Testing

The following tests will be performed to ensure that the robot works as intended. There will also be acceptance tests performed on all electronic components purchased to ensure that they are functioning properly before being installed on the robot. Testing for the MET portion of this project consisted of a deflection test, a tensile test, and a speed test. These tests were performed to ensure that the material used for the chassis would match the theoretical values found in the analyses for the strength and durability of the material done Fall quarter. The speed test was performed to ensure that the robot would still be able to maintain a competitive speed after all other components had been fastened to the chassis and the robot was at its heaviest.

Due to proper planning and ample preparation there were no issues with testing for this project. The test samples were preparied and finished with the annealing process long before any testing started and the student made sure that a faculty member with access to the Instron software was avaliable when testing was to begin.

PHYSICAL TESTS

The tests that will be performed to ensue that the hardware functions as indented as well as provide a kind of "validation" tests for the analyses calculated fall quarter are as follows:

1) The robot will be weighed to ensure it is within the weight requirement for the competition.

2) A full start up and shut down sequence will be timed to ensure it is within regulation with the organizations rules.

3) A drop test of the chassis, ramp, dustpan, and weapon arm will be performed to ensure the components strength is as calculated in the analyses.

4) The drive train will be tested by placing to robot in-front of, and touching a 3 lb. weight and then powered to see if it can push the weight 3 feet within 30 seconds.

5) The self-righting ability will be tested by placing the robot on its back and then timing how long it takes for the robot to resume the proper orientation.

6) The skids max shear force will be tested via a destructive charpy test (multiple prints of the skids will be made to run multiple trials to ensure throughout data is collected).

7) A speed test will be performed to ensure that the robot can go the required 6 mph.

8) The robot will also undergo a stright line test to ensure that the chassis is balanced and secure.

Accaptance Tests

Multiple electronic parts are being purchased for the construction of the robot. To ensure that the sensors, motors, microchips, and all other electronics are properly working before being installed on the robot accaeptance testing will be performed on each component.

Acceptance testing will include, but not be limited to, using the following tools and methods:
1) An oscilloscope will be used to ensure proper voltage and amperage is flowing through each component.

2) A digital multi-meter will be used to ensure proper resistance and continuity for each part.

3) For the parts that will be programmed, they will be tested to ensure that their interface is working and that they can connect to the proper software for coding later.

4) The ultra sonic sensor will be tested via O-scope and program interface to ensure it is giving a proper reading at a designated distance.

5) The voltage sensor will be tested via O-scope and program interface to ensure it is giving a proper reading at various different voltages.

6) The amperage sensor will be tested via O-scope and program interface to ensure it is giving a proper reading at various different amperages.

7) The temperature sensor will be tested via O-scope and program interface to ensure it is giving a proper reading within a range of temperatures.

Figure T1 - Test sample #1 10 minutes after the deflection test was run. This sample was defelcted to a maximum on 0.48".

Deflection Test

The first test performed was a deflection test to analyze the flexibility and strength of the 3D filament used to manufacture most of the parts for the robot. It was decided to do this test because the given values for the filaments properties were provided by the company only for 100% infill. Since only 30% infill was utilized it was important to ensure that the filament still met the requirements placed in fall quarter of this project. Also it was important to ensure that the filament would hold up to the impact forced it was bound to face in a battle arena. It was known that in theory this filament would be substantially stronger than required, but theoretical calculations don't account for a multitude of factors that take effect in reality.

It was found that the material still far succeeded the strength requirements for this project and had the surprising property of almost completely recovering from the test 10 minutes later. All test samples were deflected to the point of permanent deformation occurring. Meaning that at a certain amount of force the samples started to buckle and break. It is easy to tell when this happens because the force reading on the machine will cease to increase and the reading will start to decrease slightly.

Figure T2 - The Instron 34SC-5 set up used to deflect the samples

Figure T3 - The graph created from the data gathered from the Instron software

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Figure T4 - This is a video of one of the deflection tests performed.

Figure T5 - All 5 test specimens after the tests were ran.

Tensile Test

The tensile test was the second test performed during spring quarter. This test was chosen to evaluate the 3D printed filament's properties in a different manner than the deflection test. This test was performed with the expressed intention to test the materials strength in the x-y axis.

The test was ran until each specimen snapped, or stretched 0.5". calculations where done before hand to determine the probable results for the test for comparison after data was collected. it was found that the samples should break under 280 lbf, it was found during testing that the weakest sample broke at 480 lbf. This far exceeded the calculations.

The Instron 34SC-5 was used to perform this test as well. As seen to the left, all the samples broke before reaching 0.5" of displacement. The graph shown in Figure T5 shows the stress strain curve of each specimen tested. The material is interesting in the sence that it has 2 different curves for its stress/strain. the first curve is shallow and flattens out very early on, then the second curve is much larger and continues until the sample snaps.

Figure T6 - The graph gathered from the Intron data for all of the samples.

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Figure T7 - This is a slow capture video of one of the tensile tests performed. Slow capture was used to analyze in what fashion the specimen broke.

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Figure T8 - A video of one of the speed test trials performed to gather data on the robots drive motor capabilities.

Speed Test

The speed test was performed by setting up a start line and finish line with a designated area so that the tests could be done with a running start. The speed of the robot was documented by using a speedometer on the students phone and affixing the phone to the robot chassis. Due to the fact that the students phone was on the robot, no photos were captured of this test.

The phone was set to screen record so that later analysis could be done on each of the runs to determine the highest speed achieved.

The test had 5 different runs recorded and analyzed to determine the average speed of the robot, it was found that the robot reached an average speed of 7.4 MPH. This is above the requirement of 6 MPH so the test was a success.

To the left (Figure T8) is a video of one of the runs for the robot, the steering can be difficult to control. This makes its extremely difficult to get a reading of the robots speed when the joystick is completely pushed forward. There is a moment at the end where this is achieved and it is clearly evident in the video.

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