| The automotive industry is booming in the global market.As an important part of the automotive transmission system,transmission has always been a hot trend in industry research.Dual Clutch Transmission(DCT)has become a key research and development target of major R&D institutions in recent years due to its simple mechanical mechanism,high transmission efficiency,uninterrupted power and large bearing torque.The traditional DCT adopts a single clutch starting mode,similar to the Automatic Mechanical Transmission(AMT).This starting mode is simple to control,but the performance evaluation indicators such as jerk,sliding work,and starting time have a series of optimization space.If the dual clutch is used to undertake the sliding and transmitting torque during the start of the DCT vehicle,the service life of the clutch can be effectively extended and various performance indexes can be optimized.Due to the possible dynamic coupling and power interference of the DCT transmission itself,the control difficulty is greatly increased.In order to improve the driving experience during the start of DCT,this paper proposes a dual clutch starting coordination optimization control strategy,the main work includes the following aspects:(1)Firstly the working principle of the drive train system,dynamic analysis of DCT mechanical structure,actuator solenoid valve and clutch is systematically analyzed,and a DCT vehicle model including DCT,solenoid valve,clutch,engine and other modules is built in the simulink environment.Parameters required in the vehicle model is established.And the rationality of the model is verified under different control inputs,which can be used for the next controller design and analysis.(2)The control requirements of the dual clutch starting process is analyzed,the starting control scheme is formulated,the starting process is divided into two sub-phases,in the first stage where double clutches both take torque,while in the second stage the start clutch finishes startup and the non-starting clutch withdrawal.The dynamic equations are respectively given,the dual-clutch starting coordinated optimization switching controller with double closed-loop tracking is designed,and the outer ring speed tracking loop based on model prediction Control,the inner ring pressure tracking loop is based on sliding mode control.The effectiveness of the proposed dual clutch start control strategy is proved by off-line simulation under different working conditions.Finally,a comparative experiment of single clutch start-up is carried out to prove that the proposed two-clutch starting strategy can effectively improve the driving experience of the starting process.(3)In order to verify the real-time performance of the proposed strategy,hardware simulation debugging is performed.The implementation steps of the FPGA-based control algorithm are designed.In order to avoid the problem that the toolbox can't realize the code,Particle Swarm Optimization(PSO)is adopted as the optimization algorithm.Firstly,the control algorithm written in M language is converted into C code,and the floating point code is fixed.AD/DA communication interface module is designed.Next,it is integrated in VIVADO HLS(High Level Synthesis),and finally integrated/layout/routed in VIVADO environment.It is finally proved that the development platform with FPGA as the controller realizes the control requirements under the premise of satisfying the control precision.In this paper,the dual-clutch starting coordination optimization control strategy based on model predictive control is designed.The effectiveness of the controller is proved by offline simulation.The functionality of the controller is verified by hardwarein-the-loop experiments.However,there are still some work to be completed: 1)Starting strategies for different gear positions according to different road conditions should be designed;2)the clutch model should be furtherly improved;3)real vehicle verification should be developed. |
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