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Elevator Control

Monday, February 3, 2020

Lots of system integration progress this week! The project is starting to all come together. Flyn (our elevating battery handler) is mounted on its vertical v-slot extrude rails now, likely for good. With the electronics driving the stepper motors coming together on the platform below, we were able to clamp Flyn to the tensioned timing belts and run the whole subsystem for the first time. Check it out:

Precise and high-speed elevator control.

The great news here is that this validates all of our theoretical calculations. Elevator torque, belt strength, and elevation speed are well within our targeted values, even after plugging in a large factor of safety. The elevator is designed to accelerate and decelerate over an interval to reduce peak torque and avoid placing undue stress that could wear out the mechanism. This also has the effect of mitigating current spikes on the 24V supply rail, which is a nice added safety bonus.

Flyn's cable track is also now attached. Linking Flyn with a point halfway up the frame, this device snakes and bends to keep wires attached to the moving carriage. Eventually, it will hold a total of four wires: two for power (+12V and ground) and two for data (specifically, a CAN bus).

Flyn mounted on its rails. Flyn mounted on its rails.

The electronics assembly at the base of the tower deserves some attention, too. All the PCBs are mounted to a custom-designed, 3D-printed mount that keeps everything organized and insulates the electronics from the metal baseplate. The accuracy here is very good, and this really helps to keep the assembly modular, which makes it easy to work with.

Electronics setup for the controls for the elevator and stepper motors. Electronics setup for the controls for the elevator and stepper motors.

That's all for now! We have some really exciting end-to-end tests in the pipeline, but those videos will have to wait until next week.