Control of Parallel Manipulators for Very High Accelerations: the Mechanical Vibrations Issue

This paper deals with the issue of mechanical vibrations in control of parallel robots. The proposed control strategy consists in a nonlinear adaptive dual mode controller applied to the actuation redundant parallel manipulator Par2. In this context, the experimental testbed is not equipped with velocity sensors. Therefore, a highgain observer has been used to estimate the articular velocities. Real-time experiments show the effectiveness of the proposed control scheme, as well as the arised mechanical vibrations that increase with acceleration (becoming an important issue for accelerations higher than 20G). Some promising possible solutions to deal with the problem of mechanical vibrations have been discussed for future implementation.