Page 18 - Rapid Learning in Robotics

4 Introduction

istic. The solution, as seen by many researchers is, that “learning must
meet the real world”. Of course, simulation can be a helpful technique,
but needs realistic counter-checks in real-world experiments. Here, the
field of robotics plays an important role.
The word “robot” is young. It was coined 1935 by the playwriter Karl
Capek and has its roots in the Czech word for “forced labor”. The first
modern industrial robots are even younger: the “Unimates” were devel-
oped by Joe Engelberger in the early 60's. What is a robot? A robot is
a mechanism, which is able to move in a given environment. The main
difference to an ordinary machine is, that a robot is more versatile and
multi-functional, and it can be programmed, or commanded to perform
functions normally ascribed to humans. Its mechanical structure is driven
by actuators which are governed by some controller according to an in-
tended task. Sensors deliver the required feed-back in order to adjust the
current trajectory to the commanded motion and task.
Robot tasks can be specified in various ways: e.g. with respect to a
certain reference coordinate system, or in terms of desired proximities,
or forces, etc. However, the robot is governed by its own actuator vari-
ables. This makes the availability of precise mappings from different sen-
sory variables, physical, motor, and actuator values a crucial issue. Often
these sensorimotor mappings are highly non-linear and sometimes very hard
to derive analytically. Furthermore, they may change in time, i.e. drift by
wear-and-tear or due to unintended collisions. The effective learning and
adaption of the sensorimotor mappings are of particular importance when
a precise model is lacking or it is difficult or costly to recalibrate the robot,
e.g. since it may be remotely deployed.
Chapter 2 describes work done for establishing a hardware infrastruc-
ture and experimental platform that is suitable for carrying out experi-
ments needed to develop and test robot learning algorithms. Such a labo-
ratory comprises many different components required for advanced, sensor-
based robotics. Our main actuated mechanical structures are an industrial
manipulator, and a hydraulically driven robot hand. The perception side
has been enlarged by various sensory equipment. In addition, a variety of
hardware and software structures are required for command and control
purposes, in order to make a robot system useful.

The reality of working with real robots has several effects: