This paper proposes an adaptive tracking control scheme for an electronic throttle valve (ETV) based on recursive terminal sliding mode (RTSM) control strategy in the presence of parametric uncertainties and lumped disturbance. The developed RTSM dynamical structure for the controller is composed of a fast nonsingular terminal sliding surface and a recursive integral terminal sliding function, such that not only is the reaching phase eliminated, but also a sequential finite-time zero-convergence of both the recursive sliding surfaces and position tracking error are guaranteed. Due to the difficulty in ensuring a satisfactory tracking performance with respective to a broad range of operation conditions in practice, an adaptive mechanism is further developed to estimate both the lumped uncertainty bound and the sliding mode parameters, such that no prior knowledge of the system is required in the controller leading to the effective improvement of the flexibility and simplicity of sliding mode-based ETV control systems. Comparative experiments are conducted to verify that the proposed control enjoys a fast finite-time convergence and superior robustness with respect to uncertainties and disturbances.

This letter proposes a novel power-boosting strategy for strongly coupled wireless power transfer system by aligning the first and third harmonic frequencies of the inverter switching node voltage with the lower and upper splitting frequencies, respectively. Within the parity-time symmetric region, the output power at splitting frequencies significantly exceeds that at the natural resonant frequency. Additionally, when the coupling coefficient k is larger than 0.8, the output power can be further enhanced by superimposing the first and third harmonic voltages of the inverter, all while maintaining high efficiency. Finally, experimental results demonstrate that the proposed strategy achieves an output power of 609.2 W, 124.32 times greater than that of 4.9 W at the natural resonant frequency. And the efficiency by using the proposed strategy is 87.04%, which is comparable to the efficiency of 89.91% by operating at the natural resonant frequency.