A mobile robot is one which can move around its environment independently. In order to do this the robot needs to be able to navigate, and the range and accuracy of navigational ability required will vary depending on the size of the robot and the type of task it carries out. Types of mobile robot currently in production include the domestic robot, which comes in a variety of forms ranging from the robot vacuum cleaner to the robot dog. Potential future uses of the mobile robot include robot paramedics, farmhands and border guards.
In order to find its way around, a mobile robot first needs to determine where it is. There are many ways in which this can be accomplished. Gyroscopes and other devices may be used to measure wheel rotation and rate of acceleration to provide the mobile robot with more clues as to its current position. Satellite global positioning systems allow the robot to measure its position in absolute terms, according to a fixed point on the planet. Vision-based positioning systems use optical sensors to perceive information in the environment.
A large amount of information can be provided visually, and vision-based positioning is thought to hold the most potential for the future of mobile robot navigation. Limitations in visual navigation methods stem from the requirement to compare the perceived visual input with maps or known landmarks in order to establish position. In order to be truly useful, a mobile robot of the future will need to find its way in environments which were previously unknown. An alternative way of accomplishing this could lie in the simultaneous use of many simple mobile robots, known as ant robots.
The ant robot leaves a trail as it moves across terrain. This trail is then available for other ant robots to follow. Although individual robots may be destroyed or fail, the group as a whole remains robust with some of the ant robots achieving their goal even though the problem of knowing exactly where they are in the environment has not been solved.
Domestic mobile robots face additional challenges apart from navigation. Safety can be a problem, as the robot has to work around humans in the home and, should a collision occur, this could potentially cause an accident such as a fall. Appearance also becomes more important if a robot has to interact with humans every day, and while the humanoid robot might appeal to some, it could appear menacing to others. For these reasons, the design of domestic robots has to take into account the needs and attitudes of the intended users.