CWU RC Baja: Suspension and Steering
Introduction
The RC Baja Competition is an ASME competition that many colleges partake in. The competition consists of three challenges the sprint, slalom, and a Baja course. With the sprint, vehicles are to be tested in their speed, having them race down a specified distance in the best time possible. The slalom tests the turn capabilities of the vehicle in that a set of cones will be set up so that the vehicle will have to weave in and out in the most efficient manner. The Baja is the main event where the competitors will have to go head-to-head and will have to converse a rough terrain putting the vehicle’s durability and design to the test.
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This gives the engineers the task to not only make the best handling and fastest vehicle but also a vehicle that can survive a multitude of tests and rough terrain. Resulting in tests having to be made on the components' ability to handle forces from different directions. While also having to apply the learnings of statics, mechanics of material, and physics to practice. Taking additional research and some brainstorming design ideas to produce the winning vehicle.
3D Model
Full 3D Model
Sketch Up of Suspension System
Alternate Design
Front Suspension
Rear Suspension
The Constructed RC Car
RC Car Mid Jump
Stair Jump
ISO View of RC Car
360 View
Zero Point Turn
Testing Results
RC Baja Competition
Between the 3 competitions, the team took 3rd overall. Due to some operating error, the car crashed. Breaking the motor mount, hurting the team in the Baja course. Overall, the competition was a success, showing that the vehicle had one of the strongest speed and turning capabilities in the competition. Possibly winning the competition if components were able to stay intact. Below shows the placement in each competition.
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1st – Drag Race
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2nd – Slalom
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3rd – Baja Course
Dropped Test
Shown in Figure 1 is a chart representing the data collected from the drop test. The y-axis represents the amount of the springs compressed. While the x-axis shows the height at which the vehicle was dropped. The red horizontal line represents where the 1-inch spring compression requirement is. The data collected showed that the springs compress 1 inch at an 18-inch drop height. This is 50% less than the requirement stated in 1D-9. To get closer to the 3 feet, some additional springs could be purchased with increased spring ratings or lighten the weight of the car.
Figure 01: Collected Data Drop Test
Table 01: Raw Collected Data Drop Test
Turn Radius Test
Shown in Figure 4 is a bar graph representing 5 trails and an average for both turning left and right. The results showed that the vehicle could turn to the right at a turning radius of 11 inches while having a 22-inch turn radius to the left. This is nearly meeting requirements 1D-3 when turning to the right but doubles it to the left. Some theories for the issue are due to the tie rods binding in some unknown places. Or when zeroing the 90-degree servo it's causing limitations to the side it had to zero from. An additional servo will be purchased with 180-degree turning capabilities while doing some further inspections for any binding.
Figure 01: Collected Data Turn Radius
Presentation
