scholarly journals Omnidirectional Analysis of Spatial Manipulator

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Yuquan Leng ◽  
Yang Zhang ◽  
Xu He ◽  
Wei Zhang ◽  
Haitao Luo ◽  
...  
Keyword(s):  
Theoretical Approach ◽  
Sphere Surface ◽  
Space Manipulator ◽  
End Effector ◽  
Space Manipulators ◽  
Test Platform ◽  
Utilization Ratio

Space manipulators are mainly used in the spatial loading task. According to problems of the spatial loading diversity, the testing loading installing position, and the utilization ratio of a test platform, the space manipulator is asked to evaluate the position and attitude of itself. This paper proposes the Point Omnidirectional Coefficient (POC) with unit attitude sphere/circle to describe attitude of the end-effector, which evaluates any points in the attainable space of the manipulators, in combination with the manipulation’s position message, and get relationships between its position and attitude of all points in the attainable space. It represents the mapping between sphere surface and plane for mission attitude constraints and the method for calculating volume of points space including attainable space, Omnidirectional space, and mission attitude space. Furthermore, the Manipulator Omnidirectional Coefficient based on mission or not is proposed for evaluating manipulator performance. Through analysis and simulation about 3D and 2D manipulators, the results show that the above theoretical approach is feasible and the relationships about link lengths, joints angles, attainable space, and Manipulator Omnidirectional Coefficient are drawn for guiding design.

Inverse kinematics of free-floating space robots with minimum dynamic disturbance

Robotica ◽  
1996 ◽  
Vol 14 (6) ◽  
pp. 667-675 ◽  
Author(s):  
Fengfeng Xi
Keyword(s):  
Inverse Kinematics ◽  
New Method ◽  
Space Robots ◽  
Simple Fact ◽  
Generalized Jacobian ◽  
Space Manipulator ◽  
End Effector ◽  
Dynamic Disturbance ◽  
Space Manipulators

In this paper a new method is presented for solving the inverse kinematics of free-floating space manipulators. The idea behind the method is to move the space manipulator along a path with minimum dynamic disturbance. The method is proposed to use the manipulator Jacobian instead of the generalized Jacobian of the spacecraft-manipulator system. This is based on the simple fact that, if the space manipulator moves along the so-called Zero Disturbance Path (ZDP), the spacecraft is immovable. As a result, the space manipulator can in this case be treated as a terrestrial fixed-based manipulator. Hence, the motion mapping between the joints and the end-effector can be described directly by the manipulator Jacobian. In the case that the ZDP does not exist, it can be shown that the solutions obtained by the proposed method provide a path with minimum dynamic disturbance.

Dynamic Singularities in Free-Floating Space Manipulators

1993 ◽  
Vol 115 (1) ◽  
pp. 44-52 ◽  
Author(s):  
E. Papadopoulos ◽  
S. Dubowsky
Keyword(s):  
Attitude Control ◽  
Dynamic Properties ◽  
Kinematic Structure ◽  
Attitude Control System ◽  
Space Manipulator ◽  
End Effector ◽  
Planning And Control ◽  
Space Manipulators ◽  
Fixed Base ◽  
And Control

Dynamic Singularities are shown for free-floating space manipulator systems where the spacecraft moves in response to manipulator motions without compensation from its attitude control system. At a dynamic singularity the manipulator is unable to move its end-effector in some inertial direction; thus dynamic singularities must be considered in the design, planning, and control of free-floating space manipulator systems. The existence and location of dynamic singularities cannot be predicted solely from the manipulator kinematic structure because they are functions of the dynamic properties of the system, unlike the singularities for fixed-base manipulators. Also analyzed are the implications of dynamic singularities to the nature of the system’s workspace.

The Design and Comparison Study on the Large-Scale End-Effector of Large Space Manipulator

2011 ◽  
Vol 308-310 ◽  
pp. 2095-2103
Author(s):  
Fei Feng ◽  
Yi Wei Liu ◽  
Hong Liu ◽  
He Gao Cai
Keyword(s):  
Large Scale ◽  
Space Structure ◽  
Comparison Study ◽  
Residual Vibration ◽  
Steel Cable ◽  
Dynamic Simulations ◽  
Large Space ◽  
Space Manipulator ◽  
End Effector ◽  
Large Space Manipulator

The space manipulator which is mounted on a space structure or spacecraft to manipulate space payloads is important for the on-orbit-servicing. Its manipulation tasks depend on its end-effector. The flexibility of the large space manipulator will result in residual vibration on its tip, and let the manipulator have poor capability of end positioning. To overcome the drawbacks mentioned-above, the end-effector needs strong capability of misalignment tolerance and soft capturing. On the base of these requirements and analysis, two kinds of end-effector schemes are presented and designed in detail. The essential performances are in comparison based on the results of dynamic simulations and experiments. Consequently, the conclusion is drawn that the steel cable-snared end-effector which captures the interface by winding the grapple fixture probe, is the best scheme that can combine the ability of soft capturing and great misalignment tolerance perfectly.

scholarly journals Kinematic and Dynamic Characteristics of the Free-Floating Space Manipulator with Free-Swinging Joint Failure

