Sliding mode control for torque ripple reduction of an electric power steering system based on a reference model

Abstract

Torque ripple in an electric power steering (EPS) system can be induced by the phase lag between steer angle and rack displacement, non-linear friction, and disturbances from road and sensor noise, especially during high-frequency manoeuvres. This paper investigates the application of robust and non-linear sliding mode control (SMC) strategies to an EPS system, based on a reference model to reduce the torque ripple and stabilize the dynamics of the EPS system. The dynamics of the EPS system is described by a non-linear state-space model with realistic non-linear friction and disturbances from road and sensor noise. Meanwhile, the ideal EPS system, in which the rack displacement tracks the steer angle perfectly, is proposed as the reference model. A non-linear sliding mode observer (SMO) is also developed to estimate the unmeasurable states. The performance and robustness of SMC and SMO are demonstrated using various simulations and compared with traditional alternatives. The results of these simulations reveal that the non-linear SMC and SMO strategies can reduce the torque ripple to achieve a better steering feel and more stable driving, and can be applied to commercial EPS systems.

Keywords

electric power steering torque ripple sliding mode control sliding mode observer

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References

Schoener

H. P.

Hille

Automotive power electronics - new challenges for power electronics. In the IEEE 31st Annual Power Electronics Specialists Conference (PESC), 2000, pp. 6–11.

Kim

J. H.

Song

J. B.

Control logic for an electric power steering system using assist motor. Mechatronics, 2002, 12, 447–459.

Parmar

Hung

J. Y.

A sensorless optimal control system for an automotive electric power assist steering system. IEEE Trans. Ind. Electronics, 2004, 290–298.

Chabaan

R. C.

Wang

L. Y.

Control of electrical power assist systems: H design, torque estimation and structural stability. JSAE Rev., 2001, 22, 435–444.

Sugitina

Fujuwara

Uchida

Fujita

Electric power steering with H-infinity control design to obtain road information. In Proceedings of the American Control Conference, 1997, pp. 2935–2939.

Kurishige

Wada

Kifuku

Inoue

Nishiyama

Otagaki

A new EPS control strategy to improve steering wheel returnability. SAE paper 2000-01-0815, pp. 1–6.

Kurishige

Kifuku

Static steering-control system for electric-power steering, Mitsubishi Electric Advance Technical Reports, 2001, pp. 18–20.

Dixit

R. K.

Buckner

G. D.

Sliding mode observation and control for semiactive vehicle suspensions. Veh. Syst. Dynamics, 2004, 43, 83–105.

Roderick

G. H.

Edwards

Spurgeon

S. K.

An application of sliding mode control to vehicle steering in a split-mu manoeuvre. In Proceedings of the American Control Conference, 2003, pp. 4359–4364.

10.

Zaremba

A. T.

Liubakka

M. K.

Stuntz

R. M.

Control and steering feel issues in the design of an electric power steering system. In Proceedings of the American Control Conference, 1998, pp. 36–40.

11.

Edwards

Spurgeon

S. K.

Sliding mode control: theory and application, 1998 (Taylor and Francis, London).

12.

Slotine

J. E.

Weiping

Applied nonlinear control, 2004 (China Machine Press, Beijing).