The paper presents a method for controlling Switched Reluctance Motor (SRM)'s torque for force control applications. SRM's are used in AdeptOne robots, and we perform experiments with two robots, controlled in...
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The paper presents a method for controlling Switched Reluctance Motor (SRM)'s torque for force control applications. SRM's are used in AdeptOne robots, and we perform experiments with two robots, controlled in coordination, in grasping and manipulation of various objects. The object and robot parameters are not exactly known, and adaptive methods are used to control the overall system. These methods are model-based control techniques which require high bandwidth torque control. This requirement is typical for high precision mechanisms. SRM's characteristics are very nonlinear. In particular the torque ripple, friction, and the torque versus position and current relationships were analyzed in the context above-mentioned, and specifically, for force control applications. The proposed method is based on a new commutation algorithm and a measured torque versus position and current relationship, used to smoothen the SRM's torque ripple, hence generating a torque output nearly independent of position. Furthermore, the internal friction is estimated on-line, and compensated for. This renders a high accuracy torque tracking. The torque control method is based on feedback from the motor angular velocity, motor angle, armature current, and feedforward for friction compensation and cancellation of nonlinear effects. The method has been tested experimentally on Adept motors and the results were very encouraging. The method has been also used for adaptive control of two coordinated Adept robots.
The minimum achievable guaranteed H/sub /spl infin// norm bound is related to the size of uncertainties: the larger the uncertainty size, the larger the minimum achievable H/sub /spl infin// norm. The paper considers ...
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The minimum achievable guaranteed H/sub /spl infin// norm bound is related to the size of uncertainties: the larger the uncertainty size, the larger the minimum achievable H/sub /spl infin// norm. The paper considers the case of discrete-time systems. It is shown that for a very general uncertainty expression, if the state is available for feedback, then the trade-off between this H/sub /spl infin// norm bound and the maximum uncertainty tolerance can be formulated in such a form, that if one of the above two quantities are given, the other quantities can be computed through a quasiconvex optimization process.< >
This paper presents an approach for designing robust tracking controller for lumped mass model of a vibrating link (VL) robot manipulator. The control methodology is intuitively simple since it is based on concepts wh...
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This paper presents an approach for designing robust tracking controller for lumped mass model of a vibrating link (VL) robot manipulator. The control methodology is intuitively simple since it is based on concepts wh...
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This paper presents an approach for designing robust tracking controller for lumped mass model of a vibrating link (VL) robot manipulator. The control methodology is intuitively simple since it is based on concepts which are familiar to most control engineers. The approach is illustrated by developing a robust tracking controller that achieves global uniform ultimate boundedness (GUUB) stability of the link tracking error in spite of model uncertainty and the additional link dynamics.
This paper describes a method of controlling the position of a manipulator composed of active and passive joints. The active joints have actuators and position sensors. The passive joints have holding brakes instead o...
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This paper describes a method of controlling the position of a manipulator composed of active and passive joints. The active joints have actuators and position sensors. The passive joints have holding brakes instead of actuators. While the brakes are released, the passive joints are indirectly controlled by the motion of the active joints using the coupling characteristics of manipulator dynamics. While the brakes are engaged, the passive joints are fixed and the active joints are controlled. The position of the manipulator is controlled by combining these two control modes. This paper describes the basic principle of the control method and the conditions that ensure the controllability of the passive joints. An algorithm for point-to-point control of the manipulator is also presented. The feasibility of the method is demonstrated by simulations for a manipulator with two degrees of freedom.
作者：
CHIANG, PTYANG, JCSResearch Engineer
Advanced Technology and Research Corporation Laurel MD 20707 14900 Sweitzer Lane United States Robotics Laboratory
Department of Mechanical Engineering University of Maryland College Park MD 20742 United States
With the given geometrical data of a model, this paper presents a technique: (1) to prepare a workpiece with minimal material required to fabricate the model;(2) to automatically determine the necessary manufacturing ...
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With the given geometrical data of a model, this paper presents a technique: (1) to prepare a workpiece with minimal material required to fabricate the model;(2) to automatically determine the necessary manufacturing processes utilizing the concept of feature-based recognition;and (3) to optimally sequence these processes based on a tabulated optimization scheme. Four types of feature, face, hole, slot, and pocket, are considered. Computational results are provided to demonstrate the capability and advantage of the technique. Conclusions are given and recommendations for future research are discussed.
A characterization of the structure of uncertainty called the generalized matching condition is proposed. The uncertainty is further decomposed into two parts that are 'orthogonal' to each other. On the basis ...
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A characterization of the structure of uncertainty called the generalized matching condition is proposed. The uncertainty is further decomposed into two parts that are 'orthogonal' to each other. On the basis of this decomposition a linear feedback control design is proposed for linear uncertain systems. The control always exists if the generalized matching condition is met. The design is illustrated by a practical example.< >
A servo control proposed [1-5] for a class of nonlinear dynamic systems with uncertain parameters and inputs, is shown to admit a solution when specialized to a class of uncertain linear systems. The control is genera...
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A servo control proposed [1-5] for a class of nonlinear dynamic systems with uncertain parameters and inputs, is shown to admit a solution when specialized to a class of uncertain linear systems. The control is generated by output feedback where the controller and the observer gains are computed by utilizing a special separation of the uncertain effects from the nominal state equations.
A control strategy proposed [1],[2],[3] for a special class of nonlinear dynamic systems with uncertain parameters and uncertain inputs is applied to the control of a two-link manipulator with bounded but unknown iner...
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A control strategy proposed [1],[2],[3] for a special class of nonlinear dynamic systems with uncertain parameters and uncertain inputs is applied to the control of a two-link manipulator with bounded but unknown inertia and a variable payload. In this approach, "precise" tracking of a specified output trajectory is ensured despite the uncertainties entering the mathematical model. In particular, the appeal of such design procedure lies on a special decomposition which allows one to exploit linear control theory on the one hand and carry a separate treatment of the nonlinear effects together with uncertainties on the other.
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