Li Jishun

Research on developed parallel two-wheeled robot and its control system

The parallel two-wheeled robot is a natural instability body, like traditional inverted pendulum, so it is necessary to use very effective control means to make it stabilize. The study on parallel two-wheeled robot emphasizes on walking balance control technology. In the paper the system configuration and mathematic modelling of the prototype are described. According to linear system theory, the state-feedback controller is designed based on Matlab simulation, and the stability of system is also proven by the simulation results. Finally, the validity and rationality of the system modelling and the designed controller are confirmed through the actual moving tests of the prototype.

Effect of Different Textured Surfaces on Lubricating Characteristics of Area Contact Friction Pairs

A theoretical analysis model was developed for area contact friction pairs with different micro-textures considering cavitation within the fluid film between two faces. Numerical simulation method was used to study the effect of geometric parameters of different micro-textures on the load carrying capacity and the friction coefficient. Results show that hydrodynamic lubrication problem of textured surfaces has been solved with a single-dimple model and a multi-dimple model. The tendency of the multi-dimple solutions is similar to that of the single dimple model, but the magnitudes of load capacity and friction coefficient are different.

Method of three-point for measurement error of microstructure table three dimension motion based on machine vision

Based on machine vision, the paper describes a new method that measurement error of six degrees of freedom microstructure table 3D posture. The method can measure the place and stance of 3D targets by monocular vision. Make centre of three fixed standard small spheres at microstructure table as mark points characterize the pose of table in 3D space. The fixed camera trace the spheres at table by vision in 3D space and measure quantitative changes of spherespsila position and diameter in eyeshot then ascertain the 3D coordinates spheres centre. Build the mapping model from image space to natural space. In this way we can ascertain the posture of table in 3D space and measure the kinematics error of table at every sampling time.

Multibody Dynamics Modeling of Friction Winder Systems Using Absolute Nodal Coordination Formulation

The aim of this study was to develop an efficient and realistic numerical model in order to predict the dynamic response of the friction winder system. The absolute nodal coordinate formulation is an ideal approach for the modelling of friction winder systems. In this study, the rope was modelled as a planar beam element based on an absolute nodal coordinate formulation. The rope element allows the user to control the axial and bending stiffness through the use of two parameters. In this study, the interaction between the rope and the rotating drum is modelled using an elastic approach in which the contact is accounted for by the inclusion of a set of external forces that depend on the penetration between the rope and rotating drum. This made it possible for us to accurately predict the contact forces, including the stick and slip zones between the rope and the drum. Finally, the applicability of the friction winder model was presented and discussed.

Mesh Searching Algorithm for Evaluating Cylindricity Error

A new kind of method of evaluating cylindricity error, which named as Mesh Searching Algorithm (MSA), has been presented in this paper. The optimization method and linearization method usually used are not be adopted in this algorithm. The value of cylindricity error can be obtained through calling repeatedly the formula for distance between the point and straight line and the simple judgement using this algorithm. The principle and step of using the algorithm to solve the cylindricity error is detailed described. The simulation reveals that the cylindricity error can be evaluated effectually and accurately by using this method.

Control of Analogue Scan Probe in CMM Inspect of Spiral Bevel Gear

In the context of three-dimensional 3D coordinate metrology, CMM (coordinate measuring machine) have been widely adopted as general-purpose tools that have the capability of inspecting various mechanical components having complex topology and geometry. The recent developments in spiral bevel gears (SBGs) manufacturing system have made the traditional dimensional inspections bottlenecks in the production line. To overcome these bottlenecks, computer integrated dimensional inspection was proposed with the CMM being the key device. In this investigation, a framework for integrating the CMM into CAD/CAM environment is developed. In order to achieve a higher level of automation, CAD-directed inspection planning is essential. First of all, due to the distinct characteristics of various probes in terms of resolutions, digitizing speed and spatial range, The CMM probes have to be selected and controlled properly. A motorized head gives a DCC CMM the added capability of probe reorientation, allowing the probe to inspect features at the optimum angle, considering access requirements and probing best practice. An algorithm to generate an optimized control of analogue scan probe in CMM inspect of spiral bevel gear is proposed. The proposed algorithm is implemented using PC-DMIS as the CMM software system and PH10M+SP600M as the analogue scan probe system. The effectiveness of the proposed algorithm is verified by the results of the implementation

A new method of error compensation for numerical control system

This paper presents a method of rapid machine tool error modeling, separation, and compensation using grating ruler. A robust modeling procedure for geometric errors is developed and a fast data processing algorithm is designed by using the error separation technique. After compensation with the new method, the maximum position error of the experiment workbench can be reduced from 400 µm to 15 µm. The experimental results show the effectiveness and accuracy of this method.

超声场中脉冲电沉积Ni-CeO 2 纳米复合镀层的耐蚀性

在超声场中用脉冲电沉积法制备了Ni-CeO 2 纳米复合镀层, 考察了镀层中CeO 2 含量及表面形貌,研究了镀层在10wt%HCl溶液中的耐蚀性, 分析了超声作用下脉冲参数对镀层耐蚀性的影响. 结果表明：脉冲参数和超声波对镀层中CeO 2 含量和微观组织均有影响, 适宜的脉冲参数可以提高镀层中CeO 2 含量,细化镀层晶粒, 而超声波可促使镀层晶粒进一步细化; Ni-CeO 2 纳米复合镀层的耐蚀性与镀层中CeO 2 含量、镀层晶粒大小及组织致密程度有关; 在占空比0.2、脉冲频率1000Hz时超声作用下制备的镀层中CeO 2 含量较高, 镀层晶粒细小、组织致密, 腐蚀速率最低, 表现出优良的耐蚀性.在超声场中用脉冲电沉积法制备了Ni-CeO 2 纳米复合镀层, 考察了镀层中CeO 2 含量及表面形貌,研究了镀层在10wt%HCl溶液中的耐蚀性, 分析了超声作用下脉冲参数对镀层耐蚀性的影响. 结果表明：脉冲参数和超声波对镀层中CeO 2 含量和微观组织均有影响, 适宜的脉冲参数可以提高镀层中CeO 2 含量,细化镀层晶粒, 而超声波可促使镀层晶粒进一步细化; Ni-CeO 2 纳米复合镀层的耐蚀性与镀层中CeO 2 含量、镀层晶粒大小及组织致密程度有关; 在占空比0.2、脉冲频率1000Hz时超声作用下制备的镀层中CeO 2 含量较高, 镀层晶粒细小、组织致密, 腐蚀速率最低, 表现出优良的耐蚀性.

Development of Lebus groove CNC based on PMAC

Lebus groove can realize multilayer and orderly winding of wire, so it is widely used in hoisting equipment. But these types of grooves are difficult to manufacture in average lathe. Coping with this situation, the paper developed the Lebus groove CNC system based on PMAC. The hardware components, system functions, software programming and other key technologies are introduced in this article. The application result indicates that this system fully meet the requirement of Lebus groove manufacturing.

Reverse modeling of the small modulus internal gear based on CMM inspecting

An internal gear planetary transmission is an innovative type of transmission with unique advantages over traditional gear transmissions. However severe vibration, premature fatigue of bearings, high level of noise and heat producing caused by the precision of the internal gear block its further application in industry. In order to understand and solve these problems finally, it is pressingly necessary to investigate the dynamics of IGPT systematically and improve the precision of the internal gear. It is important to inspect the internal gear exactly with coordinate measuring machine (CMM). In this paper, the CMM inspect path planning of the small modulus internal gear is developed and measuring experiments is carried out. The result has been used to reconstruct the 3D model of the internal gear.