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ABSTRACT: The purpose of this article is to show how the design procedure commonly referred to as integrator backstepping can be used to design globally stable trajectory tracking controllers for Rigid-Link Flexible-Joint (RLFJ) robot manipulators. Three different types of controllers are developed: (1) an exact model knowledge-based controller, (2) an adaptive controller that compensates for parametric uncertainty, and (3) a robust controller that compensates for parametric uncertainty and unknown bounded disturbances. All three controllers are based on previously published work but are presented here in a unifying framework. © 1995 John Wiley & Sons, Inc.
Journal of Robotic Systems 03/2007; 12(3):199 - 216. · 0.48 Impact Factor
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ABSTRACT: The authors have redesigned a previously developed robust tracking
controller for rigid-link flexible-joint (RLFJ) robot manipulators to
handle flexibilities specifically induced by harmonic drive gearing. A
more realistic, and consequently more complex model for the torque
transmission dynamics which includes frictional losses, kinematic error
and nonlinear compliance is utilised. The stability result achieved for
the authors' proposed controller ensures that the link tracking error is
`globally uniformly ultimately bounded' (GUUB), in spite of additive
bounded disturbances, parametric uncertainty, and the presence of
complex nonnegligible actuator dynamics
IEE Proceedings - Control Theory and Applications 10/1995; · 1.05 Impact Factor
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ABSTRACT: In this paper, we extend the previous work of Dawson et al. (1992,
1993) to design an adaptive controller for rigid-link
electrically-driven (RLED) robot manipulators specifically actuated with
switched reluctance (SR) motors. Specifically, the controller presented
in the previous paper (1993) is redesigned from a robust algorithm to an
adaptive algorithm in order to guarantee globally asymptotically stable
link position tracking error. In particular, this paper fuses the
designed commutation strategies with several newly developed
modifications to the integrator backstepping technique to create a
controller that guarantees the desired position tracking performance in
spite of parametric uncertainty throughout the entire electro-mechanical
model
American Control Conference, 1995. Proceedings of the; 07/1995
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ABSTRACT: Extends the work of Bridges, Dawson and Gao (1993) and Hu and
Dawson (1993) to design an adaptive controller for rigid-link
electrically-driven (RLED) robot manipulators specifically actuated with
brushless direct current (BLDC) motors. In particular the adaptive
controller presented in the second paper is tailored to handle the
multi-link dynamics of a rigid-link robot as opposed to a simple
inertial load. Furthermore, the linear electrical dynamics of brushed DC
motors used in the development of the first paper, are replaced with the
multiple input nonlinear dynamics of BLDC motors. The result is an
adaptive controller that guarantees globally asymptotic convergence of
the link position tracking error in spite of parametric uncertainty
throughout the entire electro-mechanical model
Decision and Control, 1994., Proceedings of the 33rd IEEE Conference on; 01/1995
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ABSTRACT: In this paper we present the results obtained from the
implementation of a robust position/force controller on a
two-degree-of-freedom direct drive robot. The controller is based on the
theoretical work presented by McClamroch et al. (1988) and Grabbe et al.
(1993), which guarantees globally uniformly ultimately bounded (GUUB)
position tracking error and bounded force tracking error. The controller
accomplishes this stability result in spite of robot model uncertainty
and only requires: joint position and velocity measurements,
end-effector force measurements, and bounds on the model parameters.
Experimental results described in this paper serve to verify the
theoretical claims
Control Applications, 1994., Proceedings of the Third IEEE Conference on; 09/1994
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ABSTRACT: Presents an approach for designing robust tracking controllers for
rigid-link flexible-joint (RLFJ) robot manipulators with redundant
actuators in the joints. With the proposed controller, the authors prove
that the link tracking error is globally uniformly ultimately bounded
(GUUB) in spite of additive bounded disturbances, parametric
uncertainty, and other modeling uncertainty. The authors also illustrate
how the load at each joint is shared by two actuators. Finally
simulation results are presented to illustrate the effectiveness of the
proposed controller
IEEE Transactions on Systems Man and Cybernetics 08/1994;
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International Journal of Control. 05/1994; 59(5):1309-1324.
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ABSTRACT: In Su, Leung, and Zhou (1992), the authors attempt to use sliding mode control for the simultaneous position and force control of a constrained robot manipulator. They assert that their control law, along with inclusion of the constraint force error in the definition of the sliding surface, produces asymptotically stable force tracking error. However, a separate force control law must be defined and a separate stability analysis performed to determine the behavior of the force tracking error. The authors address errors in the force control stability analysis presented in the above paper.< >
IEEE Transactions on Automatic Control 02/1994; · 2.11 Impact Factor
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ABSTRACT: In this paper, we combine the approaches presented previously by
us (1991, 1992) to design an adaptive controller for rigid-link
electrically-driven (RLED) robot manipulators. With the proposed
controller, we prove that the link position tracking error is globally
asymptotically stable in spite of parametric uncertainty and the
presence of electrical motor dynamics
Decision and Control, 1993., Proceedings of the 32nd IEEE Conference on; 01/1994
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ABSTRACT: The control of robotic manipulators with joint flexibilities has
become a much addressed problem as of late. The interest that has been
stirred is mainly due to the wide use of harmonic drive gearing in
robotic manipulators and the inherent joint compliance that they
introduce. In this paper the authors present experimental results from a
two degree of freedom robot with harmonic drive gearing. In addition,
conclusions as to the major stumbling blocks preventing further
advancement in this area are given
Control Applications, 1993., Second IEEE Conference on; 10/1993
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ABSTRACT: In this paper, we redesign a previously developed robust tracking controller for rigid-link flexible-joint (RLFJ) robot manipulators to handle flexibilities specifically introduced by harmonic drive gasing. A non realistic, and consequently super complex model for the input transmission dynamics which includes frictional losses, kinematic order and nonlinear compliances is utilised. The stability result achieved for our proposed nonlinear custmos that the link tracking error is Globally Uniformly Ultimately Bounded (GUUB), in spite of additive bounded disturbances, parametric uncertainty, and the process of complex non-negligible actuator dynamics.
