scholarly journals Multitechnique Concise Robust Control for the Insulation Containment Space Pressure Control of LNG Carrier

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Zuojing Su ◽  
Xianku Zhang ◽  
Xu Han
Keyword(s):  
Time Delay ◽  
Robust Control ◽  
Energy Saving ◽  
Pressure Control ◽  
Smith Predictor ◽  
Mapping Technique ◽  
Delay Model ◽  
Nonlinear Feedback ◽  
Maintenance System ◽  
Control Scheme

In this note, a novel multitechnique concise robust control scheme, based on the mirror mapping technique (MMT), closed-loop gain shaping algorithm (CGSA), Smith predictor (SP), and nonlinear feedback technique (NFT), is proposed for the pressure control of the liquefied natural gas (LNG) carrier insulation containment space. Firstly, a kind of integral unstable time-delay model is obtained by linearizing the nonlinear model of the pressure maintenance system around its equilibrium. By using the MMT and CGSA, one acquires the corresponding stable mirror mapping model of the unstable linear model and the designed controller. And the SP is introduced to tackle the time-delay problem. In addition, for the purpose of energy saving, the NFT is added into the control scheme. Finally, a set of experiments has been employed to illustrate the control effects, and the results show that it can achieve satisfying performance in aspects of disturbance rejection and energy saving.

scholarly journals A deterministic approach for design of supervisory control of LPV systems with delay

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256408
Author(s):  
Ch. Nauman Zahid ◽  
Mina Salim ◽  
Raja Ali Riaz ◽  
Jamshed Iqbal
Keyword(s):  
Time Delay ◽  
Supervisory Control ◽  
Closed Loop ◽  
Control Structure ◽  
Real Life ◽  
Pressure Control ◽  
Smith Predictor ◽  
Delay Compensation ◽  
Lpv Systems ◽  
Time Delay Compensation

Linear Parameter Varying (LPV) systems and their control have gained attraction recently as they approximate nonlinear systems with higher order than ordinary linear systems. On the other hand, time delay is an inherent part of various real-life applications. A supervisory control structure is proposed in this paper for LPV systems subject to time delays. In the proposed control structure, a supervisor selects the most suitable controller from a bank of controllers; which desires to enhance the performance of closed-loop system in contrast with using a single robust controller. The analysis is based on the celebrated Smith predictor for time delay compensation and we provide a sufficient condition to assure the stability of the closed-loop switched system in terms of dwell time. Simulations on blood pressure control of hypertension patients in postoperative scenario are used to exemplify the effectiveness of the utilized technique. The operating region of the system is partitioned into five smaller operating regions to construct corresponding robust controllers and perform hysteresis switching amongst them. Simulation results witnessed that the proposed control scheme demonstrated a pressure undershoot less than the desired value of 10 mmHg while the Mean Arterial Pressure (MAP) remains within ±5 mmHg of the desired value.

A Robust Control Scheme for Time Delay Switch Attacks

2021 ◽  
Author(s):  
Luka Malashkhia ◽  
Laura P. Swiler ◽  
Ali Pinar ◽  
Yan Wang
Keyword(s):  
Time Delay ◽  
Robust Control ◽  
Control Scheme

Constant Pressure Control for Energy Efficient Lathe Turret

2015 ◽  
Vol 661 ◽  
pp. 3-9
Author(s):  
Jyh Chyang Renn ◽  
Wen Jen Hsu ◽  
Yun Ruei Li
Keyword(s):  
Dynamic Response ◽  
Energy Saving ◽  
Energy Efficient ◽  
Constant Pressure ◽  
Pressure Control ◽  
Gear Pump ◽  
Relief Valve ◽  
Controlled System ◽  
Control Scheme ◽  
New Energy

Hydraulic system plays an important role in many power systems such as excavator, braking system of vehicle and machine tool. Generally speaking, hydraulic control system can be divided into two different driving concepts. The first one is the well-known valve-controlled system and the second one is the pump-controlled system. The former possesses the feature of fast dynamic response. However, the poor energy-saving performance is its major fault. On the contrary, the pump-controlled system has the significant advantage of energy-saving which meets the current demand in modern machine design, but has the disadvantage of slower dynamic response. With the advancement of electric-motor system, however, this disadvantage has been greatly improved. In this paper, the simulation analysis of a newly developed energy-efficient hydraulic CNC lathe turret based on constant pressure control scheme is presented. Instead of the conventional fixed displacement hydraulic pump, the new energy-efficient system utilizes an internal gear pump together with an AC servo motor as its driving power source. In addition, a closed-loop control scheme using PID control is adopted. From simulation results, the new energy-efficient design can reduce the waste of the output flow-rate of the pump through the relief valve that generally happens in conventional hydraulic lathe and then achieve the purpose of designing an energy-efficient hydraulic lathe.

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