Basic steering control methods for the articulated body mobile robot

Abstract

This paper investigates an optimal steering control method for the articulated body mobile robot KORYU-II (KR-II), considering energy consumption and trajectory tracking performance as the optimization criteria. The computer simulations of the basic control methods of KR-II's /spl theta/ axis (bending motion between the segments) and s axis (rotation motion of the wheels), lead to the conclusion that the best methods are: the "/spl theta/2 method" combined with the "/spl theta/4 method" for the /spl theta/ axis, and the "s3 method" for the s axis. The "/spl theta/2 method" takes the moving average value of the foremost segment's control angle /spl theta//sub 0/ over a traveled distance L (intersegment length) as the next segment command /spl theta//sub 1/ and then shifts /spl theta//sub 1/ to the following segments according to the moved distance. The "/spl theta/4 method" entails setting a small position control gain for the /spl theta/ axis. The "s3 method" controls the forward velocity of the robot by equally distributed torque commands for all wheels. The experiments by the mechanical model KR-II demonstrated that the introduced control greatly reduces the energy consumption and produces very smooth locomotion; although the trajectory tracking performance is somewhat deteriorated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>