Yuhui Hu

Research on Gear Shifting Process without Disengaging Clutch for a Parallel Hybrid Electric Vehicle Equipped with AMT

Dynamic models of a single-shaft parallel hybrid electric vehicle (HEV) equipped with automated mechanical transmission (AMT) were described in different working stages during a gear shifting process without disengaging clutch. Parameters affecting the gear shifting time, components life, and gear shifting jerk in different transient states during a gear shifting process were deeply analyzed. The mathematical models considering the detailed synchronizer working process which can explain the gear shifting failure, long time gear shifting, and frequent synchronizer failure phenomenon in HEV were derived. Dynamic coordinated control strategy of the engine, motor, and actuators in different transient states considering the detailed working stages of synchronizer in a gear shifting process of a HEV is for the first time innovatively proposed according to the state of art references. Bench test and real road test results show that the proposed control strategy can improve the gear shifting quality in all its evaluation indexes significantly.

ASCS online fault detection and isolation based on an improved MPCA

Multi-way principal component analysis (MPCA) has received considerable attention and been widely used in process monitoring. A traditional MPCA algorithm unfolds multiple batches of historical data into a two-dimensional matrix and cut the matrix along the time axis to form subspaces. However, low efficiency of subspaces and difficult fault isolation are the common disadvantages for the principal component model. This paper presents a new subspace construction method based on kernel density estimation function that can effectively reduce the storage amount of the subspace information. The MPCA model and the knowledge base are built based on the new subspace. Then, fault detection and isolation with the squared prediction error (SPE) statistic and the Hotelling (T2) statistic are also realized in process monitoring. When a fault occurs, fault isolation based on the SPE statistic is achieved by residual contribution analysis of different variables. For fault isolation of subspace based on the T2 statistic, the relationship between the statistic indicator and state variables is constructed, and the constraint conditions are presented to check the validity of fault isolation. Then, to improve the robustness of fault isolation to unexpected disturbances, the statistic method is adopted to set the relation between single subspace and multiple subspaces to increase the corrective rate of fault isolation. Finally fault detection and isolation based on the improved MPCA is used to monitor the automatic shift control system (ASCS) to prove the correctness and effectiveness of the algorithm. The research proposes a new subspace construction method to reduce the required storage capacity and to prove the robustness of the principal component model, and sets the relationship between the state variables and fault detection indicators for fault isolation.

Development of pneumatically automatic mechanical transmission for a pure electric garbage truck

The pneumatically automatic mechanical transmission (AMT) system has been developed for a pure electric garbage truck. The buildup principle and control framework of the pneumatically AMT is introduced. In order to realize the coordinate control, the CAN (Controller Area Network) bus technology is adopted to realize the communications of AMT electric control unit (ECU) and induction motor controller (MC), and then the control of the motors rotate speed and torque is realized with the instructions from AMT system. Owing to the speed control of the induction machine during the period of the gear-shifting, the synchronization is always guaranteed. Furthermore, the time of shifting to target gear is reduced greatly using the pneumatically automatic mechanical transmission system. All those shorten the whole shifting time. The experimental results show that pneumatic gear-selecting and gear-shifting is quick and reliable and proposed pneumatically AMT improves some performances of the vehicle.

Research on fault detection and diagnosis strategy based on AMT system behavior

Fault detection and diagnosis strategy based on AMT (Automatic Mechanical Transmission) system trajectory is studied. Hybrid automata is used to build healthy AMT system model. Then fault definition of AMT system is analyzed from the point of system trajectory and fault diagnosability of AMT hybrid system is studied based on AMT systems fault model and fault threshold function. According to AMT system model trajectories and control cycle, AMT hybrid systems behavior is analyzed and classified into three types: steady-state system behavior, discrete event trigger behavior and physical system response behavior. At last AMT systems fault detection and diagnosis strategy is proposed based on behavior types. The fault diagnosis strategy with the diagnostic algorithm is transplanted to the real car platform and a large number of vehicle mileage prove the strategys correctness and real-time.

Research on control strategy of automatic clutch during vehicle launching

Focusing on that the automatic clutch driven by electric motor is a time-delay and multi-parameter complex electromechanical system, an adaptive control strategy based on performance measurement in launching process for automatic clutch on the basis of analysis on the character and effecting factor for the first engaged control stage is designed. And regulated rules for cluth control parameters is determined by fuzzy control method. Finally, the feasibility and advantage for this strategy is validated through vehicle road test.

Control strategy design for clutch self-calibration for AMT on single axle hybrid city bus

A new technique for clutch self-calibration for automated mechanical transmission system based on single-axle parallel hybrid city bus is proposed. A vehicle equipped with this technique, will automatically calibrate the position of the half-engaged point of its clutch when it starts up. This calibration will eliminate or compensate the clearance due to wearing and temperature difference, and provide accurate parameters for transmission control unit, which transmission control unit can make the clutch acting rapidly and accurately, and improve the smoothness of launching and power performance, as well as shifting quality. Test results indicate this method is feasible and effective.

The indirect measurement technology of shift comfort for automatic mechanical transmission

To overcome the difficulty on objective measurement of shift comfort of automatic mechanical transmission(AMT) , the feasibility and advantages of using second derivative of the transmission input shaft speed was confirmed to calculate the gear-shifting jerk. The calculation process of jerk was elaborated in more details and jerk nondimensionalization was performed for control necessity. Finally, the indirect measurement sampling period was determined by test methods. Vehicle tests show that the indirect measurement technology can be used for control feedback and objective evaluation of AMT.

Research on Gear-Shift Control Strategy With Clutch Engaged for Fixed Shaft AMT

A new automatic gear-shift control system is designed for fixed shaft manual transmission, exceeding the process of traditional gear-shifting and achieving gear-shift control without the disengagement of the clutch. The process to achieve the vision is described based on analyzing the process of traditional gear-shifting, using the integrated control methods and strategies. Finally the feasibility and advantage for this control method is validated through vehicle road test.Copyright