scholarly journals Inertia Parameter Identification for an Unknown Satellite in Precapture Scenario

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Xiao-Feng Liu ◽  
Xiao-Yu Zhang ◽  
Pei-Ran Chen ◽  
Guo-Ping Cai
Keyword(s):  
Parameter Identification ◽  
Momentum Conservation ◽  
Space Robot ◽  
Control Force ◽  
Soft Contact ◽  
Identification Scheme ◽  
Inertia Parameter ◽  
Inertia Parameters ◽  
Dynamics And Control ◽  
And Control

The problem of dynamics and control using a space robot to capture a noncooperative satellite is an important issue for on-orbit services. Inertia parameters of the satellite should be identified before capturing such that the robot can design an active controller to finish the capturing task. In this paper, a new identification scheme is proposed for parameter identification of a noncooperative satellite. In this scheme, the space robot is controlled to contact softly and then maintain contact with the noncooperative target firstly, then the variation of momentum of the target during the contact-maintaining phase is calculated using the control force and torque acting on the base of the space robot and the kinematic information of the space robot, and finally, the momentum-conservation-based identification method is used to estimate inertia parameters of the target. To realize soft contact and then maintain contact, a damping contact controller is designed in this paper, in which a mass-damping system is designed to control the contact between the robot and the target. Soft contact and then contact maintenance can be realized by utilizing the buffering characteristics of the mass-damping system. The effectiveness of the proposed identification scheme is verified through numerical simulations at the end of this paper. Simulation results indicate that the proposed scheme can achieve high-precision identification results.

Inertia parameter identification of space floating target during robotic exploratory grasping

2019 ◽  
Vol 233 (11) ◽  
pp. 4247-4260 ◽  
Author(s):  
Cheng Wei ◽  
Yue Zhang ◽  
Hongliu Wang ◽  
Yang Zhao ◽  
Lei Zhang
Keyword(s):  
Momentum Conservation ◽  
Space Robot ◽  
Target System ◽  
Identification Method ◽  
Inertial Parameters ◽  
Inertia Parameter ◽  
Inertia Parameters ◽  
Contact Models ◽  
And Performance ◽  
Identification Model

When the space robot grasps an unknown floating target on orbit, it has many advantages of knowing the inertial parameters of the target during the exploratory grasping process, since, instead of grasping blindly the better control schema can be made in the meantime to increase the safety and performance of the grasping operation. The three-finger gripper is used as the grasp mechanism for which the grasping and contact models are presented to describe the grasping procedure. Then based on the momentum conservation of the robot–target system, the linear identification model of the target inertia parameters is developed. The identification performance for one, two, and three collisions during the grasping process is investigated theoretically. It is found that the full inertia parameters will be obtained within at least three collisions between the space robot and the target. Lastly the identification model for an unknown target is applied, and the numerical simulations show the effectiveness and practicality of the model. The numerical results indicate that the identification method is effective. Furthermore, the more abundant and diverse the collisions are, the more accurate and efficient the identification method will be.

Inertia parameter identification of anunknown captured space target

2019 ◽  
Vol 91 (8) ◽  
pp. 1147-1155 ◽  
Author(s):  
Xiaofeng Liu ◽  
Bangzhao Zhou ◽  
Boyang Xiao ◽  
Guoping Cai
Keyword(s):  
Angular Momentum ◽  
Parameter Identification ◽  
Linear Momentum ◽  
Content Type ◽  
Identification Method ◽  
Robot Arms ◽  
Precise Estimation ◽  
Inertia Parameter ◽  
Inertia Parameters ◽  
Space Target

Purpose The purpose of this paper is to present a method to obtain the inertia parameter of a captured unknown space target. Design/methodology/approach An inertia parameter identification method is proposed in the post-capture scenario in this paper. This method is to resolve parameter identification with two steps: coarse estimation and precise estimation. In the coarse estimation step, all the robot arms are fixed and inertia tensor of the combined system is first calculated by the angular momentum conservation equation of the system. Then, inertia parameters of the unknown target are estimated using the least square method. Second, in the precise estimation step, the robot arms are controlled to move and then inertia parameters are once again estimated by optimization method. In the process of optimization, the coarse estimation results are used as an initial value. Findings Numerical simulation results prove that the method presented in this paper is effective for identifying the inertia parameter of a captured unknown target. Practical implications The presented method can also be applied to identify the inertia parameter of space robot. Originality/value In the classic momentum-based identification method, the linear momentum and angular momentum of system, both considered to be conserved, are used to identify the parameter of system. If the elliptical orbit in space is considered, the conservation of linear momentum is wrong. In this paper, an identification based on the conservation of angular momentum and dynamics is presented. Compared with the classic momentum-based method, this method can get a more accurate identification result.

scholarly journals The Coupled Orbit-Attitude Dynamics and Control of Electric Sail in Displaced Solar Orbits

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Mingying Huo ◽  
He Liao ◽  
Yanfang Liu ◽  
Naiming Qi
Keyword(s):  
Linear Quadratic Regulator ◽  
Coupled System ◽  
Control Force ◽  
Attitude Dynamics ◽  
Voltage Distribution ◽  
Linear Quadratic ◽  
Displaced Orbit ◽  
Dynamics And Control ◽  
And Control ◽  
Small Torque

