ServoCar Report

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For our project we decided to design a Car out of solid works and make it run using the servo motors that were used in the robot arm project with code written in MATLAB. First we designed the body of the car in SolidWorks. We went with a hollow shell with two cutouts in the back for the servo motors and two axle sized holes for the front wheel axle. We also added a cutout on the top of the car to give the E5 shield a place to rest during the demo. The hollowed out design saved a lot time in the printing process as we printed the car in 3x5x1 dimensions. Because of the servo motors design, they only travel about 180 degrees, obviously not enough to be able to drive a car. Therefore, we had to remove a mechanical and an electrical stop from the motors to allow for 360 degrees of motion. We did this by simply taking players and removing the mechanical stop and then cutting off the current resistor and soldering our own new one on. This new resistor allowed for the motor to move continuously in one direction without stops. We put in two resistors that made it that when we told the motor to get to a certain pulse count it would constantly move at that speed in that direction. This is how we wrote the code that made the different speeds possible for the forward and backwards motion in the demo. Depending on the orientation of the motors the closer to a pulse count of either 0 or 250 would be full speed forward and the inverse would be full speed backwards, while the closer to 125 the slower the motors go. Finally, we contracted the car and tested the design. We ran into a few problems in the construction, including the difficulty of attaching the front wheels to the axle, the misprint of the axle diameter and the struggle of attaching the motors to the car. Despite these hiccups, the project went very well and the demo was successful.