Xue Yujun

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.

Analysis on Kinematics and Dynamics for A Planar Flexible Driving Target Motion Simulation System

The flexible drive have made tremendous inroads into many industrial fields. This paper focuses on the kinematics and dynamics analysis of a planar flexible drive target motion simulation system. The kinematics and dynamics mathematical models of the planar flexible driving target motion simulation system are established. On the basis of this, the simulation analysis of the trajectory of the circle was carried out. The motion law and stress condition of flexible cable under given trajectory are obtained by simulation. The correctness of the model is proved theoretically, and it lays the foundation for further research on precise control. Introduction Recently, the flexible drive parallel mechanism has made great progress in many industrial fields[1]. For example, researchers from around the world have developed the product processing, port handling, sea fishing, large diameter Radio Telescope Tracking source motion, aircraft model wind tunnel test of cable driven parallel mechanism prototype[2]. The flexible driving mechanism uses flexible cable instead of the traditional rigid connecting rod[3]. Compared with the traditional rigid drive mechanism, the flexible drive mechanism is simple in structure and high in control accuracy, and different configurations and degrees of freedom can be constructed according to the requirements[4]. Among all these benefits, keeping flexible tension is one of the fundamental challenges of flexible transmission. On the other hand, the flexible cable can only exert tension and can not push the moving target[5]. Moreover, due to the flexible cable itself is flexible, its dynamic trajectory will deviate from its equilibrium position [6]. Under the effect of the outside world, due to the stiffness of flexible drive is smaller, even long rope change very slowly, the moving target vibration also can appear around its equilibrium position[7]. Therefore, it is very important to analyze the kinematics and dynamics of the flexible cable drive simulation system[8]. Regarding the above preamble, the kinematics and dynamics analysis of the flexible cable drive simulation system is carried out. The relationship between the position of moving target and the speed and acceleration of flexible cable and the length of flexible cable is obtained, and the force condition of the flexible cable is obtained when the moving target is in any position. Kinematics and Dynamics Modeling of the Under Study Flexible Drive Simulation System In this section, kinematics and dynamics analysis are carried out for the plane flexible drive target movement simulation system. Fig.1 shown the model of the plane flexible drives the target motion simulation system. The four flexible drive units drive the release of the cable, and control movement targets in the plane X direction and Y direction. The main components of the flexible drive simulation system include the driving part, the measuring part and the control part. The four driving units are fixed in the four corners of the experimental apparatus. Each driver unit includes the servo motor, reel, 7th International Conference on Social Network, Communication and Education (SNCE 2017) Copyright

Gesture detection and data fusion based on MPU9250 sensor

A gesture detection system designed with MPU9250 sensor and MSP430F149 processor was introduced in this paper. The attitude angle can be measured with internal gyroscope sensor, accelerometer and electronic compass of MPU9250, and data fusion analysis was realized by using the optimization Kalman filter algorithm. The attitude angle noise was suppressed and the accuracy of the gesture detection was improved. The system can perform 100-time detections per second with fast response characteristics. The system was used in self-balanced robot successfully for motion gesture detection.

The Measurement of Micro Platform's Position and Pose Based on Monocular Visual

This paper put forward an algorithm to measure the position and pose of the six degrees of freedom micro-platform based on monocular visual. Firstly, the micro-platform is abstracted for the Cuboid. We solid the Cuboid which knows its initial position and pose with the world coordinate system together, and select vertices and edges as the feature elements from the Cuboid. The feature elements can be traced by the fixed single camera in 3D space. According to the relationship between working micro-platform and camera model, we can get the position and pose of micro-platform in three-dimensional coordinate.

An Edge Detection Method Brought to Videogrammetric Systems for Micro-platform

This paper presents an edge detection method brought to videogrammetric systems for micro-platform. As the motion precision of platform has a direct impact on the process of precision, so the edge detection in the visual measurement process is also particularly important. The algorithm has a good ability of anti-interference, and the image which been detected is smooth, neat and it always be with good availability. At the last, a platform edge model is received and proved this method.

Method of three-point for measurement of micro-table position and posture

The paper describes a new theory and method to measure the error of micro-table 3D motion based on machine vision. Making the centre of three standard small spheres put over micro-table as mark points characterize the pose of table in 3D space. Based on machine vision, through visual tracking of the three standard spheres in 3D space, we can ascertain the pose of table in 3D space and measure the kinematics error of table.