Adaptive Neural Network Output Feedback Control Method for Electromechanical Actuator with Backlash and Saturation

doi:10.12382/bgxb.2025.0398

Abstract

Abstract:

Aiming at the problems of backlash，input saturation and unmeasured state information in the design process of electromechanical actuator controller，an output feedback control method based on adaptive neural network state observer is proposed.In order to describe the influence of backlash on system dynamics，a fourth-order servo system model with backlash is constructed by introducing an approximate dead zone function.A state observer based on adaptive neural network is designed for the unmeasurable state to realize the reconstruction of system state under the condition of model uncertainty.Under the framework of backstepping method，an output feedback controller is constructed by using the hyperbolic tangent Lyapunov function and state observer output.For the possible input saturation，an auxiliary filtering system is introduced to compensate the influence of input saturation.The boundedness of error signals in the closed-loop system is proved based on Lyapunov theory.The effectiveness of the proposed control method is verified by conducting multiple sets of simulation experiments.The results demonstrate the superior performance of the proposed method in suppressing the effect of backlash nonlinearityt on the system performance，compensating for input saturation，and achieving the actuator accurate tracking control with unmeasured state information.

Key words: electromechanical actuator, backlash nonlinearity, adaptive neural network state observer, output feedback control, control input saturation

ZHU Zejun, WANG Wei, LIN Shiyao, JI Yi. Adaptive Neural Network Output Feedback Control Method for Electromechanical Actuator with Backlash and Saturation[J]. Acta Armamentarii, 2025, 46(S1): 250398-.

Figures/Tables 9

Fig.1 Structure of electromechanical position servo system for an actuator

Fig.2 Output feedback control scheme of adaptive neural network

Table 1 Nominal parameters of electromechanical actuator with backlash

参数	数值	参数	数值
J_m/(kg·m²)	0.05	K_e/(V·s·rad^-1)	0.11
J_d/(kg·m²)	0.16	K_t/(N·m·A^-1)	0.063
b_m/(N·m·s·rad^-1)	1.5	R/Ω	0.5
b_d/(N·m·s·rad^-1)	1.6	θ_dmax/(°)	12
i	5	h/(N·m·rad^-1)	0.12
α/rad	0.005	K_PWM	8
k/(N·m·rad^-1)	70

Table 2 Neural network and adaptive control parameters

参数	数值	参数	数值
π₂	5	γ₂	10
π₄	0.1	γ₄	10
π_g	0.5	γ_g	100
${\Lambda }_{{\beta }_{2}}$	10	${\gamma }_{{\beta }_{2}}$	1
${\Lambda }_{{\beta }_{4}}$	5	${\gamma }_{{\beta }_{4}}$	1
${\overline{\pi }}_{2}$	10	${\overline{\gamma }}_{2}$	1
κ	1	c₂，c₄	1

Table 3 PID，state feedback and output feedback controller parameters

控制器	控制增益
PID	k_p		k_i		k_d
PID	-50		-100		1
状态反馈	K₁	K₂		K₃		K₄
状态反馈	15	30		2		5
输出反馈	k₁	k₂		k₃		k₄
输出反馈	15	30		2		5

Fig.3 Tracking of expected step signal under PID，state feedback and output feedback control

Fig.4 Tracking of expected square wave signal under PID，state feedback and output feedback control

Fig.5 Tracking of expected sine signal under PID，state feedback and output feedback control

Fig.6 State observation and adaptive parameter convergence characteristics

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