Polishing Tool System Research Articles

Development of a real-time force-controlled compliant polishing tool system with online tuning neural proportional–integral–derivative controller

This article presents a real-time force-controlled pneumatic compliant polishing tool with self-supplied abrasives making the abrasives added to the contact area between the polishing pad and workpiece, which can lead to good polishing performance. And a force–position decoupling pneumatic servo system for polishing force control is presented to solve the problem of force–position coupling in the traditional polishing process. However, it is difficult to realize satisfactory control performance due to the problems of time variance, compliance, hysteresis and nonlinearity in pneumatic servo system. This article proposes an online tuning neural proportional–integral–derivative controller to improve force control performance. The real-time polishing force control results of pneumatic servo control system are investigated by adopting proposed neural proportional–integral–derivative control strategies with data acquisition card and RTW toolbox in MATLAB/Simulink. The real-time experimental results of polishing force control indicate that the excellent control performance can be achieved by the proposed neural proportional–integral–derivative controller no matter the reference force is constant or varied. Compared with those by traditional proportional–integral–derivative controller, the duration for stabilizing the polishing force is shorter and the error between the output force and the reference is smaller by the proposed neural proportional–integral–derivative controller.

Study on Polishing Tool Contact Deformation for Large Robotic Aspheric Surface Compliant Polishing

Due to the problem of the mutual interaction between the polishing tool system and the control of poses and positions, it is difficult to hybrid-synchronizationally control the polishing force, the posture of polishing tool head and the polishing trajectory. So the article designed a set of compliant tools that take the pneumatic servo system as the control system, which was used for active polishing aspheric surface of Robot. It was to accomplish the Robots self-adaptive control to the posture of the polishing tool as well as to figure out the correlation of the contact deformation between the polishing tool and the work piece surface, which makes a theoretical analysis on dynamic and steady characteristics of the contact deformation of the tool system. It applied the meek and polishing tools to the polishing processing of the rough machining of large aspheric surface samples to obtain the data. According to the statistics, the polishing tools can effectively solve the problem of the mutual interaction between the polishing tool system and the control of poses and positions. It also owns good adaptive ability and its machining aspheric surface quality can achieve nanoscale.

Ballonet Polishing of Aspheric Part Based on MRF Torque Servo

This paper proposed a new ballonet polishing method for the precise polishing of aspheric parts. The method is based on the integration of a MRT (Magnetorheological fluid Torque servo)-based ballonet polishing tool system and a CNC lathe. By using this method, the decoupling control of force-position-posture can be realized in polishing process. The structure and working principle of the polishing tool system were introduced. The material removal model for ballonet polishing was established according to Preston Equation. The main factors affecting the material removal were discussed, and the control model of uniform removal was put forward.

Stability Analysis of the MRT-Based Compliant Polishing Tool System

In order to meet the needs for the precise polishing of free-form surfaces, a new compliant polishing tool system was designed based on a magnetorheological torque servo (MRT), and integrated into a CNC milling machine. Through analysis, it was pointed out that the key factor affecting the polishing quality of this system is the stability of the system. By means of the 3D geometric modeling software ProE, the finite element analysis software ANSYS, and the dynamic simulation software ADAMS, the rigid-flexible mixed model of the system was established and the stability of the polishing pressure and tool position was numerically analyzed.

The Application of the TCP/IP on the Robot System

This paper puts forward a control model that is made up of the series robot, the parallel moving platform and the polishing tool system and so on. In order to realize the communication between the two robots in the robot system, a wireless LAN access point for establishing wireless LAN of two robots communication is first provided. In the end, the mutual communication can be accomplished by two robots and the robot position and status information can be transported with programming of the win socket. The satisfied polishing effect on the curved surfaces can be obtained and the demand of the polishing can be achieved.

