Applied Mechanics and Materials Vols. 80-81

Abstract: In order to analyze accurately the dynamic characteristics of guideway joints of CNC, the finite element model(FEM) of guideway joints of CNC is built in ANASYS software, which that springs and damping units imitate guideway joints in this paper. The proposed method can predict the regular pattern which joint stiffness and joint span affect natural frequency and harmonic response. The research demonstrates that the method predicts well the dynamic characteristics of the guideway joints of CNC; therefore, it can be a reference for dynamic optimization design of guideway joints of CNC machine tool.

Abstract: The dynamic characteristics of parallel 3-TPT machine tool are researched by simulation and experiment in this paper. Firstly, modal analysis principle of machine tool was analyzed in theory, and the parameters of dynamic characteristic were identified by theoretical analysis. Then vibration model of parallel machine tool was built in ADAMS and formed vibration system of rigid and flexible coupling for simulation analysis, and from the simulation results got the value of parameters for vibration characteristic of parallel machine tool. The simulation results showed that the simulation method and result dates are validated, which provides reference for dynamic optimal design.

Abstract: A Vehicle simulation model is built by AMESim software. During the Electronic Stability Program (ESP) running on, the cases of varieties about system variables are investigated based on the automobile dynamic model. Fault modes of actuators and sensors in ESP are built up. And data-fault is acquired. Support Vector Machine (SVM) based on classification is applied for fault diagnosis of the ESP system. The basic idea is to identify the information and classify new fault samples by using the trained SVM model. Finally, simulation examples are performed to verify the effectiveness of the proposed design.

Abstract: To adjust the car yawing moment through specific wheels braking is a kind of widely used method by various auto stability control system. The braking of different wheels will have different effects on direction and the size of the car yawing moment. Based on the established simulink simulation model platform of automobile Electronic Stability Program (ESP) control system, this paper makes a research and analysis on the vehicle stability in five kinds of typical working conditions under three kinds of braking force distribution control strategies. Finally, we propose an optimized braking force distribution control strategy which is determined by the road condition.

Abstract: Clutch release bearings are an important vehicle powertrain components. Web-based collaborative design automotive clutch release bearings, making the regional formation of enterprises dynamic virtual design team, through a combination of scattered in various technological advantage, the talent to play all engineers, technicians can not subject to geographical restrictions, by computer supported collaborative design (CSCD), is a collaborative model of human and computer technology convergence of new technologies. By numerical calculation and the C^# language on the separation of the axial load bearing capacity of the design process is developed. It is established on separate static analysis of the proposed bearing model.

Abstract: A new joint space trajectory planning method for the series robot is proposed. Comparing with the traditional path planning methods which can only guarantee the planned trajectory velocity or acceleration continuous, the proposed trajectory planning algorithm can also ensure the derivative of acceleration (Jerk) continuous within a limit threshold. At the end of this paper, the proposed path planning algorithm is validated of having a great performance on robot trajectory tracking.

Abstract: In this paper, a high dynamic humanoid manipulator with DSP/FPGA-FPGAs hardware structure is designed to meet the demand of high-speed response required by playing ping-pong game. The manipulator integrates several sensors in each joint unit, and the controller is divided into two levels. The upper level mainly solves the kinematics and trajectory planning in DSP, while the lower level realizes the joint control such as vector control and sensors data processing in FPGA. The two levels communicate with each other by multipoint low-voltage differential signaling (M-LVDS) serial data bus every 200μs. Experiments of the manipulator hitting the ping-pang are done to demonstrate the design of this arm. The results show that the arm can reach the speed of 2.2m/s, and it creates a record of 22 continuous hits of the ball with a human rival.

Abstract: The design optimization of two-stage cylindrical helical gear reducer is discussed in this paper. The volume and the center gear distance are adopted as objective functions separately, and the particle swarm optimization(PSO) method is used to improve the design quality. The design variables contain discrete variables, which are converted to discrete variables by the nearby principle in order to improve the running efficiency. Inertia weight coefficient is used in the PSO algorithm to adjust the coverage speed. The optimization result shows that our method is better than other optimization method, and it proves that PSO method is meaningful to the reducer’s design.

Abstract: Purpose: A multi-leaf collimator leaf sequencing comparison program in the sense that it translates beam intensity maps into the least number of MLC field segments was presented. Methods: The IMRT leaf sequencing calculation program based on Galvin, Bortfeld algorithms was constructed. The output of the leaf sequencing program were the number of segment and the total number of monitor unit. Results: Assuming 15 x 15 bixel fields with an average of 10 intensity levels, Bortfeld algorithm could yield better result on example 1 while Galvin algorithm yielded better results on example 2. Conclusions: This represented a useful tool for optimizing the leaf sequencing of static multi-leaf collimator that can yield shorter treatment time and higher utilization of photons by comparing with the total number of monitor units and number of segments of existed typical algorithms. It was an effective strategy and could be applied in commercial Treatment Planning Systems.

Abstract: All-coefficient golden section adaptive control scheme for attitude keeping of spacecraft with unknown parameters is proposed in this paper. Based on Lyapunov’s direct method for time-variant discrete systems, the paper gives the conditions for the uniform asymptotic stability of the all-coefficient golden section adaptive control system. The given conditions are dependent on the relations between coefficients in the closed-loop system equations and the variable rates of the coefficients. The result in this paper can be used to analyze quantitatively the stability of multivariable time-variant discrete systems. Thus, a theoretical foundation is established to apply the golden section adaptive control method to control specific spacecraft.