Research And Design Of The Constant Force End-Effectors For Grinding And Polishing Robot

In today's market growing demand for high surface precision products,production enterprises through deburring,grinding,polishing,such as surface treatment,reduce the surface roughness,machining parts for high quality mould products.Before processing production enterprise is usually implemented using artificial polishing grinding operation,this way not only time-consuming and manual polishing grinding processing cannot assure consistency,work environment pollution.Manual polishing and polishing have been gradually abandoned,and it is commonly used in manufacturing enterprises to use highly automated polishing robot systems.The robot system can reduce the production cost and improve the processing quality and efficiency.According to the polishing process,the relative force between the polishing tool and the processing parts,namely the polishing force,will significantly affect the polishing accuracy of the product.Therefore,how to control the contact force between the polishing tool and the machining parts is constant,and the constant force grinding is very important to obtain the high quality polished surface.The main objective of this project is to design a kind of polishing robot end-effector,to achieve the requirement of high precision machining in the process of polishing and polishing.This paper introduces the research significance and research status of the end-effector of constant force grinding.For constant force control,the method of fusion of multiple control strategies is a novel idea.In this paper,a mechanical structure of the end-effector with constant force is proposed,and the 3d modeling of the device is made by using Solidworks drawing software,and the mechanical model of the end-effector of the constant force is established.The constant force grinding end actuator consists of buffer cylinder,proportional control valve,solenoid valve,controller and force sensor.The open loop mathematical tra nsfer function of the control system is derived by mathematical modeling of components in the constant force end-effector system.On this basis,four control algorithms including traditional PID control,pure fuzzy control,pid-fuzzy control and sliding mode variable structure control are analyzed and studied.Based on Simulink tool in Matlab,the system step response curves of traditional PID controller,pure fuzzy controller,pid-fuzzy controller and synovial variable structure controller are explored.The simulation results show that the stability and reliability of the traditional PID controller are poor and the robustness is not good enough.It is difficult to control the steady-state error of the pure fuzzy controller,and the tracking of the expected instruction cannot be realized.The controller of sliding mode variable structure controller can track the expected instruction,but the response to step instruction will generate buffeting.The PID-fuzzy controller can track the expected instruction well,the response curve is smooth,and the dynamic response and the following robustness of the control system are significantly improved.Finally,the initial set up of constant force grinding end executor experiment platform,a preliminary test,the platform can be gathering force sensor signal output control signals,and the cylinder to control the output of the cylinder,so as to lay a foundation for the test of constant force control.