 17 coupling output 18 coupling unit 19 first coupling input 20 second coupling input 21 first stepper drive unit 22 first stepper drive controller 23 first stepper drive 23R rotor of first stepper drive 23S stator of first stepper drive 24 second stepper drive unit 25 second stepper drive controller 26 second stepper drive 26R rotor of second stepper drive 26S stator of the second stepping drive 27 sensor unit 28 first position sensor 29 second position sensor 30 third position sensor 31 central unit 40 position control circuit 41 tension specification block 42 process block 43 output block 44 load angle controller 45 position controller 46 speed controller 47 integrator 48 first kinematic model 49 second kinematic model 50 initialization block 51 sensor signal block 54 additional output element 55 additional coupling output 56 third coupling input 57 third step drive unit 60 sign des Tuning unit 61 Amount formation unit 62 Limiting unit 63 Clock generator 64 Counter 65 Calculating unit 70 Function block 71 Limiting block 72 First normalization block 73 Second normalization block φRi, actual rotor angle φRi, setpoint rotor setpoint angle λi, actual load angle λi, setpoint load angle ρRi, actual setpoint angle ρRi, actrotorfield angle ρ, setpoint field angle ρ, setpoint field angle ρ, setpoint field angle for ρRi, setpoint Setpoint rotor field angle dρSi, setpoint rate of change for the setpoint stator field angle d1i, setpoint first time setpoint change rate dwdesired setpoint speed change DS rotary step M23first tensioning torque of the first stepper motor M26second tensioning torque of the second stepper motor May, sollAdditional torque P2, second position setpoint P2, position setpoint P2, position signal P2, first position signal, P2, position setpoint, position signal, P2, sub-step, position signal, P2, second step signal Directional pulse TI Clock pulse w1sollest target speed w2sollecond target speed VS Verspan nominal value XP additional parameters
    权利要求:
    Claims (16)
    [1]
    1. Positioning drive (15) which is set up for positioning an output element (16) of the positioning drive (15),with a mechanical coupling unit (18) which has a first coupling input (19), a second coupling input (20) and a coupling output (17), wherein the coupling output (17) can be connected to the output element (16),with a first stepper drive unit (21) which has a first stepper motor (23) connected to the first coupling input (19) and a first stepper drive controller (22) which is set up to control the first stepper motor (23),with a second stepper drive unit (24) which has a second stepper motor (26) connected to the second coupling input (20) and a second stepper drive controller (25) which is set up to control the second stepper motor (26),with a central unit (31), which a kinematics setpoint (PS) and / or a total tension value (VS) can be specified or in which a kinematic setpoint (PS) and / or a tension setpoint (VS) can be determined,wherein the central unit (31) is set up to determine a first control signal (A1) for the first step drive control (22) and a second control signal (A2) for the second step drive control (25) as a function of the kinematics setpoint and the tension setpoint (VS), the two control signals (A1, A2) being specified in such a way that they generate oppositely directed tensioning torques (M23, M26) in both stepping motors (23, 26),wherein the central unit (31) is set up to transmit the control signals (A1, A2) to the respective stepper drive control (22, 25),and wherein the step drive controls (22, 25) are set up to control the respectively assigned stepper motor (23, 26) depending on the control signal (A1, A2) received, so that a tension state is generated in the coupling unit (18).
    [2]
    2. Positioning drive according to claim 1, characterized in that the control signals (A1, A2) each have a desired stator field angle (ρs23, soll, ρs26, soll) and / or a desired rotor field angle (ρR23, soll, ρR26, soll) for each stepping motor (23 , 26) describe.
    [3]
    3. Positioning drive according to claim 2, characterized in that the stepper drive controls (22, 25) are set up to determine a step signal (ST1, ST2) for the respective stepper motor (23, 26) from the received control signal (A1, A2) and to transmit to the respective stepping motor (23, 26) in order to obtain an actual stator field angle (ρs23, ist, ρS26, ist) according to the desired stator field angle (ρs23, soll, ρS26, soll) and / or the actual rotor field angle (ρR23, ist, PR26, ist) according to the rotor field target angle (ρR23, soll, ρR26, soll).
    [4]
    4. Positioning drive according to claim 3, characterized in that the stepper drive controls (22, 25) are set up to generate a phase current for each existing stator phase of the assigned stepper motor (23, 26) depending on the respective stator field setpoint angle (ρs23, soll, ρS26, soll) (11, 12) to be determined.
