Point-to-point control of a 2R planar horizontal underactuated manipulator

Abstract

This paper presents a control strategy for a two-link manipulator with revolute joints (2R) with an unactuated second joint, wherein the motion of the system is confined to a horizontal plane. The model takes into account the frictional forces present in the system. The control objective is to move the end-effector from a given position to a target point. The methodology involves two stages. In the first stage a finite-time controller is used to move the passive link to its desired position. In the second stage, the first link is moved to its desired position keeping the second link at rest, using friction as a ''brake'' and subject to the constraint that the cross-coupling torque acting on the second joint does not exceed the static friction.

Development of a real-time-position prediction algorithm for under-actuated robot manipulator by using of artificial neural network

“…The coordinate q i , i ¼ 1, 2 are the joint angles. The Euler-Lagrange equation of motion is [13] M ðqÞ…”

“…The F i , b i _ q i , i ¼ 1, 2 represent the Coulomb and viscous friction forces, respectively; more details on joint friction could be found in Mahindrakar [13]. The set-valued signum function signðÁÞ is defined as:…”

“…In the case of under-actuated robots, this condition is not satisfied, which makes the behaviour of that class of robots very difficult to be predicted. Under-actuated robots can be a better design choice for robots in space and other industrial applications, and their advantages over fully actuated robots led to many studies to predict their behaviour [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. As a first advantage, a light-weight and low power consumption manipulator can be made.…”

Real-Time-Position Prediction Algorithm for Under-Actuated Robot Manipulator Using of Artificial Neural Network

“…In the case of under-actuated robots, this condition is not satisfied which make the behavior of that class of robots very difficult to be predicted. Under-actuated robots can be a better design choice for robots in space and other industrial applications, their advantages over fully actuated robots led to many studies to predict their behavior (Yu et al, 1998;Berkemeier & Fearing, 1999;Spong, 1995;Ono et al, 2001;Nakanishi et al, 2000;Funda et al, 1996;Luca et al, 2000;Luca & Oriolo, 2002;Arai & Tachi, 1991;Mukherjee & Chen, 1993;Yu et al, 1993;Bergerman et al, 1995;Mahindrakar et al, 2006;Muscato, 2006;Begovich et al, 2002). As a first advantage, a light-weight and low power consumption manipulator can be made.…”

“…Their results were verified using numerical simulation. Later on, (Mahindrakar et al, 2006) have presented a mathematical model for a two-link under-actuated manipulator wherein the motion of the system was confined to a horizontal plane; their proposed dynamic model takes into account the frictional forces acting on the joints. Results obtained were also verified through numerical simulation.…”