Organizational Unit:

Institute for Robotics and Intelligent Machines (IRIM)

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https://hdl.handle.net/1853/70657

Includes Organization(s)

Organizational Unit

Biorobotics and Human Modeling Lab

Organizational Unit

Humanoid Robotics Laboratory

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Now showing 1 - 9 of 9

Decentralized Adaptive Control of a Two Degree of Freedom Flexible Arm

(Georgia Institute of Technology, 1989-12) Yuan, Bau-San ; Book, Wayne J. ; Huggins, J. D.

A robust adaptive control is derived by signal-synthesis methods for a light, flexible two degree-of-freedom manipulator. The controller for each joint is decentralized, using measurements of one joint's position as well as one link's strain. The coupling to other dynamics is treated as a bounded uncertainty in the model. A stability proof has been developed and is outlined. Performance of the advanced controller is compared to a Linear Quadratic Regulator (LOR) and to an independent joint control. Both simulations and experiments are presented. The cases of payload variations are considered at this point.
Symbolic Modeling of Flexible Manipulators

(Georgia Institute of Technology, 1987-04) Cetinkunt, Sabri ; Book, Wayne J.

This paper presents a new systematic algorithm to symbolically derive the full nonlinear dynamic equations of motion of multi-link flexible manipulators. Lagrange's-Assumed modes method is the basis of the new algorithm and adapted in a way suitable for symbolic manipulation by digital computers. It is applied to model a two-link flexible arm via a commercially available symbolic manipulation program. The advantages of the algorithm and simulation results are discussed.
A linear dynamic model for flexible robotic manipulators

(Georgia Institute of Technology, 1987-02) Hastings, Gordon Greene ; Book, Wayne J.

The design of lightweight links for robotic manipulators results in flexible links. Accurate control of lightweight manipulators during the large changes in configuration common to robotic tasks requires dynamic models that describe both the rigid-body motions, as well as the flexural vibrations. This paper describes a linear state-space model for a single-link flexible manipulator and compares simulation of the model to measurements made on a 4-ft-long direct-drive arm.
Development of a Curriculum for Integrated Manufacturing Systems Engineering

(Georgia Institute of Technology, 1987-02) Book, Wayne J. ; Krosner, Stephen P. ; Haddad, Abraham H.

This paper describes the Computer Integrated Manufacturing Systems (CIMS) Program at the Georgia Institute of Technology, which was established with the help of a grant from the IBM Corporation. The program began its third year recently and involves a cooperative effort among eight schools (departments) within Georgia Tech, with strong support and interaction with over a dozen industries. The program is one approach to the problem of educating graduate students in industrially related interdisciplinary topics of major importance.
Modeling and Optimal Control of a Lightweight Bracing Manipulator

(Georgia Institute of Technology, 1987) Chung, Ya-Chien ; Lu, Shui-Shong ; Book, Wayne J.

Bracing strategy can improve the stiffness of a lightweight manipulator. A lightweight bracing manipulator provides better maneuverability in gross motions and higher precision in small motions. In order to maintain these advantages, the structure and dynamics of these types of manipulators become more complicated. In this paper, the dynamic model, which includes gravitational effects and an optimal regulator with prescribed relative stability, is developed. The influence of the modeling uncertainties on the controlled system is considered.
Design strategies for high-speed lightweight robots

(Georgia Institute of Technology, 1986-09) Book, Wayne J. ; Hastings, Gordon Greene ; Alberts, Thomas Edward

Industrial robots today can lift objects no. heavier than about five percent of their own weight. Imagine a robotic weight lifter competing against the current Olympic human record of 750 lb. By today's standards, that robot would have to weigh about 15,000 lb, as opposed to its human competitor, who would weigh 165 lb (and who is "rated" at 450 percent of body weight). While this analogy is inexact, the point stands that improvements in the performance of robotic manipulators require engineers to consider the weight of the structural and drive components. The advantages of lighter weight include faster motion times for large motions, smaller actuators, lower energy consumption, reduced mounting requirements, and less weight to be transported. But there are also penalties such as lower (structural) strength and lower stiffness. The stiffness constraint arising from the dynamic and static behavior of the arm is the more critical for most uses of robotic arms. Therefore, we have concentrated on controlling the motion of robotic devices that have lightweight structures.
Application of Singular Perturbation Theory to the Control of Flexible Link Manipulators

(Georgia Institute of Technology, 1986) Siciliano, Bruno ; Book, Wayne J.

The control problem for robotic manipulators with flexible links is considered in this paper. The dynamic equations of motion can be derived by means of a recently developed Lagrangian-assumed modes method. In the case of flexibility at links it has been shown that there is no analogue of the well established computed torque method widely adopted for rigid arm control. Under the assumption that the flexible dynamics is faster than the rigid dynamics, singular perturbation theory provides an engineering tool for reduced order modeling. The resulting slow subsystem allows the determination of a tracking control as for rigid manipulators, since the number of control variables equals that of control led variables. For the fast subsystem an additive control is in charge of stabilizing the deflections along the joint angle trajectory. The result is a composite control strategy which combines the advantages of rigidity ("controllability") with those of flexibility ("lightweight compliant structures").
Controller Design for Flexible Distributed Parameter Mechanical Arms via Combined State Space and Frequency Domain Techniques

(Georgia Institute of Technology, 1983-12) Book, Wayne J. ; Majette, Mark

The potential benefits of the ability to control more flexible mechanical arms are discussed. A justification is made in terms of speed of movement. A new controller design procedure is then developed to provide this capability. It uses both a frequency domain representation and a state variable representation of the arm model. The frequency domain model is used to update the modal state variable model to insure decoupled states. The technique is applied to a simple example with encouraging results.
Master-Slave Manipulator Performance for Various Dynamic Characteristics and Positioning Task Parameters

(Georgia Institute of Technology, 1980-11) Book, Wayne J. ; Hannema, Dirk

The performance of manually operated remote manipulators is limited by friction, tolerance of mating parts, limited speed of response, and other unavoidable factors which affect dynamic behavior. A review of the literature shows that little progress has been made towards describing or predicting these effects quantitatively. Such knowledge would be valuable both in understanding human motor behavior and in improving manipulator design. Single factor experiments were performed for a simple manipulator positioning task. The manipulator used was an experimental, two-degree-of-freedom, unilateral, master-slave manipulator. Microprocessor control of the dc electric torque motors which drive the joints enforced an approximately linear dynamic behavior of the arm throughout its range of motion. The characteristics of behavior which were studied were arm natural frequency, simulated Coulomb friction, and simulated backlash (deadband). The parameters of the positioning task which were varied were positioning accuracy and distance traveled. Performance was measured in task completion time. The data were analyzed statistically and regression coefficients obtained to explain the results in terms of information transmission concepts. In general, the information transmission rates were (0111'11 to differ for the gross motion (travel) and fine motion (Positioning) components of the task. For a well-trained subject and the best manipulator behavior, the two rates were the same, yielding the performance variations predicted by “Fitts' law.” The variation in performance with manipulator characteristics and task parameters is explained in terms of operator strategies to minimize time within the error constraints by changing the point or transmission from fast gross motion to the slower and more conservative fine motion.