Page 21 - Electric Drives and Electromechanical Systems

Chapter 1 Electromechanical systems 13

together with controllers based on artificial intelligence to undertake applications as
diverse as planetary exploration to acting as health care assistances. The definition given
by Arkin (1998), proposes a far more general definition, namely:

An intelligent robot is a machine able to extract information from its environment
and use knowledge about its world to move safely in a meaningful and purposive
manner.

The definition should be considered to be at the intersection between biological science
and robotic engineering. Advanced robotic systems and animals both are capable or
mobility, behavioural aspects; incorporate sensors and actuators and require an
autonomous control system that enables them to successfully carry out various tasks in a
complex, dynamic world. This allowed the following conclusion to be made, “the study
of autonomous robots was analogous to the study of animal behaviour” (Webb, 2001).
This allows the following objectives to be achieved:

Robots to be used to model aspects of animal behaviour or functionality to expand
the understanding of biological systems operate in an real world environment.
Incorprate biologically inspired attributes or systems in to robots to improve their
operational capability, for example improve mobility by using legs as opposed to
wheels.
In the following section an overview of robotic applications will be undertaking
considering both industrial robots, and the application of biological inspiration in both
manipulative and legged applications.

1.3.1 Industrial robotics
The mechanical structure of a conventional industrial robot can be divided into two
parts, the main manipulator and a wrist assembly. The manipulator will position the end
effector while the wrist will control its orientation. The structure of the robot consists of
links and joints; a joint allows relative motion between two links. A link and is associated
joint is considered as a joint-link pair for the purpose of analysis. Two types of joints are
used: a revolute joint to produce rotation, and a linear or prismatic joint to provide linear
motion. A minimum of six joints are required to achieve complete control of the end
effector’s position and orientation. Even though many robot configurations are possible,
only five configurations are commonly used within the industrial environment:

Polar. This configuration has a linear extending arm (Joint 3) which is capable of
being rotated around the horizontal (Joint 2) and vertical axes (Joint 1). This
configuration is widely used in the automotive industry due to its good reach
capability, Fig. 1.6A.
Cylindrical. This comprises a linear extending arm (Joint 2) which can be moved
vertically up and down (Joint 3) around a rotating column (Joint 1). This is a