V. M. Sukhanov

Motion equations and control of the free-flying space manipulator in the reconfiguration mode

The problem of constructing a mathematical model of the planar motion of a free-flying space manipulator meant for maintenance of the surface of manned orbital station was examined. Consideration was given to the design of an algorithm of economic control of the manipulator configuration on the basis of self-braking drives with allowance for substantial mobility of the base. Some results of modeling the space robot dynamics in the mode of manipulator configuration control with subsequent suppression of the carrying body orientation error which corroborate efficiency of the proposed algorithms were presented.

Control of multimode manipulative space robot in outer space

Some issues of safe motion of the space robot free-flying near the surface of a manned orbital station and generation of the algorithm for initial orientation to the target using a TV camera installed at the end link of the manipulator were discussed. A procedure for construction of the domain of “creeping” speeds of the manipulator where the original model may be replaced by a simplified one was proposed. Consideration was given to the design of an algorithm for installation by the manipulator of a useful load at the given point of surface of the serviced station in the presence of information about the distance to the target. Examples of modeling the robot dynamics were presented to corroborate the efficiency of the proposed algorithms.

Fuzzy Logic-based Adaptive Control System for In-orbit Assembly of Large Space Structures

Design of a fuzzy adaptive algorithm to control orientation of a large space structure during the progress of in-orbit assembly was considered. For the discretely evolving structure, a matrix description of the set of modal-physical models was given. Introduced were the functions of influence of the basic control on the dynamics of the autonomous models of isolated flexible modes that underlie the fuzzy characteristics of the orientation system. A methodology of designing a fuzzy logic-based adaptive algorithm for stabilization of a transformable flexible multifrequency space object was proposed. The results of simulating the proposed adaptive orientation system were presented.

A Method of Constructing the Mathematical Model of a Discretely Developing Large Space Structure

A new method was proposed to describe the on-orbit mounting of large space constructions that is accompanied by discrete changes in their mechanical structure and dynamic characteristics as controlled plants. Consideration was given to designing the initial (Lagrangian) model for each interval of invariable structure of the discretely developing construction. A graph-based computational procedure of reducing the initial model to the modal-physical one was proposed. Suggested was a method of designing a construction graph model which provides a most compact representation of the changes in the dynamic characteristics of the large space construction that occur in the course of its structural transformation.

Nonexciting Control by Orientation of Flexible Space Vehicles

Abstract The interaction of the orientation control moment of a flexible vehicle (FV) with the elastic oscillations in the mechanical structure is considered. With fmite control actuator saturation limits, this interaction can be the cause of instability of the closed-loop system in which the elastic oscillations increase in amplitude to a point ultimately limited by non-linearities in the structure. An approach to circumvent the problem is presented here which is based upon consideration of the resonance interaction of the non-linear controller with the elastic oscillations. This enables the controller parameters to be optimised to minimise the modal excitation. Some digital simulation results are discussed.

Some questions of control of the robotized in-orbit assembly of large space structures

Presented was an analytical review of the foreign and domestic scientific literature published over more than two decades on the dynamics and theory of motion control of large space structures and free-flying space robots meant for assisting the astronauts or replacing them at execution of diverse maintenance operations in open space. Although many results on the design of control systems for each of the aforementioned kinds of objects are very significant taken separately, nevertheless the most important problem of using the flying robots for in-orbit assembly of the large space structures remains still unsolved. Formulated was the concept of complex approach to the problem of robot-assisted in-orbit assembly of space structures which lies in combining the algorithms of all subsystems involved in the assembly of the objects with regard for the requirements on safe interaction of the participants, high resultant precision and reliability of operation, and minimal use of the consumable fuel.

Technical Controllability of the Free-flying Automated Space Module

Consideration was given to the free-flying automated space module, a facility intended for servicing the orbiting space station and its accompanying objects. The notion of technical controllability of the free-flyer was introduced. A theorem about the necessary and sufficient conditions for technical controllability was proved. Methods for establishing the domains of technical controllability in the space of the generalized coordinates of object motion were proposed. By means of an illustrative example, the results of applying the notion of technical controllability were demonstrated, the domains of the given degree of technical controllability were established, and the minimal necessary vector of constraints on control of the object was determined.

Guidance and precise motion control of free-flying robots and land-survey mini-satellites

The information mini-satellites (for communication, geodesy, radio- and opto-electronic observation of the Earth et al.) and the space free-flying robots (used for service of manned orbital space stations and for assembling the large space structures) have some principal problems with respect to their spatial guidance and control. In the paper these problems are considered and obtained results are presented.

Some issues of controlling the free-flying manipulative space robot

A brief review of the state-of-the-art in the control of free-flying space robots in the modes of manipulative target lockon by planning the gripper trajectory was presented. For the class of feedback systems, an alternative approach to this problem was proposed. Within the framework of this approach, consideration was given to the problems of constructing the working zone of the space manipulative robot and generating an algorithm to control the manipulative positioning of the load at the desired point of the inertial space with the availability of information about the direction to the target and the distance to it which is acquired using a camcorder mounted at the end link of the manipulator. Examples were presented of computer-aided construction of the working zone and modeling the space robot dynamics which corroborate operability of the proposed algorithm.

Physically realizable reference model-based algorithm of adaptive control

A physically realizable algorithm for adaptation of the adaptive systems with model was proposed. It is distinguished for the operational independence of intensity and spectral composition of the control and nonmeasurable perturbing actions. Presented was an example of the second-order system with stepwise noisy harmonic inputs. The variable system parameters also vary by the harmonic laws of various frequencies.