The Collaboration Control for the Multi-Robot Polishing System

This paper puts forward a multi-Agent alliance control model that is made up of the series robot Agent, the parallel moving platform Agent and the polishing tool system Agent and so on by the MAS theory. Based on the multi-robot system which is made up of the MOTOMAN - HP3 serial robot and NPT800 parallel robot, the MOTOMAN-HP3 serial robot communication, the NPT800 parallel robot of motion control and communication between two robots are introduced respectively. In the end, the mutual communication can be accomplished by two robots and the robot position and status information can be transported with programming of the win socket. The satisfied polishing effect on the curved surfaces can be obtained and the demand of the polishing can be achieved by the MAS.

Study on Force Control in Abrasive Polishing of Aspheric Parts

Aspheric parts are attracting many researchers’ attention for their excellent optical properties. The commonly used manufacturing technology for aspheric parts are mainly based on dedicated high precision machines, resulting in high cost and restricted application fields. To polish this kind of parts on general CNC machine tools, however, the surface quality improvement is limited due to the problem of force-position coupling. In order to solve this issue, a force-position decoupling control method for abrasive polishing was studied, a corresponding comliant polishing tool system was developed, and the mathematical model of the tool system was established. In addition, a polishing force controller was designed, and the performance of the tool system was numerically simulated. Simulation results showed that the polishing tool system can effectively achieve the tasks of force-position decoupling and the stable control of the polishing force.

The Series-Parallel Robot Coordinates Polishing System Based on the Multi-Agent

This paper puts forward a multi-Agent alliance control model that is made up of the series robot Agent, the parallel moving platform Agent and the polishing tool system Agent and so on by organically introducing the MAS (Multi-Agent System) theory into the polishing. Through the introduction of point-curve constraint, the dynamics equation of the constraint multi-body for the polishing system is established in order to accurately program the moving track of the robots. Meanwhile, the control parameters during the polishing can be optimized and the foundation can be afforded for carrying out the collocation of the optimal parameters with the series-parallel coordinates polishing and programming the optimal path on the free-form surface.

Process optimization of the serial-parallel hybrid polishing machine tool based on artificial neural network and genetic algorithm

A kind of serial-parallel hybrid polishing machine tool based on the elastic polishing theory is developed and applied to finish mould surface with using bound abrasives. It mainly consists of parallel mechanism of three dimensional moving platform, serial rotational mechanism of two degrees of freedom and the elastic polishing tool system. The active compliant control and passive conformity of polishing tool are provided by a pneumatic servo system and a spring, respectively. Considering the contradiction between the machining quality and efficiency, the optimization model of process parameters is found according to different machining requirements, namely single objective optimization and multi-objective optimization, which provide a choice of parameters as a basis for the operators in practice. Many polishing experiments are conducted to collect the data samples. The genetic algorithm integrated with artificial neural network is used for researching for the optimal process parameters in term of the various optimization objectives. This research also lays the foundation for further establishing polishing expert system.

The Dynamics Analysis of the Robot Polishing System by the Multi-Agent System

In order to solve the confliction among the working space, precision and stiffness on the free-form surface, this paper puts forward a Multi-Agent alliance control model that is made up of the series robot Agent, the parallel moving platform Agent and the polishing tool system Agent and so on by organically introducing the MAS (Multi-Agent System) theory into the polishing. Through the introduction of virtual point-curve constraint, the dynamics of the constraint multi-body equation for the polishing system is established in order to accurately program the moving track of the robots. Meanwhile, the control parameters and the optimal path during the polishing can be optimized.

Development of Compliant Tool System of Digitalized Precision Polishing for Aspheric Surfaces

Aspheric surfaces of high precision and low roughness are widely used in the military field, the aeronautics and astronautics field and some high-tech fields. Therefore, research works on the methods and equipments of digitalized polishing for aspheric surfaces are a hot issue in the modern precision manufacturing. The traditional precision manufacturing mainly depends on the higher precision equipments to promote the surface quality of aspheric surfaces, but the cost of equipments seems to be extremely expensive. Taking the general CNC lathe of two axis interpolation as a platform, and basing on the controllable damping characteristic of the Magnetorheological Fluids (MRF), a new kind of compliant polishing tool system for aspheric surfaces is developed in this paper. The tool system keeps the polishing force to be stable by the torque servo unit of MRF, and implements the compliant polishing.

