Acceleration Capability Evaluation of a Five-Axis Parallel Robot Based on Forward Dynamics with Given Maximum Driving Forces

The increasing demand for efficient machining of complex structural components puts forward higher requirements for the acceleration capability of machining equipment. Compared with traditional five-axis machine tools with large inertia, five-axis parallel machining robots with lightweight structures are promising in realizing higher acceleration. The inverse dynamics is usually used to evaluate the acceleration ability of the parallel robot, in which iterative process is necessary to obtain the acceleration with the maximum driving force. These methods usually consume more computing resources and is difficult to apply to robot's real-time update of the maximum acceleration with different trajectory. In this paper, an acceleration evaluation method of parallel machining robots based on forward dynamics is established, and the constantly renewal of the relationship between acceleration and driving forces is avoided. In this method, the acceleration direction is included in the forward dynamic modeling to replace the distribution of driving forces. With this method, the acceleration in a certain direction can be got directly with the given maximum driving force. Based on the method, the index to evaluate the size and consistency of the acceleration is proposed and the acceleration performance of parallel machining robots is analyzed. The proposed method provides a more convenient way for the acceleration performance evaluation of the parallel robot with given maximum driving forces.