Improved Sliding Mode-Active Disturbance Rejection Control of Electromagnetic Linear Actuator for Direct-Drive System

Abstract

The electromagnetic linear actuator is used as the core drive unit to achieve high precision and high response in the direct-drive actuation system. In order to improve the response performance and control accuracy of the linear drive unit, an improved sliding mode-active disturbance rejection control (ISM-ADRC) method was proposed. A motor model was established based on improved LuGre dynamic friction. The position loop adopts the improved integral traditional sliding mode control based on an extended state observer, and the current loop adopts PI control. The stability of the system is verified based on the Lyapunov theory. A nonlinear dilated state observer is used to effectively observe the electromagnetic linear actuator position and velocity information while estimating and compensating the internal and external uncertainty perturbations. At the same time, the saturation function sat(s) is used to replace the sign(s) and introduce the power function of the displacement error variable. The improved integral sliding mode control law further improves the response speed and control accuracy of the controller while reducing the jitter inherent in the conventional sliding mode. Simulation and experimental data show that the proposed improved sliding mode-active disturbance rejection control reduces the 8-mm step response time of the electromagnetic linear actuator by 21.9% and the steady-state error by less than 0.01 mm compared with the conventional sliding-mode control, while the system has 49.4% less adjustment time for abrupt load changes and is more robust to different loads and noise.

Nonlinear electromagnetic force analysis and compensation control of electromagnetic linear actuator

“…The structure is shown in figure 1, which is composed of inner yoke, outer yoke, coil skeleton, coil winding and Halbach permanent magnet array. Detailed working principle can be found in reference [31]. EMLAs are systems of coupled magnetic, electrical and mechanical subsystems.…”

Data-driven model-free adaptive sliding mode control for electromagnetic linear actuator

“…Based on the optimal conditions, the estimation algorithm for the PG vector can be obtained by using the matrix inverse lemma for equation (8) with respect to the extrema as:…”

“…The micro electromagnetic linear actuator is an automatic basic component that can directly convert electric energy into mechanical energy in the form of linear motion without an intermediate conversion device [1], which is the key to realizing linear motion control with high precision, high the controlled system will be greatly affected under complex working conditions [8]. Therefore, the improvement of high precision trajectory tracking of electromagnetic linear actuators has become a key issue.…”

Development of Sliding Mode Controller Based on Internal Model Controller for Higher Precision Electro-Optical Tracking System

“…However, it is difficult to deduce the slip variables many times, which limits the superiority of second-order SMC [27]. Chattering can also be reduced by adaptively adjusting the switching gain using fuzzy rules [28], but the design of fuzzy rules is relatively complex and it mostly relies on the experience and knowledge of researchers to establish a fuzzy rule control table [29].…”