Abstract

In this paper, we introduce an adaptive type-2 fuzzy logic controller (FLC) for flexible-joint manipulators with structured and unstructured dynamical uncertainties. Simplified interval fuzzy sets are used for real-time efficiency, and internal stability is enhanced by adopting a trade-off strategy between the manipulator’s and the actuators’ velocities. Furthermore, the control scheme is independent of the computationally expensive noisy torque and acceleration signals. The controller is validated through a set of numerical simulations and by comparing it against its type-1 counterpart. The ability of the adaptive type-2 FLC in coping with large magnitudes of uncertainties yields an improved performance. The stability of the proposed control system is guaranteed using Lyapunov stability theory.

Highlights

  • IntroductionFlexible-joint manipulators offer several advantages with respect to their rigid counterpart, such as light weight, lower cost, smaller actuators, larger work volume, better manoeuvrability

  • Flexible-joint manipulators offer several advantages with respect to their rigid counterpart, such as light weight, lower cost, smaller actuators, larger work volume, better manoeuvrabilityRobotics 2013, 2 and transportability, higher operational speed, power efficiency, and larger number of applications.they are often required to operate at high speed to yield high productivity

  • We present a comparative study between the proposed adaptive type-2 fuzzy logic controller (FLC) and its type-1 counterpart to better assess their respective performances in various operating conditions

Read more

Summary

Introduction

Flexible-joint manipulators offer several advantages with respect to their rigid counterpart, such as light weight, lower cost, smaller actuators, larger work volume, better manoeuvrability. Khorasani et al [22] illustrated how standard adaptive control schemes for rigid robots may be generalized for flexible-joint manipulators under a certain set of assumptions Many of these controllers are shown to be quite performant in theory, they failed to address important issues that might stand against their practical implementation, like basing the control laws on joint torques and their derivative [23,24], for instance, which are well known to be extremely noisy in real-life applications. The present work contributes to the merits and the latest developments of type-2 fuzzy logic theory for the design and implementation of an adaptive type-2 FLC for the control of flexible-joint robot manipulators with uncertain dynamics. This work represents one of the scarce attempts in developing adaptive type-2 FLC to control flexible-joint manipulators with uncertain dynamics.

Modeling of a Flexible-Joint Manipulator
Friction Modeling
Problem Statement
Type-2 FLSs
Interval Type-2 FLSs
Type-2 Fuzzification
Type-2 Fuzzy Rule Base
Type-2 Fuzzy Inference Engine
Type Reduction
Calculation of the Type-Reduced Set
Type-2 Defuzzification
Control Strategy
Adaptive Type-2 FLC
Simulation Setup
Numerical Simulations and Results
Conclusions
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call