Model Reference Adaptive Control of PUMA 560 Robot Manipulator for High Speed Operations
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Date
2025-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Robotic pick-and-place systems bring remarkable speed and precision to manufacturing
lines. Adaptive control is one of the effective approaches for designing controllers for
mechanical robot manipulators, particularly in addressing the nonlinearities and uncertainties
inherent in robot dynamic models. When the robotic end-effector encounters
varying masses and load conditions, the motion control directly affects the overall performance,
stability, and speed of the robot. To address these challenges, this paper presents
the design of a controller for a second-order system using a Model Reference Adaptive
Control (MRAC) scheme, where the adaptive mechanism and controller design are based
on the Lyapunov method. A Lyapunov candidate function is employed both to derive
the adaptation law and to guarantee the stability of the system.
The tracking error performance of the MRAC is demonstrated across all six joint
positions of the PUMA 560 robot. For Joint 1, the error exhibits an initial peak magnitude
of2×10
−5
rad under disturbance, settling to near-zero within 2 seconds, while the
undisturbed error remains negligible. Similarly, Joint 2 shows a slightly lower peak error
of1.8×10
−5
rad, with steady-state achieved in about 2.5 seconds. Joint 3 experiences
a slightly higher peak error of2.2×10
−5
rad and takes 3 seconds to settle. Joint 4 exhibits
the highest peak error of2.5×10
−5
rad, with a settling time of approximately 3.5
seconds, demonstrating the greatest sensitivity to disturbance among the joints. Joint 5
and Joint 6 show peak error magnitudes of2×10
−5
rad and2.3×10
−5
rad, respectively,
both reaching steady-state within 3 seconds
Description
Keywords
Adaptive control, Lyapunov, MRAC, Puma 560 Robot Manipulator.