After I built a RC plane, I was attempting to implement a computer vision system for the plane to be able to identify objects and carry out an action. After thinking it through, I felt that it would be too difficult, risky, and expensive to prototype this system on an aircraft.

Because of this downfall of the aircraft vehicle type, I decided to transfer the electronics to a RC vehicle instead.

This vehicle would be all terrain, solar powered, utilize a gear box, implement computer vision, and be mostly 3D printed.

From these design criteria came the product detailed in this page.

The chassis was made from scrap wood from an old project with aluminum axles mounted using 3D printed hardware.

Wood was selected as the frame of the vehicle was meant to be large in order to house the solar panel, gear boxes, control systems, solar inverter, and batteries.

The wood was left unsealed. If the rover finds a use being outdoors for a long time, effort would be needed for weatherproofing the chassis and electronic components

I choose to use the brushless DC motors from the RC plane to power this vehicle. Since these are typically designed for low torque, high speed applications, a gear box was needed to convert the speed to torque.

The gear box was produced using 3D printed gears with pressed in bearings mounted on short aluminum shafts. The motors were mounted directly on one side of the gear box and the drive wheels were directly driven from the output of the gear box. The ratio is approximately 55:1 and this provides sufficient torque and speed.

If this were to be redesigned, using shafts with higher tolerances would be a good start. A lot of energy is wasted from slight differences between the bearing and shaft diameters. Additionally, the gears are spinning at a low enough speed that bushings would make a suitable replacement for the bearding in order to save weight, size, and cost.

A tread drive system was selected for this vehicle for a few reasons. Practically, treads allow an off road vehicle to clear difficult obstacles and multiple terrain surfaces.

On a more exploratory note, I had never done a design using treads and I was interested to try this method on a low risk prototype. Additionally, my 3D printer was recently upgraded to print flexible materials and stress testing its ability to do so by printing treads was an interesting challenge.

The inner lugs that mesh the tread to the gears is modeled after standard high speed v belt pulleys.

The rover was intended to power itself in long term missions using the solar panel mounted to the top of the vehicle. The solar panel is 20W and capable of powering the vehicle on long duration, low distance missions.

For short missions, the vehicle runs on LiPo batteries. This allows for high density power storage that can supply the motors with full current and leaves the solar panel available to power larger electronic devices.

Currently, the rover is fitted with a Raspberry Pi B4 that runs a facial detection script written in openCV in Python. The Pi reads an image from the camera, identifies the people in that image, and navigates the rover to the nearest person. In this "Dog Mode", the rover does not add much value to a problem solving device, but demonstrates the ability of the rover