A modified impedance control design for tele-operational coordinated multiple robot manipulators

在这项研究中，提出了一种稳定的远程机器人控制系统的设计，在该系统中，远程机器人操作手可以抓取和移动物体。由于用于主系统的操纵杆只有3个运动自由度和2个力反馈自由度，因此从属控制系统必须具有自主力控制或阻抗控制，以防止从属机械手与物体不可避免地接触而损坏。在所提出的系统中，从控制器可以很容易地将运动控制切换为力控制和阻抗控制。通过多个工作实验，研究了该控制系统的有效性。实验一：协调多个机器人机械手抬起和搬运一个物体。当左右机械手运动不一致时，对象不能保持平衡，也不能跟随到所需的轨迹。使用双边控制系统，操作者可以通过操纵杆的力反馈感受到左右从机械手的接触力，并重新调整操作信号。实验二：协调多个机器人机械手抓取弹性物体。当两个机械手都抓住一个弹性物体时，每个轴向的接触力和力矩都会复杂地出现。然而，操作者对接触感觉理解不足，因为操纵杆只表示力和力矩的两个自由度。实验三：协调多个机器人机械手抓取、抬起和移动刚性物体。如果从动机械手的刀具方向受到约束，可能会产生过大的接触力和力矩。因此，从控制器对定向的顺应特性进行了修正。这样操作者就可以在没有过大接触力和力矩的情况下操纵刚性物体。

In this study, a design of a stable remote robot control system is proposed, where remote robot manipulators can grasp and move an object. Because a joystick used for master system has only 3 degree of freedom of motion and 2 degree of freedom of force feedback, the slave control system must have autonomous force control or impedance control that prevents slave manipulator and the object from being damaged caused by unavoidable contact. In proposed system, the slave controller can switch motion control to force control and impedance control easily. By performing several working experiments, the usefulness of the control system is investigated.Experiment I : coordinated multiple robot manipulators raise and convey an object. When right and left manipulators move inconsistently, an object can not be balanced and not be followed to a desired trajectory. Using bilateral control system, operator can feel the contact force of right and left slave manipulators through force feedback of joysticks and readjust the operational signal. Then slave system can keep balance of the object.Experiment II : coordinated multiple robot manipulators grasp an elastic object. When both manipulators grasp an elastic object contact forces and moments for each axial direction occur complicatedly. However, an operator understood insufficient contact feelings because the joystick only presents two degree of freedom of force and moment.Experiment III : coordinated multiple robot manipulators grasp, lift and move a rigid object. If the orientation of tools of slave manipulators is constrained, excessive contact force and moment may occur. Therefore slave controller modifies the compliance characteristic of the orientation. Then operator can manipulate a rigid object without excessive contact force and moment.