American Control Conference, 1993; 07/1993
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ABSTRACT: The purpose of this paper is to present a robust position/velocity tracking controller for rigid-link flexible joint (RLFJ) robots operating either on or off a constraining surface. The controller explcits aspects of the dynamic and kinematic models to provide a global uniform ultimately bounded (GUUB) stability result despite the presence of parametric uncertainty, joint flexibility, and mechanical actuator dynamics. The controller delivers the GUUB result for both position and velocity error. Is addition, the controller maintains bounded contact forces while the manipulator is on the constraint surfaces. Finally, it should be noted that the controller described in this development only requires position and velocity measurements from the motors and links.
American Control Conference, 1993; 07/1993
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ABSTRACT: A hybrid adaptive tracking controller for rigid-link flexible-joint (RLFJ) robot manipulators is designed. The controller is hybrid in the sense that an adaptive indirect controller is used to compensate for parametric uncertainties in the rigid-link equation whereas an adaptive robust controller corrects for the dynamics and parametric uncertainty associated with the actuators. That is, in spite of these detrimental uncertainties and effects, one is still able to ensure a global asymptotic stability result for the link position tracking error.
Control Theory and Applications, IEE Proceedings D [see also IEE Proceedings-Control Theory and Applications] 06/1993;
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ABSTRACT: The robust tracking controller for rigid-link flexible-joint
(RLFJ) robots presented by D. M. Dawson et al. (1991) is redesigned. The
controller exploits aspects of the dynamic model to provide a global
uniform ultimately bounded (GUUB) stability result despite the presence
of parametric uncertainty, joint flexibility, and mechanical actuator
dynamics. The controller delivers the GUUB result for both the position
and the velocity error. The redesign enables the final ball in which the
link tracking error resides to be arbitrarily shrunk and the exponential
rate at which the error approaches that ball to be increased by
adjustment of the control gains
System Theory, 1993. Proceedings SSST '93., Twenty-Fifth Southeastern Symposium on; 04/1993
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ABSTRACT: DNA sequences have been compared in a 4,400-bp region for Escherichia coli K12 and 36 ECOR strains. Discontinuities in degree of similarity, previously inferred, are confirmed in detail. Three clonal frames are described on the basis of the present local high-resolution data, as well as previous analyses of restriction fragment length polymorphism (RFLP) and of multilocus enzyme electrophoresis (MLEE) covering small regions more widely dispersed on the chromosome. These three approaches show important consistency. The data illustrate the fact that, in the limited context of intraspecific genomic sequence variation, clonality and homology are synonymous. Two estimable quantitative properties are defined: recency of common ancestry (the reciprocal of the log10 of the number of generations since the most recent common ancestor), and the number of nucleotide pairs over which a given recency of common ancestry applies. In principle, these parameters are measures of the degree and physical extent of homology. The small size of apparent recombinational replacements, together with the observation that they occasionally occur in discontinuous series, raises the question of whether they result from the superimposition of replacements of much larger size (as expected from an elementary interpretation of conjugation and transduction in experimental E. coli systems) or via an alternative mechanism. Length polymorphisms of several sorts are described.
Genetics 04/1993; 133(3):455-68. · 4.01 Impact Factor
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ABSTRACT: This paper presents as approach for designing robust tracking controllers for rigid-link flexible-joint (RLFJ) robot manipulators with redundant actuators in the joints. Synchronization is a major problem for the control of a single robotic joint driven by two actuators. This control problem is further complicated by the effects of actuator dynamics, model uncertainty and unknown bounded disturbances. To solve this problem, we develop a robust tracking controller that achieves global uniform ultimate bounded (GUUB) stability of the link tracking error in spite of bounded disturbances and model uncertainty.
American Control Conference, 1992; 07/1992
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ABSTRACT: The authors develop a robust position/force controller based on the impedance approach without requiring exact knowledge of the robot dynamics. The controller is designed so that a desired positional trajectory can be followed along the surface of the environment while the forces exerted on the environmental surface are regulated according to a target impedance. A global exponential stability result is obtained for the position tracking error and the force regulation error (i.e. the error between the actual manipulator impedance and the desired target impedance). The controller only requires measurement of the end effector force, joint velocity, and joint position
Southeastcon '92, Proceedings., IEEE; 05/1992
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System Theory, 1992. Proceedings. SSST/CSA 92. The 24th Southeastern Symposium on and The 3rd Annual Symposium on Communications, Signal Processing Expert Systems, and ASIC VLSI Design; 04/1992
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ABSTRACT: PCR fragments, 1500-bp, from 15 previously sequenced regions in the Escherichia coli chromosome have been compared by restriction analysis in a large set of wild (ECOR) strains. Prior published observations of segmental clonality are confirmed: each of several sequence types is shared by a number of strains. The rate of recombinational replacement and the average size of the replacements are estimated in a set of closely related strains in which a clonal frame is dotted with occasional stretches of DNA belonging to other clones. A clonal hierarchy is described. Some new comparative sequencing data are presented.
Genetics 12/1990; 126(3):505-17. · 4.01 Impact Factor
