Alternate Solutions Abstract

Propulsion

The main difference between Alternate Solution 1 and Alternate Solution 2 is the method of propulsion.  Alternate Solution 1 utilizes a propulsion system with wheels.  Alternate Solution 2 utilizes a propulsion system with tracks.  There are for the most part, two schools of thought on how a vehicle should move on dunes. 

The first says that thin tires (“tires” refers to anything that will come into contact with the ground and moves the vehicle over that ground.  Can be either regular tires or tracks) have less surface area that touches the ground and therefore, creates less damage to the environment upon which it treads.  The second school of thought says that the tires should be as wide as possible to reduce the amount of pressure applied on the ground.  Obviously, wider tires have more surface area and therefore would cause less pressure.  Both of these theories have their pros and cons and neither has been declared a specific “victor” over the other as to which is better.  Part of that has to do with the fact that different environments are going to require different modes of movement.

Also, the construction of the two designs differs mainly in the number of motors required.  If tires are used, only one motor is required.  This can be seen in both the orthographic and isometric drawings.  One motor will power the back set of wheels and the front set of wheels will be connected to a servo and will only be used for steering.  This is similar to a conventional automobile layout.  Also, the tires will have an axle that is angled downward from the main body via a universal joint.  A universal joint allows two straight rods to connect and form angles while still being able to spin.  This will allow the axles to move up and down (cushioned by the shock absorbers) and still keep the tires rotating. 

However, tracks are different.  While one motor would allow the vehicle to move back and forth, any turning would be impossible.  So, tracks require that two motors are used, one connected to each side of the vehicle.  This way, both motors can work in unison to move backward and forward; to turn left and right, the motors turn in opposite directions and cause the vehicle to pivot and point itself in the new direction of travel.  At this point without having the Vex Robotics kit, I am not sure what having two motors would do in terms of wiring.  I believe that both motors could connect to one receiver and then a double stick controller could be used.   However, I am not positive.  I am also unsure as to whether one battery would be sufficient to power two motors for a sustainable time period.  Either way, this design with tracks definitely requires two motors and possibly some additional parts, meaning this design will also weigh more than the design with regular tires. 

Electrical Component and Body

We will be using the Vex Robotics Kit for this project.  In terms of the wiring and the body of the vehicle, everything will come from the kit.  The body, as shown in the drawings, will be a basic rectangular frame simply to allow things to be attached to the vehicle while keeping the weight of the vehicle to a minimum.  For the electrical aspect, all components plug into one another and come so that they are easy to connect.  It would not be practical for me to construct a wiring system from scratch or design a new wiring system because wiring systems are available for purchase.  In addition, the system is so simple that it would be a waste of my resources to build a new one.