• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A linear—motion compliant—joint robotic arm based on series elastic actuators, comprising an articulated arm and two series elastic actuators. The articulated arm comprises a shoulder, an upper arm and a lower arm that are sequentially articulated. 5 The first series elastic actuator is mounted in the shoulder. The output end of the first series elastic actuator is connected with the upper arm through the first slider—crank mechanism. The second series elastic actuator is mounted in the upper arm. The output end of the second series elastic actuator is 10 connected with the lower arm through the second slider—crank mechanism. The present invention has a compact structure, good compliance and a large rigidity change rate, and can ensure the motion compliance and the safety of human—machine interaction. The slider—crank mechanisms are introduced to the 15 joints, so, the movement of the screw and the rotation conversion of the joints are achieved through these mechanisms .
    公开号:NL2026200A
    申请号:NL2026200
    申请日:2020-08-03
    公开日:2021-08-30
    发明作者:Zhou Lelai；Song Zhaopeng；Liu Dayu；Li Yibin；Li Jianhua；Rong Xuewen
    申请人:Univ Shandong；
    IPC主号:
    专利说明:

    LINEAR-MOTION COMPLIANT-JOINT ROBOTIC ARM BASED ON SERIESELASTIC ACTUATORS
    TECHNICAL FIELD The present invention relates to a linear-motion compliant-joint robotic arm, and belongs to the technical field of robotic arms.
    BACKGROUND With the development of science and technology, the daily serious population aging problem of all countries in the world and the increase of human cost, it urgently needs the robot to work in more fields instead of the human. The former most popular industrial robot cannot meet the daily increased demands of the human society. So, the key demand of the current robot field is to develop the new generation of more human-friendly robots.
    To meet the new social demands, the new generation of robots firstly should conduct more and more human-machine interaction. The robot is not only applied to the closed environment of the factory, but also cooperate with the human, even incorporated in the human society, to assist even take the place of the human to complete the daily activities. However, by virtue of uncertainness and safety of the human-machine interaction, an ideal robotic arm should have the compliance characteristic like the human arm. It should actively change the motion speed and the motion damping according to changes of the outside environment. Therefore, the robot body, especial the joint, should be converted fromthe rigiddrive to the compliant drive; the robot control technology should be developed from the traditional position control to the force control which can greatly express the compliance characteristic.
    In the current compliant robotic arm field, some robotic arms actively change the Joint compliance through the compliance control algorithm, which puts forward the high requirement on the controller and the sensors. There is another solution to passively change the joint compliance by introducing an elastic element. This method has a simple control system so as to be the current research hotspot of the compliance drive.
    The Chinese Patent Application with publication number CN108608458A discloses a serial-drive compliant robotic arm joint. The serial-drive compliant robotic arm joint comprises a Joint motor, a harmonic reducer, a four-connecting-rod mechanism, a joint shell and an output shell. A leaf spring is fixedly connected to the upper side of a leaf spring base. The four-connecting-rod mechanism is arranged above the leaf spring. A rigidity motor drives a driving bevel gear and utilizes gear engagement to drive a driven bevel gear so as to drive a cam to rotate. As the cam 1s in contact with a connection point of the four-connecting-rod mechanism, a supporting point position of a Four-connecting-rod saddle-shaped bracket on the leaf spring is changed; then, the rigidity of the joint is changed. Therefore, the controllable regulation of the rigidity of the joint is realized. However, this method has a complex structure and a large size, and is hard to be practically applied to the robotic arm.
    The Chinese Patent Application with publication number CN104924320A discloses a three degree-of-freedom compliant robotic arm based on a series elastic actuator, which comprises steering engines in a joint, and a connecting arm arranged between a drive conversion module and the joint. It is arranged by simulating the degree of freedom of the human body. The utilized drive conversion module can convert the rigidity drive into compliance drive, thereby ensuring the motion compliance and the safety of human-machine interaction. This robotic arm is simply assembled and easily arranged. However, a spring of the robotic arm is limited to its size; so, the deformation range is limited, and the rigidity change range is small.
