scholarly journals Adaptive Robust Quadratic Stabilization Tracking Control for Robotic System with Uncertainties and External Disturbances

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jinzhu Peng ◽  
Yan Liu
Keyword(s):  
Closed Loop ◽  
Robot Manipulator ◽  
Variable Structure ◽  
Robotic System ◽  
Loop System ◽  
Closed Loop System ◽  
Hybrid Scheme ◽  
External Disturbances ◽  
Control Approach ◽  
Quadratic Stabilization

An adaptive robust quadratic stabilization tracking controller with hybrid scheme is proposed for robotic system with uncertainties and external disturbances. The hybrid scheme combines computed torque controller (CTC) with an adaptive robust compensator, in which variable structure control (VSC) andH∞optimal control approaches are adopted. The uncertain robot manipulator is mainly controlled by CTC, the VSC is used to eliminate the effect of the uncertainties and ensure global stability, andH∞approach is designed to achieve a certain tracking performance of closed-loop system. A quadratic stability approach, which allows separate treatment of parametric uncertainties, is used to reduce the conservatism of the conventional robust control approach. It can be also guaranteed that all signals in closed-loop system are bounded. The validity of the proposed control scheme is shown by computer simulation of a two-link robotic manipulator.

Micro Autonomous Robotic System

1999 ◽  
Vol 11 (5) ◽  
pp. 443-447 ◽  
Author(s):  
Hidenori Ishihara ◽  
◽  
Toshio Fukuda ◽  
Keyword(s):  
Closed Loop ◽  
Autonomous Robots ◽  
Autonomous Robot ◽  
Robotic System ◽  
Loop System ◽  
Research Groups ◽  
Closed Loop System ◽  
Infrared Communication

Miniaturized autonomous robots have been developed by several research groups. The miniaturized autonomous robot is defined as a miniaturized closed-loop system with microprocessors, microactuators, and microsensors. We developed a micro autonomous robot (MARS) consisting of a microprocessor, microsensors, microactuators, communication units, and batteries. MARS controls itself by a downloaded program supplied through infrared communication. We demonstrate performance of MARS, and discuss system features.

scholarly journals Adaptive Impedance Control of Robot Manipulators with Parametric Uncertainty for Constrained Path–Tracking

2018 ◽  
Vol 28 (2) ◽  
pp. 363-374 ◽  
Author(s):  
Isela Bonilla ◽  
Marco Mendoza ◽  
Daniel U. Campos-Delgado ◽  
Diana E. Hernández-Alfaro
Keyword(s):  
Closed Loop ◽  
Impedance Control ◽  
Robot Manipulators ◽  
Parametric Uncertainty ◽  
Continuous Functions ◽  
Path Tracking ◽  
Robotic System ◽  
Loop System ◽  
Closed Loop System ◽  
Adaptive Impedance Control

Abstract The main impedance control schemes in the task space require accurate knowledge of the kinematics and dynamics of the robotic system to be controlled. In order to eliminate this dependence and preserve the structure of this kind of algorithms, this paper presents an adaptive impedance control approach to robot manipulators with kinematic and dynamic parametric uncertainty. The proposed scheme is an inverse dynamics control law that leads to the closed-loop system having a PD structure whose equilibrium point converges asymptotically to zero according to the formal stability analysis in the Lyapunov sense. In addition, the general structure of the scheme is composed of continuous functions and includes the modeling of most of the physical phenomena present in the dynamics of the robotic system. The main feature of this control scheme is that it allows precise path tracking in both free and constrained spaces (if the robot is in contact with the environment). The proper behavior of the closed-loop system is validated using a two degree-of-freedom robotic arm. For this benchmark good results were obtained and the control objective was achieved despite neglecting non modeled dynamics, such as viscous and Coulomb friction.

