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.

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 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 Coordinated motion control of a dual-arm space robot with joint-limit avoidance and uncertain inertial parameters

2017 ◽  
Vol 14 (5) ◽  
pp. 172988141772802 ◽  
Author(s):  
Chunting Jiao ◽  
Bin Liang ◽  
Xueqian Wang ◽  
Jingyan Song ◽  
Bo Zhang
Keyword(s):  
Motion Control ◽  
Null Space ◽  
Momentum Conservation ◽  
Space Robot ◽  
Coordinated Motion ◽  
Control Approach ◽  
Target Capture ◽  
Inertial Parameters ◽  
Dual Arm ◽  
Joint Limit

In this article, a new adaptive coordinated motion control approach is introduced for a dual-arm free-floating space robot. This adaptive algorithm is used for the post-capture of a large noncooperative target with joint-limit avoidance and uncertain dynamic parameters. To overcome the problem of dynamics coupling between the space base, its manipulators, and the target, we develop a dual-arm space robotic system. One arm is used to complete the capture task and the other is used to counteract the disturbance to the space base. In this case, a new coordinated motion control law is derived based on reaction null space control. An improved joint-limit avoidance algorithm is implemented for large noncooperative target capture; otherwise, a significant base disturbance may result if the joint-limit constraints are not explicitly considered. Based on momentum conservation, the linear regression form of the estimation problem is obtained, and we further identify the unknown inertial parameters of the target. Finally, the simulation results demonstrate the effectiveness of the proposed algorithm.

Three-Dimension Thermal Hydraulic Analysis of Stationary Target Plate for Highly Intensified Neutron Generator (HINEG)

2013 ◽  
Author(s):  
Shuzhou Li ◽  
Hongli Chen ◽  
Tao Zhou ◽  
Fengquan Song ◽  
Wen Wang
Keyword(s):  
Neutron Generator ◽  
Fusion Energy ◽  
Target System ◽  
Three Dimension ◽  
Target Plate ◽  
Stationary Target ◽  
Stationary Analysis ◽  
And Performance ◽  
As Stress ◽  
Thermal Hydraulic Analysis

Highly intensified neutron generator (HINEG) is a D-T neutron generator tritium target system; it can be used in researching fusion energy and advanced fission energy. The heat flux at the target plate is extraordinarily high, cooling the target plate effectively, limiting the working temperature, are the keys to keep the normal working of HINEG. This paper has simulated the 3D values of some different kind of target plate systems, using the computational fluid dynamics software and static analysis software, presented the stationary analysis results of temperature and fluid fields, as well as stress field. The flow and temperature distributions provide important data for advanced design and performance evaluation of HINEG.

Parameter Identification of a Cantilever Beam Immersed in Viscous Fluids With Potential Applications to the Probe Calibration of Atomic Force Microscopes

2009 ◽  
Author(s):  
Wenlung Li ◽  
S. P. Tseng
Keyword(s):  
Parameter Identification ◽  
Natural Frequency ◽  
Cantilever Beam ◽  
Present Method ◽  
Present Report ◽  
Excitation Frequency ◽  
Spring Constant ◽  
Target System ◽  
Phase Lag ◽  
Identification Method

The main objective of the report is to present a new identification method has been derived for single-degree, base-excited systems. The system is actually to mimic a probe of cantilever type of AFMs. In fact, the idea of the present report was initiated by needs for in situ spring constant calibration for such probe systems. Calibration processes can be treated as parameter identification for the stiffness of the probe before it is used. However, sine a real probe is too small to be seen by bare eyes and too costly to verify, a cantilever beam was adopted to replace it during the study. The present method starts with giving a chirp excitation to the target system, and to lock the damped natural frequency. Once the damped natural frequency is obtained, it is possible to locate the frequency at which the phase lag is equal to π/2. From which, the excitation frequency is then purposely changed to that frequency and the corresponding steady-state responses are measured. In the meantime, the system dissipative energy or power may also need to be stored. In fact, the present identification formulation is to express the spring constant of the target systems in terms of two measurable parameters: the phase angle and the system damping. The former can be computed from the damped natural frequency while the latter can be identified along with measuring the input power. The novel formulation is then numerically simulated using the Simulink toolbox of MATLAB. The simulation results clearly showed the current identification method can work with good accuracy. Following the numerical simulation, experimental measurements were also carried out by a cantilever beam that its free end was immersed to viscid fluids. The fluids of different viscosity were used to mimic the environments of a probe in use. The experimental results again substantiated the correctness of the present method. Thus it is accordingly concluded that the new recognition algorithm can be applied with confidence.

scholarly journals Impact motion control of a flexible dual-arm space robot for capturing a spinning object

2019 ◽  
Vol 16 (3) ◽  
pp. 172988141985753
Author(s):  
Xiali Li ◽  
Licheng Wu
Keyword(s):  
Motion Control ◽  
Control Method ◽  
Initial Conditions ◽  
Autonomous Vehicle ◽  
Stable State ◽  
Momentum Conservation ◽  
Space Robot ◽  
Dynamics Response ◽  
The Impact ◽  
Dual Arm

As an autonomous vehicle that moves on the space orbit, a space robot needs to be carefully treated on the motion planning and control method. In this article, the optimal impact and postimpact motion control of a flexible dual-arm space robot capturing a spinning object are considered. Firstly, the dynamic model of the robot systems is built by using Lagrangian formulation. The flexible links are modeled as Euler–Bernoulli beams of two bending modes. Through simulating the system’s postimpact dynamics response, the initial conditions are obtained from the impact model. Next, the initial velocities of base and joint are adjusted to minimize the velocity of the base after the capture according to generalized momentum conservation. After the capture, a proportional–derivative controller is designed to keep the robot system’s stabilization. The simulation results show that joint angles of base and manipulators reach stable state quickly, and motions of the space robots also induce vibrating motions of the flexible manipulators.

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