Dynamic modeling of parallel robots for computed-torque control implementation

In recent years, increased interest in parallel robots has been observed. Their control with modern theory, such as the computed-torque method, has, however been restrained, essentially due to the difficulty in establishing a simple dynamic model that can be calculated in real time. In this paper; a simple method based on the virtual work principle is proposed for modeling parallel robots. The mass matrix of the robot needed for decoupling control strategies, does not explicitly appear in the formulation; however it can be computed separately, based on kinetic energy considerations. The method is applied to the DELTA parallel robot, leading to a very efficient model that has been implemented in a real-time computed-torque control algorithm.