    SUMMARY The objective of the present invention is to propose a novel robotic arm based on series elastic actuators to meet the current social requirement on collaberative robots and to overcome the defects of the traditional driving modes. This robotic arm has the advantages of a compact structure, a large output torque, a simple control method, a large motion space and the like.
    A linear-motion compliant-joint robotic arm based on series elastic actuators of the present invention adopts the following technical solution.
    The robotic arm comprises an articulated arm and two series elastic actuators. The articulated arm comprises a shoulder, an upper arm and a lower arm that are sequentially articulated.
    The first series elastic actuator is mounted in the shoulder. The output end of the first series elastic actuator is connected with the upper arm through the first slider-crank mechanism. The second series elastic actuator is mounted in the upper arm. The output end of the second series elastic actuator is connected with the lower arm through the second slider-crank mechanism.
    The shoulder comprises a left shoulder connecting rod and a right shoulder connecting rod. One end of the left shoulder connecting rod and one end of the right shoulder connecting rod are connected together.
    The upper arm comprises a left upper arm and a right upper arm. The left upper arm and the right upper arm are connected by a fixing element.
    The lower arm is fork-shaped (one end of the lower arm is U~shaped) . Two divided portions of the fork-shaped lower arm are respectively articulated with the left upper arm and the right upper arm of the upper arm.
    The first slider-crank mechanism is connected with the upper arm through the fixing element. The fixing element is connected with the upper arm and is articulated with the output end of the first slider-crank mechanism.
    The slider-crank mechanism comprises a sliding shaft, a transmission rod and a sliding sleeve.
    The two ends of the sliding shaft are respectively connected with the output end of the series elastic actuator and the transmission rod.
    The sliding sleeve sleeves the sliding shaft and is fixedly connected with the shoulder or the upper arm.
    The series elastic actuator comprises a drive motor, a spring separator, die springs, a shell, a transmission shaft, a ball screw and a joint connecting rod.
    Guide shafts are connected with the drive motor and the shell.
    The spring separator is sleeved on the guide shafts.
    The die spring is arranged between the spring separator and the drive motor as well as between the spring separator and the shell.
    The transmission shaft is mounted in the shell and is connected with the motor spindle.
    The transmission shaft is fixedly connected with a nut.
    The ball screw is sleeved in an inner hole of the transmission shaft and is connected with the nut.
    The joint connecting rod is connected with the ball screw.
    The drive motor comprises a motor case, amotor rotor, amotor stator and a motor spindle.
    The motor stator and the motor rotor are mounted in the motor case.
    The motor rotor is fixed to the motor spindle.
    The motor stator is internally equipped with a Hall effect sensor.
    When the compliant-joint robotic arm works, the motor in the series elastic actuator drives the transmission shaft to rotate according to a control signal.
    The transmission shaft drives the nut to rotate such that the ball screw and the joint connecting rod extend or retract.
    The joint connecting rod drives the upper arm or the lower arm to rotate through the slider-crank mechanism.
    When the upper arm and the lower arm are impacted by the outside, the whole series elastic actuator except the spring separator moves through the guide shafts so as to compress the die springs.
    The die springs absorb fluctuating impact of the outside load to achieve mechanical compliance of the joint.
    The present invention has a compact structure, good compliance and a large rigidity change rate, and can ensure the motion compliance and the safety of human-machine interaction. The present invention has the following characteristics:
    1. The kinetic characteristics of the robotic arm are more compliant and safer.
    5 2. The advantages of a large output torque of a torque motor, a simple and compact structure and the like are fully utilized. Driving components of the robot can be miniaturized and lightened.
    3. The double spring design improves the rigidity change rate of the driver. Using such design, the robot joint can bear the two-way high-load impact.
    4, The slider-crank mechanisms are introduced. Therefore, the movement of the screw and the rotation conversion of the joints are achieved. The motion space of the robotic arm is greatly expanded.
    BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an integral structure of a robotic arm of the present invention.
