Sliding Mode Control For Electronic Throttle Valve Of Automotive Engine

The fuel economy, emissions and drivability of automobiles can be improvedthrough the air-fuel ratio under the control of the electronic throttle system. However, ahigh precision electronic throttle controller is difficult to design due to the nonlinearuncertainties of stick–slip friction and spring in the system and the existence of externaldisturbance. In order to improve the performance of electronic throttle control (ETC), thisthesis mainly focuses on the sliding mode control (SMC) for electronic throttle (ET) withemphasis on the accuracy and responsiveness. The main work and contributions are asfollows:Traditional SMC for ET valve. Based on the nonlinear model of ET, thetraditional SMC for ET valve is studied using the Lyapunov technique and sliding modetheory, where the throttle opening angle error and its variation are viewed as the input.Results from numerical experiments show that the proposed traditional sliding modecontroller can effectively track the desired input of ET. Note that the proposed traditionalsliding mode controller cannot reject the parametric uncertainties under the step referencesignal with respect to the tracking error (i. e.,0.7deg) and robustness.The Luenberger sliding mode observer (SMO) based global fast SMC for ETvalve. Considering the ET opening angle change is unmeasurable in practice, theLuenberger SMO is designed to estimate the throttle opening angle change of ET;Subsequently, the nonlinear term is incorporated into the sliding mode surface design toimprove the robustness of traditional SMC. And then the global fast sliding modecontroller for ET is proposed. Resutls from numerical experiments indicate that thetracking error of step reference signal is0.25deg under parametric variation, andmeanwhile, the settling time of step reference signal is0.0968s. Compared withtraditional sliding mode controller, the robustness is obviously enhanced and the settlingtime is decreased by41%.An extended state observer (ESO) based Back-stepping sliding mode control forET valve. Given that the Luenberger SMO in can only estimate the state variables ofET, an ESO is designed based on the ET nonlinear model to estimate the throttle openingangle change and total uncertainty of ET simultaneously; Subsequently, in order toenhance control performance of traditional SMC in, the Back-stepping sliding mode controller is developed using the Back-stepping control (BSC) theory and sliding modecontrol theory. Results from numerical experiments demonstrate that the tracking error ofstep reference signal is0.02deg under parametric variation, and the settling time of stepreference signal is0.0367s, which verify the effectiveness of the proposed ESO basedBack-stepping sliding model controller.An ESO based double loop integral sliding mode control (DLISMC) for ETvalve. Considering the issue that control algorithm in,, and treated only thethrottle opening angle error as feedback signal, this thesis, to the best of our knowledge, isfirst to consider both the throttle opening angle error and the throttle opening change erroras feedback signal, the ESO based DLISMC for ET is proposed. Particularly,(i) In doubleclosed loop controller, the inner loop controller is based on the throttle opening anglechange error and the outer loop controller is based on the throttle opening angle error.Thereby, the controller can track the throttle opening angle and opening angle changesimultaneously to enhance the accuracy of the proposed controller;(ii) The integral term,which can effectively eliminate the static error of the ET system, is incorporated into thesliding mode surface design, resulting in improved ET system stability;(iii) The gearbacklash torque and external disturbance are taken into consideration to reduce the effectsof parametric uncertainties and nonlinearities. Finally, results from numerical experimentsverify the effectiveness of the proposed approach in terms of accuracy andresponsiveness.