Simulation Based Analysis of Kinematics, Dynamics and Control of Space Robots

The space robotics kinematics, dynamics and control were studied by simulation. An emerging concept in space robotics is the Virtual Manipulator (VM) concept. In this study, the VM concept was enhanced and verified through simulation. The mathematical software package MATHEMATICA was used to compute the formulations. In the kinematics simulation of free-floating space robotics systems the concept of VM was enhanced which relates to the homogeneous matrix formulation. This was established by simulation results, there are no external forces condition, the inverse kinematics solution can be solved. In the area of space robot dynamic identification, the method based on conservation law of linear and angular momentum of a space robot from the VM approach was introduced. It was shown that the acceleration of the Virtual Base (VB) was proportionally equal to the change of its position in inertial space from the applied forces or torques. The forces or torques rotates about the system center of mass. A PD control law was used with the simulation test to identify the dynamic parameters. In the problem of trajectory planning, the VM concept was utilized that allow the space robot translation and rotation with respect to an inertial reference frame. A method was developed that can compute the satellite platform moments from the manipulator's motion. The resolved motion rate control algorithm was used for time periodic feedback control. In the simulation results, a satellite-based three degrees of freedom robot was simulated using schematic illustrations. The telerobotic control system was used in the space robotics control. In the masterslave control environment study, several considerations were taken into account, like the master and slave arm configuration, telemonitoring force feedback algorithm, and dynamic characteristics of master and slave arm. In this study a complete and enhanced master-slave space robotics system was established by simulation

Dynamic Balance Control of Multi-arm Free-Floating Space Robots

This paper investigates the problem of the dynamic balance control of multi-arm free-floating space robot during capturing an active object in close proximity. The position and orientation of space base will be affected during the operation of space manipulator because of the dynamics coupling between the manipulator and space base. This dynamics coupling is unique characteristics of space robot system. Such a disturbance will produce a serious impact between the manipulator hand and the object. To ensure reliable and precise operation, we propose to develop a space robot system consisting of two arms, with one arm (mission arm) for accomplishing the capture mission, and the other one (balance arm) compensating for the disturbance of the base. We present the coordinated control concept for balance of the attitude of the base using the balance arm. The mission arm can move along the given trajectory to approach and capture the target with no considering the disturbance from the coupling of the base. We establish a relationship between the motion of two arm that can realize the zeros reaction to the base. The simulation studies verified the validity and efficiency of the proposed control method

Modeling & control of a space robot for active debris removal

Space access and satellites lifespan are increasingly threatened by the great amount of debris in Low Earth Orbits (LEO). Among the many solutions proposed in the literature so far, the emphasis is put here on a robotic arm mounted on a satellite to capture massive debris, such as dead satellites or launch vehicle upper stages. The modeling and control of such systems are investigated throughout the paper. Dynamic models rely on an adapted Newton-Euler algorithm, and control algorithms are based on the recent structured H infinity method. The main goal is to efficiently track a target point on the debris while using simple PD-like controllers to reduce computational burden. The structured H infinity framework proves to be a suitable tool to design a reduced-order robust controller that catches up with external disturbances and is simultaneously compatible with current space processors capacities

Autonomous Capture of a Resident Space Object by a Spacecraft with a Robotic Manipulator: Analysis, Simulation and Experiments

AIAA/AAS Astrodynamics Specialist Conference, Long Beach, CA. The article of record may be found at:http://arc.aiaa.org | DOI: 10.2514/6.2016-5269This paper describes a set of laboratory-based experiments, which demonstrate the autonomous capture of a non-moving resident space object by a spacecraft equipped with a single robotic manipulator. An air bearing test bed is used to simulate weightlessness and frictionless maneuvering on a plane. The chaser is composed by a floating spacecraft simulator carrying a kinematically redundant four-link serial manipulator. The manipulator mass is similar to the mass of its base-spacecraft, resulting in an unusually large dynamic coupling. Emphasis is given to the guidance and control, demonstrating floating, flying and rotation-flying coordinated control strategies. A resolved-motion-rate controller regulates the manipulator joint velocities. The relative navigation problem, solved by the test bed metrology system, has been left outside the scope of this effort. The presented experiments increase the number of space robotics experimental evaluations conducted in dynamically representative environments

