Individual Blog Week 4 (6/19 - 6/23)

During this week, I was able to get a lot more of the test rig finished. However, I am starting to have problems with the steering aspect of the bogie. When introducing the magnet to the hall-effect sensor, and going through the expected logic of the entire path, the interrupt activates and the code works fine, when having the right side switches be the ones that are initially pressed. When the left side switches are the ones that are initially pressed, the steering motion occurs regardless of having a magnet be introduced even though the latter is a specifically required condition to introduce steering. Despite this, one way that we have allowed the bogie to differentiate the direction to turn is by introducing a counter that begins every time the hall-effect sensor gets activated. This variable is then taken through a modulo two operation (% 2 ), which allows us to differentiate the turn to take due to the introduction of two new conditions, when the new variable is one, and when the new variable is two.

As for the braking portion of the bogie, I have begun designing a vice-like clamping system that pulls two teeth together to bite down onto the rail. These two teeth will have brake pads attached, and the entire system will utilize a stepper motor with a pulley attachment to create the tension required. Highly capable cables will be required, and I plan to utilize mechanical bike brake cables, as they are able to stop a 250 lbf system reliably. I will finish design, and order parts next week.


Figure 1. Utilizing the modulo operation to create a new condition for steering


Figure 2. The counter that activates every time the magnet is detected.  

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