Testing

Many tests were conducted to ensure that the the robot met the design requirements, that the analyses conducted for the robot were accurate, and to evaluate how effective the robot could be before it got put into a combat robot competition where it was finally evaluated on how well it did at being a combat robot. Tests included drive speed tests, weapon deflection test, and a test to see how long it took to replace components. These tests were conducted in a variety of ways, sometimes they were simple like measuring how long it took for the robot to move from one known location to another for the speed tests and other times they were a bit more complicated like the the deflection test which utilized special equipment to get accurate results. This data helped in evaluating whether design changes were necessary before the competition.

The tests did not always go smoothly. The speed test, which was anticipated to be the most simple test, actually turned out to be quite tricky because the robot was very fast and turning was very sensitive so getting accurate straight-line data was difficult. As can be seen in the Straight-Line Speed Test section, this was solved by adding a 4-foot wide lane to nullify tests that stray too far from the line and a running start to allow for the driver to gain some control before accelerating past the start line. These changes definitely had a positive impact on the test as close to 20 tests were nullified when the robot swerved too much off the line (or in some cases got completely turned around). The percent error was deemed to be acceptable given the challenges of this test.

For the first test, a straight-line speed test was conducted to determine the speed of the robot. This was essential because being able to outmaneuver an opponent is crucial in combat robotics and having more speed allows for the weapon to "bite" more into the other robot. The test was simple, the robot was to drive at its highest speed across a 10-foot long gap and the time it took to cross was recorded into 5 trials and averaged out into an average top speed. The robot was very fast and difficult to control so, to help with this, a 4-foot wide lane was established as well as a 10-foot section before the starting line that allowed for the robot to get a running start. If the robot exited the 4-foot wide lane the test was invalid and the robot had to try again until the 5 trials were met. In the end, the robot met an average speed of 6 mph which greatly exceeded the 2.5 mph requirement and was about 14% lower than the calculated 6.91 mph top speed. Since the top speed was so much higher than the requirement, less powerful motors were purchased when spare motors needed to be ordered and they were much more controllable and still fast.

Straight-Line Speed Test

Figure 1: Straight-Line Speed Test Track

Electronic Replacement Test

For the second test test, an electronic replacement test was conducted to determine the reparability of the robot. This was crucial because in combat robotics parts break all the time and there is little time to replace them so being able to swiftly replace any component was very important to the design of this robot. There were four electronic components in this test : the weapon motor, the weapon ESC, the drive motor, and the drive ESC (see figure 2 and 3 to see these components). There were some components that were obviously more tedious to replace than others so Instead of doing multiple trials for each electronic component, one trial was carried out for each component and the trial that took the longest got three more trials to get an average time. There were some inconsistencies in times for replacement that were unavoidable, the most notable case was how long it took for the ESCs to initialize after they were rewired and tested for functionality. If this test were to be improved, the time would stop after everything was wired and if the component did not pass the functionality test to see if they were wired correctly the time trial would have to be redone. In the end, the drive ESC took the longest to replace with an average time of 6 minutes and 40 seconds which was 19.18% higher than the predicted 5 minutes and 30 seconds, likely due to the ESC functionality test. Although the actual time was higher than the predicted time, it was 78% less than the 15 minute requirement so the results of this test were deemed acceptable.

Figure 2: Electrical Components Guide

Figure 3: Electrical Components Fully Assembled

Blade Deflection Test

For the third test test, a deflection test was conducted on the robot's weapon blade to ensure it would not deflect too much in a hit and cut the weapon belt. This was important because in if the blade deflected too much it would cut the belt and disable the weapon. This test also saw if the blade would permanently bend under this load which was important information. The setup for this test can be seen in figure 5. Ideally, this test would be carried out as a cantilever beam where the center of the blade was clamped and the opposite end of the blade was bent but there were not dyes available for such a test so a three-point bend was conducted. The test was simple and went smoothly with the Instron machine applying a 500 lb. load on the blade and reaction forces being applied at the blade tip and the center of the weapon. The full test can be seen in the video below (figure 4). In the end, the blade deflected 0.0441 inches under the 500 lb. load which was a 200% difference from the 0.000075 inch predicted value. The test value is more than acceptable, however. Figure 5 and 6 below show the before and after results of the test.

Figure 5: Blade Deflection Before Bend

Figure 6: Blade Deflection After Bend

Figure 4: Blade Deflection Before Bend