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，远程机器人机械手可以抓住和移动的对象。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，因此从控制系统必须具有自主力控制或阻抗控制，以防止从机械手和物体因不可避免的接触而造成损坏。在所提出的系统中，从控制器可以切换运动控制，力控制和阻抗控制容易。通过几个工作实验，研究了该控制系统的有效性：实验一：多个机器人协调举起并搬运物体。当左右操纵器不一致地移动时，对象无法平衡，并且无法遵循所需的轨迹。采用双向控制系统，操作者可以通过摇杆的力反馈来感受左右从机械手的接触力，从而调整操作信号。实验二：多机器人协调抓取弹性物体。当两个机械手抓住一个弹性物体时，接触力和力矩在每个轴向方向上发生复杂的变化。然而，操作员理解不足的接触的感觉，因为操纵杆只提出了两个自由度的力和moment.Experiment III：协调多个机器人机械手抓住，解除和移动一个刚性物体。如果从机械手的工具的方向受到约束，可能会出现过大的接触力和力矩。因此，从控制器修改取向的顺应性特性。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.