Control of Advanced Mechatronics Systems by Means of Nonlinear Circuit Theory

早在1996年就有报道指出，不仅机械臂和机械手的运动，而且大型空间结构和机械系统的运动也可以用非线性位置相关电路来表示。今年报告了基于虚功原理的EL（欧拉-拉格朗日）形式主义暗示了这种机械系统的非线性位置相关电路的存在。特别是，研究了几何端点约束下机器人动力学的电路理论表达式的细节，并建立了端点接触处的阻抗控制理论。进一步表明，摩擦力包括静力和库仑摩擦以及重力可以同时通过引入回归量来补偿摩擦力和重力项。这意味着实现仅惯性（摩擦/无重力）机器人，而不使用任何力-扭矩传感器。用三自由度直驱机器人进行了实验，验证了这一理论结果。在这种纯惯性机器人的平台上进行了端点阻抗控制控制器的设计。更具体地说，考虑了在刀具质量未知和再现力关于位移的非线性特性未知的情况下，一自由度系统的阻抗控制的基本过程。研究表明，可以引入一种新的阻抗匹配泛化框架来处理这种情况下的非线性问题。广义阻抗匹配是通过两个被动系统的负反馈连接来定义的，一个系统表示质量估计动力学，另一个系统表示力误差控制动力学。在电路的情况下，前一种动力学对应于内部阻抗。通过考虑雅可比矩阵在关节坐标和任务坐标之间的作用，可以将初等过程的这一观察推广到多自由度机器人的任务情况。少

It was already reported in the year of 1996 that motions of only robotic arms and hands but also large-scaled space structures and mechanical systems are expressed by means of nonlinear position-dependent circuits. This year reports that the EL (Euler-Lagrange) formalism based on the principle of virtual work implies the existence of a nonlinear position-dependent circuit for such a mechanical system. In particular, details of a circuit-theoretic expression of robot dynamics under geometrical endpoint constraint have been investigated and a theory of impedance control at the endpoint contact has been developed. It has been shown further that frictional forces including static and Coulomb frictions together with gravity forces can be simultaneously compensated by introducing regressors for both frictional and gravity terms. This means the realization of inertia-only (on Friction/Gravity-free) robots without using any force-torque sensors. This theoretical results has been ascertained by … More an experiment by using a DD (Direct-Drive) robot with 3 degrees of freedom. Design of controllers for endpoint impedance control has now been carried out on a platform of such an inertia-only robot. More specifically, an elementary process of impedance control for an one-degree-of-freedom system is considered under the circumstances that the tool mass is unknown and the nonlinear characteristics of reproducing forces with respect to displacements are also unknown. It has been shown that a new framework of generalization of impedance matching can be introduced to cope with nonlinearities involved in this situation. The generalized impedance matching is defined by means of a negative feedback connection on of two passive systems, one expresses the dynamics of estimating the mass and the other does the dynamics of force error control. The former dynamics corresponds to an internal impedance in case of electric circuits. Generalization of this observation for the elementary process to the case of task for multi-degrees of freedom robots can be carried out by considering a role of the Jacobian matrix between the joint coordinates and the task coordinates. Less