Robust Temperature Control for a Variable Speed Refrigeration System Based on Sliding Mode Control Using a Kalman State Observer and Feedforward Controller

A sliding mode control (SMC) technique based on a state observer with a Kalman filter and feedforward controller was established for a variable-speed refrigeration system (VSRS) to ensure robust control against model uncertainties and disturbances, including noise. The SMC was designed using a state-space model transformed from a practical transfer function model, which was derived by conducting dynamic characteristic experiments. Fewer parameters affecting the model uncertainty were required to be identified, which facilitated modeling. The state observer for estimating the state variables was designed using a Kalman filter to ensure robustness against noise. A feedforward controller was added to the control system to compensate for the deterioration in the transient characteristics due to the saturation function used to avoid chattering. A genetic algorithm was used to alleviate the trial and error involved in determining the design parameters of the saturation function and select optimal values. Simulations and experiments were conducted to verify the control performance of the proposed SMC. The results show that the proposed controller can realize robust temperature control for a VSRS despite stepwise changes in the reference and external heat load, and avoid the trial and error process to design parameters for the saturation function.

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A new fuzzy sliding-mode control for MW variable speed-variable pitch wind turbine

7th IET International Conference on Advances in Power System Control, Operation and Management (APSCOM 2006) ◽

10.1049/cp:20062102 ◽

2006 ◽

Cited By ~ 1

Author(s):

Yigang Kong ◽

Zhixin Wang ◽

Hai Yuan

Keyword(s):

Sliding Mode Control ◽

Wind Turbine ◽

Sliding Mode ◽

Variable Speed ◽

Fuzzy Sliding Mode Control ◽

Variable Pitch ◽

Mode Control ◽

Fuzzy Sliding Mode

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An extended state observer-based full-order sliding mode control for robotic joint actuated by antagonistic pneumatic artificial muscles

International Journal of Advanced Robotic Systems ◽

10.1177/1729881420986036 ◽

2021 ◽

Vol 18 (1) ◽

pp. 172988142098603

Author(s):

Daoxiong Gong ◽

Mengyao Pei ◽

Rui He ◽

Jianjun Yu

Keyword(s):

Sliding Mode Control ◽

Sliding Mode ◽

State Observer ◽

Extended State Observer ◽

Artificial Muscles ◽

Extended State ◽

Robot System ◽

Mode Control ◽

Physical Experiments ◽

Pneumatic Artificial Muscles

Pneumatic artificial muscles (PAMs) are expected to play an important role in endowing the advanced robot with the compliant manipulation, which is very important for a robot to coexist and cooperate with humans. However, the strong nonlinear characteristics of PAMs hinder its wide application in robots, and therefore, advanced control algorithms are urgently needed for making the best use of the advantages and bypassing the disadvantages of PAMs. In this article, we propose a full-order sliding mode control extended state observer (fSMC-ESO) algorithm that combines the ESO and the fSMC for a robotic joint actuated by a pair of antagonistic PAMs. The fSMC is employed to eliminate the chattering and to guarantee the finite-time convergence, and the ESO is adopted to observe both the total disturbance and the states of the robot system, so that we can inhibit the disturbance and compensate the nonlinearity efficiently. Both simulations and physical experiments are conducted to validate the proposed method. We suggest that the proposed method can be applied to the robotic systems actuated by PAMs and remarkably improve the performance of the robot system.

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