Cooperatingly synchronized control for 6-DOF virtual-axis machine tool

This paper presents a cooperatingly synchronized control for 6-DOF virtual-axis machine tool driven by permanent magnetic linear synchronous motor (PMLSM) by keeping the 6 links in cooperating motion at any time. In this paper the coupling 6-link system is divided into 6 separate systems, and each link load disturbance and the coupling disturbance between other 5 links are regarded as the dynamic parameters´ variation of the corresponding PMLSM. An observer is presented to identify the parameters´ variation and to compensate for it, which not only eliminates the coupling but also obviates a lot of cumbersome dynamic calculations of the parallel mechanism. In each separated system, the position controller is adjusted on-line depending on the position error and the speed command to be appropriate for the time variation of the position and speed, and the speed controller is realized by one neuron, which can be rapidly trained on-line, the acceleration control is attained indirectly by the proposed observer and neuron, which improves tracking performance of the position and speed output. A simulation verifies that the control for the position, speed and acceleration of each link is attained, and the system is robust to the uncertain factors.