Abstract
Research and/or Engineering Questions/Objective
In an electromagnetic valve actuator (EMVA), in order to improve fuel economy, reduce emissions and increase the engine output torque, accurate motion control is proposed to improve the properties of the internal combustion engine. For this purpose a new control algorithm is used. The objective of this study is to make the motion in accordance with the desired trajectory.
Methodology
The EMVA can be regarded as a coupled system with strongly interactive subsystems, including electrical, magnetic and mechanical subsystems. The dynamic model of EMVA is established. Based on the model above, a backstepping sliding mode control (BSMC) is proposed in this paper. The derivation of virtual control may lead to an expansion of the differential equations in the backstepping method, the expression of the controller can become complicated. So a dynamic surface method, namely low-pass first order filter, is used to realize the derivation of virtual. The half global uniformly bounded of all signals of the closed-loop system is proved by Lyapunov stability theory, tacking error can be convergence to arbitrarily small, thus the stability of the system is ensured.
Results
In this paper simulations and an experimental device are used to demonstrate the results of the proposed control method. Simulation results show that the BSMC is robust to large parameter variations of the system and external disturbance. The experimental results are almost in agreement with the simulation results. The experimental results show a transient time less than 3ms and a low valve seating velocity. The proposed control method has realized the precise motion control of the EMVA.
Limitations of this study
Experiments based on the cylinder head of the engine are conducted in this paper, and the single cylinder condition is considered. In the future, experiments can be implemented in actual engines, and multi-cylinder control can be realized precisely.
What does the paper offer that is new in the field including in comparison to other work by the authors?
A new control algorithm is presented for the EMVA in this paper, meanwhile better simulation and experimental results are achieved. As we can see, based on the proposed control algorithm, the EMVA can have faster transient time, lower valve seating velocity and better robustness.
Conclusions
This paper presents a control model with the BSMC of the EMVA. The results of simulations and experiments prove that the proposed control algorithm (BSMC) can achieve precise motion of the EMVA.
Key Words : backstepping control; sliding mode control; robust; dynamic surface