Output Feedback Algorithm for Nonlinear Systems with Compensation of Bounded Disturbances and Measurement Noises

2019 ◽  
Vol 20 (1) ◽  
pp. 3-15 ◽  
Author(s):  
I. B. Furtat ◽  
P. A. Gushchin ◽  
A. A. Peregudin
Keyword(s):  
Output Feedback ◽  
Closed Loop ◽  
Sufficient Conditions ◽  
Loop System ◽  
Partial Recovery ◽  
Closed Loop System ◽  
External Disturbances ◽  
Control Schemes ◽  
Measurement Noises ◽  
Feedback Algorithm

The output feedback algorithm for dynamic plants with compensation of parametric uncertainty, external disturbances and measurement noises is synthesized. The plants are described by a nonlinear system of differential equations with vector input and output signals. Unlike most existing control schemes in this paper the dimensions of the measurement interference and the output signal are equal, the sources of the signals of disturbances and disturbances are different, parametric and external disturbances can be present in any equation of the plant model. For simultaneous compensation of disturbances and measurement noises it is proposed to consider two channels. On the first channel a part of the measurement noises will be estimated which will allow partial recovery the information about the plant noisy output. On the second channel the disturbances will be compensated. Thus, at least two independent measurement channels are required for simultaneous compensation of disturbances and measurement noises. Sufficient conditions for calculating the parameters of the algorithm in the form of solvability of the linear matrix inequality are obtained. It is shown that the equation of a closed-loop system obtained on the basis of the proposed algorithm depends on the disturbances and the smallest component of the measurement noise. However, if the smallest component cannot be identified a priory, the results of the transients depend on the component of the noise that will be selected in the synthesis of the control system. Thus, unlike most existing control schemes, where the equation of a closed-loop system depends on disturbance and noise, the resulting algorithm provides better transients, because they do not depend on the entire noise vector, but only on its smallest (one) component. The simulations for a third-order nonlinear plant and the synchronization of an electrical generator connected to the power grid are presented. Numerical examples illustrate the effectiveness of the proposed scheme and the robustness with respect to random components in the noises and disturbances.

Direct Adaptive CMAC PI Control for Uncertain Nonlinear Systems with Measurable Output Feedback

2013 ◽  
Vol 479-480 ◽  
pp. 612-616
Author(s):  
Chun Sheng Chen
Keyword(s):  
Nonlinear Systems ◽  
Closed Loop ◽  
Control Structure ◽  
Loop System ◽  
Pi Control ◽  
Uncertain Nonlinear Systems ◽  
Closed Loop System ◽  
External Disturbances ◽  
Lyapunov Stability Criterion ◽  
System Output

A stable direct adaptive CMAC PI controller for a class of uncertain nonlinear systems is investigated under the constrain that only the system output is available for measurement. First, a state observer is used to estimate unmeasured states of the systems. Then, the PI control structure is used for improving robustness in the closed-loop system and avoiding affection of uncertainties and external disturbances. The global asymptotic stability of the closed-loop system is guaranteed according to the Lyapunov stability criterion. To demonstrate the effectiveness of the proposed method, simulation results indicate that the proposed approach is capable of achieving a good trajectory following performance without the knowledge of plant parameters.

scholarly journals Disturbance Observer-Based Control for Trajectory Tracking of a Quadrotor

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1624
Author(s):  
Sang Wook Ha ◽  
Bong Seok Park
Keyword(s):  
Trajectory Tracking ◽  
Closed Loop ◽  
Control Method ◽  
Control Strategies ◽  
Hierarchical Control ◽  
Loop System ◽  
Nonlinear Controller ◽  
Closed Loop System ◽  
External Disturbances ◽  
Dynamic Surface

This paper presents a new control approach for the trajectory tracking of a quadrotor in the presence of external disturbances. Unlike in previous studies using hierarchical control strategies, a nonlinear controller is designed by introducing new state transformations that can use Euler angles as virtual control inputs. Thus, the proposed method can eliminate the timescale separation assumption of hierarchical control strategies. To estimate the external disturbances involved in the translational and rotational dynamics of the quadrotor, disturbance observers are developed. Using state transformations and estimates of external disturbances, we design a robust nonlinear controller based on the dynamic surface control method. The stability of the closed-loop system is analyzed without separation into two subsystems. From the Lyapunov stability theory, it is proven that all error signals in the closed-loop system are uniformly ultimately bounded and can be made arbitrarily small. Finally, simulation results are presented to demonstrate the performance of the proposed controller.

