Idea Screening
Individually, each team member came up with three course strategies, three chassis and drivetrain combinations, and three mechanisms for completing each task. After forming the company on January 31, they discussed and compared their individual ideas. First, they listed all of their brainstormed ideas, starting with the concepts previously generated individually. During the conversation, the individual ideas led to additional combinations and extensions of ideas, which they also listed. Next, they screened the top ideas for each chassis and drivetrain combination and for several mechanisms. Each idea was rated on its ability to meet certain criteria, such as speed, cost, and durability. They used a screening matrix that compared each idea to an average reference, with a “+” representing better performance than the reference, a “-” representing worse performance than the reference, and a “0” suggesting average performance. The company totaled the “+”s, “-”s, and “0”s, and determined the net score of each idea to decide which concepts to proceed with. This was completed with at least four ideas for the chassis and drivetrain, the car jack mechanism, the fuel crank mechanism, and the wrench mechanism.
Chassis and Drivetrain
The discussion regarding the chassis and drivetrain centered around wheel orientation. The team came up with five chassis and drivetrain options: four powered wheels, two powered and two unpowered wheels, a circular wheel layout, two powered wheels and a chain attached to two wheels, or two robots each with a triangular frame. Specific motors and chassis materials were not a priority at the time of the discussion. As a result of the screening, the team chose to proceed with four powered wheels, two powered wheels and two unpowered wheels, and a circular wheel layout.
Car Jack Mechanism
The team came up with four ideas for the car jack mechanism: a sloped front to run into the jack, a lever to lift it, an arm to clamp onto and lift the jack, or a rod on a gear that could be turned upwards to toggle the jack. Since the jack could be toggled with relative ease, the team focused on simplicity when screening the ideas. As a result of the screening, the team proceeded with a sloped front or a lever.
Buttons
The team brainstormed four ideas for pressing buttons on the control panel: using a narrow part on the robot to poke buttons with, adding a plate that extends out of the robot to press buttons, attaching three rods to the robot, and pushing two of them forward to press the white RPS button and the specified test button, or simply running into the buttons with the front of the robot.
The team also brainstormed five ideas for pressing the final button to recharge the robot: driving into the button with the chassis, driving into it with a slanted sled, poking the button with mechanisms used for other tasks such as a rod or a gear, constructing an arm to slap the button from the upper level, or adding a plate that extends from the robot to press the button. Since the button mechanisms largely use mechanisms from other tasks, the ideas were not screened using a matrix.
Fuel Crank
The team came up with four mechanisms for rotating the fuel crank: a rod on a gear that is capable of rotating, a rotating disk that aligns with the crank, an arm that moves up and down to spin the crank, or two rods on opposite sides of the gear. The team proceeded with the rod on a gear and the rotating disk after screening the ideas.
Wrench
The Speed D8ers brainstormed four mechanisms for controlling and depositing the wrench: an arm that slides through the hole of the wrench and turns or lifts to pick it up, a forklift, a rod with a stopper that pokes through the hole and drags the wrench to the garage, and an arm with clamping ability to grab the wrench. In each scenario, the wrench would be deposited by simply pushing in the garage door and allowing the wrench to drop when caught of the base of the garage. The team proceeded with all of the ideas except for the arm with a clamp due to its cost and inefficiency.
Concept Scoring
Next, the Speed D8ers took the top ideas produced from each of the screening matrices and produced three combinations for a full robot layout. These combinations became the company’s preliminary ideas for the robot layout.
The team used a concept scoring matrix to rate each combination on its ability to meet specified criteria. In the concept scoring matrix, each combination was given a score from 1-5 for each criteria and compared to a reference concept, which received an average score of 3. Each criteria was weighted, so the importance of each requirement was reflected in each concept’s score. For example, the company determined that maneuverability was the most important criteria, so it was 25% of the total score while less prominent criteria were a smaller percentage. The weighted score for each criteria was calculated by multiplying its rating (on a scale from 1-5) by the criteria’s percentage of the total score. Then, the team added the weighted scores to give each combination a total score. Finally, they sketched each robot concept, and weighed the pros and cons of each. Then, the team produced a physical and CAD mockup of their top idea while considering the practicality of the preliminary concepts and making adjustments.
The three combinations are detailed on the following pages: Combo A, Combo B, Combo C.