Papers by Author: Guan Bin Gao

Abstract: Abstract. Currently, traffic law enforcement agencies rely mainly on the license plate to identify illegal vehicles. But for those vehicles with no license plates or license plates are obscured or slipped, the existing techniques do not work. In this paper, a method to reconstruct the external dimensions of vehicles from 2D images is therefore proposed to identify those illegal vehicles above. The external characteristics of vehicles and methods to model vehicles are analyzed. Based on the analysis, we simplified vehicles as a combination of a rectangular parallelepiped and trapezoidal polyhedron which can be produced with corner points from 2D images. The process to establish the vehicle model with corner points is studied. Finally with Visual C++ and SolidWorks API, the 3D model of a vehicle is established based on a 2D image. The vehicle's primary outlines information including length, width and height are restored, and the information can be used to identify the vehicle.

Abstract: The AACMM is a kind of new coordinate measuring instrument based on non-Cartesian system. The errors of structure parameters are the main factors which affect the measuring accuracy, and the structural parameters identification can effectively improve the measuring accuracy of AACMM. The measuring model of an AACMM was established using the D-H method. Then the error model of the AACMM was established with total differential transforming method, from which the Jacobian matrix was obtained. The structure parameters’ errors which need to be identified through singular value decomposition of Jacobian matrix and the decomposition of orthogonal matrix elementary row transform can be determined. Finally, the least squares method was used in identifying the structure parameters’ errors of the AACMM, the results shows that the method proposed in this paper can identify the structure parameters efficiently.

Abstract: The articulated arm coordinate measuring machine (AACMM) is a new type coordinate measuring machine (CMM) base on the linkage structure with the characteristics of small size, light weight, large measurement range and flexible movement. The kinematic modeling methods of six degree of freedom (6-DOF) AACMMs are studied in this paper. By analyzing the structural characteristics of AACMMs the kinematic model of a 6-DOF AACMM with DH method was established. From the kinematic model the coordinate systems and structural parameters of the AACMM are obtained. Then the homogeneous transformation matrixes from the probe to the base of the AACMM are derived. Finally, methods of numerical computing and graphical simulation are used in verifying the kinematic model. The kinematic model provides a basis for measurement, calibration and error compensation of the AACMM.

Abstract: The kinematic model of robots is to describe the nonlinear relationship between the displacement of joints and the position and orientation of the end-effector, which is an important part of robotics. Kinematic model has great influence on the robot’s accuracy and motion control. In this paper, we studied the robot’s kinematic modeling methods and analyzed the characteristics and singularity of traditional DH method. By analyzing and comparing the structural characteristics of a 6-DOF industrial robot a MDH method was chosen to establish kinematic model. From the kinematic model the joint coordinate systems, structural parameters and homogeneous transformation matrixes of the robot are obtained. The kinematic model provides a theoretical basis for the robot motion control, calibration and error compensation.

Abstract: The measuring space is the set of positions a flexible arm coordinate measuring machine (FACMM) can reach, and it is an important measure for the evaluation of a FACMM. To study the measuring space of FACMMs the kinematic model was established. Furthermore, a new method based on Monte Carlo method to calculate the measuring space of FACMMs was proposed. The method generates the data of joint angles with Monte Carlo method, which is used to calculate the coordinates of the FACMM’s probe through the kinematic model. These coordinates make up the measuring space. The results of the analysis on the measuring space show that the measuring space of FACMMs is not a sphere usually considered as but an ellipsoid, and there is lack of flexibility near the border of the measuring space.

Abstract: The mounting eccentric error is one of the largest error sources for circular grating angle sensors (CGASs). To improve the measuring accuracy of CGASs, one error compensation method based on mounting eccentricity is proposed in this paper. The mounting eccentricity and measuring error of CGASs was modeled after analysis. Six joints mounted with CGASs were used in the eccentric error compensation experiment. The rotation error of the joints was calibrated with a coordinate measuring machine and a gauge block. Then with the calibration data, the parameters of the eccentric error compensation model were calculated. The experimental result shows that after error compensation the rotation angle errors of the joints are reduced about 58 to 543 times.