    FIG. 2 is an external view of a robotic arm of the present invention after a right shoulder connecting rod and a right upper arm are removed.
    FIG. 3 is an external view of a series elastic actuator in the present invention.
    FIG. 4 is an internal view of a series elastic actuator in the present invention.
    In the drawings: l-base, 2-left shoulder connecting rod, 3-right shoulder connecting rod, 4-left upper arm, 5-right upper arm, 6-lower arm, 7-fixing element, 8-first series elastic actuator, 9-second series elastic actuator, 10-first slider-crank mechanism, 11-second slider-crank mechanism, 12-sliding sleeve, 13-bushing, 14-sliding shaft, 15-transmission rod, 16-motor case cover, 17-motor case, 18-guide shaft, 19-die spring, 20-spring separator, 21-shell case, 22-shell case cover, 23-joint connecting rod, 24-motor stator, 25-motor rotor, 26-motor spindle, 27-parallel key, 28-transmission shaft, 29-crossed roller bearing, 30-ball screw, 31-nut, 32-thin section bearing, 33-0il-less bushing, 34-ball bearing, and 35-spindle fixing sheet.
    DESCRIPTION OF THE EMBODIMENTS As shown in FIG. 1, the present invention proposes a linear-motion compliant-joint robotic arm based on series elastic actuators, comprising an articulated arm and two series elastic actuators. The whole articulated arm is connected with a base 1. The articulated arm comprises a shoulder, an upper arm and a lower arm 6 that are sequentially articulated. A joint is formed between the shoulder and the upper arm, and another joint is formed between the upper arm and the lower arm 6.
    The shoulder comprises a left shoulder connecting rod 2 and a right shoulder connecting rod 3. One end of the left shoulder connecting rod 2 and one end of the right shoulder connecting rod 3 are connected together and are fixed to the base 1 through bolts. The first series elastic actuator 8 is mounted between the left shoulder connecting rod 2 and the right shoulder connecting rod 3. A spring separator 20 of the first series elastic actuator 8 is fixedly connected with the left shoulder connecting rod 2 and the right shoulder connecting rod 3 (shown in FIG. 3). The output end of the first series elastic actuator 8 is articulated with the upper arm through the first slider-crank mechanism 10.
    The upper arm comprises a left upper arm 4 and a right upper arm 5. A fixing element 7 connects and is arranged between the left upper arm 4 and the right upper arm 5. One end of the left upper arm 4 and one end of the right upper arm 5 are respectively articulated with the left shoulder connecting rod 2 and the right shoulder connecting rod 3 through a rotary shaft. Besides, the fixing element 7 is connected with the output end of the first series electric actuator § through the first slider-crank mechanism. The second series elastic actuator 9 is fixedly mounted between the left upper arm 4 and the right upper arm
    5. A spring separator of the second series elastic actuator 9 is fixed to the left upper arm 4 and the right upper arm 5 {shown in FIG. 3). The output end of the second series elastic actuator 10 is articulated with the lower arm 6 through the second slider-crank mechanism 11.
    One end of the lower arm 6 has a U-shaped fork structure, as shown in FIG. 2. Two divided portions of the U-shaped fork structure are respectively articulated with the left upper arm 4 and the right upper arm 5.
    Using the first slider-crank mechanism 10 and the second slider-crank mechanism 11, the joint between the shoulder and the upper arm and the joint between the upper arm and the lower arm 6 utilize the slider-crank mechanism driving mode so as to greatly expand the motion space of the robotic arm, as shown in FIG. 2. To observe the motion mode of the slider-crank mechanism clearly, a sliding sleeve 12, a graphite bushing 13, a sliding shaft 14 and a transmission rod 15 may be utilized as components in one slider-crank mechanism. The two ends of the sliding shaft 14 are respectively articulated with a joint connecting rod 23 (shown in FIG. 3) of the series elastic actuator and the transmission rod 15. The transmission rod of the first series elastic actuator 8 is articulated with the fixing element 7. The transmission rod of the second series elastic actuator 9 is articulated with the lower arm 6. The sliding sleeve 12 sleeves the sliding shaft 14. The bushing 13 (namely the graphite bushing) is arranged in an inner hole of the sliding sleeve 12. The sliding shaft 14 slides in the bushing 13. The sliding sleeve 12 is fixed to the left shoulder connecting rod 2 and the right shoulder connecting rod 3 (corresponding to the first series elastic actuator 8) or to the left upper arm 4 and the right upper arm 5 (corresponding to the second series elastic actuator 9).
