|  | | | | | | Control, Autonomy and Intelligence
What makes the difference between robots and mechanisms is the
ability of robots to adapt to changes of their tasks or their subjects
of operation or of their operating environment.
A robot should be able to
- interprete the directives that describe its task,
- understand the operating environment from data provided by
its perception sensors,
- reason about its state and the state of other robots/human
("agents") present in the same environment
- perform motion planning and activity planning based
on task description, on the environment
and own/agents states,
- control the execution of the actions,
while allocating attention to task-related events,
- and anticipate outcome of actions,
When all this is performed without human guidance the robot can be
called Autonomous.
| | | The EXOMARS rover (artist impression) will make use of unprecedented levels of autonomy |
Degrees of Autonomy
There are several degrees of "smartness" of how Robot Autonomy can be
implemented. Examples of possible degrees of Robot Autonomy
for a mobile robot (with respect to the abilities mentioned
above):
- the robot could understand directives in the form of
- low level program sequences (e.g. drive to x,y; move
robot arm to x,y,z)
- natural language (e.g. analyse any strange stone closeby)
- the understanding of the environment could be
- limited to determination of the configuration of a
standard environment (e.g. the positions of doors in a corridor)
- reconstruction of the 3D model of an outdoor environment
and association of entities to it (e.g. boulder, tree, pond)
- reasoning on own/co-agent states could be
- simple tracking of own resources (e.g. level of energy in
batteries)
- determining how tasks could be performed in co-operation
with other agents
- planning could be
- geometrical/temporal planning of motion (e.g.
interpolating a trajectory)
- break down high level task into elementary actions
including resources and contingency actions (e.g. survey area; stop on strange
looking stone; grasp stone; deposit in analysis instrument; run
analysis procedure)
- control could be implemented as
- feedback execution of a command (e.g. a proportional,
integrative and derivative control to follow a trajectory in space)
- a set of behaviours triggered by events (e.g. when bump in obstacle backtrack)
The implementation of even the simplest Autonomy requires a computer
with suitable interfacing means to the robot sensors and actuators.
Such computer is called Robot Controller.
| | The electonic cards that make-up the CESAR robot controller | |
Robot Controller
Robot Autonomy is implemented by means of a computer system, dedicated electronics and software making the so-called robot controller.
Due to the absence of suitable space-rated Robot Controllers, the A&R section has developed one in the course of several R&D projects.
The first one was the “SPAce Robot COntroller” (SPARCO) in 1994, followed by “Common European Space A&R COntroller” (CESAR) in 1996, by “Servo and Power Electronics for A&R” in 1997, by “Compact Integrated Robot Controller Unit and Servo Amplifier” (CIRCUS) in 1999 and “space A&R CONTroller Extensions” (CONTEXT) in 2002.
All robot control software has been designed to support the “Interactive Autonomy” control mode.
Last update: 30 November 2006 | |
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