Spinoza is being built as part of a long-term project intended to develop a new approach to the specification, design and implementation of robotic systems. We will describe the elements of the system architecture that appeared in several of these robotic systems.
The UBC Vision Engine[13] is a general-purpose vision system that consists of multiple architectures: pipelined (a Datacube MaxVideo200) image processor and a MIMD multicomputer (20 T800 2MB Transputers, connected via a crossbar). These are connected by a bidirectional video-rate interface. The Vision Engine has been used in a range of visually-guide robots, such as an eye-head system: a pair of cameras on a pointable platform[15]. The eye-head follows a moving object, with no knowledge of its target, using dense optical flow input computed on the MaxVideo200. The Transputer system processes the flow data and controls the eye-head platform for vergence, pan and tilt.
Figure 2: Dynamites: soccer playing robots
Another predecessor to Spinoza was the Dynamite testbed, shown in Figure 2. The Dynamite testbed is a collection of independently controlled mobile robot vehicles that play soccer [3,16]. It has been used to explore novel reactive strategies for control[19] as well as for ideas on control, specification, and reasoning about real-time systems[20]. The system demonstrates offboard vision processing and distributed computation. The vision component was originally prototyped on the MaxVideo200 in the Vision Engine with the control programs running on the Transputers. Currently the system is realized as simple custom hardware to process RGB signals, followed by run-length encoding and centroid calculation on Transputers. A single offboard camera sensor communicates its signals to the centralized sensor processor. The sensor processor provides positional information to the control processes for each competing soccer player at 60Hz (once per image field) with a lag of at most 5 ms after the end of field. The structure of the full system is shown in Fig. 3. Four robots can be controlled concurrently.
Figure 3: Dynamite Architecture
The ``remote brain'' idea, offboard visual processing, was used for soccer players because of size/weight limitations, and for our initial work with Spinoza: ROLL, (Real-time Onboard Localization with Landmarks) identifies its position in real-time, using passive visual localization of a single landmark[14]. ROLL used a set of TI C40 DSPs and transmitters to support offboard visual processing.