The Study Of Backlash Nonlinear In The Automotive Driveltne

The nonlinear factors which affect the accuracy in transmission systemare backlash, saturation, and friction characteristics, among which the mostsignificant affect on system is the backlash nonlinearity.In the gear transmission system, the backlash nonlinearity is the one cannot be neglected, and it can not be eliminated by improving the machiningaccuracy. Backlash plays a positive role in gear engagement transmission tosome extents, creating lubricant film on the tooth surface and reducing thewear. So backlash nonlinearity which affects system dynamic characteristics isalso the main issue to be solved in accurate transmission system. Backlashusually exits in mechanical drive and hydraulic system, and it severely limitsthe performance of whole system. The backlash nonlinearity is equivalent tothe affection of dead zone nonlinearity, reducing tracking accuracy of system.Backlash is piecewise function, which means under the same conditions as theinput values, the output also depends on the symbols of the state variablederivative. So backlash will affect the degree of load changes. With largebacklash and too much storage, it may bring out the phenomenon of self-oscillation, and seriously affect the system dynamic performance and stability.In this paper, research object is the backlash nonlinear phenomena inautomotive driveline. Investigate the backlash nonlinear effects of drive shaftunder auto startup and design model predictive controller.According to the automotive driveline model, model predictive controlmethod can be used to eliminate the influence of backlash on drive shaft. Onthe basis of system dynamic performance, the control system transits frombacklash phase to gear contact phase in order to achieve non-impact contact.Design model predictive controller applies to prevent the system fromoscillation in the gear contact phase, and to pass through backlash phaserapidly in backlash phase. Two solutions could be found to mitigate shock atcontact moment.Finally, simulation experiment needs to be conducted in terms of simulationsoftware SIMULINK and analysis results. Model predictive controller has asatisfactory performance in response to the backlash and robustness, and it isan effective strategy of the backlash nonlinearity in the process of auto motivetransmission.