Applied Mechanics and Materials Vols. 433-435

Abstract: Based on finite element method, model analysis of input shaft of the toroidal drive is introduced, natural frequency and vibration model are obtained. The analysis result is in a good orderliness, matches the results calculated by the model analysis method and can be lead to a new research field for the toroidal drive.

Abstract: The boom crane of marine drilling platform is an important part of the automated pipe racking system. It has important engineering significance to study the kinematics of boom crane for the automatic control and accurate positioning. Using the method of robot mechanisms, the kinematics of mechanism for boom crane on marine drilling platform is discussed in this paper. According to the structure and motion characteristics of the boom crane, a special joint coordinate system is chosen. The kinematics model of the boom crane is established. The forward kinematics equations, inverse kinematics calculation formulas are derived. The correctness of formulas is verified by examples. The theoretical basis is provided for the movement automatic control and subsequent dynamics and boom crane mechanics analysis when considering the elastic deformation.

Abstract: The SGA170 mine truck was used as research object, the full hydraulic steering system and it's dynamic characteristics was simulated by the AMESim, the characteristics and simulation curve of the steering system and the steering mechanical under various conditions was obtained, which provided theoretical reference and technical support to the design and analysis of full hydraulic steering system of the heavy-duty mine truck, and has important value in the engineering.

Abstract: In this paper, out-moving jaw crusher machine is regarded as the research object and we established the simulation model of virtual prototype based on Nastran. Through the simulation analysis of the movement process, trajectories of moving jaw side plate and a movable jaw toggle plate and related parameters were obtained and compared and verify the simulation model and theory model. The results show that: the simulation model reflects the motion characteristics of the theoretical model well. So it provides theoretical reference for improvement of dynamic performance analysis and structure design of jaw crusher and has important application value in engineering.

Abstract: With the high-speed and high-precision development of CNC machine tool, the vibration problem of ball screws linear guide feed unit has become more and more prominent. The dynamic characteristics was analyzed for ball screws linear guide feed unit, the 3D finite element model was built, the finite element modal analysis was discussed, the natural frequency and vibration modes were obtained, which were compared with the test results. The vibration weaknesses of ball screws linear guide feed unit were found out. The results show that the vibration weaknesses of ball screws linear guide feed unit occur mainly in the ball screws and its connection part with the worktable, its natural frequency are affected by its supporting pattern, and more close to the test results compared with those of ball screw feed unit without considering linear guide, which provide theoretical basis for the structure optimization of ball screws linear guide feed unit.

Abstract: This article presents performance results of a novel jetting dispenser system actuated dual piezostack actuators. The proposed piezo jetting dispenser system consists of a couple of piezostack actuators, lever mechanism, and needle part. The proposed dispenser can provide a very small dispensing dot size of high viscous adhesive, 10,000cp at 100°C, at a high dispensing flow rate in semi-conductor packaging processes. After describing the mechanism and operating principle of the proposed dispenser, a mathematical model of the system is obtained by considering behaviors of the piezostack, the return spring, the dispensing needle, and the adhesive fluid dynamics. For the computer simulation, the specific geometric dimensions of the proposed jetting dispenser are chosen in order to achieve operation requirements: needle motion amplitude: up to 0.15 mm; operating frequency: up to 500 Hz. With the high viscosity conditions, the dispensed amount of the adhesive and the maximum displacement of the piezo and the needle at 500Hz are evaluated in time domain.

Abstract: A design scheme of ellipsograph-mechanism-based pipe auto-handling device (PAD) in continental scientific drilling rig is presented. The working principle of ellipsograph and its characteristics are firstly analyzed to satisfy the requirements of the movement structure of the PAD. Then, the kinematics and dynamics analyses of the structure are conducted respectively to obtain the relationship among each key joints and the relationship between force and its kinematics parameters. Finally, for a certain behavior path, a computation formula of the theoretical consumed energy is developed, and the relationship between energy consumption and the boom length of the structure is acquired. An energy consumption law of the movement structure of PAD under the given condition is obtained. The method presented in this study provides a theoretical basis for the design of ellipsograph-mechanism based PAD, and the energy consumption computation can be applied to many other structures for minimizing their energy and force.

Abstract: Through the judgment of slip or not, human make proper adjustment to the grasping force and achieve stable manipulations. To reconstruct this function on a prosthetic hands platform, this paper presents a hybrid slip detect algorithm utilizing the PVDF sensor and FSR sensor. Then a reflex force estimation model is built to quantify the reflex force according to the intensity of slip in the reflex control process. Finally, through comparative experiments, the anti-jamming performance of the hybrid slip detect scheme is tested. A fuzzy controller is used to control the applied force and test the whole reflex control system. The results show that the hybrid slip detect scheme can make accurate judgment and has strong anti-jamming capacity; The output of the reflex force estimation model is accordance with the factual case; And as a whole, the grasping ability of prosthetic hand is substantially enhanced.

Abstract: An adaptive fuzzy proportional-integral-derivative (PID) force control strategy for a prosthetic hand is presented. The classical PID controller is also applied on the prosthetic hand as comparison. The parameters of PID controller are firstly tuned by Cut and Try method. Then a fuzzy logic system is used to adjust those parameters on line. Real-time force control experiments are realized on LabVIEW and PXI (PCI eXtensions for Instrumentation) real-time (RT) platforms. A rigid object and a compliant object are grasped by the prosthesis respectively to test the performance of controllers. Experimental results indicate that the adaptive fuzzy PID force controller is more effective than PID controller.

Abstract: Aimed at seeking a optimal task space where robot’s flexibility is better than other task space in the whole workspace, then analyzed robot flexibility indexes which domestic and foreign scholars had described, analyzed k(J)、w andσ_r comprehensively in task space, proved the rationality of k(J) as the flexibility index and proposed a new method which combining the global performance index η with the minimum flexibility index D_min (D=1/k(J))to evaluate the flexibility in task space, then proved the method effectively by genetic algorithm . It has a practical significance for solving the problem of optimal task space in robot work space.