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RISS 인기검색어
- 검색키워드
- 저자 : Jiacheng Liang (검색결과 3 건)
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Robust Observer-based Trajectory Tracking Control for Unmanned Aerial Manipulator
Jiacheng Liang,Yanjie Chen,Ningbin Lai,Bingwei He 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.2
This paper aims at the stable motion control problem of the unmanned aerial manipulator (UAM) with internal interactions and external environment disturbances, and proposes a robust observer-based trajectory tracking control framework. Considering the large-dimensional nonlinearity and underactuated of UAM dynamics, a separate control scheme is adopted, including a geometric controller for quadrotor UAV and prescribed performance control (PPC) method for onboard active manipulator (OAM). In particular, an observer-based geometric control scheme is developed for the position and attitude tracking of the quadrotor UAV to ensure steady flight, where the quadrotor UAV attitude is represented by the rotation matrix to eliminate singularities or ambiguities. Subsequently, an observer-based PPC method is presented for the OAM to guarantee the prescribed transient and steady-state performance responses. Finally, the simulation comparisons and experimental study validate the effectiveness and performances of the proposed control framework.
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Yanjie Chen,Jiacheng Liang,Zhiqiang Miao,Yaonan Wang 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.10
This paper considers the problem of the formation control for multiple underactuated quadrotor UAVs without linear velocity measurements. The objective of this paper is expected to realize smooth formation performances for a quadrotor group. A distributed formation controller is designed directly using rotation matrices to obviate the singularities associated with the Euler-angles or the ambiguity of quaternions. A two-step procedure isadopted for the control development after transforming the dynamics of each quadrotor into a new form. At first, an intermediary control variable is introduced to achieve the formation control, where some auxiliary systems are designed in the presence of lacking linear velocity measurements. Then, based on the thrust force and reference angular velocity decoded from the intermediary control variable, the torque input of each quadrotor is proposed for angular velocity tracking. The case of formation control with a virtual leader is also investigated, where at least one quadrotor has the information of the leader. The asymptotic stability of the proposed control system is analyzed by Lyapunov-like tools, and the effectiveness of the proposed control method is verified by simulation studies. Thesimulation results show that the proposed method can guide the quadrotor group to form the desired formation smoothly without linear velocity feedback, which has great potentials for the UAV group to execute the challenging mission in hostile environments.
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Jingyu Zhang,Jiacheng Zhu,Shurong Ding,Liang Chen,Wenjie Li,Hua Pang 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.7
Delayed hydride cracking (DHC) is an important failure mechanism for Zircaloy tubes in the demandingenvironment of nuclear reactors. The threshold stress intensity factor, KIH, and critical hydride length, lC ,are important parameters to evaluate DHC. Theoretical models of them are developed for Zircaloy tubesundergoing non-homogenous temperature loading, with new stress distributions ahead of the crack tipand thermal stresses involved. A new stress distribution in the plastic zone ahead of the crack tip isproposed according to the fracture mechanics theory of second-order estimate of plastic zone size. Thedeveloped models with fewer fitting parameters are validated with the experimental results for KIH andlC. The research results for radial cracking cases indicate that a better agreement for KIH can be achieved;the negative axial thermal stresses can lessen KIH and enlarge the critical hydride length, so its effectshould be considered in the safety evaluation and constraint design for fuel rods; the critical hydridelength lC changes slightly in a certain range of stress intensity factors, which interprets the phenomenonthat the DHC velocity varies slowly in the steady crack growth stage. Besides, the sensitivity analysis ofmodel parameters demonstrates that an increase in yield strength of zircaloy will result in a decrease inthe critical hydride length lC , and KIH will firstly decrease and then have a trend to increase with the yieldstrength of Zircaloy; higher fracture strength of hydrided zircaloy will lead to very high values ofthreshold stress intensity factor and critical hydride length at higher temperatures, which might be themain mechanism of crack arrest for some Zircaloy materials
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