15-10-2012, 01:07 PM
A Tele-operated Humanoid Robot Drives a Lift Truck
A Tele-operated Humanoid.pdf (Size: 369.11 KB / Downloads: 38)
Abstract
We have been developing new abilities of humanoid
robot to realize proxy drives of a lift truck. Construction
machines such as a lift truck play an important
role in many tasks, but sometimes the environments
are too hazardous for human operators. If
a tele-operated humanoid robot can drive a construction
machine, it can work at a dangerous place. This
humanoid robot operator has two advantages than automated
construction machine. It is much easier to
carry the robot to a disaster site than moving the special
construction machine. Besides, the robot may be
less expensive than developing the special automated
machine whose required number is relatively small.
We have been developing new abilities of tele-operated
humanoid robot HRP-1 to realize the application. This
paper describes results of investigations and experiments
as for proxy drives of a lift truck by HRP-1.
Introduction
A humanoid robot has substantial advantages when
working in an environment where human beings usually
live, because a humanoid robot can act as a human
being in such a space without any previous reconstructions
of the environment. In recent years, many
universities [2][11] [12][17] and some companies [6][9]
have produced humanoid robots. However the application
area of the humanoid robots are still limited in
the research, the amusement, and the entertainment.
Humanoid Robot HRP-1
The humanoid robot of the platform is a human
type robot with two arms and two legs, which walks
by biped locomotion[7]. We call the robot HRP-1. It
has 1600 [mm] height, 600 [mm] width, and 99 [kg]
weight excluding batteries. It has 12 d.o.f. in two legs
and 16 d.o.f. in two arms including hands with 1 d.o.f.
grippers.
Each joint is actuated by a brushless DC servo motor
with a harmonic-drive reduction gear. Brushless
DC servo amplifiers, a Ni-Zn battery, a wireless ethernet
modem are within the body.
The body is equipped with a inclination sensor
which consists of gyroscopes and G-force sensors.
Each foot and wrist is equipped with a force/torque
sensor. In the head of the robot, there are two video
cameras.
The humanoid robot can be operated according to
the command inputted from the remote computer such
as the remote control cockpit. The operating commands
are listed in Table 1.
The orientation and acceleration of the body, the
position and the orientation of the wrist, and the other
measurements are output every 5 [msec]. The list of
the output data is presented in Table 2.
Remote Control Cockpit
Figure 3 shows the configuration of the remote control
cockpit system. It consists of an audio-visual
display system and a tele-operation master system.
The audio-visual display system includes surrounded
projection display consiting of nine display screens,
a head mount display (HMD) with a head tracker,
and a 3D sound system[14]. The tele-operation master
system includes right and left master-arm with two
gripping operation devices, a motion-base, and a 3D
mouse[4][5].
Experimental System
As a sample of construction machine for proxy drive
experiments, we focused a lift truck because a it is one
of the most popular construction machines in several
fields. For the experiments, we introduced a standing
operation type electric lift truck (Nichiyu FBR9-60)
with 900 [kg] load capacity. Figure 6 shows the outlook
of the lift truck driving by tele-operated HRP-1.
HRP-1 has to control a fork (up-and-down, tilt, and
reach), traveling speed and direction using the control
levers and the steering wheel for proxy drives of
the lift truck. Experiments of fork operations (lever
operations), traveling operations (lever and steering
wheel operations), and overall operation using levers
and steering wheel were carried out. Through these
experiments, we extracted points at issue and examined
the measures. In these experiments, length of
the levers and the dimensions of grips of the levers
and the steering wheel were modified on purpose to
suit the range and force needed to operate the levers
and steering wheel to specifications of the remote control
humanoid robot platform. HRP-1 grasps a lever
or a handle of the lift truck loosely in order to avoid
a lack of stability of the control system.
Experimental Results
First, lever operation experiments were carried out
(Fig. 7). Figure 8 shows the force acting on the wrist
of HRP-1 and the operation force of the master-arm.
This figure shows the value of the force acting on the
wrist of HRP-1 kept under 700 [gf] because HRP-1
cannot generate the force over 1 [kgf]. The time to
operate the lifting lever by a tele-operated HRP-1 is
about 20 [sec]. It took approximately 2.2 times longer
than a human operator did. Also the time to operate
the fork-reaching levers by a tele-operated HRP-1 is
about 19 [sec]. It took approximately 2.8 times longer
than a human operator did.
Conclusions and Discussions
This paper presented the current status of research
and development on the application of the teleoperation
of a construction machine by a tele-operated
humanoid robot under going on HRP in Japan. We
have succeeded in making the experiments as for the
proxy drive of a forklift by the tele-operated humanoid
robot HRP-1.
From the experiments, we found out several points
to be improved as follow.
1. Software program for leg control at climbing will
be modified to make commands corresponding to
various shapes of stairs, which makes it easy to
climb various types of construction machines.