2019 ◽  
Vol 2019 ◽  
pp. 1-22 ◽  
Author(s):  
Qingxuan Jia ◽  
Bonan Yuan ◽  
Gang Chen ◽  
Yingzhuo Fu
Keyword(s):  
Dynamic Characteristics ◽  
Nonholonomic Constraint ◽  
Dynamic Coupling ◽  
Velocity Mapping ◽  
Joint Failure ◽  
Space Manipulator ◽  
End Effector ◽  
First Order ◽  
Kinematic Coupling ◽  
Active Joints

For the free-floating space manipulator with free-swinging joint failure, motions among its active joints, passive joints, free-floating base, and end-effector are coupled. It is significant to make clear all motion coupling relationships, which are defined as “kinematic coupling relationships” and “dynamic coupling relationships,” inside the system. With the help of conservation of system momentum, the kinematic model is established, and velocity mapping relation between active joints and passive joints, velocity mapping relation between active joints and base, velocity mapping relation between active joints and end-effector. We establish the dynamic model based on the Lagrange equation, and the system inertia matrix is partitioned according to the distribution of active joints, passive joints, and the base. Then, kinematic and dynamic coupling relationships are explicitly derived, and coupling indexes are defined to depict coupling degree. Motions of a space manipulator with free-swinging joint failure simultaneously satisfy the first-order nonholonomic constraint (kinematic coupling relationships) and the second-order nonholonomic constraint (dynamic coupling relationships), and the manipulator can perform tasks through motion planning and control. Finally, simulation experiments are carried out to verify the existence and correctness of the first-order and second-order nonholonomic constraints and display task execution effects of the space manipulator. This research analyzes the kinematic and dynamic characteristics of the free-floating space manipulator with free-swinging joint failure for the first time. It is the theoretical basis of free-swinging joint failure treatment for a space manipulator.

Dynamic Analysis of Flexible Space Manipulators with Harmonic Reducer

2013 ◽  
Vol 584 ◽  
pp. 200-207 ◽  
Author(s):  
Jie Liang Zhao ◽  
Yong Xia Gu ◽  
Shao Ze Yan ◽  
Jia Ning Wu
Keyword(s):  
High Frequency ◽  
Dynamical Property ◽  
Hysteresis Phenomenon ◽  
Harmonic Drive ◽  
Dynamical Models ◽  
Space Manipulator ◽  
Space Manipulators ◽  
Nonlinear Dynamic Characteristics ◽  
Angular Velocities ◽  
Dynamical Properties

Space manipulator is an important tool for spacecraft to complete a variety of tasks in space. The trajectory precision of the manipulator determines whether the mechanism performs normally. Nowadays the harmonic drive is widely used as the reducer in the space manipulator, which may influence the dynamical properties of the flexible space manipulator. This paper establishes the dynamical models of space manipulator considering the harmonic hysteresis phenomenon derived from the harmonic reducer. A numerical simulation is proposed to analyze the nonlinear dynamic characteristics of flexible space manipulator with harmonic drive. The results of angular velocities reveal that non-linear and high-frequency disturbance detected in the output dynamical property is caused by flexibility of the space manipulator. Moreover, the observed hysteresis phenomenon in the dynamic behavior is not only determined by the flexibility of manipulator but the transmission feature embedded the harmonic drive.

Design and Analysis of Suspension Scheme for Space Manipulator Low-Gravity Test

2014 ◽  
Vol 940 ◽  
pp. 321-326
Author(s):  
Wei Feng ◽  
Wang Min Yi ◽  
Fan Wei Meng ◽  
Xiao Peng Shen ◽  
Xiao Dong Song
Keyword(s):  
Theoretical Analysis ◽  
Optimal Location ◽  
Motion Path ◽  
Test Results ◽  
Low Gravity ◽  
Space Manipulator ◽  
Experimental Scheme ◽  
Space Manipulators ◽  
Gravity Test

In this paper, a low gravity experimental scheme with weight-balanced suspenders is proposed to solve the problem of the low-gravity environments simulation for the space manipulators (SM), in which the optimal location of the hanging point can be obtained from theoretical analysis. In addition, according to low gravity experiment requirement and motion path of the SM, the kinematical equation in terms of D-H method is built, the suspender adaptability under horizontal and inclined conditions are studied respectively using MATLAB, and a solution for suspender interference is proposed and verified. The test results confirmed the validity of the proposed scheme.

Force Control of a Space Manipulator

2000 ◽  
Vol 12 (4) ◽  
pp. 351-355 ◽  
Author(s):  
Katsuyoshi Tsujita ◽  
◽  
Kazuo Tsuchiya ◽  
Yousuke Kawano
Keyword(s):  
Force Control ◽  
Attitude Control ◽  
The Other ◽  
Main Body ◽  
Space Manipulator ◽  
Sample Return ◽  
End Effector ◽  
Passive Compliance ◽  
Sample Return Mission ◽  
Compliance Mechanism

This paper deals with the force control of a space manipulator for a sample-return mission. There are two difficulties in force control of this class of space manipulator: One is that a space robot has no fixed point in space and moves when its manipulator exerts force on the environment. The other is that physical properties of the environment on which the manipulator exerts force are not well known. In order to overcome these difficulties, a hierarchical controller is proposed in this paper. The controller manages attitude control of the main body and force control of the manipulator. The end effector is attached to the manipulator by a passive compliance mechanism. The performance of the proposed controller is verified by numerical simulations and hardware experiments.

Sign in / Sign up

Export Citation Format

Share Document