Deflection Compensation Analysis of a 3-RRS Parallel Mechanism

Abstract

Abstract Parallel mechanisms have the advantage of high rigidity, large payload capability, and so on, but the positioning accuracy is affected by the elastic deflection arising from external load and gravity. An approach to improving accuracy by compensating elastic deflection is presented with a 3-RRS parallel mechanism as the research object. The approach is implemented by introducing springs on the moving platform and the limbs. Taking the external load, spring force, and gravity, the mechanical and deflection models are established, which can effectively separate the influence of spring force and gravity on the deflection at the endpoint. In addition, considering the constraints of the mechanism’s operating capacity, the springs’ layout and parameters optimization design are studied based on the compensation effect of springs on the global deflection of the platform. The example shows that the method can effectively compensate for the deflection, and the spring applied on the moving platform has the best compensation effect, which can compensate for 91% of the deflection.