六自由度装配机器人的动态柔顺性控制

为了提升工业机器人装配的精确性与柔顺性，提出适合工业六自由度装配机器人的动态柔顺性控制策略，使之不仅能够实现快速高精度的参考轨迹跟踪，而且能够动态地切换到工件装配时的接触力控制，并能够保持良好的柔顺性接触力.构建机器人关节空间的标准动力学模型，并变换到末端执行器操作空间，获得操作空间的动态特性.给出该控制策略，主要包含参考轨迹给定模块、内环的轨迹跟踪控制器以及动力学参数辨识模块等.采用滑模算法设计轨迹跟踪控制器；采用阻抗滤波器，生成装配作业时末端执行器的期望运动轨迹；采用sigmoid函数设计轨迹跟踪与接触力控制的判别模块；采用最小二乘算法，设计动力学参数辨识模块.采用Lyapunov函数证明了该控制策略的大范围渐进稳定性和收敛性.基于装配实验台上进行现场装配和动态轨迹跟踪的对比性仿真实验研究.仿真实验结果表明：与典型的比例微分（PD）控制相比，动态柔顺性控制能够在较宽广的范围内实现更精确的空间轨迹跟踪和接触力柔性控制，平均相对误差可以有效地控制在-4%到+4%之内.

Dynamic compliant control of six DOF assembly robot

A dynamic complaint control was presented in order to improve assembly accuracy and flexibility for 6 DOF assembly industrial robot. Then the industrial robot can not only track reference trajectories in working spaces, but also can be dynamically switched to contact force control with high flexibility. The dynamic model of the 6 DOF assembly industrial robot was established in joint space and was transformed into the working space of the end effector. The overall over control framework of the proposed control strategy consisted of reference tracking module, inner tracking control module, dynamic parameter identification module. The reference tracking module was designed based on sliding mode control while the trajectory of contact force was given by using an impedance filter. The switching condition between space tracking and contact force control was designed using sigmoid function. The dynamic parameter identification module was designed by using least square algorithm. All the control modules were verified through Lyapunov function to converge to stable region over wide working ranges. The proposed control was validated through simulations based on an industrial robot platform. Comparative results demonstrate that the proposed dynamic complaint control can significantly improve reference tracking accuracy and contact force control flexibility over wide working range as compared to typical proportional derivative (PD) control. The average relative tracking error of the complaint control can be well maintained within -4% and +4%.