Testing
All requirements, designs, and analyses were in preparation to have a completive edge in the RC Baja. There will be three parts of the competition testing its speed, mobility, and capability. This is what inspired the requirements that were stated in the project report. For preparation of the Baja, the vehicle will be tested before the competition described as requirements. This will be what the design and analyses are based on for the duration of the project.
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Some requirements for buckling and defection were to ensure that the vehicle had the durability to survive the duration of the testing and compete in the Baja race. The vehicle will have a requirement of a turn radius of 10 inches preparing it for the slalom portion of the competition. As the vehicle will need to be able to weave in and out of a series of cones providing a small turn radius will be beneficial to the race.
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Additional requirements prepare the vehicle for the sprint portion of the race. Requiring the vehicle to have the ability to drive in a straight line. One has a straight-line deviation test and the other has the requirement for alignment within the tires. This was a problem with most vehicles in the 2023 Baja Competition. The RC car will also be tested to prepare the vehicle with a good start, by requiring that when a sudden increase in throttle is applied the vehicle does not wheelie. All requirements and test perimeters will be numerically defined within the project report.
Dropped Test
- Testing Procedure
The drop test was to measure and record the drop height from which the device could be dropped before compressing the springs 1 inch. As per requirements 1D-9, when the device is dropped from 3 feet the springs cannot compress any more than 1 inch. Using the 3D measuring tool shown in Figure 02 and a slow-motion camera. Then dropping the vehicle at varying heights as shown in Figure 01. Data can be collected at 1/16th of an inch accuracy. Figure 03 and Table 01, shows the data collected in the testing.
Figure 01: Testing Setup
Figure 02: Measuring Tool Attached to Suspension.
- Testing Results
Figure 03: Collected Data
Table 01: Raw Collected Data
Video 01: 6 in. Drop Test
Video 03: 3 Ft. Drop Test
Video 02: 6 in. Close Up Drop Test
The vehicle only reached 18 inches before the springs compressed 1 inch. 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 rating or just buy higher quality suspension. Or an alternative could be to attempt to cut weight as this would lighten the impact force of the vehicle, putting less force on the springs.
Turn Radius Test
- Testing Procedure
The turn radius test is to measure and record the turning capabilities of the device, as this would play a factor in the slalom portion of the competition. Per requirements 1D-3, the vehicle must be able to turn 180° in a 10-inch radius. Simple tools were used to collect the turn radius abilities of the RC car. As seen in Figure 04 a T-shape was made using masking tape. The vehicle was then lined up two the tape. Then turn the RC car until it becomes parallel with the original starting point. Then measuring the turning diameter of the turn, as seen in Figure 05.
Figure 04: Testing Setup
Figure 05: Measuring Turn Diameter
- Testing Results
Figure 06: Collected Data
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.
Wishbone Buckling Test
- Testing Procedure
The wishbone buckling test is to measure and record the amount of force the wishbones can take from an axial load. Impacts from spin-outs and crashes could cause these components to break in competition. Using the Instron will give a measurement of displacement to the force applied to a 0.0001-inch and pound load accuracy. Per requirement 1D-11, the wishbones are not to buckle under a 75 pound axial load. A fail requirement of 0.10 inches or success requirement of 75 pounds was made so no damage came to the wishbones.
Figure 07: Testing Setup
Figure 08: 3D Printed Collars
These 3D printed collars were designed and made so when applying a load to the wishbones. It would keep them for rolling, as the ends of the wishbones were rounded. Proving quite useful as there was no slippage during testing.
- Testing Results
Figure 09: Upper Front Wishbone Results
Figure 10: Lower Front Wishbone Results
Figure 11: Upper Rear Wishbone Results
Figure 12: Lower Rear Wishbone Results
