Research of a novel 2-DOF planar parallel robot system

The paper proposes a novel 2-DOF high-speed/high-accuracy robotic system: two permanent linear motors drive a planar parallel mechanism which has advantages of both high-speed and high-accuracy motion and high stiffness, and presents an equivalent finite element method to model the mechanism and establish its dynamical equations. Analysis of mechanism dynamical model verifies that load variation is violent. Due to the direct-drive principle of a linear motor, the load disturbance has a significant effect on motor performance. For this purpose, a feedback controller based on a discrete time disturbance observer is designed. Experiment results validate that: with little effort, high-performance motion system is obtained with this approach, the maximum acceleration is 2 g, steady time is less then 60 ms, and repeatability error is less then ±2 μm. The high-speed/high-accuracy point-to-point control is realized.