Local path modifications of heavy load manipulators

Motion control of the tool center point (TCP) of a heavy load manipulator can be realized with a virtual elastic band in the workspace of the TCP. In this paper we present an efficient method to modify the virtual elastic band, which enables it to react in real-time to local changes in the environment. The method is based on the B-spline technique. The advantage of this new method is that the path of the TCP is changed near the moving obstacles only, and points which are reached by the TCP remain unchanged. A feature which is important to real-time applications. A local modification of the virtual elastic band, the influence of parametrization and an effect of the relocation of one point of the elastic band on the neighbour points are investigated. An example is given to illustrate the advantage of the method presented