Mini Robot BeBot


Mobile robots are getting more attractive, especially the small and resource-efficient ones, as they do not need special laboratory infrastructures. Another requirement for such platforms is the reasonable price and ease for programming. Additionally, they should provide enough computation power for supporting the implementation and the porting of software to other platforms. This is the reason for the development of our BeBot mini-robot.


The BeBot mini robot


The BeBot mini robot has a dimension of about 9cm x 9cm and is approximately 7cm high (See Figure 1). The chassis of the robot is developed with the MID (molded interconnect device) technology, which enables the on-surface circuitry.

The BeBot has a modular architecture consisting of three layers (see Fig. 2). At the bottom we can find two microcontrollers, each is used for processing the left and right arrays of infra-red sensors. The processed sensor data is transferred over I2C bus to the other processors. The chain-drive along with 2W DC motors, each of which is coupled by an incremental encoder, enables a robust movement even on rough surfaces. In the middle, the baseboard provides basic functionality, such as motor control and power supply. This board comes with an ARM 7-based microcontroller. It is also equipped with a 3-axis accelerometer, a gyroscope, and a battery-monitoring sensor. The third module on top, called as Expansion module, provides a powerful computing hardware and a radio-based robot communication. The board comes with a 520MHz processor and a 64 MB memory and Flashcard. A FPGA (field programmable gate array) allows hardware reconfiguration. Three possible wireless communications, ZigBee, Bluetooth and WLAN are supported. Additionally, this module also provides different interfaces, e.g. USB, MMC / SD-Card, audio, LCD and camera.


Hardwarearchitecture of the BeBot


The software environment of the BeBot mini robot is a Linux operating system. It comes with drivers for the robot hardware. Additionally, BeBot also supports the Player/Stage programming framework, which offers a platform-independent and real/simulated robot programming. The framework consists of the Player client/server model and two robot simulators, the 2D Stage and the 3D Gazebo simulator. The Player provides a server and a library which is used to build the Player client.

A video of the BeBot camera
The BeBot in a simulated world using Stage robot simulator