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.

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.

scholarly journals Kane Method Based Dynamics Modeling and Control Study for Space Manipulator Capturing a Space Target

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Yanhua Han
Keyword(s):  
Attitude Control ◽  
Dynamics Modeling ◽  
Attitude Control System ◽  
Constraint Forces ◽  
Inertia Moment ◽  
Modeling And Control ◽  
And Control ◽  
Kane Method ◽  
Control Study ◽  
Space Target

Dynamics modeling and control problem of a two-link manipulator mounted on a spacecraft (so-called carrier) freely flying around a space target on earth’s circular orbit is studied in the paper. The influence of the carrier’s relative movement on its manipulator is considered in dynamics modeling; nevertheless, that of the manipulator on its carrier is neglected with the assumption that the mass and inertia moment of the manipulator is far less than that of the carrier. Meanwhile, we suppose that the attitude control system of the carrier guarantees its side on which the manipulator is mounted points accurately always the space target during approaching operation. The ideal constraint forces can be out of consideration in dynamics modeling as Kane method is used. The path functions of the manipulator’s end-effector approaching the space target as well as the manipulator’s joints control torque functions are programmed to meet the soft touch requirement that the end-effector’s relative velocity to the space target is zero at touch moment. Numerical simulation validation is conducted finally.

scholarly journals Hysteresis Nutation Damper for Spin Satellite

2013 ◽  
Vol 6 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Hamed Shahmohamadi Ousaloo
Keyword(s):  
Attitude Control ◽  
Principal Axis ◽  
Dynamic Properties ◽  
Magnetic Hysteresis ◽  
Pure Spin ◽  
Attitude Control System ◽  
Magnetic Attitude Control ◽  
Separation Phase ◽  
Nutation Damper ◽  
Damping Torque

Hysteresis dampers are commonly used in Passive magnetic Attitude Control System (PACS). In PACS these rods produce a damping torque and reduce the satellite angular momentum and angular velocity. In this paper, a spin satellite was investigated which utilizes a passive magnetic damper consisting of magnetic hysteresis rods aligned with principal axis or spin axis of satellite and de-tumbling of the satellite, and the pure spin was achieved. An analytical model was presented to analyze hysteresis damper and a numerical simulation was performed to obtain dynamic properties of the spin attitude. In addition, assuming a dynamic imbalance, attitude behavior and damper effect on the spin rate of satellite were analyzed. The behavior of this passive magnetic stabilized satellite was simulated from the initial post separation phase.

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.

Free-flying robots in space: an overview of dynamics modeling, planning and control

Robotica ◽  
2007 ◽  
Vol 25 (5) ◽  
pp. 537-547 ◽  
Author(s):  
S. Ali A. Moosavian ◽  
Evangelos Papadopoulos
Keyword(s):  
Control Strategies ◽  
Equations Of Motion ◽  
Experimental Studies ◽  
Robotic Manipulators ◽  
Microgravity Environment ◽  
Dynamics Modeling ◽  
Planning And Control ◽  
Fixed Base ◽  
And Control ◽  
Flying Robots

SUMMARYFree-flying space manipulator systems, in which robotic manipulators are mounted on a free-flying spacecraft, are envisioned for assembling, maintenance, repair, and contingency operations in space. Nevertheless, even for fixed-base systems, control of mechanical manipulators is a challenging task. This is due to strong nonlinearities in the equations of motion, and consequently different algorithms have been suggested to control end-effector motion or force, since the early research in robotic systems. In this paper, first a brief review of basic concepts of various algorithms in controlling robotic manipulators is introduced. Then, specific problems related to application of such systems in space and a microgravity environment is highlighted. Basic issues of kinematics and dynamics modeling of such systems, trajectory planning and control strategies, cooperation of multiple arm space free-flying robots, and finally, experimental studies and technological aspects of such systems with their specific limitations are discussed.

scholarly journals Genetic algorithms for GNC settings and DACS design application to an asteroid Kinetic Impactor

2018 ◽  
Author(s):  
P. Vernis ◽  
V. Oliviero
Keyword(s):  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Control System ◽  
Attitude Control ◽  
Medium Size ◽  
Attitude Control System ◽  
Data Set ◽  
Earth Object ◽  
Navigation And Control ◽  
And Control

This paper deals with an application of Genetic Algorithm (GA) tools in order to perform and optimize the settings phase of the Guidance, Navigation, and Control (GNC) data set for the endgame phase of a Kinetic Impactor (KI) targeting a medium-size Near Earth Object (NEO). A coupled optimization of the GNC settings and of the GC-oriented design of the Divert and Attitude Control System (DACS) is also proposed. The illustration of the developed principles is made considering the NEOShield study frame.

