Control of robotic manipulators by joint acceleration controller

The authors propose a simple and high-performance motion control method for robot manipulators in Cartesian coordinates. It is called the acceleration tracing orientation method (ATOM). In the proposed method, it is necessary that each joint should trace the specified acceleration. A high-performance position controller and a hybrid position/force controller are easily realized by the ATOM. Analyses of the controller reveal that the precise acceleration controller is the key to improving the performance of the ATOM. However, an acceleration controller is almost impossible to realize by using conventional disturbance compensation methods. For example, the inverse dynamics is complicated to calculate and is weak against parameter variations. In contrast to the inverse dynamics, a disturbance observer method is simple and robust against the parameter variations and makes possible a high-performance acceleration controller. Experimental results show the effectiveness of the ATOM.