Quarter Scale Tractor Design
Scott Dick, Garrett Dollins, Logan Gary
Each year ASABE holds the international quarter scale tractor student design competition in Peoria, Illinois. This competition is designed to give students an opportunity to take a project from concept to finished product. The competition is made up of several parts. Each portion is assigned a maximum possible point value.
Design Judging is an interactive portion of the competition where teams present their design’s attributes in the particular category to the panel of judges. The judges may then ask questions for further details or provide comments for development of the team’s next model. The design judging portion is made up of the following six categories; manufacturability, serviceability, ergonomics, safety, test and development, and sound judging. Each category is worth 70 points and are judged by professional engineers, technicians, or operators from industry.
Technical inspection is the pass or fail portion of the competition. All teams are required to pass a full technical inspection prior to participating in practice pulls or competing in any Performance Competition. This process is broken into two independent portions: Initial Weigh-in and a Detailed Technical Inspection. Technical inspection verifies compliance with the rules set forth by the competition committee. Operator safety and weight limit are the main focus of this inspection. The initial weigh-in will receive a 100 point bonus for starting and operating under its own power, having all shielding in place as best as possible, being on time to the scheduled tech time slot, and completing the inspection in under 24 hours from the end of the assigned time slot.
The pull performance event is comprised of a multi-stage tractor pull using a progressive sled. Points are gained by the number of feet the sled is pulled by the respective tractor. Each team will be allowed one scored pull in three separate heats.
The Maneuverability Course Event is held to encourage consideration for maneuverability in tractor design. The team(s) with the lowest number of overall ‘course demarcations’ will receive a maximum of 100 points (course demarcations indicate number of direction changes, distance traveled, and number of collisions with cones).
The Durability Event is conducted on an oval course setup on the pulling track that consists of bumps and loose sand. The bumps are no taller than 2.5 inches and set up in a random array to be determined at competition. The loose sand has a depth of approximately 6 inches. Teams will be required to tow a 4-wheel cart weighing up to 2000 lbs (with approximately 0% tongue weight) through the entire course. The cart attaches to the rear hitch of the tractor. Laps are 250 +/- 50 feet in length.
Points allotted to teams for sound level are based on the sound decibel level recorded during the team’s first attempt in the sound level Tech Inspection station. The team with the lowest value below the required 91 decibel will receive the full 70 points. Other teams will receive points on a scale from 91 decibel to the lowest level, with allowed points weighted more heavily toward the lowest decibel value (i.e. this will not be a linear scale). No points will be awarded if the sound technical inspection is not passed during the first attempt.
To design and build a cost effective, reliable, and innovative frame, steering system, and suspension system for the Oklahoma State University Quarter Scale tractor team. The design will take into account the team’s budget, timeline, and resources for the 2016-2017 competition.
Scope of Work
The proposed project redesigns the main frame, support structures, suspension, and steering of the ¼ scale pulling tractor for the 2017 international competition. The basis of the project is to increase competitiveness of the tractor by increasing functionality of the frame, suspension, and steering. This is achieved by providing a product that makes use of CAD programs to model and test the product. By doing so, the design will have the added benefit of a seamless assembly while optimizing the use of materials required for the product.