Dynamic Angular Transmission Error Compensation by Adaptive Estimation of Angular Transmission Error Characteristics Based on Reaction Force Observer for Strain Wave Gearing

This paper presents an adaptive dynamic angular transmission error (ATE) compensation method in strain wave gearing, employing a feedforward control approach to suppress vibrations excited by ATE. In such mechanisms, significant issues can arise when the frequency of the ATE coincides with the mechanical system's resonant frequency. The ATE is caused by manufacturing and assembly errors, and its characteristics are determined during the assembly process, leading to variations among products. The proposed method is particularly suitable for semi-closed loop control systems. It estimates and compensates for ATE characteristics after assembly without requiring additional sensors such as load-side encoders or laser trackers. Specifically, the proposed method comprises: (1) the design of a dynamic ATE compensator using the control system structure, control parameters, and estimated ATE characteristics as design inputs, (2) an ATE estimation mechanism based on a reaction force observer, and (3) an adaptive algorithm for auto-estimation of ATE characteristics. The effectiveness of the proposed method is validated through numerical simulations and experimental evaluations using a prototype positioning device equipped with strain wave gearing.