Jian Ming Zhan

Research on the Automatic Programming System for Industrial Robots in Free-Form Surfaces Polishing

Because of the industrial robot’s advantages and characteristics of degree of freedom, it is broadly applied in mold and die of curved surfaces polishing. But its excessive degree of freedom also brings great difficulties in programming for there is CAD/CAM software can do it well. By analyzing the ISO NC code and robot’s programming criterion, this paper develops off-line programming software for industrial robots in free-form surfaces polishing.

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.

Study on Compliant Control by Cutter Radius Compensating for Rotating Curved Surfaces Polishing on NC Lathes

. Lots of new automatic polishing methods and equipments have been developed to solve the problem of low efficiency and quality in the traditional handwork curved surfaces polishing. However, these methods and equipments are complex and difficult to be applied in the industrial production. This paper proposes a new technology of rotate surface compliant polishing based on NC lathe cutter radius compensation. An efficient and compact rotate surfaces compliant polishing system is developed, which consists of a NC lathe, flexible polishing tool, workpiece, fixture and also the automatic programming software MASTERCAM. The polishing tool-path and NC code can be created in MASTERCAM. The value of the cutter radius compensation can also be set in NC code, so that the rotated surfaces can be polished by a traditional NC lathe. Experiment of polishing the aluminum sphere workpiece is taken, and the satisfying surface quality is achieved.

Study on NC Compliant Bonnet Tool Abrasive Polishing Based on Magnetorheological Torque Servo

In this paper, a NC compliant abrasive polishing system was developed based on a magnetorheological torque servo (MRT), using a bonnet as the polishing tool. The MRT was uesd to provide a load acting on bonnet tool to produce the polishing force. In order to find the factors affecting the polishing quality, the models of the applied load, polishing force and contact pressure between the bonnet and the part were established based on Hertz theory, and the factors affecting the contact pressure were analyzed. Theoretical analysis indicated that there was a significant effect of the applied load, the initial pressure of the bonnet and the radius of curvature of the part on contact pressure. Experiments were carried out to verify the validity of the models, and experiment results showed that the roughness of the part was improved greatly and the polishing efficiency could be controlled by changing the initial pressure of the bonnet and applied load.

Study on Experiments of Nano-Abrasive Polishing in Hydrodynamic Suspension Liquid

When nano-abrasives of high speed polish work-piece, they cut it and crush it and there are brittle fracture and surface distortion. For work-pieces of hard-brittle materials, there should be no surface distortion. Therefore, the efficiency of nano-abrasives polishing work-pieces of brittle materials should be much lower than that of metals. In this paper, work-pieces of Cr12MoV and glass K9 are polished by nano-abrasives driven by high speed hydrodynamic suspension fluid to study how it works. The experiments show that the efficiency of nano-abrasives polishing work-pieces of hard-brittle materials is much higher than that of metals.

Study on Path Planning for Industrial Robots in Free-Form Surfaces Polishing

Expected path of polishing tool is one of the most essential needs for movement scheduling and movement controlling of polishing robot in free-form surfaces polishing. By analyzing the expected movement and position of polishing tool and based on the traditional movement scheduling methods, this paper carries out systematic research works on contour-parallel-machining tool path planning method and direction-parallel-machining tool path planning method for polishing tool paths figuring out. Compared with contour-parallel-machining tool path planning method, the direction-parallel-machining tool path planning method needs one less number of degree of freedom and is much easier to avoid physical interventions and mechanic singularity, so it is an improved one.

Steer-by-Wire Force Feedback System Based on Magnetorheological Fluid Damper

In order to achieve the performance of the steer-by-wire force feedback based on magnetorheological fluid (MRF) damper, an experimental system was developed. The aligning torque model and the return model based on MRF damper were built up. The general structure and hardware components were introduced. The change course of feedback force is achieved followed the change of the current of the MRF damper. Experiments showed that the force feedback system based on MRF damper can be used for automobile steer-by-wire system in the little angle.

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.

Development on Shape-Adaptive Compliant Tool System

A new shape-adaptive compliant tool system is developed in this essay, which can be effectually integrated with industrial robots and five-axis NC machines. The main principle of the above compliant tool system can be described as follows: a passive servo mechanism of bi-directional rotating sphere hinge, working with the robots to control the tool-path which can meet the requirements of the adaptive capability on free-form surfaces. The normal polishing force could be controlled by the designed linear stepping motor and column helix spring system. The virtual prototyping of the tool system is created in ADAMS, and used to take the simulating experiments on workpieces which have typical free-form surfaces. The experimental results indicate that the tool system developed in this essay performs well on shape-adaptive capacity on free-form surfaces.

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.