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3D laser radar is widely used in unmanned driving systems due to its high precision, strong anti-interference ability and omni-directional scanning. It is used for road environment detection and anti-collision detection. In order to increase the accuracy of the laser radar to segment the scanning point cloud, firstly, voxel filtering is applied to the point cloud to reduce the number of point clouds, and then the point cloud is removed by using the point cloud progressive morphology filtering method. Finally, the point cloud is divided into several independent clusters by the region-growing algorithm, and the segmented point cloud clusters are generated into a bounding box. By detecting the relative positional relationship of the bounding box of the three-dimensional space, it is determined whether there is a collision of the two physical models. The experimental results show that after the point cloud preprocessing and clustering segmentation, the collision detection of the model combined with the bounding box can effectively identify and accurately determine the spatial positional relationship of the object and improve the accuracy of collision recognition.

Auxiliary bearing is used to support the high-speed falling rotor in the active magnetic bearing. Its impact resistance directly affects the safety and reliability of the active magnetic bearing. In order to study the impact resistance of the auxiliary bearing in the vertical active magnetic bearing, full angular contact hybrid ceramic ball bearing was used as the auxiliary bearing, and ADAMS was used to simulate the impact force of the auxiliary bearing when the balanced rotor was fell on the auxiliary bearing. The influence of friction factor, axial protection clearance, rotor mass and rotor drop speed on the initial axial impact force of the vertical balanced rotor falling to the auxiliary bearing is analyzed. The results show that the initial axial impact force on the auxiliary bearing is the maximum axial impact force. The initial axial impact force on the protected bearing decreases with the increase of dynamic friction factor. It increases with the increase of axial protection clearance and rotor mass. Unchanged with the increase of falling speed. The influence of axial impact on the bearing can be reduced by increasing the friction factor, reducing the clearance of axial protection and the mass of rotor appropriately.

Aiming at the problem that the measuring precision of thin-walled bearing's outer diameter in our country is not high enough to match the precision and capability of production completely, on the basis of studying the principle of contact and non-contact measurement at home and abroad, the characteristics of thin-walled bearings with high precision and high surface quality are analyzed. A new method of measuring external diameter is proposed by using IFS2403-0.4 high precision spectral confocal sensor produced by German Iridium Company as measuring tool. It not only ensures the surface quality of the measured parts, but also reduces the mechanical errors caused by the mechanical structure and vibration. At the same time, it can effectively avoid the rotary errors and improve the measuring accuracy. Finally, the experimental results show that the method is simple, efficient and highly accurate, and can be used for production.

The antifriction bearing is the basic component in modern machine which kinematic accuracy affects directly machine performance. Besides influenced by the design, manufacture and environment, it is more important that the kinematic accuracy of bearings is influenced by dimension and shape precisions of inner raceway, outer raceway and rollers. For cylindrical roller bearing, the principal index of the kinematic accuracy is the radial run-out of the bearing inner-outer ring. The dimension-shape error of the components and interaction among them can induce the radial run-out of the bearing. There are dependent relationships between the bearings kinematic accuracy and component geometrical precision which actions are very complicated and extremely difficultly described by mathematical formula. But, the component geometrical error and the radial run-out of the bearing inner-outer ring follow mathematical statistic law and have their distribution characteristics. So, the joint copula distribution function can be introduced to establish the transmit relationships that join the radial run-out of the bearing to multiple components geometrical precision distribution. Based on the copula estimation of distribution algorithm, the mathematic modeling of the run-out of inner-outer ring can be built to forecast bearings kinematic accuracy.

In order to realize the tracking motion of the moving target, a planar flexible target motion simulator is designed in this paper. The kinematic and dynamic models of the planar flexible cable driven target motion simulator are established. The moving space of moving object under different rope angles is analyzed. The trapezoidal velocity planning of moving target is carried out. The design parameters are obtained according to the simulation data. Tracking motion of a predetermined trajectory of a moving target is achieved.

In order to meet the high requirement in data processing and solve the problems in status data acquisition in condition monitoring of the widely distributed wind turbines, a device condition monitoring hardware based on ADSP-BF518 processor was introduced in this paper. The key technologies, such as CPLD-based function expansion, ADC, DAC, synchronization logic and network interface, were presented in details. Besides, a wind turbine bearing online monitoring software system for wind farm is also proposed and its key components are insensitively studied as well. The constructed hardware and software system are put into practical use to support the wind turbines fault diagnosis and verify the accuracy, effectiveness and scalability of the system architecture design.

The mathematical model of cylindricity error measurement based on the roundness errors separating with three point method is presented in this paper. Three key elements, the roundness errors, the radius error of different cross sections and the coordinates of the least square centers of measured cross sections, can be separated by this method. The precision cylindricity error measurement system is designed for cylindricity error measurement, reconstruction and analysis. The sensor installation and adjustment system is designed to improve the precision of the spectral confocal displacement sensors' installation. The measured data is processed with the designed software. 3-Dimensional cylindrical surface topography is reconstructed based on OpenGL technology. The color linear interpolation method is used to show cylindricity error distribution. It could be helpful for engineer to realize visual qualitative analysis of cylindricity error.

