Estimation Method of Inertia Term Based on Disturbance Estimation and Its Application to Automatic Tuning.

Generally, readjusting the control system is necessary for the servomechanism when the load is changed, and the automatization of the controller is important for the servomechanism. This paper describes the estimation method of the inertia term and the automatic tuning system using this estimate. Firstly, we propose the estimation method of the inertia term using the disturbance observer. In this method, we make use of the characteristic that the estimate error of the inertia term has an effect on the disturbance estimate. The estimate error can be obtained by integrating the disturbance estimate between some specified intervals. Therefore, the new estimate of the inertia term is obtained by adding the estimate error to the inertia term value being obtained. Secondly, we try to apply the above-mentioned method to the feedforward compensation of the inertia force and the disturbance torque compensation for the automatic tuning. A cyclic test signal is prepared in order to estimate the inertia term and the proposed method is applied after one cycle motion has been completed. The obtained inertia value is used for renewing the inertia term of the feedforward compensator and the disturbance observer. As a result, the actuator can operate more accurately at the following motion. The effectiveness of this method is demonstrated in the experimental results.