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Nonholonomic motion planning for a free-falling cat using spline approximation

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Science China(Physics,Mechanics & Astronomy) 2012年第11期55卷 2100-2105页

作者： ge xinsheng GUO ZhengXiong College of Mechanical&Electrical Engineering Beijing Information Science&Technology UniversityBeijing 100192China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China

An optimal motion planning of a free-falling cat based on the spline approximation is *** arises in a free-falling cat subjected to nonintegrable velocity constraints or nonintegrable conservation *** equation of dynamics of a free-falling cat is obtained by using the model of two symmetric rigid *** control of the system can be converted to the motion planning problem for a driftless system.A cost function is used to incorporate the final errors and control *** motion planning is to determine control inputs to minimize the cost function and is formulated as an infinite dimensional optimal control *** using the control parameterization,the infinite dimensional optimal control problem can be transformed to a finite dimensional *** particle swarm optimization(PSO) algorithm with the cubic spline approximation is proposed to solve the finite dimension optimal control *** cubic spline approximation is introduced to realize the control *** resulting controls are smooth and the initial and terminal values of the control inputs are zeros,so they can be easily generated by *** are also performed for the nonholonomic motion planning of a free-falling *** experimental results show that the proposed algorithm is more effective than the Newtoian algorithm.

关键词： falling cat nonholonomic constraint motion planning spline approximation particle swarm optimization

Optimal control of a spacecraft with deployable solar arrays using particle swarm optimization algorithm

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Science China(Technological Sciences) 2011年第5期54卷 1107-1112页

作者： ge xinsheng SUN Kai College of Mechanical & Electrical Engineering Beijing Information Science & Technology University Beijing 100192 China Department of Mechanics Peking University Beijing 100871 China

The optimal control problem of the multibody dynamics of a spacecraft in space, modeled as a central body with one-sided connected deployable solar arrays, is investigated. The dynamical equations of motion of the spacecraft with solar arrays are derived using the multibody dynamics method. The control of the attitude motion of a spacecraft system can be transformed into the motion planning problem of nonholonomic system when the initial angular momentum is zero. These are then used to investigate the motion planning of the spacecraft during solar arrays deployment via particle swarm optimization (PSO) and results are obtained with the optimal control input and the optimal trajectory. The results of numerical simulation show that this approach is effective for the control problem of the attitude of a spacecraft during the deployment process of its solar arrays.

关键词： multibody spacecraft attitude dynamics optimal control particle swarm optimization

Optimal control of attitude for coupled-rigid-body spacecraft via Chebyshev-Gauss pseudospectral method

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Applied Mathematics and Mechanics(English Edition) 2017年第9期38卷 1257-1272页

作者： xinsheng ge Zhonggui YI Liqun CHEN College of Science Beijing Information Science and Technology UniversityBeijing 100192China College of Mechanical and Electrical Engineering Beijing Information Science and Technology UniversityBeijing 100192China Shanghai Institute of Applied Mathematics and Mechanics Shanghai UniversityShanghai 200072China

The attitude optimal control problem （OCP） of a two-rigid-body space- craft with two rigid bodies coupled by a ball-in-socket joint is considered. Based on conservation of angular momentum of the system without the external torque, a dynamic equation of three-dimensional attitude motion of the system is formulated. The attitude motion planning problem of the coupled-rigid-body spacecraft can be converted to a dis- crete nonlinear programming （NLP） problem using the Chebyshev-Gauss pseudospectral method （CGPM）. Solutions of the NLP problem can be obtained using the sequential quadratic programming （SQP） algorithm. Since the collocation points of the CGPM are Chebyshev-Gauss （CG） points, the integration of cost function can be approximated by the Clenshaw-Curtis quadrature, and the corresponding quadrature weights can be calculated efficiently using the fast Fourier transform （FFT）. To improve computational efficiency and numerical stability, the barycentric Lagrange interpolation is presented to substitute for the classic Lagrange interpolation in the approximation of state and con- trol variables. Furthermore, numerical float errors of the state differential matrix and barycentric weights can be alleviated using trigonometric identity especially when the number of CG points is large. A simple yet efficient method is used to avoid sensitivity to the initial values for the SQP algorithm using a layered optimization strategy from a feasible solution to an optimal solution. Effectiveness of the proposed algorithm is perfect for attitude motion planning of a two-rigid-body spacecraft coupled by a ball-in-socket joint through numerical simulation.

