Matt Obradovic
SE 423 Final Project
This project implements wall following on three-wheeled car. Two range-finding IR sensors are used for the wall following. Two of the three wheels are motorized with encoders. Their velocities are regulated by closed loop P.I. Control. The IR sensors have an analog output between 0 and 3 volts. The IR sensors are connected to two of the ADCs on the TI launchpad.
Because there are only 2 IR sensors the robot only performs right wall-following. The wall-following algorithm utilizes a state machine with two states. The states are WALL_FOLLOWING and LEFT_TURN. WALL_FOLLOWING is the default state. In the wall-following state, a P.I.D controller is steers the robot so that the distance from the right-facing IR sensor to the wall is constant. When the front facing IR sensor detects a wall in front of the robot, the state machine enters the LEFT_TURN state. In the LEFT_TURN state, the robot will turn with a constant velocity until the front facing IR sensor sees no wall in front of the robot and the right-facing IR sensor sees a wall to the right of the robot. While the state machine is in the WALL_FOLLOWING state it is able to make right turns meaning that the robot can make both left and right turns.
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