Stable Control of Multi-link Manipulator Using Collision Phenomena

In this paper, a methodology using the Lyapunov direct method is proposed to analyze the stability of a multi-link manipulator system, which is positioned on a flexible wall, with collision phenomenon. The stability and response of the system are examined by parameter studies of numerical simulation. Because industrial demands for rapid motion of robotics have been increasing in order to achieve higher efficiency, collision has become a problem because every task involves contact when a manipulator interacts with an object. However, few research has been initiated to overcome this problem. In this paper, we employ a Hertz-type model which includes an energy loss parameter to express the impact force between the manipulator and the wall. Using this model, we have verified the stabilization effect of collision by the Lyapunov method. The effect has been confirmed by simulation. As a result, stable positioning of the manipulator on a flexible wall is assured, and the use of collision is sometimes effective to control the manipulator to performs tasks with rapid contact.