Modeling and Control of Twin Parallel-Axis Linear Servo Mechanisms for High-Speed Machine Tools

Wu-Sung Yao, Fu-Yun Yang, Mi-Ching Tsai


This paper presents a synchronous control scheme for a twin parallel-axis linear servo mechanism with mechanical coupling which appears inherently in the so-called box-in-box configuration of machine tools. To identify the two-port mathematical model, a multi-variable identification method is developed to construct a dynamic model of the controlled servo mechanism. Moreover, a synchronous controller framework based on the identified model is proposed to reduce position and velocity errors of the two coupled linear servomotors. To demonstrate the capacity of the mathematical model as well as the effectiveness of the control scheme, a gantry-type platform was utilized as an illustrated example, where the steady-state synchronization error reaches 0.5 m with a velocity of 830mm/s.


dynamic modeling; synchronous control; linear servomotor; system identification


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