Forty foot linear motion, bidirectional
My company is interested in building a prototype system for measuring soil stability by running various tires (atv thru semi size) across prepared soil beds. Putting it in a 40 foot shipping container allows particulates to be measured and is wind and precipitation independent; but it limits the space available. My idea is to lay down two tracks that carry a wheeled cart. The tire under test will be mounted to the cart via a pivoting arm; load will be controlled by adding weights to the arm. The assembly will weigh about 1200 pounds. The cart and test tire need to be driven independently, probably using electric motors. At times the tire will be driving, braking, or free wheeling across the soil bed.
The goal is to accelerate in about 12 feet, hold a constant speed for 12 feet and then decelerate in 12 ft. Top speed is 10 mph. My concerns are what type of guide rails to use so the cart will be stable underway and what type of drive to use on the cart wheels. A friction traction drive would be simplest and 2 or 4 of the wheels can be powered. If I get information on friction coefficients it should indicate if that is practical. Cable could be used to move the cart, but that seems more complicated since it would require one on each end (to accelerate and retard motion). It will require multiple passes so controlled motion in each direction is desireable.
Has anyone seen anything similar or have any suggestions on rails, cart, and drive type? If possible the design should provide for future growth in length and speed.