A novel actuator composed of the load-sensing unit, speed-reducer, and RRERR spatial mechanism

Abstract

This paper proposes and exploits a novel actuator with self-adaptability to variable transmission angles. Based on the RRERR (R stands for revolute pair, E stands for planar pair) spatial mechanism, this paper creatively melts the K-H PGT (planetary gear train) as part of the input carrier, and the LSU (load-sensing unit) as part of the output carrier. While the RRERR configuration has previously remained a mathematical concept, this paper is the first to present a detailed RRERR mechanical design. In theoretical analysis of the mechanism, the system DOF (degree of freedom), motion trajectory, and kinematic characteristics are discussed. Furthermore, the show-force-pair methodology is used to solve the forcing balance of the planar pair. Instead of modeling the whole system and calculating all the constraint reactions simultaneously, the planar pair on the imaginary mirror plane is selected as a breakthrough point, which improves the calculation efficiency tremendously. Finally, the mechanical model of the actuator is constructed for the ADAMS simulation, which validates the theoretical analysis. For the LSU, the FEM results prove the linear relationship between the channel output and the dimensional load, which demonstrates the elastic beams with prerequisite strain distribution.