Self-adaptation dynamic sliding mode controlling method controlled by virtual axis lathe parallel connection mechanism motion

Abstract

The invention discloses a self-adaptation dynamic sliding mode controlling method controlled by virtual axis lathe parallel connection mechanism motion, which comprises first building a controlled object mathematical model of each branch controller of a virtual axis lathe with motor driving shaft distracters, then planning the motion route of a virtual axis lathe parallel connection mechanism, confirming the expected motion curve of each branch driving motor of the virtual axis lathe in a process of achieving parallel connection mechanism expected motion, detecting actual motion state of each branch driving motor, constructing dynamic switching functions, designing self-adaptation ratio aiming at motor driving shaft disturbance, finally designing self-adaptation dynamic sliding mode control law, calculating driving control quantity of each control branch motor of the virtual axis lathe, transmitting the quantity to each motor driver, and driving the virtual axis lathe parallel connection mechanism to achieve the expected motion. The method can reduce negative effect of virtual axis lathe execution mechanism fast changing dynamic characteristics on the system control performance and improve resistance of the virtual axis lathe system on strong disturbance.

Description

technical field [0001] The invention relates to a virtual axis machine tool driven by a motor, in particular to a motion control method of its parallel mechanism. Background technique [0002] Virtual axis machine tools are composed of multi-rod parallel kinematic mechanisms. At present, it is still a recognized problem in the industry to realize high-performance control of virtual axis machine tools. One, seriously restricting its advantages to play. One of the key technologies to realize high-performance control machining of virtual axis machine tools is to implement high-performance control on the movement of its main structure—parallel mechanism. At present, the PID control method is commonly used in the industry, that is, the proportional integral differential action of the deviation between the expected position and the actual position of the drive motor of each branch of the parallel mechanism is used as the drive control quantity of each branch motor. This control m...

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Problems solved by technology

Outside the boundary layer, the system satisfies the sliding mode condition, and its performance is not affected by system parameter changes and disturbances, and has good control quality. However, once the system operating state enters the boundary layer, the control performance of the system will be reduced because the sliding mode condition has been broken. Especially when the system is strongly disturbed, the control quality of the system will be further reduced due to the expansion of the boundary layer

In addition, the above-mentioned related control technologies cannot solve the problem that the fast-changing dynamic characteristics of the virtual axis machine tool actuator have an adverse effect on the system control performance.

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