RESEARCH ON POLISHING PROCESS OF A SPECIAL POLISHING MACHINE TOOL

In this paper, a serial-parallel hybrid special polishing machine tool based on the elastic polishing theory is developed, which is used for polishing mould surface by using bound abrasives. This machine tool mostly consists of parallel mechanism of three-dimensional moving platform, series rotational mechanism of two degrees of freedom and elastic polishing tool device. The parallel mechanism controls the spatial position of the polishing tool. The series mechanism controls the pose of the polishing tool. The elastic polishing tool system can realize active control by a pneumatic servo system and passive conformity by a spring. The main process parameters that have influence on surface roughness and polishing efficiency are tool speed, feed rate, force, pose angle and polishing number of times. Optimal combination of process parameters is presented by the Taguchi and grey relational analysis, which provide a choice of parameters as a basis for free-form surface polishing in practice.

Research on the Hydrodynamic Electro-Chemical Mechanical Polishing for Silicon Wafer with Suspension Fluid

Silicon wafer is one of the key materials of LSI and SLSI and has been widely used in the electronic industries and IT products. In the new century of nano times, silicon wafer needs higher geometry accuracy, lower surface roughness and higher precision machining effecency, but no disfigurement in its surface layer. Nowadays, non-contact polishing still seems to be most efficient method to achieve nano-scale geometry accuracy and maintain surface roughness in the nanometer level even for silicon wafer, but it is still not easier to control its machining course and to obtain well-pleasing machining effecency. In this paper, a hydrodynamic electro-chemical polishing system based on CNC is established with micro-displacement compensating for nano-scale polishing. A new type of compliant polishing tool system is developed, which can turn orthogonal force control subspace and position control subspace to isomorphic position servo space. Moreover, it convert force control deflection to position servo deflection and in this way the polishing force is controlled by micro-displacement compensating with piezoelectricity. Polishing experiments on silicon wafer, in hydrodynamic polishing fluid mixed with nano-scale SiO2 abrasive particles, have been conducted to investigate the fundamental machining mechanism.

Research on hydrodynamic suspension nanoscale polishing for K9 optical glass

In this paper, a hydrodynamic suspension nanoscale polishing system based on Computer Numerical Control (CNC) is established. A new type of compliant polishing tool system is developed, which can realise nanoscale displacement compensating. Also polishing experiments on K9 optical glass, using the polishing fluid mixed with nanoscale SiC abrasive particles, have been conducted to investigate the fundamental machining mechanism. A high-quality surface without crystallite dislocation and micro cracks is achieved. It is shown that the removal of atomic layers size can be done by colliding nanoscale abrasive particles with the workpiece surface.

Research on the Inverse Dynamics of the Flexible Multi-Body Systems for the Hybrid Polishing Kinematics Machine Tool

The hybrid polishing kinematics machine tool (HPKMT) which is made up of “3 axes parallel + 2 axes series” is developed with the specially designed elastic polishing tool system for the polishing operation on the free-form surfaces by using the characteristic of the elastic polishing adequately by the authors. In order to control the HPKMT effectively, its characteristic of the kinematics and dynamics need be known deeply. Moreover, the problem of inverse dynamics is the theory foundation to apply dynamic control of the HPKMT. The analysis of the inverse of mechanism is the important part in the research of dynamics. On the basis of the differential equations of flexible multi-body dynamics, this paper discusses on the condition of knowing the trace, posture and velocity for the end of bodies how to solve the constraint force and constraint moment of each joint on the 3- PTT parallel mechanism and two-joint series mechanism.