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Soft Arm 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Soft Arm 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,Soft Arm 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.
As the fastest land animal,cheetah has important reference significance for the research of high-speed quadruped robots in terms of its body structure,motion characteristics and control mechanism.In this paper,we used digital reconstruction to analyze the mechanism of the cheetah’s high-speed movement.Considering the body size and quality of a real cheetah,a simplified virtual model of cheetah was built.Using the D-H method,the kinematics and dynamics of the cheetah’s leg mechanism were established.By using the foot trajectory data of the cheetah’s running gait obtained from biological research,each joint angle,virtual leg length,leg-to-ground contact angle,leg energy,joint torque,and the manipulability of the leg mechanism were analyzed and compared in the time dimension.Finally,the high-speed motion law of engineering guiding significance was extracted.