关键词： coupled rigid body spacecraft optimal control pseudospectral method(PM) Chebyshev-Gauss (CG) point

Control strategy of optimal deployment for spacecraft solar array system with initial state uncertainty

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Applied Mathematics and Mechanics(English Edition) 2018年第10期39卷 1437-1452页

作者： xinsheng ge Qijia YAO Liqun CHEN School of Mechanical and Electrical Engineering Beijing Information Science and Technology University Shanghai Institute of Applied Mathematics and Mechanics Shanghai University

A control strategy combining feedforward control and feedback control is presented for the optimal deployment of a spacecraft solar array system with the initial state uncertainty. A dynamic equation of the spacecraft solar array system is established under the assumption that the initial linear momentum and angular momentum of the system are zero. In the design of feedforward control, the dissipation energy of each revolute joint is selected as the performance index of the system. A Legendre pseudospectral method(LPM) is used to transform the optimal control problem into a nonlinear programming problem. Then, a sequential quadratic programming algorithm is used to solve the nonlinear programming problem and offline generate the optimal reference trajectory of the system. In the design of feedback control, the dynamic equation is linearized along the reference trajectory in the presence of initial state errors. A trajectory tracking problem is converted to a two-point boundary value problem based on Pontryagin’s minimum principle. The LPM is used to discretize the two-point boundary value problem and transform it into a set of linear algebraic equations which can be easily calculated. Then, the closed-loop state feedback control law is designed based on the resulting optimal feedback control and achieves good performance in real time. Numerical simulations demonstrate the feasibility and effectiveness of the proposed control strategy.

关键词： optimal control trajectory tracking spacecraft solar array system twopoint boundary value problem Legendre pseudospectral method(LPM)

OPTIMAL MOTION PLANNING FOR A RIGID SPACECRAFT WITH TWO MOMENTUM WHEELS USING QUASI-NEWTON METHOD

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Acta Mechanica Solida Sinica 2006年第4期19卷 334-340页

作者： ge xinsheng Zhang Qizhi Chen Li-Qun Basic Science Courses Department Beijing Institute of Machinery Beijing 100085 China Department of Mechanics Shanghai University Shanghai 200444 China

An optimal motion planning scheme based on the quasi-Newton method is proposed for a rigid spacecraft with two momentum wheels. A cost functional is introduced to incorporate the control energy, the final state errors and the constraints on states. The motion planning for determining control inputs to minimize the cost functional is formulated as a nonlinear optimal control problem. Using the control parametrization, one can transform the infinite dimensional optimal control problem to a finite dimensional one that is solved via the quasi-Newton methods for a feasible trajectory which satisfies the nonholonomic constraint. The optimal motion planning scheme was applied to a rigid spacecraft with two momentum wheels. The simulation results show the effectiveness of the proposed optimal motion planning scheme.

关键词： rigid spacecraft nonholonomic constraint motion planning quasi-Newton method

Dynamic modeling of spacecraft solar panels deployment with Lie group variational integrator

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Theoretical & Applied Mechanics Letters 2018年第6期8卷 415-424,I0005页

作者： Long Bai xinsheng ge School of Mechanical and Electrical Engineering Beijing Information Science and Technology University

The spacecraft with multistage solar panels have nonlinear coupling between attitudes of central body and solar panels, especially the rotation of central body is considered in space. The dynamics model is based for dynamics analysis and control, and the multistage solar panels means the dynamics modeling will be very complex. In this research, the Lie group variational integrator method is introduced, and the dynamics model of spacecraft with solar panels that connects together by flexible joints is built. The most obvious character of this method is that the attitudes of central body and solar panels are all described by three-dimensional attitude matrix. The dynamics models of spacecraft with one and three solar panels are established and simulated. The study shows Lie group variational integrator method avoids parameters coupling and effectively reduces difficulty of modeling. The obtained continuous dynamics model based on Lie group is a set of ordinary differential equations and equivalent with traditional dynamics model that offers a basis for the geometry control.

