Papers by Author: Yu Hong Dong

Abstract: Friction nonlinear is common in mechatronics system. It can decrease dynamic tracking accuracy, rapidity and relative stability of the system. For NC servo system as an example the simulation analysis is carried out for friction nonlinear. Analyzing friction torque, the difference between dynamic and static friction torques have effects on the system performances. The simulation results illustrate that friction nonlinear mainly affects lower speed track performance of servo system lower. With rotation velocity instruction lower dynamic tracking accuracy and relative stability of servo system more decreasing, the response lag more severity. In the condition of rotation velocity instruction invariable, the bigger the difference between dynamic and static friction torques the worse relative stability and response lag of the system. The paper’s study has the reference value for design and improving lower speed performances of servo system.

Abstract: In order to implement basic motion functions of lunar rover over uneven terrain, wheel kinematics of a novel lunar rover with each wheel independently driven was studied. In terms of mechanism principle and configuration features of the rover the kinematics model of wheels was set up by utilizing modified D-H method. The simulation analyses of wheels traversing over uneven terrain were carried out by using MATLAB software. The velocity simulation curves of wheels’ centers relative to rover body were acquired. The research results give motion parameters of wheels varying with rough terrain, and from the velocity simulation curves we can gain velocity control instructions of rover wheels over uneven terrain. It illustrates varying of lunar rover wheels’ velocity with uneven terrain. The paper provides a theoretical basis for accomplishing motion control and autonomously avoiding obstacles of lunar rover and so on.

Abstract: In order to improve NC machining precision this article analyzes the effects of cutting force on NC machining precision by means of simulation, and builds up the mathematical models of CK7815 feed drive system and radial action force of cutting feed, in order to study the effects of cutting load torque and radial cutting force on work pieces processing precision. The simulation results illustrate that cutting load torque and radial cutting force have respectively effects on axial precision and radial precision of work piece. The bigger is cutting load torque, the bigger is axial error. The smaller is cutting process coefficient and the higher is converting spring stiffness of lathe and tool, the smaller is radial error. In practice NC machining precision is improved by trying to decrease the cutting load torque and cutting process coefficient and increase converting spring stiffness.