Applied Mechanics and Materials Vols. 303-306

Abstract: A dynamic mechanical model for actuating performance of piezoelectric material bonded on the surface of structures was established based on the second class of piezoelectric equation and continuum dynamics. Piezoelectric patches such as lead zironate titanate (PZT) to be used as an actuator were pasted on the surface of structures by bonding layers. An electrically and mechanically coupled model based on the piezoelectric equation and Newton's second law was set up and the dynamic equations of the coupled system were theoretically solved under the harmonic effect of the alternating voltage. Moreover, the effect of physical properties and the layer thickness of the PZT actuator were determined. The theoretical and experimental results showed that the proposed model was reasonable and precise to a certain extent.

Abstract: Walking rehabilitation training robot generally divided into exoskeleton rehabilitation robot and foot board rehabilitation robot. The purpose of this study is to develop a 6-DOF foot board rehabilitation robot, measurement and analysis the motion parameters of ankle for people walking on the treadmill. This paper introduces the basic method of get ankle motion data based on the NDI motion capture instrument, and screening and fitting for the measurement data, after these processes, then can get the motion law of ankle when people walking on the treadmill. The results are very helpful for the design of foot board rehabilitation robot device and the formulation of control strategy.

Abstract: This paper presents an efficient force position control scheme for high precision drilling on soft surfaces using industrial robot. The control problem is divided into two parts; the gross motion control problem and the drilling control problem. In the gross motion stage the robot motion is controlled using computed torque technique. The drilling process is controlled using hybrid force position control that maintains the desired force and trajectory profiles. The soft surface is represented by single degree of freedom mass-spring-damper system. The performance of the system is tested using 6-dof PUMA 560 robot model.

Abstract: Micro-motor is the core component of surgical power plant, this paper research a new method of measuring micro-motor speed and output power. This system takes WTK-10 Groove-type photoelectric sensor and 6 gap speed code disc to measure micro-motor speed, uses TQ661 torque sensor to measure output torque of micro-motor, takes electronic load loading circuit, torque-speed measuring circuit, brushless motor driver circuit and control circuit of single chip microcomputer to realize the detection of micro-motor speed and output power, and to display results on PC. This system has the functions of data gathering, data processing, displaying and alarm etc, is accurate, economical and practical etc.

Abstract: The amplitude of the output signal of prisms laser gyro with mechanical dither bias is always modulated. Theoretical analysis and experimental research on the ray trajectories, assembly situation and polarized properties of light were carried out. Results show that during the dither bias, the light transmitting route deviation caused by stress induced birefringence of prisms and the relative displacement between the photodetector and output light spot was the main reason responsible for the modulation. Polarized experiment data demonstrated that when the value of polarized power of output light below the 25.5% of that in ideal static situation, the standard error over 0.0337dBm, and the displacement extent of prism is higher than the 53% of radius of the beam waist in gyro cavity, the amplitude modulation extent of gyro output signal would be up to 16%, which badly influences measurement precision of laser gyro. Using the symmetric structure for laser gyro design, adopting prisms material with a suitable refractive index and reducing the photodetector deviation could reduce the extent of output signal's amplitude modulation obviously.

Abstract: In the Enzyme-Linked ImmunoSorbent Assay(ELISA) test, automatic pipetting for liquid samples is key factor to improve test efficiency and quality. In this paper, a multi-channel pipetting system used to perform pipetting and incubation automatically is constructed, which is equipped with three-dimensional motion platform and four pipetting channel. The system contains electronic control system based on DSP, which communicates with ELISA host software by USB. The experiment demonstrates the effectiveness of this multi-channel pipetting system.

Abstract: Magneto-rheological fluid damper is widely driven by current source. The nonlinear factors become inevitable in system performance improvement. This paper mainly put forward and demonstrated a new theoretical model of MRF damper by the method of experimental modeling. Then a current source circuit was constructed with this model by PSpice. At last, the circuit response influenced by load parameters was analyzed, then get the relationships of load parameters and current response time. The research results show the model can characterize the MRF damper load characteristics accurately and the analysis of the load parameters can gave some useful suggestions to the current source design.

Abstract: For the formation control problem of multiple nonholonomic mobile robots with actuator and formation dynamics, this paper propsed a new control strategy that integrated kinematic controller with input voltages controller of actuator. This control law was designed by backstepping technique based on formation control structure of leader-follower. The RBFNN was adopted to achieve on-line estimation for the dynamics nonlinear uncertain part for follower and leader robots. The adaptive robust controller was adopted to compensate modeling errors of neural network. This strategy not only solved the problem of parameters and non-parameter uncertainties of mobile robots, but also ensured the desired trajectory tracking of robot formation in the case of maintaining formation. The stability and convergence of the control system were proved by using the Lyapunov theory. The simulation results showed the effectiveness of this proposed method.

Abstract: Behaviors of multi-robot system based on task-oriented architecture are intuitional according to the flow of task processing that is obvious to plan and monitor. This paper tables a novel task-oriented architecture for space robot application, which consists of task description, task completion analysis, task compromise. For this architecture, author designed a knowledge interchange mechanism base on KIF (Knowledge Interchange Format) and OKBC (Open Knowledge Base Connectivity). Using this knowledge interchange mechanism, knowledge bases designed by different languages comprehend information transmitted form each other.

Abstract: The purpose of this research is to improve the machining accuracy of a CNC machine tool through thermal error modeling and compensation. In this paper, a thermal error model based on back propagation networks (BPN) is presented, and the compensation is fulfilled. The results show that the BPN model improves the prediction accuracy of thermal errors on the CNC machine tool, and the thermal drift has been reduced from 15 to 5 after compensation.