Optimal control of a flexible robot arm

The mathematical model of a single-link flexible manipulator is obtained by measuring transverse deflections in a rotating reference frame which is floating with respect to the link. The use of this particular frame, the rigidbody mode frame, enables one to obtain weakly coupled equations of motion. The size of the inertia coupling terms can be easily evaluated: these terms can be shown to be negligible thus leading to an essentially linear model. An example of optimal control of manipulator's tip position is numerically reproduced. The same controller is first applied to the mechanical model of the arm accounting for non-linear coupling and then to the linear model: the two responses are found to be very close to each other.

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Load estimation and load-adaptive optimal control for a flexible robot arm

10.1109/robot.1986.1087736 ◽

2005 ◽

Cited By ~ 14

Author(s):

W. Nelson ◽

D. Mitra

Keyword(s):

Optimal Control ◽

Load Estimation ◽

Robot Arm ◽

Flexible Robot ◽

Adaptive Optimal Control

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Inverse Dynamics of a Flexible Robot Arm by Optimal Control

Journal of Mechanical Design ◽

10.1115/1.2919190 ◽

1993 ◽

Vol 115 (2) ◽

pp. 289-293 ◽

Cited By ~ 2

Author(s):

T. Kokkinis ◽

M. Sahraian

Keyword(s):

Optimal Control ◽

Inverse Dynamics ◽

Robot Arm ◽

Flexible Robot ◽

Joint Torques ◽

Practical Applications ◽

End Point ◽

Point Tracking ◽

Flexible Arms ◽

High Frequency Content

The problem of end-point positioning of flexible arms is discussed. Because of the nonminimum phase nature of the problem, inversion fails to produce bounded joint torques. Bounded noncausal joint torques for achieving the task of end-point tracking for a multilink arm are found using optimal control theory. The torques obtained have no high-frequency content, and are suitable for practical applications. The method is illustrated by simulation of a single-link arm, for which stability and robustness considerations for design are given.

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Integration of model-based and sensor-based control for a two-link flexible robot arm

10.1109/icsyse.1990.203188 ◽

2002 ◽

Cited By ~ 4

Author(s):

J.T. Feddema ◽

G.R. Eisler ◽

D.J. Segalman

Keyword(s):

Robot Arm ◽

Flexible Robot ◽

Model Based

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Design, Kinematics and Prototype of a Flexible Robot Arm With Planar Springs

Volume 5A: 39th Mechanisms and Robotics Conference ◽

10.1115/detc2015-46503 ◽

2015 ◽

Cited By ~ 2

Author(s):

Peng Qi ◽

Hongbin Liu ◽

Lakmal Seneviratne ◽

Kaspar Althoefer

Keyword(s):

Preliminary Test ◽

Industrial Applications ◽

Robot Arm ◽

Kinematic Modeling ◽

Flexible Robot ◽

Element Analysis ◽

Robot Arms ◽

Environmental Interactions ◽

In Series ◽

Fea Simulation

Flexible robot arms have been developed for various medical and industrial applications because of their compliant structures enabling safe environmental interactions. This paper introduces a novel flexible robot arm comprising a number of elastically deformable planar spring elements arranged in series. The effects of flexure design variations on their layer compliance properties are investigated. Numerical studies of the different layer configurations are presented and finite Element Analysis (FEA) simulation is conducted. Based on the suspended platform’s motion of each planar spring, this paper then provides a new method for kinematic modeling of the proposed robot arm. The approach is based on the concept of simultaneous rotation and the use of Rodrigues’ rotation formula and is applicable to a wide class of continuum-style robot arms. At last, the flexible robot arms respectively integrated with two different types of compliance layers are prototyped. Preliminary test results are reported.

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