Weida Wang

Synthetical efficiency-based optimization for the power distribution of power-split hybrid electric vehicles

Now the optimization strategies for power distribution are researched widely, and most of them are aiming to the optimal fuel economy and the driving cycle must be preknown. Thus if the actual driving condition deviates from the scheduled driving cycle, the effect of optimal results will be declined greatly. Therefore, the instantaneous optimization strategy carried out on-line is studied in this paper. The power split path and the transmission efficiency are analyzed based on a special power-split scheme and the efficiency models of the power transmitting components are established. The synthetical efficiency optimization model is established for enhancing the transmission efficiency and the fuel economy. The identification of the synthetical efficiency as the optimization objective and the constrain group are discussed emphatically. The optimization is calculated by the adaptive simulated annealing (ASA) algorithm and realized on-line by the radial basis function (RBF)-based similar models. The optimization for power distribution of the hybrid vehicle in an actual driving condition is carried out and the road test results are presented. The test results indicate that the synthetical efficiency optimization method can enhance the transmission efficiency and the fuel economy of the power-split hybrid electric vehicle (HEV) observably. Compared to the rules-based strategy the optimization strategy is optimal and achieves the approximate global optimization solution for the power distribution. The synthetical efficiency optimization solved by ASA algorithm can give attentions to both optimization quality and calculation efficiency, thus it has good application foreground for the power distribution of power-split HEV.

Analysis method and principle of dual-mode electro-mechanical variable transmission program

Automotive industry, as an important pillar of the national economy, has been rapidly developing in recent years. But proplems such as energy comsumption and environmental pollution are posed at the same time. Electro-mechanical variable transmission system is considered one of avilable workarounds. It is brought forward a kind of design methods of dual-mode electro-mechanical variable transmission system rotational speed characteristics and dual-mode drive diagrams. With the motor operating behavior of running in four quadrants and the speed characteristics of the simple internal and external meshing single planetary gear train, four kinds of dual-mode electro-mechanical transmission system scheme are designed. And the velocity, torque and power characteristics of one of the programs are analyzed. The magnitude of the electric split-flow power is an important factor which influences the system performance, so in the parameters matching design, it needs to reduce the power needs under the first mode of the motor. The motor, output rotational speed range and the position of the mode switching point have relationships with the characteristics design of the planetary gear set. The analysis method is to provide a reference for hybrid vehicles’ design. As the involved rotational speed and torque relationships are the natural contact of every part of transmission system, a theory basis of system program and performance analysis is provided.

A control strategy to reduce torque variation for dual-mode power-split hybrid electric vechile during mode shift

The paper presents a mode shift control strategy of dual-mode power-split hybrid electric vehicle during the mode shift phase, intended to reduce the torque variation in the driveshaft and improve the shift quality. To evaluate the shift characteristics of this power-split hybrid electric vehicle, the detailed dynamic models are developed. Based on the dynamic models, a mode shift performance simulator is built using MATLAB/Simulink, and simulations are carried out. To analyze the shift characteristics during the mode shift phase, a bond-graph model for the transition state is constructed, and dynamic equations are derived. From the bond-graph model and dynamic equations, it is seen that the transition torque occurs because of the inertia torques of the first motor/generator and the second motor/generator. To avoid the unwanted transition torque, a mode shift control strategy that coordinates the motor-generator torque to compensate for the transition torque. It is found that the torque variation in the driveshaft during the mode shift phase is effectively reduced by the proposed control strategy.

Forward flight attitude control of unmanned small-scaled gyroplane based on μ-synthesis

In this paper the detailed design process of μ-synthesis for a modified small-scaled unmanned gyroplane is presented. Firstly, a comprehensive nonlinear model of gyroplane is established, which is of inherent instability and with the longitudinal and lateral dynamics highly coupled. Therefore, the design of flight controllers is not straightforward as for the conventional gyroplane. The μ-controller for attitude stabilization is then designed based on the linearized model extracted in forward flight configuration. Finally, a series of computer simulation experiments for performance evaluation are presented, together with a comprehensive analysis of simulation results.

Distributed Communication System Design Based on Can Bus for Parallel-Serial Hybrid Electrical Vehicles

Distributed network system based on Controller Area Network (CAN) protocol has been widely applied into the vehicle industries. CAN communication protocol for the parallel-serial hybrid electrical vehicles (PSHEV) has been designed in the paper. Real-time scheduling algorithms based on optimization periodic algorithm (OPA) with non-preemptive and preemptive scheduling are also proposed with an optimization goal function to decrease the delay time for sporadic tasks and increase the CPU utilization for a real-time controller. Then a kind of method of solving the OPA have been designed namely exhaust algorithm (EA). With a view to avoid real vehicles experiment failures in advance, it is necessary for us to make an experiment set-up to verify the validity of the CAN protocol designed and OPA for the PSHEV. So the related hardware circuits for testing CAN system have been made. Finally, communication experiments are made based on CAN protocol proposed above. The results show the CAN protocol and OPA scheduling algorithm for the PSHEV are valid, all messages can be transmitted and received efficiently and completely avoiding the occurrence of loss of messages in the process of communications in all nodes of the system and the optimized periodic tasks as a result of OPA scheduling algorithm can decrease the delay time for sporadic tasks and increase the CPU utilization for a real-time controller.