Advanced Materials Research Vols. 694-697

Abstract: A novel double-catalyst layer MEA using CCM-GDE (Catalyst Coated Membrane,CCM;Gas Diffusion Electrode,GDE) fabrication method is provided. The double-catalyst layer is formed with an inner catalyst layer (in anode side: PtRu black as catalyst, in cathode side: Pt black as catalyst) and an outer catalyst layer (in anode side: PtRu/C as catalyst, in cathode side: Pt/C as catalyst). By study of the catalyst loading in the double-catalyst layer, an optimization of the catalyst layer structure is obtained, that is the cell may perform best when the ratio of the inner catalyst and outer catalyst is 1:1 (both in inner and outer catalyst layer, the catalyst loading is 1.5mg/cm²). As the hydrophilicity and pore structure are important to the MEA performance, they are optimized by adding pore former and Nafion in the GDL and outer catalyst layer, respectively. Thus three gradients from the PEM to the GDL are formed in the novel MEA: catalyst concentration gradient, porosity gradient and hydrophilicity gradient. These gradients may increase the mass transfer and quicken the electrochemistry reaction in MEA. The CCM-GDE technology may enhance the contact properties between the catalyst and PEM, and increase the electrode reaction areas, resulted in increasing the performance of the μDMFC.

Abstract: Based on the integrated circuits LM629 and MC33035, a design method of small power servo brushless DC motor (BLDC) driver is presented, and the main control circuit, the driving of power circuits and the structure of software are introduced yet in the paper. This driver can communicate externally with RS485 bus and accomplish speed servo and position servo with the scheduled parameters. The experiment shows that the driver provides good stability and precision when driving the 18V 80W brushless DC motor.

Abstract: This paper presents a full drive-by-wire vehicle named Urban Future Electric Vehicle (UFEV) and introduces the detailed design of its vehicle control unit (VCU). The LabVIEW and PXI solution is selected for the rapid prototyping of VCU, which also acts as a real-time test, measurement and control platform for UFEV. To address its unique features, the design and transition of specific driving modes are introduced. Experiments show that omnidirectional moving can be implemented accurately and reliably by using the proposed design.

Abstract: This paper describes an integral scheme of the design and simulation of the Attitude Determination and Control Subsystem (ADCS) of CubeSat. CubeSat is an educational low-cost, cube-shaped Pico spacecraft. Attitude Determination (AD) is the problem of expressing the orientation of a spacecraft with respect to a given coordinate system. Three axis magneto-resistive digital magnetometer is selected as an attitude sensor. The International Geomagnetic Reference Field (IGRF) is used as reference for magnetometer to obtain attitude information. An enhanced orbit estimate/propagator is implemented to provide position information to IGRF model. Satellite environmental torque is modeled along with satellite kinematics and dynamics. Attitude estimation is done using Extended Kalman Filter (EKF) while the magnetic coils are used as actuators. Attitude Control is applied using Linear Quadratic Regulation (LQR) Controller. The designed ADCS is implemented in Matlab/Simulink.

Abstract: A new kind of power train was developed for electric hybrid vehicle, which is mainly consisted of engine, two generator/motors, two sets of planetary gear, power mode selection mechanism. The power mode selection mechanism has three positions, it make the power train have three different operation modes which are pure electric driving mode, pure engine driving mode and hybrid driving mode. Different operation mode is corresponding to different vehicle load conditions for economy and dynamics requirements.

Abstract: A new type test bench was developed for power train used in electric hybrid vehicle. This bench was mainly composed of inertial flywheels, brake, clutch, dynameters, and controller. When testing the power train, the engine, power train, inertial flywheels, brake, clutch and dynameters are connected in series. One end of inertial flywheels is connected with output end of power train; the other end is connected with a clutch. Between the inertial flywheels and clutch, there is a brake for braking of flywheels. The clutch is for connection and disconnection of inertial flywheels and dynameters. This new test bench can perform different power modes with corresponding operation modes set in the main controller.

Abstract: Computational fluid dynamics (CFD) method is applied to analyze airflow field of acoustic-induced vibration piezoelectric generator. In this paper, numerical simulation has been performed for the unsteady flow field of nozzle vortex shedding with inlet and outlet boundary conditions. Distribution of velocity, pressure and vortices field has been calculated and analyzed in the process of vortex shedding in order to provide a reference for optimizing source frequency. The result shows that jetting initially shows vortex shedding when adopting the nozzle of variable flow tube structure, which is an equal section flow tube with necking cross section flow tube. The analysis method of this paper is laid the foundation for the design of power airflow acoustic source generator.

Abstract: According to the regenerative braking system(RBS) with a pedal emulator as well as the control strategy. Design a hardware test platform of power regenerative system and the scheme of software experiment. Aim at the control strategy, braking safety and braking feeling of RBS with a braking pedal emulator is confirmed via hardware in loop (HIL) test. A high regenerative rate is obtained. From the result of simulation, the pedal force line from RBS with a pedal emulator is between the envelope curve of the pedal force from conventional vehicle. Actual wheel cylinder pressure can follow the change of target pressure very well. The regenerative braking rate reaches 53%.

Abstract: Moving-magnet linear compressors with sensorless top dead center (TDC) control method are an efficient solution for domestic refrigerators to save energy. TDC can be determined by the inflection point of phase difference between the sinusoidal current and piston displacement (I-X phase difference). A digital correlation method is used to calculate the I-X phase difference to obtain the TDC position for control. The TDC determining system using digital correlation method is manufactured and the error is 2.29% under various discharge pressures.

Abstract: According to the inverse solutions of 3-UPU translational parallel robot mechanisms, in which both the base and the mobile platform are triangle and similar to each other, the accuracy model of parallel robot mechanisms is established by the differentiation of the kinematic. The effects of length error of driving poles, structure size change and posture change on the accuracy of robot are studied by simulations,which provided the foundation for practical error compensating and controlling of the mechanism.