Yoshifumi Okitsu

Compensation for synchronous component of angular transmission errors in harmonic drive gearings

This paper presents a modeling and compensation methodology for angular transmission errors in harmonic drive gearings. In this research, effects of synchronous component in the transmission error on the positioning performance are analytically examined. On the basis of the examinations, a transmission error model-based feedforward compensation is adopted to improve the positioning performance during both static and dynamic positioning motions. The proposed approach has been verified by experiments using a prototype with harmonic drive gearings.

Modeling and compensation for angular transmission error of harmonic drive gearings in high precision positioning

This paper presents a novel modeling and compensation approach for the angular transmission error in harmonic drive gearings. In the modeling, physical phenomena of the transmission error due to nonlinear elastic deformations in micro-displacement region are especially dealt with, as well as the synchronous component which has been discussed in a variety of conventional studies. Based on the analyses of the phenomena, the nonlinear elastic component is mathematically modeled by applying a modeling framework for the rolling friction with hysteresis attributes. The proposed transmission error model has been adopted to the positioning system as a model-based feedforward compensation manner. Experimental results using a prototype show the effectiveness of the proposed modeling and compensation.

GA-based auto-tuning of vibration suppression controller for positioning devices with strain wave gearings

This paper presents a practical genetic algorithm (GA)-based auto-tuning of vibration suppression controller for positioning devices with strain wave gearings. In the system design for the proposed GA-based tuning, guidelines of the fitness evaluation are set as the response bandwidth of the control system and the gain characteristics of load position for angular transmission error (ATEs) of the strain wave gearing. The proposed function autonomously tunes parameters of a positioning controller by GA, where mechanical vibrations due to the ATEs can be suppressed using resonant and all-pass filters. Effectiveness of the proposed approach has been verified using a prototype.