Research On Resonance Suppression Method Of Linear Servo Device

Servo systems or servo devices are generally required for the manufacture and normal operation of palletizing machinery,packaging machinery and sorting machinery.Because of this,servo technology has become one of the key technologies in mechanical system design.The huge market demand has promoted the rapid development of servo technology.This paper studies the linear servo device,which is a kind of linear feed servo system driven by linear motor.Linear servo system is very important in palletizing machine,packing machine and sorting machine.Even in CNC machining centers and some industrial robots,the use of linear servo devices is also indispensable.The application of linear servo device in various mechanical systems has many performance requirements.If the linear travel of the mechanical system is short,the linear servo device is needed to provide accurate position control and ensure accurate start-stop,which indirectly involves the instantaneous speed pull-up and drop.For the linear servo system itself,not only the control scope should be large,the dynamic characteristics should be good,and the position accuracy should be high,but also the stiffness should be higher to avoid the resonance caused by the implementation of the control process.The main research work in this paper is as follows:Firstly,the experimental platform of the self-built linear servo device and the linear motor in the device are given.Then,the working principle of the linear motor is expounded from three aspects:voltage equation,thrust equation and mechanical equation.The mathematical model of this kind of motor is constructed.Second,a controller is designed for the linear servo system in this paper.In the overall structure of the controller,the current loop and the position loop play a controlling role together.The current loop acts on the torque control of the linear motor through the actuator,while the position loop provides input for the current loop before the current loop.Thirdly,the mechanism of mechanical resonance is studied,and the position of mechanical resonance of linear servo device is determined at 220 Hz by experiment.The influence of key parameters and load quality on the dynamic stiffness of linear servo system is analyzed.The experimental results show that the increase of proportional gain,integral frequency and differential frequency will lead to the increase of the dynamic stiffness of the system;the increase of load quality will lead to the decrease of the dynamic stiffness of the system and the induction of resonance.The linear servo system in this paper is due to the load quality.The frequency of resonance is about 150Hz.Fourthly,the resonant suppression mechanism of notch processing is analyzed,and a control structure based on Notch processing is proposed for the mechanical resonance of the linear servo device in this paper.The resonance suppression mechanism of integral processing is analyzed,and a control structure based on integral processing is proposed for load-mass resonance of linear servo system in this paper.The experimental results show that the resonant suppression model of notch processing and integral processing is proposed,which can effectively suppress the mechanical resonance and load mass resonance of linear servo system.