Identification and control of the motor‐drive servo turntable with the switched friction model

Abstract

In this study, the identification and control scheme of the motor-drive servo turntable are researched to achieve accurate tracking. Firstly, the input-output identification experiments are designed and realised for the global model of motordrive servo turntable. The order of the global controlled auto-regressive model is determined by the Akaike information criterion, and the parameters are estimated by a particle swarm optimisation-cuckoo search algorithm. Secondly, the switched friction model is built combining the LuGre structure and the Stribeck curve. The switching conditions and the parameters of the switched friction model are determined though the input-output and the friction experiments. A constrained multi-objective optimisation problem is constructed for the parameter identification of the switched friction model. It is solved via a fuzzy comprehensive evaluation. Finally, the composite control strategy, in which the proportional-integral-derivative controller and model-based friction observer are combined, is proposed in the azimuth angle system of the motor-drive servo turntable. The trajectory tracking results in simulation and experiment illustrate the effectiveness of the proposed switched model, identification method, and composite control strategy.

Improved Active Disturbance Rejection Control of Dual-Axis Servo Tracking Turntable with Friction Observer

“…In order to compensate for the influence of nonlinear friction disturbance on the tracking performance better, a friction observer is designed based on the improved ESO, which regards the immeasurable part of EP friction model as a new state. In our previous work, the nonlinear friction parameter identification experiments using genetic algorithm (GA) is analyzed in [23]. Similarly, in this study, the parameter identification results of EP friction model based on GA are listed in Table 3.…”

“…Assumption 2. The controlled plant described as Equation ( 17) is rewritten with a linear structure as follows { 𝑥̇1 = 𝑥 2 ⋯ 𝑥̇𝑛 = 𝑎 𝑛 𝑥 1 + 𝑎 𝑛−1 𝑥 2 + ⋯ + 𝑎 1 𝑥 𝑛 + 𝑏 0 𝑢 𝑦 = 𝑥 1 (23) where 𝑎 𝑖 (𝑖 = 1, ⋯ , 𝑛) are the systematic parameters. Substitute Equations ( 12) and ( 22) into ( 23), then…”

“…The turntable servo system often fails to achieve accurate tracking due to nonlinear disturbance factors such as friction [22][23][24][25][26], backlash [27], dead-zone [28], and motor torque fluctuation [29], etc. Friction is a common non-linear phenomenon, which exists in almost all electromechanical servo system between two contact surfaces with relative motion.…”

“…Friction is a common non-linear phenomenon, which exists in almost all electromechanical servo system between two contact surfaces with relative motion. Among the existing nonlinear friction models, the LuGre friction model [22,23] is most widely employed to describe nonlinear friction phenomenon because of its ability to capture most of the observed frictional behaviors. Nevertheless, some drifting behavior inevitably exists in the LuGre friction model.…”

Linear switched system modelling and analysis for the servo system

“…The electromechanical servo system can be described by a switched linear discrete-time system operated under conditions of parameter uncertainty [24][25][26] as follows:…”