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Requirements
As with any projects, a set of requirements need to be met. Below
lists the set of requirements we set out for our robot.
The minimum speed the robot must be fast enough to completely traverse the maze in about 2 minutes. This is a relaxed constraint, as we do not expect to have much difficulty in propelling the robot. We will be able to satisfy this requirement by making use of an algorithm that efficiently traverses the maze.
In order for the robot to traverse the maze and locate the candle, the robot must be able to recognize its position in the maze. We intend to use a "half reckoning", where the robot's path is specified by using landmarks in the maze such as the presence or absence of walls. Distances will not be a part of this algorithm, instead the algorithm knows the maze ahead of time and guides the robot through a series of way points.
The processor used will be a digital processor. Our first choice of processor is called an OOPic (Object Oriented Programmable Integrated Circuit). This processor has the ability to execute basic computer instructions and simulate actual hardware components, similar to an EPLD. The processor is programmed via a Visual Basic like language, where virtual hardware objects can be created just like data objects. The OOPic virtual hardware objects provide PWM generators, A/D converters, OP-amps and basic digital logic components. Some of the functionality we require can be implemented using the OOPic's virtual hardware, which will run in parallel with the navigation instructions.
The drive motors must be powerful enough to move the robot. We will be using Lego motors provided by the Mindstorm kits for the robot drive. We require three motors, two for maze traversal and an additional motor for discharging fire suppressant.
The electrical power requirements will not be outrageous, the motors we intend to use will be geared down and therefore do not require excessive currents. The processor will be supplied by a 9-volt battery and regulated internally.
The steering for the robot will be based on differential drive. The robot has two main driving wheels that may be independently controlled. Independently controlling the wheel speed and direction of rotation will move the robot in any direction desired.
Due to limitations on the overall cost of the robot, we have been forced to choose low cost sensors. We will improve the effectiveness of the sensors by filtering and level detection techniques implemented partially in software.
In order to promote system flexibility, software will be used in control applications. This would include navigation control, sensor switching and motor control. Hardware will be used only where it is required.
The maze will present some challenges to the robot's navigation system. So far, the largest challenges seem to be floating rooms and knowing when the robot has entered a room. The floating room problem is addressed by the algorithm itself. The algorithm follows a preset path and part of this path will drive the robot to the floating room. This works because we know what the maze will be ahead of time. The algorithm will be able to inform the robot when it is in a room. From there appropriate fire detection can take place.
The robot will not be adaptable to the maze layout. As that is predefined by the algorithm. However, we hope to implement some adaptable sensor techniques that can account for infrared light interference.
Debugging the robot system will be made much simpler by having basic system blocks display errors and it's modes. This can be displayed by means of LED's on the robot.
The robot's physical design needs to be modular so that faulty components can be swapped out with ease.
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of Operation
Last Modified: Feb 14, 2000
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