Development And Experimental Research Of Radial Micro-Vibration Assisted Grinding And Polishing Tool System

With the development of modern science and technology,high surface quality parts or components have become more and more widely used in the fields of national defense,biomedicine,aerospace,optoelectronics,etc.,and the requirements for surface quality are becoming higher and higher.For example,engine blades in the aerospace field,artificial prostheses in the biomedical field,and solar photovoltaic devices in the new energy field all have high requirements for surface quality.Whether it is possible to further improve the surface quality of parts and produce high-precision surface components has become an important criterion for measuring the manufacturing level of a country.To achieve high quality of the part surface,commonly used machining methods include grinding,polishing,and single-point diamond turning.The traditional grinding method uses fixed abrasive grinding.It is a grinding method that removes material by micro cutting at the front end of the abrasive grain and the surface of the workpiece.This method is difficult to obtain a mirror surface without cutting marks in principle and in actual operation.Therefore,to obtain a mirror surface without cutting marks through high-precision machining,a grinding and polishing method with free abrasives is currently required.In addition,in grinding and polishing,the positive pressure between the contact surface of the grinding and polishing tool and the workpiece is also an important factor that determines the processing quality.In order to improve the participation of abrasive particles in the grinding and polishing process and achieve a constant grinding and polishing pressure,a set of radial micro-motion-assisted pneumatic constant force grinding and polishing tool system is introduced in this paper.The radial micro-motion grinding and polishing tool system developed in this paper mainly includes three parts: radial micro-motion auxiliary subsystem,pneumatic compliant spindle subsystem,and spindle end motion platform subsystem.The radial micro-motion auxiliary subsystem is driven by two vertically placed piezoelectric ceramic stacks,and the force and displacement are passed to the grinding and polishing spindle through a flexible hinge,so that the grinding and polishing spindle produces a micron-level displacement in the radial direction.By controlling the piezoelectric The driving voltage of the ceramic stack makes the grinding and polishing spindle move regularly in the radial plane;the pneumatic compliant spindle system is composed of a cylinder,a force sensor,a displacement sensor,a motor,and a spindle.The grinding and polishing tool axis is realized by the feed motion of the cylinder output shaft Displacement compensation in the direction to achieve active compliance control of the grinding and polishing pressure;the motion platform subsystem at the end of the spindle consists of three linear motion modules to provide a square effective motion area for the upper end of the pneumatically compliant spindle to adapt to the processing of complex curved surface parts.With the help of Solidworks,this paper builds a three-dimensional model of the tool system,draws a two-dimensional engineering drawing of the required parts,completes the processing of the corresponding parts,and combines the hardware purchased with the selection to obtain the actual polishing tool system.The grinding and polishing tool system is mounted on a three-axis motion platform to form a radial auxiliary grinding and polishing experimental platform.The relationship between the force and displacement of the piezoelectric ceramic stack under low spring stiffness and the relationship between force and displacement under constant mass is deduced;and the modal dynamics analysis of the flexible hinge verifies that it can run smoothly within the operating frequency,No resonance phenomenon will occur;the unidirectional dynamic model of the micro-motion platform is established,the expression of the piezoelectric ceramic stack control voltage corresponding to the unidirectional target trajectory equation is derived,and the movement through the given target is proposed The method of obtaining the control voltage of the piezoelectric ceramic stack is obtained by reverse trajectory;a simplified model of the flexible hinge structure is established,and the relationship between the displacement of the flexible hinge in one direction and the position change of the center point of the moving platform is obtained.The output performance of the flexible hinge motion platform was verified by the Keyence displacement sensor test,and the law of displacement output coupling in the two directions of the flexible hinge motion platform was determined;the traditional PID control was built with the help of the RTW real-time control toolbox in MATLAB / Simulink System model and single neuron control system model,and completed the system debugging work,the system of traditional PID controller and single neuron controller built a system of grinding and polishing pressure control experiment.The experimental results show that the two control methods have ideal control effects when the system input value is unchanged or the change frequency is not high,and the single neuron control method follows the higher accuracy when the system input value changes frequently.The better output performance of the system is verified.