Device and method for correcting transmission error of closed-loop servo system of precision numerical control machine tool

Abstract

The invention discloses a transmission error correction device and method of a closed-loop servo system of a precision numerical control machine tool. The position detection and feedback unit receives the encoder signal sent by the main servo motor and the grating signal fed back by the grating signal detection system, that is, receives the numerical control machine tool. The actual position and speed signal of the workbench is compared with the position and speed command value issued by the CNC machine tool to calculate the position and speed compensation amount, and then the position compensator and speed compensator send commands to drive the auxiliary servo motor to drive the CNC machine tool to work The corresponding position and speed are adjusted by the platform, so as to realize the position and speed compensation function. The invention reduces the phenomenon of aggravated wear caused by repeated and rapid small-angle rotation of the lead screw, not only improves the reliability and service life of the lead screw, but also improves the compensation accuracy of the system, reduces the high requirements on the performance of the servo motor, and reduces the In order to reduce the cost, the device of the present invention can also be used as an auxiliary device for rapid feed and deceleration.

Description

technical field [0001] The invention relates to the field of error correction of a CNC machine tool servo system, in particular to a transmission error correction device and method for a closed-loop servo system of a precision CNC machine tool. Background technique [0002] The fully closed-loop servo system is mainly composed of a position speed comparison link, a servo drive amplifier, a feed servo motor, a mechanical transmission device and a linear displacement measurement device; it has the functions of detection and feedback correction for the movement of the moving parts of the machine tool, and adopts DC servo motor or AC Servo motors are used as drive components. The grating or inductive synchronizer installed directly on the workbench is used as the position detection device to form a high-precision full-closed-loop position control system. Through position detection and feedback, the system adjusts the position and speed of the servo motor through the comparison ...

AI Technical Summary

Problems solved by technology

The control and compensation of the position and speed of the workbench are realized by the rotation of the screw driven by the servo motor. The structure is simple, but various nonlinear factors such as the stiffness of the mechanical transmission device, frictional damping characteristics, and backlash have a great impact on the stability of the system. The impact makes the installation and debugging of the closed-loop feed servo system more complicated, so it is only used on high-precision and large-scale CNC machine tools

[0004] Even if the installation and debugging are careful, after using this compensation mechanism for a period of time, due to the slender lead screw and large moment of inertia, repeated and rapid small-angle rotations for error compensation will lead to increased wear of the lead screw and rotation at both ends. The rigidity of the pair decreases and the gap becomes larger, which causes the movement of the screw itself, so that when the full closed-loop system performs error compensation, it will drive the worktable to move through the screw nut, causing the error compensation of the closed-loop system to have a negative effect, the movement is intensified, and the speed is further accelerated. Vibration and wear of the lead screw are caused, and the accuracy cannot be maintained. In severe cases, the lead screw must be replaced, which reduces the reliability of the lead screw and reduces the service life of the lead screw

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