    The first series elastic actuator 8 and the second series elastic actuator 9 have the same structure, as shown in FIG. 3 and FIG. 4. The series elastic actuator comprises a drive motor, a spring separator 20, die springs 19, a shell, a transmission shaft 28, a ball screw 30 and the joint connecting rod 23. Four guide shafts 18 are connected between the drive motor and the shell. The four guide shafts 18 are fixed to a motor case 17 and a shell case 21 through screws. The spring separator 20 sleeves the four guide shafts 18 and can move along the guide shafts. The spring separator 20 of the first series elastic actuator 8 is fixedly connected with the left shoulder connecting rod 2 and the right shoulder connecting rod 3. The spring separator 20 of the second series elastic actuator 9 is fixedly connected with the left upper arm 4 and the right upper arm 5. The die spring 19 is arranged between the spring separator 20 and the drive motor as well as between the spring separator 20 and the shell. The shell comprises the shell case 21 and a shell case cover 22 connected to the shell case 21. The transmission shaft 28 is mounted in the shell. The two ends of the transmission shaft 28 are supported by bearing seats of the shell case 21 and the shell case cover 22 respectively through a crossed roller bearing 29 and a thin section bearing
    32. The transmission shaft 28 is connected with a motor spindle 26 through parallel keys 27. The transmission shaft 28 is fixedly connected with a nut through a screw. The ball screw 30 is sleeved in an inner hole of the transmission shaft 28 through an oil-less bushing 13 and is in threaded connection with the nut. The joint connecting rod 23 is connected to the ball screw 30. The ball screw 30 is connected with a fixing nut 31 in the shell case 21. The joint connecting rod 23 of the first series elastic actuator 8 is connected with the left upper arm 4 and the right upper arm 5 through the first slider-crank mechanism 10. The joint connecting rod of the second series elastic actuator 9 is also connected with the lower arm 6 through the second slider-crank mechanism 11. The drive motor comprises the motor case cover 16, the motor case 17, a motor rotor 25, a motor stator 24 and a motor spindle
    26. The motor stator 24 is mounted in the motor case 17. The motor rotor 25 is arranged in the motor case 17. The motor case cover 16 is mounted at the motor case 17 to tightly press the motor stator 24. The motor stator 24 is internally equipped with a Hall effect sensor. The motor rotor 25 is fixed to the motor spindle 26 through a spindle fixing sheet 35. The motor spindle 26 is supported by the bearing seats of the motor case 17 and the motor case cover 16 through two ends of the two ball bearings 34.
    When the compliant-joint robotic arm works, the motor rotor 25 in the series elastic actuator rotates according to a control signal and outputs to the transmission shaft 28 through the motor spindle 26 and the parallel keys 27. The transmission shaft 28 drives the nut 31 to rotate such that the ball screw 30 and the joint connecting rod 23 extend or retract. The joint connecting rod 23 extends or retracts to do linear motion to drive the sliding shaft 14 to do linear motion in the sliding sleeve 12. Thus, the transmission rod 15 rotates around the joint to push the upper arm and the lower to rotate respectively around the central point. When the upper arm and the lower arm are impacted by the outside, the whole series elastic actuator except the spring separator 20 moves through the guide shafts 18 so as to compress the die springs 19. The die springs 19 absorb fluctuating impact of the outside load to achieve mechanical compliance of the joint. The two die springs 19 have the preset compression, 80, the elasticity change rate generated by the two die springs doubles that of one spring. The present invention introduces the slider-crank mechanisms to the joints and achieves the movement of the ball screw 30 of the series elastic actuators and the rotation conversion of the joints through these mechanisms.
