This week, we are waiting for the parts that we sent to Central Shop last week. There for we start researching on regenerative braking. We found that, most regenerative braking has to be implement on the brushless motor, which is an AC motor. However, we are using DC motor for the bogie, so it will be hard to use regenerative braking, but we will keep researching on this topic. Meanwhile, we start working on the mechanics stuff. We got the code working. The Arduino connect to a Mega, and form a full circuit to power the step motor, As soon as the limit switch pressed the motor will spin in different direction.
This week we got the materials from Mcmaster, and we start machining our new shaft and spacer. We gave some materials to Roger, and he made some space for us. We also send our original gear to Central Shop. We have a new and modified design of the gear. We need Central Shop to use CNC mill machine to tap two drills two holes and tap threads. So we can put a set screw in the gear to secure the shaft. On, Friday, we went to KLA-Tencor with FSAE team members. We visit the Clean lab room.
In the first intro week, my team and I studied the previous bogie. We disassembled the bogie and try to take out the steering shaft. However, it is impossible to take it out if we don't break the bearing. The steering shaft is attached to the gearbox, and the gearbox is attached to step motor. There is a wall welded to the frame perpendicularly. So it blocks the way between the gear box and step motor. According to the previous project design report, the shaft broke as the top steering attempted to move above the expected limit. The failure was due to the rotating bending and the torque exerted by the gearbox which caused a fatigue failure. We have to by a 4130 steel rod and turn down to the shaft diameter to replace it.