Full closed-loop control system and method based on servo press without sensor

Abstract

The present invention belongs to that technical field of control and plastic forming, and particularly relates to a full closed-loop control system and method based on a servo press without a sensor.The whole electric control system of the present invention is provided with a process curve interpolation algorithm, dynamic analysis and model building module, a nonlinear prediction controller and arobust controller; a speed observer without a position sensor is adopted in a servo driver, including a Luenberger observer. The difference between a process forming curve and the actual position ofa sliding block is input into the dynamic analysis and model building module, the given output torque is taken as the input parameter of the robust controller, the nonlinear prediction controller replaces the function of PI in the robust controller, the output of the nonlinear prediction controller is taken as the input parameter of the robust controller, and the output of the robust controller istaken as that of the Luenberger observer, so that the position of the sliding block is precisely controlled, and the problem of overshooting in the position control mode of the traditional servo press is solved.

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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