Backaround of the Invention It is known for robots to be controlled by wireless communication means. It is also known for multiple robots to operate in distributed wireless systems, in which a plurality of robots interact with one another. Such a system is sometimes referred to as a distributed mobile robotics system.

When developing a distributed mobile robotics system, for example in a laboratory, it is desirable to conduct large scale experiments in collective robotics, so that features such as swarming and self-organisation can be investigated. Ideally, such experiments should be conducted using about fifty robots, or more.

However, laboratory experiments are limited by the physical size of the robots themselves. Existing robots which are capable of operating in a wireless local area network (L-AN) are approximately 30cm (twelve

inches) in diameter. This means that laboratory experiments are constrained to a relatively small population or robots, being typically between twelve to for for even a large sized laboratory. Carrying out experiments with greater numbers of robots, for example fifty, would require extremely large laboratories, which would therefore be impractical.

To allow experiments to be carried out with large populations of robots, each robot must be made as small as possible. miniature robots themselves are known, the physical constraints placed on available processing space means that known miniature robots do not have wireless networking capabilities, and are generally not intelligent enough to take part in experiments relating to distributed mobile robotics.

The miniaturisation of a robot is constrained by a number of factors. For example, a robot requires a plurality of wheels to enable it to move from one location to another. Some form of steering mechanism is also needed to enable the direction of the robot to be controlled. A robot also requires some form of power source, such as a battery, for supplying power : : o the drive mechanism of the robot. All these elements act against the miniaturisation process.

For example, ideally the size of the battery should be as small as possible. However, reducing the size of the battery also reduces its capacity, which means that it must be replaced, or recharged more often.

The aim of the present invention is to provide miniature robot which is physically small enough to

allow large scale distributed mobile robotic experiments to be conducted in a laboratory environment, yeu having the processing capabilities which allow it to function in a wireless distributed mobile robctics system, and without having the disadvantages mentioned above.

The robot or the present invention is also suited for many other applications which require miniature robots. As indicated above, these include cooperative <BR> <BR> <BR> robotics, or industrial applications such as cleaning or inspecting machinery, environmental applications such as monitoring gases, military applications such as mine clearance, commercial applications such as vac or communication applications such as mobile web-sites or telecommunication applications.

Summarv of the Invention According to a first aspect of the invention, there is provided a robot as defined in the claims hereof.

According to another aspect of the invention, there is provided a development system for conducti distributed mobile robotic experiments.

According to yet another aspect of the invention, there is provided a method of conducting distributed mobile robotic experiments.

Brief Description of the drawings For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference be made, by way of example, to the accompanying drawings, in which :- Figure 1 shows a robot according to a preferred embodiment of the present

Figure 2 shows a underside view of the robot of Figure 1.

Detailed description cf a-preferred embodiment of the 'present invention.

Figure 1 shows a miniature robot 1 according to a preferred embodiment or the present invention. The robot 1 comprises a chassis 3, which houses a vertically mounted control box E. The control box 5 contains the control electronics required for controlling the operation of the robot 1.

The underside of the chassis 3 houses two drive wheels 7, each drive wheel having an associated motor/gearbox assembly 9, as shown in Figure 2. The chassis 3 also houses a set of brushes 11, which act to stabilise the robot, and maintain it in its upright position.

Figure 2 shows an underside view of the robot of Figure 1. Each wheel 7 is driven by a respective motcr/gearbox assembly 9. The provision of an independent motor/gearbox assembly 9 for each wheel 7 enables the direction of the robot 1 to be controlled.

A plurality of batteries 13 are provided for powering the motors 9, and are preferably evenly distributed in the chassis 3 so that the robot 1 is evenly balanced.

The brushes 11 mounted in chassis 3 are sufficiently stiff so as to maintain the robct'in its upright position, yet sufficiently flexible horizontally to allow the robot 1 to turn under the power of the wheels 7, with negligible resistance from

the brushes 11. In this way, the need for castors or trailing wheels associated with conventional robots is avoided. The horizontal flexibility of the brushes also allows acceleration and braking of the robot.

In Figure 2, the robot is shown having two pairs of brushes ; 1, each opposite sides of the axis of the wheels, and also being equally spaced from the axis.

