Applied Mechanics and Materials Vols. 303-306

Abstract: In parallel coordinate plots, the density could not be represented where the polylines were over intensive. Based on the problem, the aggregation degree conception was proposed. The three-dimension parallel coordinate system with the aggregation degree axis was built, and the mapping from aggregation degree to gray degree value was built. The three-dimension polylines with gray color were projected onto the original two-dimension plane, and the two-dimension parallel coordinate plots with the aggregation degree information were acquired. The results show that they are effective in representing the density change of polylines on parallel coordinate plots.

Abstract: When large-scale images acquisition conducted on an Integrated Circuit (IC) chip by using an optical microscope, multi-layer routing structure and transparent inter-layer dielectric of IC chips can interfere with auto-focusing of an optical microscope, which significantly increases the images’ acquisition time. To solve the forementioned problems, a fast acquisition system is proposed based on surface fitting. First of all, we obtain focus plane height of multiple scattered points through pre-acquisition. Then, the surface fitting method, with Thin Plate Spline (TPS) model is applied, to get the height of the rest points. Thus the system can acquire correct surface-layer images of an IC chip without background interference. The experimental results suggest that the proposed technology is highly superior to manual acquisition system and auto-focusing based acquisition system in acquisition accuracy and speed, and it also decreases the amount of manual workload by 70%-80%.

Abstract: A two-degrees-of-freedom voice coil motor and its control system are proposed for linear and rotary motions with high speed. This VCM consists of two individual motion parts driven by two separated DSP embedded controllers. For servo control of the VCM, an improved PID control algorithm is adopted. The performance of the control algorithm is evaluated under actual environment. When the targets of position and angle are set at 5mm and 15°, the time response shows 48ms and 70.4ms settling time with 5μm and 3’ steady state error without overshoot. Settling time is reduced to 36% as compared to that of original PID controller.

Abstract: Articulated structure of mobile robot presents high flexibility on the environment adaptation. It has been widely used on the mobile robot to get through rough terrain. This class of robots named as articulated mobile robots can move in hard condition with high stability and environment adaptability. In order to satisfy the requirement of Urban Search and Rescue (USAR), a series of articulated mobile robots are analyzed. The performance of articulated mobile robots is analyzed for get an appropriate robot for USAR. Two snake-like robots named Perambulator I and II are analyzed. Based on the structure of Perambulator II, the articulated mobile robot Ameba II are presented based on track drive mechanism. Ameba II has high performance on mobility and adaptability in complex environment. The comparisons among of some typical articulated robots are given based on mobility and environment adaptation. The experimental results of both Perambulator II and Ameba II show that the Ameba II mobile robot is a better than the snake-like robot Perambulator II on the urban search and rescue applications.

Abstract: In this paper we present a parallel robot with flexure hinges for target alignment system of a high power laser facility. The robot contains a parallel mechanism with 6 DOF which has nanometer positioning accuracy and is driven by six linear actuators. We design a new flexure hinge which has higher accuracy, strong environmental suitability and simple structure compared with conventional flexure hinge which has backlash and friction issues. The kinematics analysis of the parallel mechanism is also discussed. The simulation analysis of the mechanism is done by ADAMS. The mechanism is proved meeting the design requirements by comparing the results of the theory analysis and the simulations.

Abstract: According to the plentiful early failure data collected on the spots of 30 CNC machining tools with ATC (Automatic Tool Changer), FMECA method is used to analyze the main fault mode and facts which usually make a great possible impact on the reliability of these products during early failure period.We find out the fault positions and the ratios of the fault modes and fault causes. We further analyze the fault modes and fault causes which frequently arise in the subsystems and parts. Through the analyses of FMECA, we learn the weak links of CNC machining tools and provide bases for removing the products faults. Suggestions how to enhance reliability level of these products are proposed.

Abstract: For the precision rotor position control of stream selector, a control system based on direct current motor (DC motor) has been constructed. The DC motor, with a high-precision incremental encoder used as the driving force, was assembled with the stream selector rotor through a shaft coupling. Following the motor rotation, the encoder generated two-channel quadrature pulses and one channel index pulses. An ultralow-power consumption microcontroller (msp430f2232) received theses pulses and calculated them. The position of the slot was determined by the number of pulses counted from the index pulse. Operator can set and monitored the slot positions of five stream selectors simultaneously through the program which was written with LabVIEW on the host computer. This module featured high reliability and low power consumption compared with the one driven by step motor. Beyond that, it was much smaller and lighter.

Abstract: In this paper, a novel piezoelectric actuator structure - 4-9-9-14 piezoelectric actuator is constructed, and it is made of piezoelectric buzzer to drive a piezoelectric actuated stage. The 4-9-9-14 piezoelectric actuator offers a better balanced capability of forward rotation and reverse rotation than the conventional edge-driving piezoelectric actuator. According to the rotational speed experiment, the CW/CCW ratio of the 4-9-9-14 piezoelectric actuator is probably 1:0.8. The movement of the pie-zoelectric actuated stage is read and analyzed by means of data acquisition card and LabVIEW software operating in conjunction with a linear encoder. In a natural environment, plenty of noise interferes with linear encoder signals and results in erroneous addition performed by a counter. Therefore, the LabVIEW program set forth the means of filtering and the method for retrieving a correct position signal.

Abstract: For the pick-and-place operations of GDL, this paper presents and obtains the control system model using system identification method, and analyzes three distinct stages for the motion characteristics in pick-and-place operations. To satisfy the stick requirements for contact force control, a force controller based on fuzzy adaptive PID algorithm and a position controller based on feed-forward control are presented and designed. Simulations are carried out to verify the feasibility and effectiveness of the proposed control method. The above control strategies and methods are applied to pick up and place GDL. They can also be extended to the pick-and-place operations of the chips and other filed, which has broad application prospects.

Abstract: Parallel robot inverse kinematics solution is relatively easier to obtain than forward kinematics forward, this paper assumes that the forward kinematics of six-DOF parallel robot is given then using the kinematics inverse solution to approximate the forward solution. To improve efficiency and stability of the approximation, an adaptive parameters differential evolution algorithm is proposed and applied to the forward kinematics problem. The experimental results show that the modified algorithm can gain the forward kinematics of parallel robot efficiently.