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

Author(s):  
Carlos Chávez-Guzmán ◽  
José Esqueda-Elizondo ◽  
Jovan Merida-Rubio ◽  
Juan Miguel Colores-Vargas

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.

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jinzhu Peng ◽  
Yan Liu

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.


1987 ◽  
Vol 109 (4) ◽  
pp. 320-327 ◽  
Author(s):  
C. K. Kao ◽  
A. Sinha ◽  
A. K. Mahalanabis

A digital state feedback control algorithm has been developed to obtain the near-minimum-time trajectory for the end-effector of a robot manipulator. In this algorithm, the poles of the linearized closed loop system are judiciously placed in the Z-plane to permit near-minimum-time response without violating the constraints on the actuator torques. The validity of this algorithm has been established using numerical simulations. A three-link manipulator is chosen for this purpose and the results are discussed for three different combinations of initial and final states.


2018 ◽  
Vol 151 ◽  
pp. 04008
Author(s):  
Rouzbeh Moradi ◽  
Alireza Alikhani ◽  
Mohsen Fathi Jegarkandi

Reference trajectory management is a method to modify reference trajectories for the faulty system. The modified reference trajectories define new maneuvers for the system to retain its pre-fault dynamic performance. Controller reconfiguration is another method to handle faults in the system, for instance by adjusting the controller parameters (coefficients). Both of these two methods have been considered in the literature and are proven to be capable of handling various faults. However, the comparison of these two methods has not been considered sufficiently. In this paper, a controller reconfiguration mechanism and a reference trajectory management are proposed for the spacecraft attitude fault tolerant control problem. Then, these two methods are compared under the same conditions, and it is shown that the proposed controller reconfiguration has better performance than the proposed reference trajectory management. The reason is that the controller reconfiguration has more variables to modify the closed-loop system behavior.


2016 ◽  
Vol 39 (7) ◽  
pp. 1007-1016 ◽  
Author(s):  
Yu Wang ◽  
Bingxiu Bian

The electric sail (ES) is a novel propellantless propulsion concept, which extracts the solar wind momentum by repelling the positively charged ions. Due to the difficulty of attitude adjustment by the large flexible structure and the uncertainty of ion density, velocity and electron temperature by solar wind, there exist thrust input uncertainty and saturation with time-varying bounds for ES. The trajectory tracking problem for ES in three-dimensional (3-D) space is studied, and the composite sliding mode control scheme with corresponding guidance strategy is proposed for the single-input–multiple-output (SIMO) non-linear system. The hierarchical sliding surfaces are constructed with an auxiliary design system to analyse the effect of input saturation constraints and decouple the SIMO non-linear system to reduce the control complexity. Also, the disturbance estimation based on a super-twisting algorithm is employed to decrease the switch chattering and improve the system robustness. It is proved that all the sliding mode surfaces are asymptotically stable, and all the signals of the closed-loop system are bounded with input saturation constraints. Furthermore, all the signals are converging to zero and the closed-loop system is asymptotically stable without saturation. Finally, the simulation demonstrates the proposed composite sliding mode control is fit for ES 3-D trajectory tracking.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Jinsheng Xing ◽  
Naizheng Shi

This paper proposes a stable adaptive fuzzy control scheme for a class of nonlinear systems with multiple inputs. The multiple inputs T-S fuzzy bilinear model is established to represent the unknown complex systems. A parallel distributed compensation (PDC) method is utilized to design the fuzzy controller without considering the error due to fuzzy modelling and the sufficient conditions of the closed-loop system stability with respect to decay rateαare derived by linear matrix inequalities (LMIs). Then the errors caused by fuzzy modelling are considered and the method of adaptive control is used to reduce the effect of the modelling errors, and dynamic performance of the closed-loop system is improved. By Lyapunov stability criterion, the resulting closed-loop system is proved to be asymptotically stable. The main contribution is to deal with the differences between the T-S fuzzy bilinear model and the real system; a global asymptotically stable adaptive control scheme is presented for real complex systems. Finally, illustrative examples are provided to demonstrate the effectiveness of the results proposed in this paper.


2015 ◽  
Vol 727-728 ◽  
pp. 692-696
Author(s):  
Gui Ling Ju ◽  
Wei Hai Sun

This paper deals with the adaptive control design of stochastic nonholonomic system with uncertainties. The state-input scaling technique, stochastic Lyapunov-like theorem and back-stepping approach are used to design the feedback controller. The controllers guarantee all states of the closed-loop system are largely asymptotically stable in probability, In order to make the state scaling effective, a new switching control strategy based on the output measurement of the first subsystem is employed.


2014 ◽  
Vol 945-949 ◽  
pp. 2539-2542
Author(s):  
Hong Yang ◽  
Huan Huan Lü ◽  
Le Zhang

For the non-measurable states, a control of switched fuzzy systems is presented based on observer. Using switching technique and multiple Lyapunov function method, the fuzzy observer is built to ensure that for all allowable external disturbance the relevant closed-loop system is asymptotically stable. Moreover, switching strategy achieving system global asymptotic stability of the switched fuzzy system is given. In this model, a switching state feedback controller is presented. A simulation shows the feasibility and the effectiveness of the method.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Lina Jin ◽  
Shuanghe Yu ◽  
Dongxu Ren

This paper deals with the circular formation control problem of multiagent systems for achieving any preset phase distribution. The control problem is decomposed into two parts: the first is to drive all the agents to a circle which either needs a target or not and the other is to arrange them in positions distributed on the circle according to the preset relative phases. The first part is solved by designing a circular motion control law to push the agents to approach a rotating transformed trajectory, and the other is settled using a phase-distributed protocol to decide the agents’ positioning on the circle, where the ring topology is adopted such that each agent can only sense the relative positions of its neighboring two agents that are immediately in front of or behind it. The stability of the closed-loop system is analyzed, and the performance of the proposed controller is verified through simulations.


Author(s):  
Bing Xiao ◽  
Qinglei Hu ◽  
Michael I. Friswell

This paper investigates the design of spacecraft attitude stabilization controllers that are robust against actuator faults and external disturbances. A nominal controller is developed initially, using the adaptive backstepping technique, to stabilize asymptotically the spacecraft attitude when the actuators are fault-free. Additive faults and the partial loss of actuator effectiveness are considered simultaneously and an auxiliary controller is designed in addition to the nominal controller to compensate for the system faults. This auxiliary controller does not use any fault detection and isolation mechanism to detect, separate, and identify the actuator faults online. The attitude orientation and angular velocity of the closed-loop system asymptotically converge to zero despite actuator faults providing the nominal attitude system is asymptotically stable. Numerical simulation results are presented that demonstrate the closed-loop performance benefits of the proposed control law and illustrate its robustness to external disturbances and actuator faults.


Author(s):  
Michael C. Reynolds ◽  
Peter H. Meckl

This work presents a novel technique for the solution of an optimal input for trajectory tracking. Many researchers have documented the performance advantages of command shaping, which focuses on the design of an optimal input. Nearly all research in command shaping has been centered on the point-to-point motion control problem. However, tracking problems are also an important application of control theory. The proposed optimal tracking technique extends the point-to-point motion control problem to the solution of the tracking problem. Thus, two very different problems are brought into one solution scheme. The technique uses tolerances on trajectory following to meet constraints and minimize either maneuver time or input energy. A major advantage of the technique is that hard physical constraints such as acceleration or allowable tracking error can be directly constrained. Previous methods to perform such a task involved using various weightings that lack physical meaning. The optimal tracking technique allows for fast and efficient exploration of the solution space for motion control. A solution verification technique is presented and some examples are included to demonstrate the technique.


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