Estimation of load-side position of two mass resonant systems using MEMS accelerometers

This paper presents a load position estimation methodology of a linear motor driven table system using a MEMS accelerometer. The system is composed of a table and a load connected via an elastic beam attached on the table. In order to improve the performance of the load positioning, the load position measurement would be important. However it might be difficult to place position sensors on the load from the viewpoint of cost saving and available space. In this research, the load acceleration measured by a low cost and small size MEMS accelerometer and the motor angle acquired by a linear encoder are utilized to the Kalman filter for estimating the position information at the load side as well as the sensor bias of the accelerometer. In the Kalman filter design, the discrete time plant system is needed, where the discretization method should be selected appropriately to improve estimation performance especially for two mass resonant systems. The effectiveness of the proposed estimation methodology has been verified by experiments using a linear motor driven table system.