Control of a Flexible Robot Arm: Experimental and Theoretical Results

Chalhoub, Nabil G.; Ulsoy, A. Galip

doi:10.1115/1.3143859

Cited by 91 publications

(21 citation statements)

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“…The position vector of an arbitrary point P of link 1 can be written in F 0 as P (1) = T (1)r (1) (29) Fig. 1 Planar two-link manipulator with flexible forearm wherer (1) is the position vector of the same point with respect to F 1 and T (1) the transformation matrix from F 1 to F 0 .…”

Section: Mathematical Modellingmentioning

confidence: 99%

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Motion control of flexible-link manipulators

Kiliçaslan

İder

Özgören

2008

Proceedings of the Institution of Mechanical Engineers, Part C:

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A new method is proposed for the end-effector trajectory tracking control of flexible robot manipulators. The equations of motion are separated into two parts that represent the pseudostatic equilibrium and the deviations from it. The part of the control input for the pseudostatic equilibrium is determined algebraically, and the other part of the control input for the stabilization of the deviations is obtained by a state variable feedback law, by using strain, joint variable, and end-effector position measurements. The feedback gain matrix is determined online by continuously updated pole placement. The pseudostatic equilibrium is defined here as a hypothetical state, in which the velocity and acceleration of the end-effector have their desired values whereas the elastic deformations are instantaneously constant. In order to demonstrate the method, a planar two-link robot with a flexible forearm is taken into consideration. The elasticity of the forearm is approximately described by the first two modes, and a controller is designed by using this two-mode model. Furthermore, in order to investigate the effects of modelling discrepancies, a 'submodel controller' is designed by using a model with only the first mode and it is applied to the same system with the two-mode model. The performances of these two controllers are compared by means of simulations. The behaviour of the flexible robot is also simulated by using the computed torque method as if the robot is rigid in order to illustrate the importance of including the flexibility effects in the formation of an appropriate control law. The spillover effect that causes the dominant poles to approach towards the imaginary axis is inspected by monitoring the real parts of the dominant poles of the closed-loop system under the effect of the 'submodel' and 'computed torque' controllers.

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Section: Mathematical Modellingmentioning

confidence: 99%

“…Chalhoub and Ulsoy [1] studied robust pole assignment and optimal regulator controls by using a linearized model of the structure. Pham et al [2] developed an inverse dynamics controller with a joint-space PD action, which is stable for positioning but unstable for trajectory tracking.…”

Section: Introductionmentioning

confidence: 99%

Motion control of flexible-link manipulators

Kiliçaslan

İder

Özgören

2008

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Photo sensors have also been used for detecting beam displacement to provide an output feedback signal (Cannon and Schmitz 1984;Sridhar et al 1985;Wang et al 1989). Accelerometers are often used to measure the beam vibration (Chalhoub and Ulsoy 1987). By combining some strain gauge and/or displacement measurements, the states of the vibration can be obtained indirectly (Sundararajan and Montgomery 1985).…”

Section: Introductionmentioning

confidence: 99%

A Video Signal Processing Technique for Vibration Measurement of a Flexible Beam

Tang

1992

The International Journal of Robotics Research

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A video system is used as a single contactless multipoint displacement sensor to measure the vibration displacement of a beam. In this article, several schemes are proposed to reduce the image processing time and to increase its accuracy. The vibration displacements of the entire beam are measured with a sampling rate of 60 Hz. From these measured data, the mode shapes and vibration states can be calculated. The video system is shown to have a potential for on-line control and on-line identification of flexible beam systems.

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“…Some researchers have approached this problem by modifying the controller design of the robot arm to account for the flexible motion of the manipulator (Cannon and Schmitz 1984;Chalhoub and Ulsoy 1987;Usoro et al 1984). Others have focused on methods developed to stiffen mechanical structures.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Modeling of a Laminated Composite- Material Flexible Robot Arm Made of Short Beams

Chalhoub

Gordaninejad

Lin

et al. 1991

The International Journal of Robotics Research

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High-precision assembly tasks are often performed by compact industrial robots with small work envelopes. The end-effector positional accuracy of compact robots can be accurately predicted by considering the links of the robot arm as short beams. In this study, a general procedure to derive a dynamic model for a revolute flexible robot arm, which takes into consideration the rotary inertia and shear deformation effects, is presented. Only the last link of the arm is considered to be flexible and assumed to be fabricated from laminated composite materials.Hamilton's principle is used to derive the equations of motion. A displacement finite element model based on the Timoshenko beam theory is implemented to approximate the solution. The digital simulation studies predict the deflections at the end effector and examine the combined effects of rotary inertia and shear deformation. Furthermore, the improvement in the dynamic response of the robot arm resulting from the fabrication of the manipulator from laminated composite materials is demonstrated.

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Control of a Flexible Robot Arm: Experimental and Theoretical Results

Cited by 91 publications

References 0 publications

Motion control of flexible-link manipulators

Motion control of flexible-link manipulators

A Video Signal Processing Technique for Vibration Measurement of a Flexible Beam

Dynamic Modeling of a Laminated Composite- Material Flexible Robot Arm Made of Short Beams

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