A full-closed-loop control system and method based on a sensorless servo press

Abstract

The invention belongs to the field of control technology and plastic forming technology, and in particular relates to a full-closed-loop control system and method based on a sensorless servo press. The electronic control system of the whole machine of the present invention is equipped with process curve interpolation algorithm, dynamic analysis and model building modules, nonlinear predictive controller and robust controller, and the speed observer without position sensor is used in the servo driver. grid viewer. The difference between the forming process curve and the actual position of the slider is used as the input of the dynamic analysis and model building module, and the given output torque is used as the parameter input of the robust controller, and the nonlinear predictive controller replaces the PI in the robust controller. Function, the output of the nonlinear predictive controller is the parameter input of the robust controller, and the output of the robust controller is used as the input of the Lunberg observer, and finally realizes the precise position control of the slider, which solves the problem of the position of the traditional servo press. There is a problem of overshoot in the control mode.

Description

technical field [0001] The invention belongs to the field of control technology and plastic forming technology, and in particular relates to a full-closed-loop control system and method based on a sensorless servo press. Background technique [0002] At this stage, in the field of metal forming, servo motor power system has been widely used, but it is used in a very different way. At present, the most commonly used servo press slider position control method is semi-closed-loop control, that is, the encoder is used as the sensor for the closed-loop feedback of the crankshaft angle, and the drive system is composed of a servo motor and a servo driver. The problem with this control method is that it does not use The actual position of the slider is used as the feedback object. The servo press consists of two power parts, the fine-tuning control unit and the main drive power system. The fine-tuning control unit can automatically adjust the mold or set the height of the closed ...

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Problems solved by technology

For example, the invention patent application CN102320157 of Yangzhou Zhike Opto-Mechanical Technology Development Center Co., Ltd. discloses a fully closed-loop control method and clearly writes a specific control process, but the control method of this servo press obviously has the following four defects : First, the control method of the bottom dead point adopts the comparison module and the threshold value module, which will cause the actual position of the slider to exceed the position of the bottom dead point, causing the workpiece to wrinkle or break easily; Control function, the servo driver does not adjust for other positions within the stroke range of the servo press, which will seriously affect the speed and efficiency of the stamping stroke; third, the patent uses the angle collected at the crankshaft as the bottom dead center control, Due to the multiple requirements of the assembly process, movement clearance and design tolerance of the servo press, there will be deviations from the crankshaft angle during the actual movement of the slider. This control method cannot solve such precision problems; The position signal of the feedback motor is easily affected by electromagnetic interference and noise, which will affect the control of the servo drive and reduce the reliability of the system

Fundamentally speaking, the control accuracy of the slider position of the servo press is still unsolved, and the system reliability is not very high

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