Adaptive Robust Controller Designs Applied to Free-Floating Space Manipulators in Task Space (original) (raw)
Related papers
Adaptive control of free-floating space manipulators
SMC 2000 Conference Proceedings. 2000 IEEE International Conference on Systems, Man and Cybernetics. 'Cybernetics Evolving to Systems, Humans, Organizations, and their Complex Interactions' (Cat. No.00CH37166), 2000
In this paper, adaptive control of free-floating space manipulators is considered. The dynamics based on the momentum conservation law for the free-floating space manipulator has non-linear parameterization properties. Therefore, the adaptive control based on a linear parameterization model cannot be used in this dynamics. In this paper, the dynamics of the free-floating space manipulator system are derived using the Dynamically Equivalent Model (DEM) approach. The DEM is a fixed-base manipulator system and allows us to linearly parameterize the dynamic equations. Using this linearly parameterized dynamic equation, an adaptive control method is developed to control the system in joint space. Parameter identification and torque calculations are done using the DEM dynamics. Simulations show that the tracking errors of the manipulator joints to a given desired trajectory become zero when the calculated torques act on the joints of the space manipulator system.
Strategies for Control of Space Robots: A Review and Research Agenda
Modelling and control of space robots is not an easy task to perform, because the equations of motion that govern phenomenon are highly nonlinear. Furthermore, unlike fixed base manipulators a freefloating space robot exhibits non-holonomic behavior as a result of the non-integrability of the angular momentum conservation law. In recent days space robots are extensively used to play a significant role in space applications like, scheduled servicing of satellites and spacecrafts including refuelling tasks, inspection of remote sites or verification of structures, retrieval of tumbling tools or astronauts, and assembly or welding of space structures. In a large number of these applications, the manipulator endeffector is required to interact with the environment. Due to the interaction between the endeffector and the environment, the interaction torques act on the endeffector which gets transmitted through links to the base of the vehicle and the orientation of the vehicle changes. He...
Adaptive control of space-based robot manipulators
Robotics and Automation, IEEE …, 1991
For space based robots in which the base is fl'ee to move, motion planning and control is complicated by uncertainties in the inertial properties of the manipulator and its load. This paper presents a new adaptive control method for space based robots which achieves globally stable trajectory tracking in the presence of uncertainties in the inertial parameters of the system. The paper begins with a partitioning of the fifteen degree of freedom system dynamics into two components: a nine degree of freedom invertible portion and a six degree of freedom noninvertible portion. The controller is then designed to achieve trajectory tracking of the invertible portion of the system. This portion of the system consist of the manipulator joint positions and the orientation of the base. The motion of the noninvertible portion is bounded, but unpredictable. This portion of the system consist of the position of the robot's base and the position of the reaction wheels. [14] M. W. Walker, "Adaptive control of manipulators containing closed kinematic loop , IEEE Transactions on Robotics
Modelling and control of space robots is not an easy task to perform, because the equations of motion that govern phenomenon are highly nonlinear. Furthermore, unlike fixed base manipulators a freefloating space robot exhibits non-holonomic behavior as a result of the non-integrability of the angular momentum conservation law. In recent days space robots are extensively used to play a significant role in space applications like, scheduled servicing of satellites and spacecrafts including refuelling tasks, inspection of remote sites or verification of structures, retrieval of tumbling tools or astronauts, and assembly or welding of space structures. In a large number of these applications, the manipulator endeffector is required to interact with the environment. Due to the interaction between the endeffector and the environment, the interaction torques act on the endeffector which gets transmitted through links to the base of the vehicle and the orientation of the vehicle changes. Hence, precise control of the manipulator's trajectory, attitude and impedance are critically important. This paper addressed the current state-oftheart in key areas of the space robotics by reviewing recently available literatures particularly on free flying and free floating space robots which help in summarizing various research outcomes in a structured manner.
Analysis of reaction torque-based control of a redundant free-floating space robot
Chinese Journal of Aeronautics, 2017
Owing to the dynamics coupling between a free-floating base and a manipulator, the non-stationary base of a space robot will face the issue of base disturbance due to a manipulator's motion. The reaction torque acted on the satellite base's centroid is an important index to measure the satellite base's disturbance. In this paper, a comprehensive analysis of the reaction torque is made, and a novel way to derive the analytical form of the reaction torque is proposed. In addition, the reaction torque null-space is derived, in which the manipulator's joint motion is dynamically decoupled from the motion of the satellite base, and its novel expression demonstrates the equivalence between the reaction torque null-space and the reaction null-space. Furthermore, the reaction torque acted as an optimization index can be utilized to achieve satellite base disturbance minimization in the generalized Jacobian-based end-effector Cartesian path tracking task. Besides, supposing that the redundant degrees of freedom are abundant to achieve reaction torque-based active control, the reaction torque can be used to realize satellite base attitude control, that is, base attitude adjustment or maintenance. Moreover, because reaction torque-based control is a second-order control scheme, joint torque minimization can be regarded as the optimization task in reaction torque-based active or inactive control. A real-time simulation system of a 7-DOF space robot under Linux/RTAI is developed to verify and test the feasibility and reliability of the proposed ideas. Our extensive empirical results demonstrate that the corresponding analysis about the reaction torque is correct and the proposed methods are feasible.
Adaptive control of free-floating space manipulators using dynamically equivalent manipulator model
Robotics and Autonomous Systems, 2004
In this paper, adaptive control of free-floating space manipulators is considered. The dynamics based on the momentum conservation law for the free-floating space manipulator has non-linear parameterization properties. Therefore, the adaptive control based on a linear parameterization model cannot be used in this dynamics. In this paper, the dynamics of the free-floating space manipulator system are derived using the Dynamically Equivalent Model (DEM) approach. The DEM is a fixed-base manipulator system and allows us to linearly parameterize the dynamic equations. Using this linearly parameterized dynamic equation, an adaptive control method is developed to control the system in joint space. Parameter identification and torque calculations are done using the DEM dynamics. Simulations show that the tracking errors of the manipulator joints to a given desired trajectory become zero when the calculated torques act on the joints of the space manipulator system.
Robust Trajectory Tracking Control of Space Manipulators in Extended Task Space
Pomiary Automatyka Robotyka
This study provides a new class of controllers for freeflying space manipulators subject to unknown undesirable disturbing forces exerted on the end-effector. Based on suitably defined taskspace non-singular terminal sliding manifold and the Lyapunov stability theory, we derive a class of estimated extended transposed Jacobian controllers which seem to be effective in counteracting the unstructured disturbing forces. The numerical computations which are carried out for a space manipulator consisting of a spacecraft propelled by eight thrusters and holonomic manipulator of three revolute kinematic pairs, illustrate the performance of the proposed controller.
A unified approach to Space robot kinematics
IEEE Transactions on Robotics and Automation, 1996
An essential step in deriving kinematic models of free-flying space robots, consisting of a free-base and a manipulator mounted on it, is to write the total momenta of the system at hand. The momenta are, usually, expressed as the functions of the velocities of apreselected body that belongs to the robot, e.g., the free-base. In this paper, no preselection is recommended. On the contrary, the total momenta are expressed as the functions of the velocities of an arbitrary body of the space robot, namely, the primary body (PB). The identity of the PB, unlike the conventional approaches, need not be known at this stage. Therefore, the generalized expressions for the total momenta are obtained. The resulting expressions can explain the existing kinematic models and how they affect the efficiencies of the associated control algorithms. Based on the proposed approach, it is shown that if the end-effector motion is the only concern, as desired in kinematic control, it should be selected as the PB. This leads to the most efficient algorithms.