The Research On Coupling Of Push V-belt Continuously Variable Transmission

With the increasing production of cars, more and more families own a private car. And the rapid development of logistics makes the increasing demand for cars. In 2010 Chinese automobile sales was expected to reach 18 million. So the issues of energy and environmental become more and more important. Therefore the Push V-belt Continuously Variable Transmission, for its energy saving benefits, more and more is applied to the car.The ratio control and the clamping force control of the Push V-belt Continuously Variable Transmission is the two most important parts of its control. For the reasons of structure and transmission mechanism, the ratio control and clamping force control is coupling, that plagues Researchers in the field. The original solution of the coupling and efficiency of the CVT transmission can not be increased to better levels.At present, the issues of climate and increasing demands for energy conservation is more and more important. And the research on CVT transmission efficiency has also got great progress. Therefore, an appropriate control strategy is needed to solve the coupling, and make the efficiency of the Push V-belt Continuously Variable Transmission the research results be played.In this paper, based on the efficiency of Push V-belt Continuously Variable Transmission, for the coupling following research was done:1) By analyzing the relationship of kinematics of Push V-belt CVT, the structure and transmission mechanism was analyzed. With analysis the stress of metal ring and metal sheet, the mathematical model of torque was founded. For the problem of low efficiency of Push V-belt CVT, the mechanism of transmission losses have been studied from the 3 parties, and founded a detailed mathematical model. The transmission loss factors was simulated with Matlab. Simulation results show that CVT transmission device by the clamping force of the impact of the loss is obvious.2) The coupling Of ratio control and the clamping force control were studied. Analyzed the relationship between the two controls. Determine the coupling relationship through logic and mathematics. Through the static force balance of radial, dynamic balance of radial and metal band theoretical analysis of the Transfer torque, proposed factor s of relative gain are:the the initial transmission ratio, the transmission torque and the clamping force. the impact of proposed of coupling index was evaluated:the degree of the change gear ratio and ratio rate of change. 3) Study on the Decoupling control theory. Accordance with the decoupling theory and process control theory, the decoupling method on ratio control and clamping force control is studied. Decoupling theory and process control in accordance with the actual method of decoupling control is studied.On this basis, Designed and analyzed the control of several clamping force control strategy for decoupling control, And a more detailed analysis of the decoupling effect of various control strategies is done. Combined with previous studies, and in a variety of clamping force control mode, the coupling conditions on the transmission ratio control strategy are studied. The characteristics of different control strategies and the impact on the coupling were analysised.Clamping force for the slip control mode was analyzed, in this strong coupling mode, the need to design a more complex control system to solve the coupling problem. On this basis, the design of the feedback linearization and feedforward compensation decoupling PID control of two options, and the feasibility of the two programs were analyzed.4) By Experiments the relationship of coupling between the ratio control and clamping force control is researched under Slip control mode.Slip rate calculation method to offset the impact is designed and analyzed, with the former compared to slip more accurate calculation method and calculation method is verified by experiment accuracy.On this basis, the clamping force control for slip was realized. And the factors that affect the slip control for the slip is analyzed. The foundation of the decoupling control under the slip control mode is founded.On the basis of slip control, two measurement of critical clamping force was designed. And through the clamping force, the critical data tables was achieved, And mutual authentication using two methods of measurement to ensure the accuracy of the measurement set.Base on determined the critical basis of clamping force, the pilot program of studying Coupling was designed. Through a large number of tests, for torque at different load conditions, different initial transmission ratio, the relative of the slave cylinder pressure variations and the transmission ratio the relation between was gain. And analyzed the influence factors and variation of the relative gain and. Basis on the test, when a large amount of clamping force change, At this point the relative gain of the transmission ratio can not accurately reflect the relationship between the coupling because of Structural constraints, the rate of change of ratio as a supplementary means to describe the metal clip CVT tight coupling of force and the relationship between transmission ratio.5) In order to validate the design of feed-forward compensation for the effects of PID decoupling controller, in the original test bed, based on the need for data measured on the test rig has been transformed, the required sensors is installed.Two proposed laws were founded for coupled relative gain of the feedforward table into the method table, And using the results of experimental method to revise calculation method.Determine the compensation rules, analysis of the amount of pressure in the hydraulic cylinder large enough to change the transmission ratio to the limit leaving the position, put forward by the rate of change gear ratio under this condition the value of the modified feed-forward compensation method.under torque step condition and the transmission ratio step condition, The feed-forward compensation decoupling and PID decoupling control effect was verified. The results show that the decoupling effect of the decoupling controller was basically solved the coupling of transmission ratio control and clamping force control under the control of slip.Through these research, analysis of the metal belt CVT gear ratio control of clamping force and the coupling relationship between the determined couple the relative gain factor. Test for the metal through the CVT transmission ratio of the clamping force and the coupling between the control laws. Decoupling control strategy and research and analysis, control objectives identified under the different decoupling control strategy, and to improve the transmission efficiency for the purpose of the slip rate control mode feedforward compensation design PID control strategy and in the test bench to verify the control strategy on the test. Vehicle control for the future provides a basis.