Saturday, September 7, 2013

More brake work!

Hi, I am Pepe Nacho. I am a freshman looking to major in Course 2, and I will be giving you an update on what goes on in the Electrical Vehicle Team (EVT). I just joined the team and I'm really looking forward to learning how to build things.

Today, we pretty much divided into two teams. I was on the team that worked on getting the regen system on the eBike working. The regen system is actually pretty cool, it extracts energy from the motor and uses that energy to charge the battery. In the process of extracting energy from the motor it acts as a mild brake (not a substitute for one though), so it comes in handy when going downhill or other situations where you want to slow down a bit. We first looked up the data sheet on the motor controller to find out how the regen system could be activated. It could either be activated by a switch or a throttle, but we decided to go with throttle (way more fun). Attaching the throttle was actually not as hard as I thought it would be. We had to rewire the throttle because the because its original wires were too small to be crimped. To get around that we spliced the throttle's wires with wires that were large enough to be crimped. Splicing is the process of connecting two wires. After we spliced the wires we added connectors and we connected it to the motor controller. We did not get a chance to test it just yet, but we will be testing soon! Videos coming along!

The other team designed and created a prototype to activate the brakes on the trailer. The first thing they had to decide on was what kind of system would be used: electrical or mechanical. To avoid adding extra batteries or actuators we went with an entirely mechanical design. You see, the trailer has two wheels, each with a brake on them. Most brakes on bicycles work with a lever, a cable, and the actual brake. To activate a bicycle's brakes, you usually pull on the lever, the lever in turn pulls the cable, and the cable then activate's the brakes. The team had to devise a way to pull two brakes with one lever. They ended up designing some mounting brackets for the brakes and we also started prototyping some pulling mechanisms to translate the cable lever pulling to the brakes contacting the tire.

rango mounting brakes!
design and meeting notes

half of lauren working under the bike

brake parts

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