Research And Development Of The CVT Test Bench Control System

Metal belt type continuously variable transmission (CVT) is an advanced vehicle's transmission equipment, which can realize smooth transmission without gear shift. Many of the world vehicle manufacturers are conducting a large number of theoretical and experimental research in order to obtain optimal transmission efficiency and further reduce fuel consumption and emissions. The test of the continuously variable transmission can be carried out in the vehicle, but the consumption time is long and the cost is high, also it is difficult to achieve extreme working condition test. Therefore, it is necessary to establish a test bench to simulate the actual driving conditions of the vehicle, and to detect the performance of CVT under various operating conditions.Jianglu&Rongda vehicle transmission limited company (Jianglu&Rongda) is one of the first domestic CVT technology research and production enterprises, and the subject of this article is CVT motor calibration and durability test bench project of Jianglu&Rongda. This paper mainly focuses on the research of the test bench control system.The test bench is designed in accordance with the need of enterprise development, which is used to verify the metal belt CVT performance indicators, control algorithm improvement and other tasks. After analyzing the experimental conditions, the hardware, software and control method of the control system are designed and studied. Finally, the test bench was tested and verified. Specific work of this paper are as follows:(1) The structure design and hardware selection of the hardware of the test bench control system are carried out. Variable-frequency and variable-speed motor is selected as the speed and load control device of the test bench;(2) The load control of the test bench is studied, and the load torque of the feed-forward and feedback compound control method is established, which provides the theoretical foundation and the simulation model for the load control of the test bench;(3) The structure design of the software of the test bench control system is designed, and the modular, high flexibility and extensibility software system is built up. The stability of the software is determined by the stability of the structure;(4) After the completion of the hardware and software of the test bench, the whole test bench was tested and verified. Except the control performance and stability of the motor were verified, the stability of the load control system was verified by the fatigue life test. At the same time, the experiment of speed ratio tracking algorithm optimization was carried out, and through the comparison of real vehicle test, the effectiveness of the CVT algorithm is demonstrated.This test bench has high automation degree, strong adaptability, good real-time, friendly man-machine interface, can perform a variety of complex test. It is proved by experiments that the design of the test bench control system is in accordance with the requirements of the enterprise, the selection of the control method is successful.