Simulation of a dead reckoning embedded system security patrol robot for deployment inside structures and buildings

Abstract

Dead Reckoning (DR) is the process of estimating a robot's current position based upon a previously determined position, and advancing that position based upon known speed and direction over time. It is therefore a simple way for an autonomous mobile robot to navigation within a known environment such as a building where measurements have been taken and a predetermined route planned based upon which doors (or areas) the robot would have enough force to enter. Discussed here is the design of a DR navigation system in Altera's DSP Builder graphical design process. The wheel circumference to the step size of stepper motor used to drive the robot are related and so this ratio can be easily changed to easily accommodate changes to the physical design of a robot with minimal changes to the software. The robot calculates its position in relation to the DR map by means of the number of revolutions of the wheels via odometry, in this situation there is no assumed wheel slippage that would induce an accumulative error in the system overtime. The navigation works by using a series of counters, each corresponding to a measurement taken from the environment, and are controlled by a master counter to trigger the correct counter at the appropriate time given the position of robot in the DR map. Each counter has extra safeguards built into them on their enables and outputs to ensure they only count at the correct time and to avoid clashes within the system. The accuracy of the navigation is discussed after the virtual route is plotted in MATLAB as a visual record in addition to how feedback loops, identification of known objects (such as fire safety doors that it would navigate through), and visual object avoidance could later be added to augment the system. The advantages of such a system are that it has the potential to upload different DR maps so that the end robot for can be used in new environments easily.