    [5]
    5. Positioning drive according to claim 4, characterized in that all phase currents (I1, I2) for a stepping motor (23 or 26) or for all stepping motors (23, 26) have the same constant current amplitude value (ID).
    [6]
    6. Positioning drive according to one of the preceding claims, characterized in that the central unit (31) is set up to specify control signals (A1, A2) in the tensioned state such that the output element (16) carries out a sub-step position change (SUB) with a position change amount which is smaller than the position change amount that each of the stepping motors (23, 26) can perform outside of the tensioned state.
    [7]
    7. Positioning drive according to claims 3 and 6, characterized in that the central unit (31) is set up to set the stator field actual angle (ρs23, ist, ρS26, ist) for the stepper motors (23, 26) to carry out the sub-step position change (SUB ) to change alternately.
    [8]
    8. Positioning drive according to one of the preceding claims, characterized in that the stepping motors (23, 26) in the tensioned state each have a load angle (λi, ist), which is the difference between a rotor field target angle (ρR23, soll, ρR26, soll) and an actual rotor field angle (ρR23, ist, ρR26, ist) and yields.
    [9]
    9. Positioning drive according to claim 8, characterized in that the desired rotor field angle (ρR23, soll, ρR26, soll) corresponds to the actual stator field angle (ρs23, ist, ρS26, ist).
    [10]
    10. Positioning drive according to claim 8 or 9, characterized in that the actual rotor field angle (ρR23, ist, ρR26, ist) is dependent on the actual rotor angle (φR23, ist, φR26, 1st) and the number of pole pairs (pzi).
    [11]
    11. Positioning drive according to one of claims 8 to 10, characterized in that the target load angle (λ23, soll, λ26, soll) corresponds at most to a maximum load angle (λmax) specified for the stepper motor (23, 26).
    [12]
    12. Positioning drive according to one of the preceding claims, characterized in that the coupling unit (18) is designed to be self-locking.
    [13]
    13. Positioning drive according to one of the preceding claims, characterized in that there is a force coupling between the coupling inputs (19, 20) and between each coupling input (19, 20) and the coupling output (17).
    [14]
    14. Positioning drive according to one of the preceding claims, characterized in that a sensor unit (27) with at least one position sensor (28, 29, 30) is present, the sensor unit (27) generating at least one position signal (P1, P2, P3), which describes the position and / or the change in position of the output element (16).
    [15]
    15. Positioning drive according to claim 14, characterized in that the central unit (31) is set up to process the at least one position signal (P1, P2, P3) and a virtual sensor signal (PV1, PV2, PV3) depending on a position signal received last (P1, P2, P3) and a determined change value.
    [16]
    16. A method for positioning an output element (16) using a positioning drive (15) with a mechanical coupling unit (18) which has a first coupling input (19), a second coupling input (20) and a coupling output (17), the coupling output (17) is connected to the output element (16), with a first stepping drive unit (21) which has a first stepping motor (23) connected to the first coupling input (19) and a first stepping drive control (22) which is set up to control the to control the first stepper motor (23) with a second stepper drive unit (24) which has a second stepper motor (26) drive-connected to the output element (16) and a second stepper drive controller (25) which is set up to control the second stepper motor (26) , and with a central unit (31), with the following steps:- Transmission of a desired position signal (PS) and / or a desired tension value (VS) to the central unit (31) or determination of a desired position signal (PS) and / or a desired tension value (VS) by means of the central unit (31),- Determination of a first control signal (A1) for the first step drive control (22) and a second control signal (A2) for the second step drive control (25) as a function of the position setpoint signal (PS) and the tension setpoint (VS) by the central unit (31) in such a way, that they generate oppositely directed tensioning torques (M23, M26) in both stepping motors (23, 26),- Transmission of the control signals (A1, A2) to the respective stepper drive control (22, 25),- Control of the stepper motors (23, 26) by the respectively assigned stepper drive control (22, 25) depending on the control signal (A1, A2) received, so that a state of tension is generated in the coupling unit (18).
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    同族专利:
    公开号 | 公开日
    CN107852118A|2018-03-27|
    DE102015107583A1|2016-11-17|
    TW201711369A|2017-03-16|
    US20180109214A1|2018-04-19|
    CN107852118B|2021-06-22|
    WO2016180890A1|2016-11-17|
    US10700623B2|2020-06-30|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE102015107583.0A|DE102015107583A1|2015-05-13|2015-05-13|Positioning drive and method for positioning an output element|
    PCT/EP2016/060581|WO2016180890A1|2015-05-13|2016-05-11|Positioning drive and method for positioning an output element|
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