Experiment Of New EMCVT Dynamic Characteristics And Study On Its Control

Researches on CVT technology have been more than one hundred years.In the early due to manufacturing and control technology constraints,CVT technology had not been widely used.With the breakthrough of some key technologies,CVT technology has entered a stage of rapid development.Faced with a wide range of CVT technology application prospects,it is particularly important to carry out the relevant technology research.Speed ratio and clamping force are the two mainly important control objectives in CVTs.Adjusting speed ratio is to ensure that the engine is in the best working condition,and controlling the clamping force to ensure the transmission of power.The automatic pressurization electronic mechanical continuously variable transmission,which adopts a new mechanical compression structure,is the research object of this article.There are the following features about it.On the one hand,because the inefficient hydraulic system is abandoned,the economic effectiveness of this transmission is greatly improved.On the other hand,because the clamping force of the transmission can be adjusted according to the actual working load,the control strategy of the clamping force can be omitted to simplify the control flow.The research work is based on the following aspects in this article.First of all,the change characteristics of speed ratio and clamping force of CVT and the reasons of chain offset are analyzed theoretically,and the related mathematical model established.To simulate those mathematical models with Simulink,the relationship between speed ratio and thrust ratio and the tendency of chain offset with speed ratio are studied.Secondly,the relevant control strategy is developed.The transmission studied in this paper is only used for functional testing and experimental research,so the speed ratio control strategy of the transmission mainly for tracking the target speed ratio.According to the experimental purpose,an experimental platform based on PLC controller is set up,and the tracking of target speed ratio is achieved with incomplete derivative PID speed ratio control strategy.These tasks are the first research on the product of transmission.Finally,a series of functional test experiments were made on the automatic pressurization continuously variable transmission.As a result of a new mechanical compression structure to achieve the application of clamping force,the compression structures need to make functional testing.Through these test experiments,the mathematical model of automatic pressure is verified,the potential problems of transmission explored,and the direction for further improvement of the transmission provided.With high transmission efficiency,simple control methods and other advantages,the automatic pressurization electronic mechanical continuously variable transmission has great potential applications,so follow-up researches on this kind of transmission will be more and more.The results of this article have certain reference value for the related research in the future.