Advanced Materials Research Vols. 139-141

Abstract: This paper presents a novel low-cost poly(dimethylsiloxane) (PDMS) micropump with simple planar design featuring use of compliant in-contact check valves for reliable operation and easy system integration. The micropump mainly consists of two PDMS functional layers: one through-opening layer incorporating the planar in-contact check valves, pump chamber and flow channels, and the other thin membrane layer covering the chamber with a miniature permanent magnet on top for actuation. A special clamping molding technique was used to fabricate the through-opening functional layer, with which the flap-stopper based planar check valve was manipulated to contact each other enabling the minimized leakage flow. The micropump was then characterized by investigating the dependence of pumping flow rate on the driving frequency and backpressure. Testing results exhibit that the micropump is able to produce a flow rate at least of 3.0 μL/min, and work reliably against a backpressure of 1900 Pa, demonstrating the feasibility of this micropump for potential use in various lab-on-a-chip systems.

Abstract: An analytical model is derived for obtaining the dynamic performance of a thin curved composite piezoelectric beam with variable curvatures for the MEMS piezoelectric vibration energy harvester. The plane curved beam theory with rectangular section is employed to explore the bending and twisting coupling vibration characteristics. In order to satisfy the most available environmental frequencies, which are on the order of 1000Hz, the parameters of the spiraled composite beam bonded with piezoelectric on the surfaces are investigated to provide a method of how to design low resonance beams while keeping the compacting structural assembly. The results indicate the adoption of ANSYS® software to carry out the MEMS piezoelectric vibration energy harvester’s numerical simulation can improve the accuracy of the harvester designing and manufacturing consumedly. And the simulation data also provide a theory analysis foundation for the engineering, design and application of harvester.

Abstract: Aiming to the application requirements of high overload environment, a MEMS acceleration sensor with high overload ability was designed in this paper. It adopted beam - island structure, which dispersed the stress by the chamfer that was on the root and the end of the structure beam when the acceleration effect on the structure. ANSYS simulation results showed that the structure can improve the ability of anti-overload of the acceleration sensor significantly, and the first- order natural frequency can up to 550 kHz. The designed sensor was processed by the standard processing technology, and the ability of anti-overload of the acceleration sensor was tested by Hopkinson bar. The results of the test showed that the signal and structure of the sensor is normal when the designed acceleration sensor was effected on the 230,000 g. The sensitivity of the senor is 0.88uV/g. In such situation, the designed sensor can meet application requirements of high overload environment effectively.

Abstract: Time grating sensor transforms space domain information to time domain and measures spatial displacement with time. To develop high precision time grating CNC rotary table and reduce the dynamic position feedback error of the table, circular position predictive measurement method is proposed for transforming time domain information back to the space domain based on time-space transformation technology. Predicted values are obtained by modeling the measured values with time series theory, and the last prediction error is corrected in real time using the current measured values. Modeling method and parameter estimation algorithm are presented. To confirm the validity of the position prediction method, an experimental system is designed. The dynamic prediction error of the rotary table circular position is 2, and precise predicting is achieved.

Abstract: The hybrid vehicle is currently one of the research focuses of automotive industry. The mode of ‘engine start/stop strategy’ has become a crucial part in (hybrid) vehicle control strategy. In this paper, both home and abroad researches of the ‘engine start/stop control strategy’ were summed up. From automotive engineering perspective, several aspects were in-depth analyzed and discussed, including the engine providing control energy or power resources, substitutability of energy and the negative problems brought by starting/stopping the engine. According to economy and overall loss, the objective function of optimization of the strategy was proposed. For solving the related engineering application problems caused by using the engine start/stop strategy on hybrid vehicles, the appropriate additional solutions were given from three aspects such as adding power source, controlling and switching clutch program of power source, and coupling and connection of the engine and auxiliary energy, providing an important reference for related study.

Abstract: By study on the current domestic cutting technics of vertical-pull glass pipe, in this paper a new and practical design of automatic cutting robot is peoposed. Its motion process is introduced on the basis of performance requirement, and then the overall structure of automatic cutting robot for vertical-pull glass pipe is designed, especially the electro-hydraulic proportional control systems for frame rotation and fuselage lifting. Meanwhile the stability and respond speed of hydraulic systems is well analyzed with matlab software. The results of open-loop bode diagram of the frame rotation system and unit step response diagram of fuselage lifting system indicate that the automatic cutting robot has excellent system stability and respond speed. It can content the requirement of position accuracy, reduce the labor intensity with high productivity and liberate the workers from wicked environment.

Abstract: This paper presents how a capacitive voltage source is connected in series to the rotor of induction motor to improve power factor, reduce stator current, and improve efficiency and ability of overloading. The principle of the reactive power compensating device for windings rotor induction motor is described and mathematical model in dq0 reference frame is set up. A single phase to three phases AC-AC cycloconverter is adopted in order to produce capacitive voltage, which make the circuit simple and capacity of transformer much decremented. Using an 89S52 sing-chip microcomputer as the control kernel and MAX197 as A/D, the system is capable of automatic adjusting the function of power factor compensation as the change of the motor load. The system was tested on a JR138-8 motor. The result shows that the power factor is over 0.96 and the current of the stator reduces over 15%.

Abstract: A set of drive control system has been developed for the scanning drive system of radar scatterometer antenna, according to the requirements of its scanning motion for speed stability with three-phase AC permanent-magnet synchronous motor(PMSM) driven by sine wave current as the execute component. The system can achieve the aim of controlling motion trace. The system composition, matching design of characteristic parameters such as speed and torque as well as control realization method, are described in this paper and the testing of main system performances such as speed stability is also briefly introduced. It is shown from the simulation and test that the designed system can complete the control of motion track with speed ability of up to 0.5% and can satisfy the given index requirements.

Abstract: In view of the problems existing in the cleaning of municipal drainage pipes with diameter of 300-600 mm, a new type of robot was developed to replace the manual to clean the sewers automatically. It was powered by the self-contained storage battery. To make the robot have a degree of operating autonomy, four photoelectrical encoders were used to detect the stepper motor overload, the wheel slippage and the robot’s blockage in real time; an inclinometer was used to detect the robot’s operating posture; an ultrasonic sensor to the thickness of the calcified layer deposited on the pipe wall. Regular fuzzy control was introduced in the motor overload ajustment. To improve the control performance and simplify the control complexity, a hierarchical fuzzy control algorithm was presented in the robot’s posture-load regulation. The engineering result verifies the effectiveness of the fuzzy controllers and the enhanced autonomous operating capability of the robot.

Abstract: The structure and control system of full electric driven loader after electrified modification are introduced firstly. The main technical parameters of the modified loader are described. The feasibility of the application and major programme of the FlexRay communication protocol in full electric driven loader are discussed. Finally, the corresponding designing and controlling schemes are given to the main controller and minor controller, the design plan for the control system of engineering vehicle is proposed, and the performance of the engineering vehicle using FlexRay is analyzed, which provide solid theory and experiment support for the FlexRay application in engineering vehicle.