Robotic Manipulation and Capture in Space: A Survey

Space exploration and exploitation depend on the development of on-orbit robotic capabilities for tasks such as servicing of satellites, removing of orbital debris, or construction and maintenance of orbital assets. Manipulation and capture of objects on-orbit are key enablers for these capabilities. This survey addresses fundamental aspects of manipulation and capture, such as the dynamics of space manipulator systems (SMS), i.e., satellites equipped with manipulators, the contact dynamics between manipulator grippers/payloads and targets, and the methods for identifying properties of SMSs and their targets. Also, it presents recent work of sensing pose and system states, of motion planning for capturing a target, and of feedback control methods for SMS during motion or interaction tasks. Finally, the paper reviews major ground testing testbeds for capture operations, and several notable missions and technologies developed for capture of targets on-orbit

Control of free-flying space robot manipulator systems

New control techniques for self contained, autonomous free flying space robots were developed and tested experimentally. Free flying robots are envisioned as a key element of any successful long term presence in space. These robots must be capable of performing the assembly, maintenance, and inspection, and repair tasks that currently require human extravehicular activity (EVA). A set of research projects were developed and carried out using lab models of satellite robots and a flexible manipulator. The second generation space robot models use air cushion vehicle (ACV) technology to simulate in 2-D the drag free, zero g conditions of space. The current work is divided into 5 major projects: Global Navigation and Control of a Free Floating Robot, Cooperative Manipulation from a Free Flying Robot, Multiple Robot Cooperation, Thrusterless Robotic Locomotion, and Dynamic Payload Manipulation. These projects are examined in detail

Computed torque control of a free-flying cooperat ing-arm robot

The unified approach to solving free-floating space robot manipulator end-point control problems is presented using a control formulation based on an extension of computed torque. Once the desired end-point accelerations have been specified, the kinematic equations are used with momentum conservation equations to solve for the joint accelerations in any of the robot's possible configurations: fixed base or free-flying with open/closed chain grasp. The joint accelerations can then be used to calculate the arm control torques and internal forces using a recursive order N algorithm. Initial experimental verification of these techniques has been performed using a laboratory model of a two-armed space robot. This fully autonomous spacecraft system experiences the drag-free, zero G characteristics of space in two dimensions through the use of an air cushion support system. Results of these initial experiments are included which validate the correctness of the proposed methodology. The further problem of control in the large where not only the manipulator tip positions but the entire system consisting of base and arms must be controlled is also presented. The availability of a physical testbed has brought a keener insight into the subtleties of the problem at hand

Space robotics: Recent accomplishments and opportunities for future research

The Langley Guidance, Navigation, and Control Technical Committee (GNCTC) was one of six technical committees created in 1991 by the Chief Scientist, Dr. Michael F. Card. During the kickoff meeting Dr. Card charged the chairmen to: (1) establish a cross-Center committee; (2) support at least one workshop in a selected discipline; and (3) prepare a technical paper on recent accomplishments in the discipline and on opportunities for future research. The Guidance, Navigation, and Control Committee was formed and selected for focus on the discipline of Space robotics. This report is a summary of the committee's assessment of recent accomplishments and opportunities for future research. The report is organized as follows. First is an overview of the data sources used by the committee. Next is a description of technical needs identified by the committee followed by recent accomplishments. Opportunities for future research ends the main body of the report. It includes the primary recommendation of the committee that NASA establish a national space facility for the development of space automation and robotics, one element of which is a telerobotic research platform in space. References 1 and 2 are the proceedings of two workshops sponsored by the committee during its June 1991, through May 1992 term. The focus of the committee for the June 1992 - May 1993 term will be to further define to the recommended platform in space and to add an additional discipline which includes aircraft related GN&C issues. To the latter end members performing aircraft related research will be added to the committee. (A preliminary assessment of future opportunities in aircraft-related GN&C research has been included as appendix A.