绳索驱动式变刚度关节柔顺控制与力补偿方法研究

机器人柔顺运动有助于提高机器人交互运动时的安全性与稳定性,越来越受到人们的重视。针对一种绳索驱动式具有主被动柔顺性的柔性机器人关节,提出一种适用于绳索驱动式变刚度关节的刚度与位置解耦控制方式,实现了关节位置控制的同时,又实现了关节柔顺性的统一。利用雅可比矩阵和模型间静力学关系,得到关节刚度模型,并通过优化方法对变刚度装置的力学模型和刚度模型构成的非线性方程组求解,实现变刚度关节刚度与位置的非线性解耦。在解耦控制基础上提出一种力矩观测方法,实现了关节力矩补偿,增强了关节位置控制能力;建立了绳索驱动式变刚度关节样机和控制系统,并通过仿真和实验分析的方式验证了所提柔顺控制方式的可行性和有效性。

Study on compliant control and torque compensation method of wire driven variable stiffness joint

The compliant motion of robot helps to improve its safety and stability in interactive motion, which has attracted much more attention in recent years. In this paper, aiming at a wire driven flexible robotic joint with active and passive compliance, a decoupling compliant control method for the stiffness and position of the wire driven variable stiffness joint is proposed, which realizes the joint position control and also achieves the uniformity of joint compliance. The stiffness model of the joint is obtained using the Jacobian matrix and the static relationship between the models. The nonlinear equations composed of the mechanical model and stiffness model of the variable stiffness device are solved with optimization method to realize the nonlinear decoupling of the stiffness and position of the variable stiffness joint. Based on the decoupling control, a torque observation method is proposed to realize the torque compensation of the joint and enhance the joint position control ability. The prototype and control system of the wire driven variable stiffness joint were built, and simulation and experiment analysis verify the feasibility and effectiveness of the above compliant control method.