This paper describes a calculation model for pre-stressed bolted joints used to connect turntable bearing to the flanges. A traditional pre-stressed bolted joint calculation model is described and its insufficiencies for the direct application on turntable bearings are pointed out. The suggested stress analysis is done by modeling the most loaded single bolt segment of the turntable bearing assembly, applying the preload and the working load on it. The alternating stress in the bolt is done by finite element analysis. The results show that the alternating load of the bolt is significantly decreased and is lower than the fatigue limit of the bolt under the condition of the larger tightening force. Therefore, it should be possible to increase the preload in the conditions that the maximum stress of bolt is below its yield limit stress situation.

This paper introduces a new control scheme for active steering of vehicle. An ideal reference model followed by the four-wheel steering (4WS) vehicle is established resulting from the front-wheel steering (FWS) vehicle, and an H ∞ optimum controller for the 4WS vehicle is designed based on model following technology. The dynamic simulation is performed to verify control effect of the H ∞ controller, and the result shows that the H ∞ controller can apply to the 4WS vehicle system. It can not only minimize the sideslip angle of the 4WS vehicle to zero value, but also keep the yaw rate of the 4WS vehicle in accordance with the FWS vehicle. The handleability is further improved for 4WS vehicle.

Based on binocular visual theory, a new method is proposed for solving the marking-points matching and tracking issues in the micro-table 3D posture measurement system. The four marking-points of the micro-table are detected by Harris corner detection algorithm, an improved epipolar constraint match method is used to make the corresponding marking-points be restricted in a region, circle region search method is used to match the same marking-point, and the template-based recognition algorithm is used to track the marking-points in real-time image frames. The experiment results verify the effectiveness of this method.

In the numerically controlled manufacturing process of the spring, there are some problems such as lower automation and inconvenient operation. In view of this situation, the paper presents the approach of digital manufacturing for spring. The composition and the key technology of the digital manufacturing system are revealed, and an example is given to illustrate the system application. The digital manufacturing system provides the new method for spring coiling as well as forms the basis for integrating of spring's design and manufacture.

Based on binocular vision measurement principle, this paper describes a new method that measures the 3D posture of micro-table, this method can match and track the micro-table and get its three-dimensional position. We use the four corners of the table points as signalized points to describe the position and posture of the micro-table, and track the four corners by the dual-CCD cameras in the three-dimensional space, detect the changes of corners in the coordinate of the image, According to the mapping model of image coordinate system and world coordinate system, get the changes of the corners in the world coordinate, establish the posture equation of the micro-table using the four corners coordinates in order to achieve the 3D posture measurement of the micro-table.

A new method for evaluating roundness error using polar measurement data, which named as polar mesh searching algorithm (PMSA), has been presented in this paper. The principle of the algorithm was that series of polar-coordinate mesh points were collocated around the periphery of the least square circle according to certain rule, the radius of all the measured points were calculated by regarding each mesh point as the ideal center, and the roundness error from minimum circumscribed circle method, maximum inscribed circle method and minimum zone circle method were achieved accurately through comparing these radius. In the paper, the process and steps using the PMSA to solve the roundness error were described in detail and the mathematical formula and program flowchart were given. The simulation and experiment results show that roundness error can be evaluated effectually and accurately by this algorithm.

Piezoelectric fiber composites is one of the new type piezoelectric devices for actuators, since it has obvious anisotropy as well as high toughness that couldn't be gotten from normal piezoceramics. Piezoelectric fiber composites is denominated by piezoelectric fiber, polymer and interdigitated electrode layer. Through design processes, better mechanical and electrical characteristics than piezoceramic materials can be obtained. Its theory model is not founded completely yet because of the complexity of this device. So a series of piezoelectric unit's equations about longitudinal length extension vibration mode are established. According to the dynamic FEM (finite element method) equations for piezoelectric actuators, which were established by means of Lagrange function and Hamilton principle, some finite models are established. Then, the effect of polymer's material characteristics on performance of actuators is studied. The results show that piezoelectric fiber composites has orthotropic properties. And the strain of piezoelectric fiber composites can be improved markedly by employing polymer with larger permittivity, Poisson ratio or smaller elastic modulus. At the same time the stress of actuators is studied. In addition, the effect of polymer's thickness and material constants around electrodes are studied. Several rules summed. At last, the maximum strain (170µ ) is got from the numeric model of optimized samples, which is very large considering composites.

Based on fuzzy-set theory, a method is considered for estimating and forecasting the performance parameters of a system under the condition of unknown probability distribution and small sample. Some concepts including point estimation, interval estimation, optimal level, empirical probability distribution and confidence level are recommended. The performance prediction in the system for application is also investigated. The validity of this method is examined by computer simulation experiments under the condition of small sample and typical distributions such as normal distribution, uniform distribution, Rayleigh distribution, and unknown distribution. The confidence level is proved to be higher than 95% via engineering experiment on noise of rolling bearings.

The mathematical model of and the solution to cylindrical form error separation are presented in this paper. The roundness, the radius error of different cross sections and the initial coordinates of the least square centers of measured cross sections can be separated by this technique. Meanwhile, the rotation motion error of spindle and the rectilinear motion error of guide way can be separated effectively. Based on the periodicity of roundness error, a method of solving the roundness of measured cross sections is put forward by means of system of linear equations without using the Fourier transform of discrete data. According to the separated process of the above errors, the reconstruction datum of cylindrical surface and the mathematical formula to reconstruct measured cylindrical form are established.