Autonomous robots are robots that can perform desired tasks in unstructured environments without continuous human guidance. Many kinds of robots have some degree of autonomy. Different robots can be autonomous in different ways. A high degree of autonomy is particularly desirable in fields such as space exploration, cleaning floors, mowing lawns, and waste water treatment.
Some modern factory robots are "autonomous" within the strict confines of their direct environment. It may not be that every degree of freedom exists in their surrounding environment, but the factory robot's workplace is challenging and can often contain chaotic, unpredicted variables. The exact orientation and position of the next object of work and (in the more advanced factories) even the type of object and the required task must be determined. This can vary unpredictably (at least from the robot's point of view).
One important area of robotics research is to enable the robot to cope with its environment whether this be on land, underwater, in the air, underground, or in space.
A fully autonomous robot has the ability to
- Gain information about the environment.
- Work for an extended period without human intervention.
- Move either all or part of itself throughout its operating environment without human assistance.
- Avoid situations that are harmful to people, property, or itself unless those are part of its design specifications.
Autonomous robots still require regular maintenance, as do other machines
Examples of progress towards commercial autonomous robots
[edit] Self-maintenance
Exteroceptive sensors: 1. blue laser rangefinder senses up to 360 distance readings in a 180-degree slice; 2. 24 round golden ultrasonic sensors sample range readings in a 15-degree cone; 3. ten touch panels along the bottom detect shoes and other low-lying objects. 4. break beams between the lower and upper segments sense tables and other mid-level obstacles.
Self maintenance is based on "proprioception", or sensing one's own internal status. In the battery charging example, the robot can tell proprioceptively that its batteries are low and it then seeks the charger. Another common proprioceptive sensor is for heat monitoring. Increased proprioception will be required for robots to work autonomously near people and in harsh environments.
- Common proprioceptive sensors are
- Thermal
- Hall Effect
- Optical
- Contact
[edit] Sensing the environment
Exteroception is sensing things about the environment. Autonomous robots must have a range of environmental sensors to perform their task and stay out of trouble.- Common exteroceptive sensors are
- Electromagnetic spectrum
- Sound
- Touch
- Chemical sensors (smell, odor)
- Temperature
- Range to things in the environment
- Attitude (Inclination)
[edit] Task performance
The next step in autonomous behavior is to actually perform a physical task. A new area showing commercial promise is domestic robots, with a flood of small vacuuming robots beginning with iRobot and Electrolux in 2002. While the level of intelligence is not high in these systems, they navigate over wide areas and pilot in tight situations around homes using contact and non-contact sensors. Both of these robots use proprietary algorithms to increase coverage over simple random bounce.The next level of autonomous task performance requires a robot to perform conditional tasks. For instance, security robots can be programmed to detect intruders and respond in a particular way depending upon where the intruder is.
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Robot interface GUI showing a robot building map with forbidden areas highlighted in yellow on the right side of the screen. Defined task sequences and goals are in the second column. Robots listed on the left side of the GUI can be selected by mouseclick. The selected robot will then travel to any location clicked in the map, unless it is in a forbidden area. (Courtesy of MobileRobots Inc)
At first, autonomous navigation was based on planar sensors, such as laser range-finders, that can only sense at one level. The most advanced systems now fuse information from various sensors for both localization (position) and navigation. Systems such as Motivity can rely on different sensors in different areas, depending upon which provides the most reliable data at the time, and can re-map a building autonomously.
Rather than climb stairs, which requires highly specialized hardware, most indoor robots navigate handicapped-accessible areas, controlling elevators and electronic doors.[2] With such electronic access-control interfaces, robots can now freely navigate indoors. Autonomously climbing stairs and opening doors manually are topics of research at the current time.
As these indoor techniques continue to develop, vacuuming robots will gain the ability to clean a specific user specified room or a whole floor. Security robots will be able to cooperatively surround intruders and cut off exits. These advances also bring concommitant protections: robots' internal maps typically permit "forbidden areas" to be defined to prevent robots from autonomously entering certain regions.
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Outdoor autonomy is most easily achieved in the air, since obstacles are rare. Cruise missiles are rather dangerous highly autonomous robots. Pilotless drone aircraft are increasingly used for reconnaissance. Some of these unmanned aerial vehicles (UAVs) are capable of flying their entire mission without any human interaction at all except possibly for the landing where a person intervenes using radio remote control. But some drone aircraft are capable of a safe, automatic landing also.Outdoor autonomy is the most difficult for ground vehicles, due to: a) 3-dimensional terrain; b) great disparities in surface density; c) weather exigencies and d) instability of the sensed environment.
In the US, the MDARS project, which defined and built a prototype outdoor surveillance robot in the 1990s, is now moving into production and will be implemented in 2006. The General Dynamics MDARS robot can navigate semi-autonomously and detect intruders, using the MRHA software architecture planned for all unmanned military vehicles. The Seekur robot was the first commercially available robot to demonstrate MDARS-like capabilities for general use by airports, utility plants, corrections facilities and Homeland Security.[3]
The Mars rovers MER-A and MER-B (now known as Spirit rover and Opportunity rover) can find the position of the sun and navigate their own routes to destinations on the fly by:
- mapping the surface with 3-D vision
- computing safe and unsafe areas on the surface within that field of vision
- computing optimal paths across the safe area towards the desired destination
- driving along the calculated route;
- repeating this cycle until either the destination is reached, or there is no known path to the destination
- reconstructing 3D models of the terrain surrounding the Rover using a pair of stereo cameras
- determining safe and unsafe areas of the terrain and the general 'difficulty' for the Rover to navigate the terrain
- computing efficient paths across the safe area towards the desired destination
- driving the Rover along the planned path
- building up a 'Navigation Map' of all past navigation data
[edit] Open problems in autonomous robotics
| This section requires expansion. |
There are several open problems in autonomous robotics which are special to the field rather than being a part of the general pursuit of AI.
[edit] Energy autonomy & foraging
Researchers concerned with creating true artificial life are concerned not only with intelligent control, but further with the capacity of the robot to find its own resources through foraging (looking for food, which includes both energy and spare parts).This is related to autonomous foraging, a concern within the sciences of behavioral ecology, social anthropology, and human behavioral ecology; as well as robotics, artificial intelligence, and artificial life.
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