Hardware-in-the-Loop Simulation Research On Continuously Variable Transmission In Driver-Vehicle-Road Closed Loop System

Hardware-in-the-loop (HIL) test system for vehicle automatic transmission driveline system is advanced vehicle automatic transmission driveline test system appeared in recent years, which makes driver, engine, chassis, driving environment and so on simulation model embedded into software environment by utilizing HIL real-time simulation technology combined with hardware and software, for simulating automatic transmission actual operation state, detecting and analyzing the working performance of automotive controller, hydraulic/electrical control system and actuator, then offering a test and development platform for the research and development of automatic transmission automotive.Against the limitation of current hardware-in-the-loop test for vehicle automatic transmission driveline system which only can test control strategies, HIL theory modeling and simulation test research on continuously variable transmission in driver-vehicle-road closed-loop system are carried out relying on the projects of the scientific and technological project of Chongqing《Research and Development of Hardware-in-the-loop Test System for Vehicle Automatic Transmission》and 985 platform national key laboratory open funds《Hardware-in-the-loop Simulation Platform Research on Automatic Transmission》in this paper. The main research work as follows:(1) In view of driving manipulation qualification which current driver models can not embody out, following running error minimum and physical ability-to-pay minimum principle, fuzzy PID scale factor and quantization factor is off-line optimized adopted with genetic algorithms, then direction fuzzy PID based on genetic algorithms and speed fuzzy integrated control virtual driver simulation model is established; the model is simulated and analyzed under typical mode such as longitudinal speed one-way variation and lateral double lane and big curvature test road, and then compared with traditional PID and fuzzy PID control methods; finally, identification system are regulated adopted with fuzzy deduce method by determining the expressing features of different driver styles and different driver intentions.(2) Based on 15 degrees of freedom (DOF) vehicle dynamics model, considering road characteristic parameters influence such as lateral gradient, longitudinal gradient and synthetic gradient, the vehicle dynamics model and tire vertical load variation model are established, then virtual vehicle dynamic simulation model is established combined with steering system, braking system, power train system, wheel and suspension models, and analyzed and compared under different lateral, longitudinal, synthetic gradient and vehicle speed; finally the driver-vehicle closed-loop system simulation model is established combined with virtual driver simulation model.(3) From the requirement of driver-vehicle-road closed-loop system and real-time virtual simulation system, according to the code for design of road and principle for design of road, and consulted with the design of the proving ground of domestic and international, one high fidelity enclosed three-dimension virtual road which is accorded with road design standard and can reflect different driving environment is developed for further researching on ratio self adapted intelligent integrated shift control strategies for continuously variable transmission. Then the driving environment fuzzy identification system is proposed by determining the expressing feature of driving environments including good road section, complicate road section, bumpy road section, upslope road section, downslope road section and curve road section.(4) Based on dynamic simulation model for continuously variable transmission,τalgorithm, engine torque compensation and engine speed compensation integrated control are proposed by synthetically considering stand-by power, powertrain loss, and CVT ratio change response lag. And then the three integrated control methods are simulated to compare with dynamic and economic performance; Based on CVT optimal dynamic and economy ratio control strategies, CVT ratio control strategies are proposed for different driver styles, different driver intentions and different single driving environment and CVT ratio weight control strategy is proposed for multi-driving environments coupling mode, including turning modified ratio control strategy proposed synthetically considering throttle opening rate, steering wheel steering angle and steering vehicle speed; bumpy road section discretion ratio control strategy proposed synthetically considering throttle opening and vehicle speed micro-variation; upslope modified ratio control strategy proposed synthetically considering throttle opening and longitudinal gradient; downslope modified ratio control strategy synthetically considering downslope initial vehicle speed, longitudinal gradient and downslope length; and CVT ratio self adapted intelligent integrated control strategy for coupling operating mode combined with driver styles, driver intentions and driving environments.(5) According to driver-vehicle closed-loop system simulation models, self adapted intelligent integrated control model for continuously variable transmission system, and virtual road simulation model developed under VRML, self adapted intelligent integrated control simulation models for continuously variable transmission system in driver-vehicle-road closed-loop system are established based on simulink and VR co_simulation platform by developing virtual proving ground with VR toolbox, then CVT ratio control strategies are simulated and analyzed under different driver styles, driver intentions and single driving environment modes, and CVT ratio self adapted intelligent integrated control models are simulated and analyzed under the coupling operating modes combined with driver styles, driver intentions and driving environments to validate the feasibility and accuracy of the control strategies.(6) Based on Matlab/Simulink and dSPACE RTI co_simulation platform, hardware-in-the-loop test system for continuously variable transmission is developed, including overall planning design, device purchase, components design and processing and manufacturing, signal collecting and processing, hardware design and software design. By utilizing the test system, and according to firstly bench performance test results, further the CVT ratio control test for different driver intentions, upslope, downslope, curve road and bumpy road section are carried out, then CVT ratio self adapted intelligent integrated control test is carried out for coupling operating modes to validate the availabilty of control strategies.