Papers by Author: Liang Zhao

Abstract: Software reliability is an important attribute of software quality. Based on the concept of software reliability and reliability indicator, this paper presents the analysis techniques of software reliability for the vehicle navigation system, obtains the appropriate forecasting model of vehicle navigation software reliability through tests and calculation, and puts forward suggestions for promoting the vehicle navigation software reliability.

Abstract: This paper takes one kind of 3-TPT Hybrid Machine Tools (HMT) as the object to study. It mainly analyzes the influence of the parallelogram mechanism as the restraining chain of machine on the posture error of movable platform. Firstly, on the basis of introducing the structure of HMT, the kinematics of the restraining chain of this machine is analyzed, and the kinematics equation of the restraining chain is established. Secondly, the influence of two kinds of factors including the shape error of parallelogram mechanism and the micro-rotation of Hooker joint around the axis of connecting rod is analyzed respectively, and the theoretical relationship expression is acquired between various errors influencing factor and the posture error of movable platform, thus the foundation for the theoretical error analysis of the HMT is laid.

Abstract: This paper deals with the dimensional synthesis of a 2UPS-UPR parallel mechanism tool newly designed by Northeastern University. On the basis of establishing kinematics equations and obtaining Jacobian matrix, the performance index of dimensional synthesis is given which is the average of 729 values of the condition number of Jacobian matrix corresponding to 729 positions in the workspace. With MATLAB software, the effects are simulated which the structural parameters of parallel machine tools have on dimensional synthesis, their change laws are gained, and then dimensional synthesis of parallel machine tools is conducted based on these laws.

Abstract: The stiffness model of the parallel machine tool is established by static analysis, the static stiffness analysis is carried out through numerical Simulation and the stiffness distribution is given. On the basis of this, the optimal objective is given which is the average of 729 values of -axis stiffness and -axis stiffness corresponding to 729 positions in the workspace. With MATLAB software, the effects are simulated which the structural parameters of the parallel machine tool have on their stiffness, their change rules are gained, and this provides a basis for the structural design of this type of machine tools.

Abstract: On the basis of static analysis, the stiffness model of the parallel grinding machine tool is established from the 3-TPS parallel grinding machine tool newly designed by Northeastern University. By analyzing its stiffness matrix, the optimal objective is given which is the average of the twenty condition numbers of stiffness matrix corresponding to the twenty positions in the margin areas of the workspace. With MATLAB software, the effects are simulated which the structural parameters of the parallel grinding machine tool have on their stiffness, their change laws are gained, and then the stiffness design of the parallel grinding machine tool are conducted based on these laws.