Analysis and Control of Settling Process of High-Speed, High-Precision Positioning Mechanism : 1st Report, Modeling and Computer Simulation

Abstract

We describe a theoretical and experimental investigation of overshoot in the positioning process of an access mechanism in a semi-closed-loop control system. A high-speed, high-precision positioning system is made and its dynamic model of two degrees of freedom and a higher-order model are constructed for theoretical analysis and computer simulation. It is found from omputer simulation that a certain amount of overshoot is always induced at the target position when a large deceleration curve is employed as a reference, and that the amount of the first overshoot cannot be suppressed by any feedback control. Experimental results agree well with those of computer simulation. Computer simulation reveals that the overshoot is caused by deformation of the first natural mode of vibration. Analytical solutions are presented for estimating the amount of overshoot and the lowest natural frequency of the positioning mechanism whose overshoot does not exceed the settling width.