Li Yong Hu

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.

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.

Fuzzy-PID Control of Electronic Controlled Diesel Engine

In order to satisfy the demand of increasingly stringent emission regulations and enhance fuel economy and increase dynamic performance of vehicle diesel engine, the working parameters of electronic controlled diesel engine should be changed properly. An electromagnetic actuator controlled system was designed based on DSP56F807. The control strategy of fuzzy-PID and fuzzy control model for electro-magnetic actuator was established. The control effect of fuzzy-PID for electro-magnetic actuator and diesel engine was validated through experiment. Experimental results showed that good static and dynamic control effect can be obtained using fuzzy-PID control method.

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.

Direct Pulse Signal Interpolation for Robot Movement Control Programming in INFORM III Language

First it sets up a kinematical model for a kind of industrial robots by D-H notation, and inverse kinematics solutions of its end effector are deduced according to its motion trail. By transforming the rotation angles of the robot’s joints into impulse signals, pulse signals could be used to interpolate its motion trail. Finally, it uses Matlab software to join various curve of each joint impulse signal, and formulation a mathematical model about various curve of each joint impulse signal. In this way, it could simplify program in INFORM Ⅲ language. Simulation shows that direct pulse signal interpolation improves the accuracy of trajectory positioning.

Application of Genetic BP Algorithm in Low Strain Test of Pile Integrity

This paper puts forward a neural network algorithm in pile integrity test on the basis of field data and the strengths of genetic algorithm and neural network algorithm. The result proves that it has faster convergence speed than simple BP algorithm, which can avert the artificial intervention during the data handling procedure and improve the reliability of the test result.

Design and Analysis of a Novel Magnetorheometer

Rheology is an important property of MRF (Magnetorheological fluids) and an important basis for designing a MRF device. For researchers and engineers, therefore, a practical and reliable magnetorheometer is certainly required for the study and application of the MRF and its devices. In this paper, the principle of a novel magnetorheometer was introduced, the structure and the function of major components were explained, the test process for the rheological property of the MRF by using this magnetorheometer was illustrated, the distribution of the electromagnetic field in the gap, where the MRF is filled, was analyzed by means of ANSYS software tools, and experiments were conducted to ascertain the validity of the magnetorheometer.

Design of MRF-Damper-Based Experimental System for Steer-by-Wire Force Feedback Study

In order to meet the requirements of research on steer-by-wire force feedback, a MRF- damper-based experimental system was developed. In the paper, the necessity of the experimental system was analyzed, the general structure and hardware components were introduced. The design of the rotary MRF dampers was illuminated in detail. Experiments showed that the MRF-damper-based haptic system can be used for the study of automobile steer-by-wire system.

A Novel MRF-Based Torque Servo Device

In mechanical equipments or manufacturing processes, force control is definitely required to achieve desired performance or to ensure product quality. Aiming at this issue, this paper introduced an author-invented torque servo device that utilizes magnetorheological fluids (MRF) to provide a controllable torque. In the paper, the structure and working principle of the MRF-based torque servo device (MRT) were introduced, the constitutive model and the characteristics of the MRF were established and discussed. On the basis, the static and dynamic models of the MRT were both analytically and experimentally studied, and the control of the output torque of the MRT was demonstrated. As an example, the application of the MRT to the polishing of aspheric surfaces was presented in the end.

Implementation of Wavelet Analysis Program Using a MATLAB- Generated Dynamic Link Library in Visual Basic Programming

Abstract: This paper describes mainly about using the technology of DLL to realize merging programming , integrating the visual interface of VB and the wavelet analytical function of Matlab. Design of simulation software shows the implementation approach provides a novel idea for the application of wavelet analysis.