Integration Test with Mechanical Assembly

Once the battery, buck converter, and Arduino perf board were all tested separately, we combined all the components for a full integration test. This test closely replicated what was done previously in log book 4, accounting for both manual and automatic states. This allowed us to verify both the perfboard design, as well as the system integration code that will be used in the demo and symposium.

To start, we tested it with an isolated motor, to ensure that no damage to the mechanical system would be done. The power button was turned on, and manual deploy and retract was verified. Next, the automatic states were checked, using the software planning chart previously discussed in log book 1. Each use case was checked for the appropriate response by the motor. For example, if the bottom sensor was pressed, the motor should only move if the current leg position was retracted. Going through these use cases allowed us to find and fix issues with the code as well as gain confidence to test with the mechanical system.

An interrupt was added to the power button, to ensure the power would be shut off whenever the button was pressed. In addition, the IMU was de-scoped from the project. The pressure sensors were sufficient for detecting the crutch use cases described in log book 4. The IMU was to be used for verification, but the addition of it would drastically increase the prototype’s timeline.

Lastly, once everything was verified with the isolated motor, it was replaced with the mechanical system. We initially started with a very slow motor speed to ensure that we would be able to respond fast enough with the emergency stop button if anything was to go wrong. Once we could see that the limit switches were responding adequately and the retraction and deployment of legs was successful, we incrementally increased the motor speed. Thankfully, the system was able to successfully operate at varying speeds. As a bonus, the supporting legs seemed to move smoother as the speed increased!

Video - Legs retracting and deploying through perfboard integration testing