However, the arrangement of the brushes 11, or other supports, can be chosen to suit any particular application. For example, the front of the robot may have a different arrangement to that of the back of the robot. A number of different variables may be considered when choosing the arrangement of the supports. These include the actual number of supports, the horizontal and vertical stiffness of the individual supports and the position of the supports in location to the axis of the wheels.

For example, a plurality of supports, each having a relatively low stiffness, may be chosen as an alternative to a smaller number of supports, each having a higher stiffness.

Also, the choice of stiffness can vary depending on distance between the support and the axis of the wheels. The further the support is located away from the axis, the greater the vertical stiffness needed to support the robot, but the lower the horizontal stiffness needed to produce the required turning moment.

All these factors enable the arrangement cf

supports to be chosen to suit the particular application, or acceleration/braking requirements, turning requirements, and so on. Examples include a robot having two supports on one side, and a single support on the other. In such an embodiment, the stiffness of each support can vary, such that the single support may have a stiffness which is equivalent to the combined stiffness of the pair of supports located on the opposite side.

Moreover, in Figure 2, the brushes 11 are made from an electrically conductive material, which allows the brushes 11 to collect DC power from a powered floor, as will be described below. For example, the brushes can advantageously be formed from individual bristles made of a copper alloy or copper coated steel.

The number of bristles must be chosen to give the vertical stiffness required to support the weight of the robot, while allowing sufficient horizontal flexibility as described above.

The powered floor can advantageously consist of conducting strips, alternately connected to positive and negative voltage sides of a DC power supply. 3y choosing strip widths which are suitable for the dimensions of the robot, and by providing a diode bridge in the-robot, power can be collected by the conducting brushes 11, regardless of the orientation of the robot.

To prevent the brushes from electrically shorting, the chassis 3 is made from an insulating material, for example Delrin, which is a machinable, nylon-like insulating material. This aspect of the invention avoids the need for the batteries 13 to be replaced, or

removed for recharging, which is a major advantage in a highly populated distributed mobile robotics system.

The control electronics the control box contains a complete PC compatible micro controller, sufficiently powered to run an operating system such as Linux. The control electronics controls the power management, motor drive electronics and wireless communications. The Linux operating system includes full TCP/IP networking, including Telneu, FTP and Web servers, which enable the robot to operate as a node on a wireless IP network. It is therefore possible for the e robot @ to be controlled remotely from any PC or workstation with Internet connectivity.

The robot 1 may have a miniature magnet mounted within the inside walls of each drive wheel 7, having a corresponding Hall-effect sensor set into the chassis 3, close to the drive wheels 7, thereby enabling the control electronics to count drive wheel revolutions for closed loop or speed control. Alternatively, each motor 9 may be a stepped motor, _he robot being controlled by stepping each motcr through a predetermined number of revolutions.

The chassis 3 is preferably made as a single-piece machined chassis, with insets for the motor/gearbox assemblies 9, brushes 11 and batteries 13. The chassis 3 is preferably circular, and the miniaturisation techniques described above enable the diameter to be made less than 6cm.

The miniauure rcbou described above allows large scale experiments to be concucted-r. collective robotics to enable, for example, swarming or self-

organisation to be studied.

Although the preferred embodiment has been shown to have a plurality or batteries 13, it will be readily understood by a person skilled in the art that the invention may equally be used with just one battery 13.

Further, although the preferred embodiment has been shown to have four brushes 11, it will be readily understood by a person skilled in the art that the invention mav equally be used with just one pair of conductive brushes. Indeed, if the robot is to be supplied wich electrical power only from its battery or batteries, and is not pick up power from a powered floor, the wheels 7 can be mounted on an offset axle, and only one brush or other supporting member need be used.

Furthermore although the robots have been described mainly for use in conducting experiments in distributed mobile robotics, the robots may also used be used in other applications. For example, the brushes 11 may have inbuilt strain gauges to allow the roko_ to sense surface textures, cracks or flaws, allowing the robot 1 to be used in applications such as surface inspection, particularly in situations where larger robots are unable to access.

In addition, the robots described above are suited to other applications, such as cooperative robotics, or industrial applications such as cleaning or inspecting machinery, environmental applications such as monitoring gases, military applications such as mine clearance, commercial applications such as vacuuming, or communication applications such as mobile web-sites or telecommunication applications.