关键词： Lie group Variational integrator Spacecraft Solar panels deployment Dynamics modeling

Dynamic response analysis of liquefiable ground due to sinusoidal waves of different frequencies of shield construction

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Earthquake Engineering and Engineering Vibration 2023年第3期22卷 637-646页

作者： Wang Jingyue ge xinsheng Sun Jingyuan Liu Yasheng Shang Zhuo Wang Zhiqiang Tian Maoguo College of Civil Engineering Taiyuan University of TechnologyTaiyuan 030024China The 3rd Engineering Co.Ltd.of China Railway 18th Bureau Zhuozhou 072750China

Vibration induced by shield construction can lead to liquefaction of saturated *** on FLAC3D software,a numerical model of tunnel excavation is established and sinusoidal velocity loads with different frequencies are applied to the excavation *** pattern of the excess pore pressure ratio with frequency,as well as the dynamic response of soil mass under different frequency loads before excavation,is *** the velocity sinusoidal wave acts on the excavation surface of the shield tunnel with a single sand layer,soil liquefaction ***,the ranges and locations of soil liquefaction are different at different frequencies,which proves that the vibration frequency influences the liquefaction location of the *** sand-clay composite strata with liquefiable layers,the influence of frequency on the liquefaction range is different from that of a single *** the frequency range of 5-30 Hz,the liquefaction area and surface subsidence decrease with an increase in vibration *** research results in this study can be used as a reference in engineering practice for tunneling liquefiable strata with a shield tunneling machine.

关键词： shield tunnel liquefiable formation FLAC3D numerical simulation excess pore pressure ratio dynamic response analysis

Optimal control of stretching process of flexible solar arrays on spacecraft based on a hybrid optimization strategy

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Theoretical & Applied Mechanics Letters 2017年第4期7卷 258-263页

作者： Qijia Yao xinsheng ge School of Mechanical and Electrical Engineering Beijing Information Science and Technology University Beijing 100192 China School of Applied Science Beijing Information Science and Technology University Beijing 100192 China

The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM） is presented. First, the elastic deformation of flexible solar arrays was described approximately by the assumed mode method, and a dynamic model was established by the second Lagrangian equation. Then, the nonholonomic motion planning problem is transformed into a nonlinear programming problem by using GPM. By giving fewer LG points, initial values of the state variables and control variables were obtained. A serial optimization framework was adopted to obtain the approximate optimal solution from a feasible solution. Finally, the control variables were discretized at LG points, and the precise optimal control inputs were obtained by DSM. The optimal trajectory of the system can be obtained through numerical integration. Through numerical simulation, the stretching process of solar arrays is stable with no detours, and the control inputs match the various constraints of actual *** results indicate that the method is effective with good robustness.

关键词： Motion planning Multibody spacecraft Optimal control Gauss pseudospectral method Direct shooting method

Optimal motion planning of an underactuated spacecraft using wavelet approximate method

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Progress in Natural Science:Materials International 2006年第8期16卷 868-873页

作者： ge xinsheng, CHEN Liqun and LIU Yanzhu (Beijing Institute of Machinery, Beijing 100085, China Department of Mechanics, Shanghai University, Shanghai 200072, China Department of Engineering Mechanics, Shanghai Jiaotong University, Shanghai 200030, China) [a]Beijing Institute of Machiner Beijing China [b]Department of Mechanics Shanghai University Shanghai China [c]Department of Engineering Mechanics Shanghai Jiaotong University Shanghai China

An optimal motion planning scheme using wavelet approximation is proposed for an underactuated spacecraft. The motion planning of an underactuated spacecraft can be formulated as an optimal control of a drift-free system. A cost functional is used to incorporate the control energy and the final state errors. The motion planning is to determine control inputs to minimize the cost functional. Using the method of wavelet, one can transform an infinite-dimensional optimal control problem to a finite-dimensional one and use Gauss-Newton algorithm to solve it for a feasible trajectory which satisfies nonholonomic constraints. The proposed scheme has been applied to a rigid spacecraft with two momentum wheels. The numerical simulation results indicate that optimal control with wavelet approximation is an effective approach to steering an underactuated spacecraft system from the initial configuration to the final configuration.

关键词： underactuated spacecraft motion planning optimal control nonholonomic constraint wavelet analysis.