An electronic throttle is a dc-motor-driven valve that regulates air inflow into the combustion system of the engine. The throttle control system should ensure fast and accurate reference tracking of the valve plate angle while preventing excessive wear of the throttle components by constraining physical variables to their normal-operation domains. These high-quality control demands are hard to accomplish since the plant is burdened with strong nonlinear effects of friction and limp-home nonlinearity. In this paper, the controller synthesis is performed in discrete time by solving a constrained time-optimal control problem for the piecewise affine (PWA) model of the throttle. To that end, a procedure is proposed to model friction in a discrete-time PWA form that is suitable both for simulation and controller design purposes. The control action computation can, in general, be restated as a mixed-integer program. However, due to the small sampling time, solving such a program online (in a receding horizon fashion) would be very prohibitive. This issue is resolved by applying recent theoretical results that enable offline precomputation of the state-feedback optimal control law in the form of a lookup table. The technique employs invariant set computation and reachability analysis. The experimental results on a real electronic throttle are reported and compared with a tuned PID controller that comprises a feedforward compensation of the process nonlinearities. The designed time-optimal controller achieves considerably faster transient, while preserving other important performance measures, like the absence of overshoot and static accuracy within the measurement resolution

Hybrid Theory-Based Time-Optimal Control of an Electronic Throttle

Adaptive control of automotive electronic throttle

An electronic throttle is a low-power dc servo drive which positions the throttle plate. Its application in modern automotive engines leads to improvements in vehicle drivability, fuel economy, and emissions. Transmission friction and the return spring limp-home nonlinearity significantly affect the electronic throttle performance. The influence of these effects is analyzed by means of computer simulations, experiments, and analytical calculations. A dynamic friction model is developed in order to adequately capture the experimentally observed characteristics of the presliding-displacement and breakaway effects. The linear part of electronic throttle process model is also analyzed and experimentally identified. A nonlinear control strategy is proposed, consisting of a proportional-integral-derivative (PID) controller and a feedback compensator for friction and limp-home effects. The PID controller parameters are analytically optimized according to the damping optimum criterion. The proposed control strategy is verified by computer simulations and experiments.

An electronic throttle control strategy including compensation of friction and limp-home effects

The control of automobile electronic throttle (AET) systems is a challenging task owing to multiple nonlinearities, i.e., transmission friction, gear backlash, limp-home spring set, and external load disturbance. In this paper, a practical tracking control scheme of an AET system is developed using a continuous fast nonsingular terminal sliding mode (CFNTSM) technique based on uncertainty observer. By using the prescribed CFNTSM surface and fast terminal sliding mode-based reaching element, the proposed control implementation guarantees the fast error convergence characteristic and high tracking accuracy under parameter uncertainties and perturbations. Furthermore, due to the adoption of the finite-time exact observer (FEO) for the lumped uncertainty estimation in the controller, the ease of the selection of the control gains is well-achieved since they only depend on the uncertainty estimation error. The closed-loop stability and finite-time convergence are presented based on the Lyapunov stability theory. Experimental verifications are conducted to validate the remarkable performance of the proposed control, in terms of the step and sinusoidal tracking as well as anti-disturbance ability.

Continuous Fast Nonsingular Terminal Sliding Mode Control of Automotive Electronic Throttle Systems Using Finite-Time Exact Observer

By adding an electronic throttle and a torque sensor to an engine, it is potentially possible to improve emissions and fuel economy while preserving the torque response of a conventional engine. To do so effectively, however, requires the use of proper control strategy for electronic throttle. In this paper, a kind of fractional order fuzzy PID controller is proposed and it is applied to an electronic throttle. An efficient way to tune fractional order fuzzy PID controller parameters is proposed using a fruit fly optimization algorithm (FOA), which treats the controller parameters tuning as an optimization problem with a proper fitness function. The obtained simulation results show the effective performance of the proposed method.

Fruit fly optimization algorithm based fractional order fuzzy-PID controller for electronic throttle

Transmission friction and the return spring limp-home nonlinearity affect the performance of electronic throttle servosystems. The influence of these effects is analyzed by means of computer simulations and experiments. A novel friction model is developed, in order to adequately capture the experimentally observed characteristics of the presliding displacement and breakaway effects. A control strategy consisting of a PID controller and a compensator of friction and limp-home effects is proposed. It is verified by computer simulation and experiment.

A self-tuning strategy for an electronic throttle servo-system is proposed in order to account for the variations of DC motor armature resistance, battery voltage, and limp-home position. Different self-tuning algorithms have been derived depending on the availability of armature current sensor and control strategy auto-tuning procedure. The presented self-tuning algorithm has been experimentally verified on an experimental setup of electronic throttle control system. For the purpose of experimental verification, a real-time simulator of process parameters variations has been developed.

Self-tuning control of an electronic throttle

Detailed off-line experimental identification of an automotive electronic throttle body (ETB) servo drive is carried out with the aim to aid design of a high-performance electronic throttle control strategy. The linear and nonlinear parts of the ETB model are conveniently identified separately. Identification of ETB linear dynamics includes a multi-step identification method based on the physical ETB model form, and single-step methods based on the black-box continuous-time and discrete-time ETB model forms. The nonlinear effects identified include static and dynamic friction effects, and distinctive limp-home nonlinearity.

Martin Jansz

Papers

Adaptive control of automotive electronic throttle

An electronic throttle control strategy including compensation of friction and limp-home effects

An electronic throttle control strategy including compensation of friction and limp-home effects

Self-tuning control of an electronic throttle

Experimental Identification of an Electronic Throttle Body