Sliding Mode Control and Elastic Mode Stabilization of a Robotic Arm With Flexible Links

1991 ◽  
Vol 113 (4) ◽  
pp. 669-676 ◽  
Author(s):  
P. J. Nathan ◽  
S. N. Singh
Keyword(s):  
Closed Loop ◽  
Joint Angle ◽  
Sliding Mode ◽  
Variable Structure ◽  
Terminal State ◽  
Loop System ◽  
Robotic Arm ◽  
Closed Loop System ◽  
Elastic Mode ◽  
Mode Stabilization

This paper treats the question of control of an elastic robotic arm of two links based on variable structure system (VSS) theory and pole assignment technique for stabilization. A discontinuous joint angle control law, based on VSS theory, is designed which accomplishes asymptotic decoupled joint angle trajectory tracking. In the closed-loop system, the trajectories are attracted toward a chosen hypersurface in the state space and then slide along it. Although, joint angles are controlled using variable structure control (VSC) law, the flexible modes of the links are excited. Using center manifold theory, it is shown that the closed-loop system, including the sliding mode controller, is stable. Based on a linearized model about the terminal state, a stabilizer is designed using pole assignment technique to control the elastic oscillations of the links. A control logic is included which switches the stabilizer at the instant when the joint angle trajectory enters a specified neighborhood of the terminal state. Simulation results are presented to show that in the closed-loop system, accurate joint angle trajectory tracking, and elastic mode stabilization are accomplished in the presence of payload uncertainty.

OUTPUT FEEDBACK ADAPTIVE VARIABLE STRUCTURE CONTROL OF CHAOS IN LORENZ SYSTEM

2002 ◽  
Vol 12 (03) ◽  
pp. 571-582 ◽  
Author(s):  
ALDAYR D. ARAUJO ◽  
SAHJENDRA N. SINGH
Keyword(s):  
Closed Loop ◽  
Lorenz System ◽  
Digital Simulation ◽  
Variable Structure ◽  
Transient Behavior ◽  
Loop System ◽  
Reference Trajectory ◽  
Closed Loop System ◽  
Output Variable ◽  
Control Of Chaos

Based on the variable structure model reference adaptive control (VS-MRAC) theory, a new control system for the control of chaos in Lorenz system, using only the measured output variable, is designed. For the derivation of the control law, it is assumed that the parameters of the model are unknown. Moreover, it is assumed that a disturbance input is present in the system. It is shown that in the closed-loop system, the output variable tracks a given reference trajectory, and the state vector converges to the equilibrium state. Digital simulation results show that the closed-loop system has good transient behavior and robustness to the uncertainties and disturbance input.

scholarly journals Control Robusto H∞ en forma Global para Robot Manipulador

2019 ◽  
pp. 8-18
Author(s):  
Carlos Chávez-Guzmán ◽  
José Esqueda-Elizondo ◽  
Jovan Merida-Rubio ◽  
Juan Miguel Colores-Vargas
Keyword(s):  
Control Problem ◽  
Motion Control ◽  
Closed Loop ◽  
Robot Manipulator ◽  
Asymptotically Stable ◽  
Tracking Problem ◽  
Closed Loop System ◽  
External Disturbances ◽  
Control Techniques ◽  
Rotational Joint

In this paper is proposed a solution to the tracking problem with robust H_∞ global control, applied to robot manipulator completely actuated with rotational joint in presence of external disturbances. The Hamilton-Jacobi-Isaacs inequality is verified by a strict function of Lyapunov and enough conditions will be found under which the equilibrium point of the closed-loop system is asymptotically stable globally while the disturbed system has a gain L_2 less than or equal to a predetermined constant. Currently, one of the disadvantages of the H_∞ control, with respect to other control techniques, is the linearization of the system around a point of equilibrium, which converts the Hamilton-Jacobi-Isaacs inequality into algebraic of Riccati equations, which facilitate the solution to the motion control problem H_∞, however, the controller becomes local. Now, through a strict function of Lyapunov it was possible to verify that the Hamilton-Jacobi-Isaacs inequality is satisfied globally. The theory is validated in a robot manipulator with l degree of freedom.

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