Displaced solar orbits for spacecraft propelled by electric sails are investigated. Since the propulsive thrust is induced by the sail attitude, the orbital and attitude dynamics of electric-sail-based spacecraft are coupled and required to be investigated together. However, the coupled dynamics and control of electric sails have not been discussed in most published literatures. In this paper, the equilibrium point of the coupled dynamical system in displaced orbit is obtained, and its stability is analyzed through a linearization. The results of stability analysis show that only some of the orbits are marginally stable. For unstable displaced orbits, linear quadratic regulator is employed to control the coupled attitude-orbit system. Numerical simulations show that the proposed strategy can control the coupled system and a small torque can stabilize both the attitude and orbit. In order to generate the control force and torque, the voltage distribution problem is studied in an optimal framework. The numerical results show that the control force and torque of electric sail can be realized by adjusting the voltage distribution of charged tethers.

Parameter Identification of Inertia Properties of Space Robot Based on Momentum Conservation

2011 ◽  
Vol 328-330 ◽  
pp. 1916-1921 ◽  
Author(s):  
Chao Wang ◽  
Yong Ming Gao ◽  
Xiao Ping Du
Keyword(s):  
Parameter Identification ◽  
Momentum Conservation ◽  
Inertia Tensor ◽  
Space Robot ◽  
Second Step ◽  
Mass Center ◽  
Unknown Parameters ◽  
Initial Momentum ◽  
Precise Control ◽  
Inertia Properties

The parameter identification is necessary for precise control orbit and attitude of Space Robot. This paper presents a method for parameter identification of inertia properties of space robot which is based on the momentum conservation. As the initial momentum of the Space Robot is hardly known, we have to discuss detailed in two options. The first option, the initial momentum is known and assumes it is zero, then we can solve all the unknown parameters in the momentum equations; the second it’s unknown, it has to be solved in two steps. The first step is to identify the mass and mass center of the spacecraft; and the second step is to identify the inertia tensor of the spacecraft. In the end, we build the model for simulation; the result shows that the method has the high precise and the error can be ignored.

Dynamics and control of a 6-DOF space robot with flexible panels

2016 ◽  
Vol 231 (6) ◽  
pp. 1022-1034 ◽  
Author(s):  
Yu Zhang-Wei ◽  
Liu Xiao-Feng ◽  
Li Hai-Quan ◽  
Cai Guo-Ping
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Torque Control ◽  
Space Robot ◽  
Velocity Variation ◽  
Variation Principle ◽  
Dynamics Modeling ◽  
Dynamics And Control ◽  
Flexible Panels ◽  
And Control

With the development of space exploration, researches on space robot will cause more attentions. However, most existing researches about dynamics and control of space robot concern planar problem, and the effect of flexible panel on dynamics of the system is not considered. In this article, dynamics modeling and active control of a 6-DOF space robot with flexible panels are investigated. Dynamic model of the system is established based on the Jourdain's velocity variation principle and the single direction recursive construction method. The computed torque control method is used to design point-to-point active controller of the space robot. The validity of the dynamic model is verified through the comparison with ADAMS software; the effects of panel flexibility on the system performance and the active controller design are studied in detail. Simulation results indicate that the proposed model is effective to describe the dynamics of space robot; panel flexibility has large influence on the dynamic behavior of space robot; the designed controller can effectively make the robot reach a specified position and the elastic vibration of the panels may be suppressed simultaneously.

Dynamics and Control of Adaptive Nonlinear Piezothermoelastic Structures With Coupled Electric, Thermal and Mechanical Fields: A Finite Element Approach

2002 ◽  
Author(s):  
H. S. Tzou ◽  
D. W. Wang
Keyword(s):  
Finite Element ◽  
Electric Potential ◽  
Shell Element ◽  
Shell Structures ◽  
Control Analysis ◽  
Control Force ◽  
Vibration Sensing ◽  
Dynamics And Control ◽  
And Control ◽  
Piezoelectric Shell

Piezoelectric sensors and actuators are widely used in smart structures, mechatronic and structronic systems, etc. This paper is to investigate the dynamics and control of nonlinear laminated piezothermoelastic shell structures subjected to the combined mechanical, electrical, and thermal excitations by the finite element method. Governing relations of nonlinear strain-displacement, electric field-electric potential, and temperature gradient-temperature field for a piezothermoelastic shell are presented in a curvilinear coordinate system. Based on the layerwise constant shear angle theory, a generic curved triangular laminated piezothermoelastic shell element is developed. Generic nonlinear finite element formulations for vibration sensing and control analysis of laminated piezoelectric shell structures are derived based on the virtual work principle. Dynamic system equations, equations of electric potential output, and feedback control force are derived and discussed. The modified Newton-Raphson method is used for efficient nonlinear dynamic analysis of complex nonlinear piezoelectric/elastic/control structural systems. For vibration sensing and control, various control algorithms are implemented. The developed nonlinear piezothermoelastic shell element and finite element code are validated and applied to analysis of nonlinear flexible structronic systems. Vibration sensing and control of constant/non-constant curvature piezoelectric shell structures are studied. Thermal effect to static deflection, dynamic response, and control is investigated.

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