scholarly journals A dϕ-Strategy: Facilitating Dual-Formation Control of a Virtually Connected Team

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Bibhya Sharma ◽  
Jito Vanualailai ◽  
Avinesh Prasad
Keyword(s):  
Autonomous Vehicles ◽  
Formation Control ◽  
Field Method ◽  
Mobile Manipulators ◽  
End Effector ◽  
Planning And Control ◽  
Potential Field Method ◽  
Control Scheme ◽  
And Control ◽  
First Time

This paper describes the design of new centralized acceleration-based controllers for the multitask problem of motion planning and control of a coordinated lead-carrier team fixed in a dual-formation within an obstacle-ridden environment. A dϕ-strategy, where d and ϕ are Euclidean measures with respect to the lead robot, is developed to ensure virtual connectivity of the carrier robots to the lead robot. This connectivity, built into the system itself, inherently ensures globally rigid formation between each lead-carrier pair of the team. Moreover, a combination of target configuration, dϕ-strategy, orientation consensus, and avoidance of end-effector of robots results in a second, locally rigid formation (not infinitesimally rigid). Therefore, for the first time, a dual-formation control problem of a lead-carrier team of mobile manipulators is considered. This and other kinodynamic constraints have been treated simultaneously via the overarching Lyapunov-based control scheme, essentially a potential field method favored in the field of robotics. The formulation of this new scheme, demonstrated effectively via computer simulations, is timely, given that the current proposed engineering solutions, allowing autonomous vehicles on public roads, include the development of special lanes imbued with special sensors and wireless technologies.

scholarly journals SATELLITE GUIDANCE AND CONTROL DURING OPERATIVE OPTOELECTRONIC IMAGERY FOR DISASTER MANAGEMENT

2018 ◽  
Vol XLII-3/W4 ◽  
pp. 475-482
Author(s):  
Y. Somov ◽  
C. Hajiyev
Keyword(s):  
Disaster Management ◽  
Attitude Control ◽  
Attitude Determination ◽  
Earth Surface ◽  
Attitude Control System ◽  
Control Laws ◽  
Guidance And Control ◽  
The Earth ◽  
Synchronous Orbit ◽  
And Control

<p><strong>Abstract.</strong> We consider problems on surveying the Earth surface during operative optoelectronic imagery for disaster management with respect to attitude guidance and control of the agile spacecraft. The land surveying is carried out by a set of extended orthodromic routes of scanning optoelectronic observation for a given part of the Earth surface. We present developed methods for synthesis of nonlinear guidance and attitude control laws, dynamic research of the spacecraft attitude control system with the satellite astroinertial attitude determination and digital control by the excessive gyro moment cluster. We present results on the efficiency of the developed vector spline guidance laws, algorithms for discrete filtering and the digital gyromoment control of a satellite orientation during the areal landsurveying of Istanbul neighborhoods for the spacecraft on sun-synchronous orbit with altitude of 720&amp;thinsp;km when the allowed deviation of the target line from Nadir is within the cone with semi-angle of 40&amp;thinsp;deg.</p>

scholarly journals Automated Synthesis and Optimization of Robot Configurations

1998 ◽  
Author(s):  
Chris Leger ◽  
John Bares
Keyword(s):  
Object Oriented ◽  
Control Algorithms ◽  
Modular Robots ◽  
Planning And Control ◽  
Fixed Base ◽  
Flexible Planning ◽  
Key Issues ◽  
Task Oriented ◽  
And Control ◽  
Robot Configurations

Abstract We present an extensible system for synthesizing and optimizing robot configurations. The system uses a flexible representation for robot configurations based on parameterized modules; this allows us to synthesize mobile and fixed-base robots, including robots with multiple or branching manipulators and free-flying robots. Synthesis of modular robots is also possible with our representation. We use an optimization algorithm based on genetic programming. A distributed architecture is used to spread heavy computational loads across multiple workstations. We take a task-oriented approach to synthesis in which robots are evaluated on a designer-specified task in simulation; flexible planning and control algorithms are thus required so that a wide variety of robots can be evaluated. Our system’s extensibility stems from an object-oriented software architecture that allows new modules, metrics, controllers, and tasks to be easily added. We present two example synthesis tasks: synthesis of a robotic material handler, and synthesis of an antenna pointing system for a mobile robot. We analyze several key issues raised by the experiments and show several important ways in which the system can be extended and improved.

Sign in / Sign up

Export Citation Format

Share Document