Second-order sliding mode control system of direct drive servo system and its control method

Abstract

The invention discloses a second-order sliding mode control system of a direct drive servo system and a control method of the -order sliding mode control system. The method is characterized in that a position controller is designed by adopting a second-order sliding mode method of a hybrid non-singular terminal, so that the problem of singularity of a terminal sliding mode is solved, and a linear sliding mode surface is introduced to accelerate the system convergence rate. Through adding the second-order sliding mode, a control acts on a differential of higher order of a variable, so that the buffet phenomenon of the system can be weakened. In addition, through designing a self-adaptive controller, a control gain is dynamically adjusted and limitation of the control gain in need of an uncertain boundary is overcome. The whole control system hardware part comprises three parts of a main circuit, a control circuit and a control object, wherein the control circuit comprises a DPS (Data Processing Station) processor, a current sampling circuit, a rotor position sampling circuit and an IPM (Intelligent Power Module) isolation drive protection circuit, and the main circuit comprises a voltage regulation circuit, a rectifier filter unit and an IPM inverter unit. The method is finally implemented by a control program embedded in the DPS processor.

Description

technical field [0001] The invention belongs to the technical field of numerical control, and relates to a direct drive servo system hybrid non-singular terminal second-order sliding mode control method and system. Background technique: [0002] For half a century, although the feed drive technology has undergone changes, the basic transmission form is still "rotary motor + ball screw" for a long time, and it is difficult to meet the requirements of high speed, high precision and technical production. With the improvement of progress and processing quality and efficiency requirements, linear motors have been well applied in the field of machine tools. [0003] The traditional feed system has its inherent disadvantages. Since the traditional servo feed method is composed of "rotary motor + ball screw", the rotational motion of the motor must go through a series of intermediate transmission links to become the linear motion of the skateboard and props. As a result, the stiffn...

AI Technical Summary

Problems solved by technology

The sliding mode indicates that the system has a special mode, and the variable structure indicates that the structure of the controller will change. The basic principle is to design a sliding hyperplane sliding mode in the state space of the system first, so that the system on the sliding mode has stability And good dynamic performance; redesign the controller to make the system reach the sliding mode in a limited time. When the system state passes through the sliding mode, the controller structure changes to keep the system moving on the sliding mode. Traditional variable structure control adopts linear Sliding mode, after the system reaches the sliding mode, the tracking error asymptotically converges to zero, and the speed of asymptotic convergence can be adjusted by selecting the sliding mode parameters, but no matter how it is adjusted, the state tracking error will converge indefinitely

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