    权利要求:
    Claims (9)
    [1]
    A linearly driven flexible joint robotic arm based on elastic series actuators comprising an articulated arm and two elastic series actuators, the articulated arm comprising a shoulder, an upper arm and a lower arm which are sequentially articulated; wherein the first elastic series actuator is arranged in the shoulder; wherein the output end of the first elastic series actuator is connected to the upper arm by the first slider-crank mechanism; wherein the second elastic series actuator is arranged in the upper arm; wherein the output end of the second elastic series actuator is connected to the lower arm by the second shifter-crank mechanism.
    [2]
    The linear driven flexible joint robotic arm based on elastic series actuators according to claim 1, wherein the shoulder comprises a left shoulder connecting rod and a right shoulder connecting rod, wherein one end of the left shoulder connecting rod and one end of the right shoulder connecting rod are connected together .
    [3]
    The linearly driven, flexible joint robotic arm based on elastic series actuators according to claim 1, wherein the upper arm comprises a left upper arm and a right upper arm; wherein the left upper arm and the right upper arm are connected by a fixing element.
    [4]
    The linear driven robotic arm with flexible joints, based on elastic series actuators, according to claim 1, wherein the lower arm is fork-shaped.
    [5]
    The linear driven robotic arm with flexible joints based on elastic series actuators according to claim 1, wherein the first slider-crank mechanism is connected to the upper arm by the fixing element; wherein the fixing element is connected to the upper arm and is pivoted to the output end of the first slider-crank mechanism.
    [6]
    The linear-driven robotic arm with flexible joints based on elastic series actuators according to claim 1, wherein the shifter-crank mechanism comprises a slide rod, a transmission rod and a slide sleeve; wherein the two ends of the slide rod are connected to the output end of the series elastic actuator and the transmission rod, respectively; wherein the sliding cover encases the slide bar and is rigidly connected to the shoulder or the upper arm.
    [7]
    The linear-driven robotic arm with flexible joints based on elastic series actuators according to claim 1, wherein the elastic series actuator comprises a drive motor, a spring separator, high-pressure springs, a shell, a transmission shaft, a ball screw and a pivot connecting rod includes; wherein guide shafts are connected to the drive motor and the shell; the spring separator enveloping the guide shafts; wherein the high-pressure spring is disposed between the spring separator and the drive motor and between the spring separator and the shell; wherein the transmission shaft is arranged in the shell and is connected to the motor shaft; wherein the transmission shaft is fixedly connected with a nut; wherein the ball screw is encased in an internal cavity of the transmission shaft and is connected to the nut; wherein the hinge connecting rod is connected to the ball screw.
    [8]
    8. Linear driven robotic arm with {flexible joints, based on elastic series actuators,
    according to claim 7, wherein the driving motor comprises a motor housing, a motor rotor, a motor stator and a motor shaft; wherein the motor stator and the motor rotor are mounted in the motor housing; wherein the motor rotor is fixed to the motor shaft.
    [9]
    The linear driven robotic arm with flexible joints based on elastic series actuators according to claim 7, wherein the motor stator is internally equipped with a Hall effect sensor. -0-0-0-0-0-0-0-0-
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    同族专利:
    公开号 | 公开日
    CN111113399A|2020-05-08|
    ZA202003802B|2021-04-28|
    NL2026200B1|2022-02-22|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CN104924320A|2015-05-21|2015-09-23|北京交通大学|Three-freedom-degree flexible mechanical arm based on series-connection elastic driver|
    CN108608458A|2018-07-26|2018-10-02|中国石油大学|A kind of submissive joint of mechanical arm of tandem drive|
    CN109202956A|2018-11-09|2019-01-15|山东大学|A kind of submissive articulated mechanical arm based on series elastic driver|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    CN202010024547.0A|CN111113399A|2020-01-10|2020-01-10|Linear motion joint flexible mechanical arm based on series elastic driver|
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