张秀丽, 谷小旭, 赵洪福, 王昆. 一种基于串联弹性驱动器的柔顺机械臂设计[J]. 机器人, 2016, 38(4): 385-394. DOI: 10.13973/j.cnki.robot.2016.0385
引用本文: 张秀丽, 谷小旭, 赵洪福, 王昆. 一种基于串联弹性驱动器的柔顺机械臂设计[J]. 机器人, 2016, 38(4): 385-394. DOI: 10.13973/j.cnki.robot.2016.0385
ZHANG Xiuli, GU Xiaoxu, ZHAO Hongfu, WANG Kun. Design of a Compliant Robotic Arm Based on Series Elastic Actuator[J]. ROBOT, 2016, 38(4): 385-394. DOI: 10.13973/j.cnki.robot.2016.0385
Citation: ZHANG Xiuli, GU Xiaoxu, ZHAO Hongfu, WANG Kun. Design of a Compliant Robotic Arm Based on Series Elastic Actuator[J]. ROBOT, 2016, 38(4): 385-394. DOI: 10.13973/j.cnki.robot.2016.0385

一种基于串联弹性驱动器的柔顺机械臂设计

Design of a Compliant Robotic Arm Based on Series Elastic Actuator

  • 摘要: 为了应对工作环境的动态变化以及人机交互的不确定性,设计了基于被动柔顺结构和主动柔顺控制的柔顺机械臂SoftArm II.在关节电机和连杆之间加入串联弹性驱动器(SEA)传动模块,SEA传动模块由线弹簧周向均布构成;建立了3DOF柔顺机械臂的运动学/动力学模型以及系统刚度模型,基于系统刚度模型提出工作空间典型位姿下关节刚度加权平均的SEA弹簧刚度确定方法;柔顺机械臂采用位置PID(比例-微分-积分)控制,并通过监控末端接触力和关节力矩适时修改指令轨迹.在柔顺机械臂SoftArm II上执行了自由空间中的圆形轨迹跟踪、人机直线对推和碰撞模拟实验,结果显示,SoftArm II在自由空间中具有较好的轨迹跟踪性能,能够实现与操作者的柔顺交互以及对碰撞的安全避让.基于SEA的被动柔顺结构设计以及基于末端力和关节力矩监控的控制策略能够满足人机共存环境对机械臂柔顺性及安全性的要求.

     

    Abstract: A compliant robotic arm with passive compliant mechanical structure and active compliant control, SoftArm II, is designed to cope with the dynamically-changing work environments and uncertain human-robot interactions. Series elastic actuators (SEA) are introduced between joint motors and links as transmission module, which is composed of linear springs evenly arranged circumferentially. Firstly, the kinematic model, dynamic model and system stiffness model are set up for the compliant 3DOF robotic arm. Then, SEA spring stiffness can be determined using weighted average joint stiffness at several representative poses in the workspace based on the system stiffness model. Position PID (proportional-integral-derivative) control is employed in the robotic arm, while contact forces at the arm's end-point and joint torques are monitored to modify the planned trajectory adaptively. Experiments of the circle trajectory tracking in free workspace, human and the robot pushing along a straight line, and collision imitating, are carried out using the compliant robotic arm SoftArm II. The results show that SoftArm II reaches a good position tracking accuracy in free workspace, compliant interaction between the robotic arm and human is achieved, and collision of the robotic arm is safely avoided. The results indicate that the SEA-based passive compliant mechanical structure and the control approach based on end force and joint torque monitoring have the potential to meet the compliance and safety requirements of a robotic arm used in human-robot coexistence environment.

     

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