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비선형 외란관측기를 이용한 가변추력 고체추진기관의 강인 압력제어
강대겸(Dae-Gyeom Kang) 유공압건설기계학회 2021 드라이브·컨트롤 Vol.18 No.4
In this paper, a mathematical pressure dynamics model for a variable thrust solid propulsion system with an electric actuator was derived from the mass conservation of gas. To solve the problem induced by modeling uncertainties in the propellant model and the dead zone of the actuator, a nonlinear pressure controller combined with a nonlinear disturbance observer was designed using a mathematical model of the system. The simulation results showed that the proposed pressure controller could reduce tracking errors compared to another conventional nonlinear controller even in situations where input disturbances were present.
외란 관측기를 이용한 유체정역학적 구동 시스템의 백스테핑 제어
서형태,강대겸,김경수,김수현 제어·로봇·시스템학회 2018 제어·로봇·시스템학회 논문지 Vol.24 No.1
In this paper, a backstepping control based on disturbance observer is proposed for an electro-hydrostatic actuation (EHA) system. Compared to a conventional hydraulic system, the EHA system, which employs a closed circuit with a bi-directional pump, is known to be more energy efficient and environmentally clean. To solve the problem induced by mismatched disturbances in the cylinder position control, a backstepping controller combined with a disturbance observer is designed using the derived nonlinear model of the system. The experimental result shows that the performance of the proposed controller is more robust than that of a conventional backstepping controller and a PID controller.
Design of an aerodynamic load simulator for pintle actuators
Jisuk Kim,한승철,강대겸,이하준 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8
In this study, a novel aerodynamic load simulator design for a pintle actuator is proposed. The proposed load simulator is composed of two ring magnets magnetized along their geometric axes and a ferromagnetic disk between them. The net magnetic force on the disk is transmitted by a nonmagnetic rod that is attached to the disk and moves through the ring magnets’ internal holes. The force is then amplified by a lever between the rod and actuator. The size of the disk, size of the magnets, size of the magnet brackets, and fixed distance between the two magnets are parameterized to reproduce a target load profile using finite element method magnetics (FEMM) software. The FEMM results show that the net force profile along the disk’s position is similar to the target load profile according to the computational fluid dynamics (CFD) analysis results of pintle’s operating conditions. Based on the FEMM results, all parts of the load generating unit are machined and assembled to build a prototype of the aerodynamic load simulator for the pintle actuator. The test results of the developed magnetbased load simulator are compared with FEMM results and with the test results of a conventional spring-based load simulator to verify the effectiveness of the developed load simulator.