Adaptive control of robot manipulators with flexible joints
TL;DR: In this paper, an adaptive control scheme for flexible joint robot manipulators is presented, and joint position and velocity tracking errors are shown to converge to zero with all the signals in the system remaining bounded.
Abstract: Presents an adaptive control scheme for flexible joint robot manipulators. Asymptotic stability is insured regardless of the joint flexibility value, i.e., the results are not restricted to weak joint elasticity. Moreover, the joint flexibility is not assumed to be known. Joint position and velocity tracking errors are shown to converge to zero with all the signals in the system remaining bounded. >
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TL;DR: A survey of the literature related to dynamic analyses of flexible robotic manipulators has been carried out in this article, where both link and joint flexibility are considered in this work and an effort has been made to critically examine the methods used in these analyses, their advantages and shortcomings and possible extension of these methods to be applied to a general class of problems.
791 citations
TL;DR: An amplitude-limited torque input controller is developed for revolute robot manipulators with uncertainty in the kinematic and dynamic models and yields semiglobal asymptotic regulation of the task-space setpoint error.
Abstract: Common assumptions in most of the previous robot controllers are that the robot kinematics and manipulator Jacobian are perfectly known and that the robot actuators are able to generate the necessary level of torque inputs. In this note, an amplitude-limited torque input controller is developed for revolute robot manipulators with uncertainty in the kinematic and dynamic models. The adaptive controller yields semiglobal asymptotic regulation of the task-space setpoint error. The advantages of the proposed controller include the ability to actively compensate for unknown parametric effects in the dynamic and kinematic model and the ability to ensure actuator constraints are not breached by calculating the maximum required torque a priori
249 citations
TL;DR: These questions for three different controller design techniques as applied to the problem of global tracking of robots with flexible joints are investigated and the connection between the various controllers is investigated.
202 citations
01 Jan 2016
TL;DR: Design issues, dynamic modeling, trajectory planning, and feedback control problems are presented for robot manipulators having components with mechanical flexibility, either concentrated at the joints or distributed along the links.
Abstract: Design issues, dynamic modeling, trajectory planning, and feedback control problems are presented for robot manipulators having components with mechanical flexibility, either concentrated at the joints or distributed along the links The chapter is divided accordingly into two main parts Similarities or differences between the two types of flexibility are pointed out wherever appropriate
176 citations
01 Jun 2001
TL;DR: An adaptive controller is designed that compensates for uncertain camera and mechanical parameters and ensures global asymptotic position/orientation tracking and simulation and experimental results are included to illustrate the performance of the control law.
Abstract: This paper considers the problem of position/orientation tracking control of wheeled mobile robots via visual servoing in the presence of parametric uncertainty associated with the mechanical dynamics and the camera system. Specifically, we design an adaptive controller that compensates for uncertain camera and mechanical parameters and ensures global asymptotic position/orientation tracking. Simulation and experimental results are included to illustrate the performance of the control law.
172 citations
References
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TL;DR: In this paper, an adaptive robot control algorithm is derived, which consists of a PD feedback part and a full dynamics feed for the compensation part, with the unknown manipulator and payload parameters being estimated online.
Abstract: A new adaptive robot control algorithm is derived, which consists of a PD feedback part and a full dynamics feedfor ward compensation part, with the unknown manipulator and payload parameters being estimated online. The algorithm is computationally simple, because of an effective exploitation of the structure of manipulator dynamics. In particular, it requires neither feedback of joint accelerations nor inversion of the estimated inertia matrix. The algorithm can also be applied directly in Cartesian space.
2,117 citations
1,542 citations
"Adaptive control of robot manipulat..." refers background in this paper
...where TI is the kinetic energy of the rigid links, T2 is the kinetic energy of the actuators where the effect of q, has been neglected assuming a high-gear ratio [ 12 ], and V is the total potential energy considering both gravity and elasticity....
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TL;DR: The intent is to lend some perspective to the growing list of adaptive control results for manipulators by providing a unified framework for comparison of those adaptive control algorithms which have been shown to be globally convergent.
1,212 citations
TL;DR: In this article, a simple adaptive controller for manipulator trajectory control problems is proposed, which is shown to have the same level of robustness to unmodeled dynamics as a PD (proportional and differential) controller yet achieves much better tracking accuracy than either PD or computed-torque schemes.
Abstract: The author's previous work (1986, 1987) utilized the particular structure of manipulator dynamics to develop a simple, globally convergent adaptive controller for manipulator trajectory control problems. After summarizing the basic algorithm, they demonstrate the approach on a high-speed two-degree-of-freedom semi-direct-drive robot. They show that the dynamic parameters of the manipulator, assumed to be initially unknown, can be estimated within the first half second of a typical run, and that accordingly, the manipulator trajectory can be precisely controlled. These experimental results demonstrate that the adaptive controller enjoys essentially the same level of robustness to unmodeled dynamics as a PD (proportional and differential) controller, yet achieves much better tracking accuracy than either PD or computed-torque schemes. Its superior performance for high-speed operations, in the presence of parametric and nonparametric uncertainties, and its relative computational simplicity, make it an attractive option both for addressing complex industrial tasks, and for simplifying high-level programming of more standard operations. >
1,013 citations
TL;DR: A computationally efficient adaptation scheme that is a modified version of the original scheme that utilizes the desired trajectory outputs, instead of the actual joint outputs in the parameter adaptation algorithm and the non linearity compensation controller is proposed.
Abstract: The stability and robustness properties of the adaptive control scheme proposed by Sadegh and Horowitz (1987) are stud ied. The properties include the global exponential stability and Lpinput/output stability of the nonadaptive (i.e., fixed- parameter) control system and the global asymptotic stability of the adaptive control scheme. Sufficient conditions for the convergence of the estimated parameters to their true values are also given. A computationally efficient adaptation scheme that is a modified version of the original scheme is proposed. The modified scheme utilizes the desired trajectory outputs, which can be calculated a priori, instead of the actual joint outputs in the parameter adaptation algorithm and the non linearity compensation controller. Sufficient conditions for guaranteeing all the stability properties of the original scheme in the modified scheme are also explicitly derived. A com puter simulation study of the performance of both schemes in the presence of noise disturbances is cond...
516 citations
"Adaptive control of robot manipulat..." refers methods in this paper
...In the case of rigid manipulators the robot’s passivity property, i.e., passivity of the mapping: U + q1 has been very useful in the design of the adaptive control schemes [I]-[ 4 ]....
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