A reduced-order dynamic model for end-effector position control of a flexible robot arm

1996 ◽  
Vol 41 (5-6) ◽  
pp. 539-558 ◽  
Author(s):  
C.W. Jen ◽  
D.A. Johnson ◽  
R. Gorez
Keyword(s):  
Dynamic Model ◽  
Position Control ◽  
Robot Arm ◽  
Flexible Robot ◽  
End Effector ◽  
Reduced Order

Control of a Flexible Robot Arm: Experimental and Theoretical Results

1987 ◽  
Vol 109 (4) ◽  
pp. 299-309 ◽  
Author(s):  
N. G. Chalhoub ◽  
A. G. Ulsoy
Keyword(s):  
Partial Evaluation ◽  
Digital Simulation ◽  
Robot Arm ◽  
Flexible Robot ◽  
Motion Controller ◽  
Positional Accuracy ◽  
Spherical Coordinate ◽  
End Effector ◽  
Theoretical Results ◽  
Observation Spillover

The operation of high precision robots is severely limited by. their manipulator dynamic deflection, which persists for a period of time after a move is completed. These unwanted vibrations deteriorate the end effector positional accuracy and reduce significantly the robot arm production rate. A “rigid and flexible motion controller” is derived to introduce additional damping into the flexible motion. This is done by using additional sensors to measure the compliant link vibrations and feed them back to the controller. The existing actuators at the robot joints are used (i.e., no additional actuators are introduced). The performance of the controller is tested on a dynamic model, developed in previous work, for a spherical coordinate robot arm whose last link only is considered to be flexible. The simulation results show a significant reduction in the vibratory motion. The important issue of control and observation spillover is examined and found to present no significant practical problems. Partial evaluation of this approach is performed experimentally by testing two controllers, a “rigid body controller” and a “rigid and flexible motion controller,” on a single joint of a spherical coordinate, laboratory robot arm. The experimental results show a significant reduction in the end effector dynamic deflection; thus partially validating the results of the digital simulation studies.

Dynamic Finite Element Analysis of the Position Control System of a Two-Link Horizontal Flexible Robot

1990 ◽  
Vol 2 (2) ◽  
pp. 83-90
Author(s):  
Hiroyuki Kojima ◽  
Keyword(s):  
Finite Element ◽  
Control System ◽  
Position Control ◽  
Velocity Curve ◽  
Element Formulation ◽  
Robot Arm ◽  
Flexible Robot ◽  
Element Analysis ◽  
Flexible Arm ◽  
Position Control System

In this paper, a finite element formulation method for a horizontal flexible robot arm with two links is first presented. In the analysis, the kinetic energy of the flexible arm is represented in brief compared with previous methods, and the matrix equation of motion in consideration of the nonlinear forces, such as the Coriolis force, is derived by the finite element method and the variational theorem. Then, the state equation of the mechatronics system consisting of the flexible arm and the position control system is obtained. Secondly, numerical simulations in the case of applying path control based on the trapezoidal velocity curve are carried out by use of the Wilson-<I>θ</I> method, and the effects of the bending rigidity and the shape of the trapezoidal velocity curve on the dynamic characteristics of the mechatronics system are demonstrated.

Controller Design Robust to Frequency Variation in a One-Link Flexible Robot Arm

1989 ◽  
Vol 111 (1) ◽  
pp. 9-14 ◽  
Author(s):  
V. V. Korolov ◽  
Y. H. Chen
Keyword(s):  
Position Control ◽  
Controller Design ◽  
Wide Spectrum ◽  
Operating Conditions ◽  
Frequency Variation ◽  
Robot Arm ◽  
Flexible Robot ◽  
Complete Knowledge ◽  
Control Scheme ◽  
Frequency Variations

The end-point position control problem of a one-link flexible robot arm under wide spectrum of operating conditions is considered. Natural frequency variations may arise in practice and are treated as the uncertainty. A robust control scheme is designed for the manipulator for some guaranteed performances without the complete knowledge of uncertainty. The only required information of the uncertainty is its possible bound.

Experiments on the position control of a one-link flexible robot arm

1989 ◽  
Vol 5 (3) ◽  
pp. 373-377 ◽  
Author(s):  
W.-J. Wang ◽  
S.-S. Lu ◽  
C.-F. Hsu
Keyword(s):  
Position Control ◽  
Robot Arm ◽  
Flexible Robot

Nonlinear Regulation of End-Effector Motion for a Flexible Robot Arm

1991 ◽  
pp. 229-236 ◽  
Author(s):  
Alessandro De Luca ◽  
Leonardo Lanari ◽  
Giovanni Ulivi
Keyword(s):  
Robot Arm ◽  
Flexible Robot ◽  
End Effector ◽  
Nonlinear Regulation

scholarly journals Motion and Vibration Control of a Flexible Robot Arm (Example of the Extended Reduced Order Physical Model)

2003 ◽  
Vol 69 (687) ◽  
pp. 2914-2920 ◽  
Author(s):  
Yukifumi OHTSUKA ◽  
Kouhei TSUCHIDATE ◽  
Takahito SAGANE ◽  
Hiroshi TAJIMA ◽  
Kazuto SETO
Keyword(s):  
Vibration Control ◽  
Physical Model ◽  
Robot Arm ◽  
Flexible Robot ◽  
Reduced Order

Tip Position Control of a Flexible Robot Arm Considering the Reduction Gear's Friction

1990 ◽  
Vol 2 (2) ◽  
pp. 91-96
Author(s):  
Yasuo Yoshida ◽  
◽  
Masato Tanaka
Keyword(s):  
Feedback Control ◽  
Dynamic Characteristics ◽  
Position Control ◽  
Viscous Friction ◽  
Open Loop ◽  
Robot Arm ◽  
Flexible Robot ◽  
Position Feedback ◽  
Linear Friction ◽  
Tip Position

The reduction gear's friction strongly affects the dynamic characteristics of a one-link flexible robot arm. Experiments of open loop response by motor torque were performed in two cases of large and small values of the reduction gear's friction, and compared with simulation. The reduction gear's friction has both viscous and Coulomb aspects and can be approximately treated as an equivalent viscous friction. However, tip position control was very difficult in the case of large friction with an equivalent viscous friction. Experiments indicated that tip position feedback control was possible by using a dither signal and linearizing the non-linear friction.

Output Tracking for a Nonlinear Flexible Arm

1993 ◽  
Vol 115 (1) ◽  
pp. 78-85 ◽  
Author(s):  
P. Lucibello ◽  
M. D. Di Benedetto
Keyword(s):  
Rigid Motion ◽  
Inverse System ◽  
Inertial Forces ◽  
Robot Arm ◽  
Bounded Solutions ◽  
Flexible Robot ◽  
Controlled System ◽  
End Effector ◽  
Output Tracking ◽  
Flexible Arm

In this paper, an inversion-based control of the end effector of a two-link flexible robot arm is investigated. The challenge in solving this problem consists in the instability of the inverse system. Arbitrary initialization of the inverse system leads to unbounded elastic vibrations, even if along the desired trajectory the inertial forces associated with the rigid motion are bounded. We show that bounded solutions of the inverse system exist and we provide procedures for computing such solutions in the case of periodic velocities of the end effector. In particular, we consider the case of tracking an unbounded trajectory, e.g., an end point ramp. A technique for the stabilization of the trajectories to be tracked is also proposed and some numerical simulations illustrate the performance of the controlled system.

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