This week we continued work on the bogie. Brandon and Greg continued working on the switch mechanism, and discovered a solution to the recurring issue of the stepper motor only turning in one direction. As Hector from the previous year's team had provided us with the pinout for the Arduino, Edward began work on the modifications to the control box, with the intent of compacting the control system into a format that the bogie could easily carry suspended below it. I (Keanu) modified the code so that the bogie now can activate the switch mechanism while in forward motion.
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This week we met with Oscar and Hector of the previous year's Half-Scale team. From them we determined the causes of the issues with Stepper 2 and discussed the modifications that could be done to the switch mechanism. We also discovered that the previous year's team had never attempted to run the bogie through the switch. The following day we modified the drive shaft and the gears of the switching mechanism, while unsuccessfully attempting to fit a new wheel onto the left side of the lower switching arm to improve traction. We then ran the bogie on the track, encountering problems with the lumps on the track caused by the welding process. We used a hand sander to grind the lumps until the bogie could pass, then attempted a switch. The bogie quickly failed and we determined that it needs more modifications to the switching mechanism to allow it to grab the track better, welding on the drive mechanism to keep the gears from slipping, and bug fixes in the code to make the steppe
Modification for the code and problem analysis for the bogie
October 2, 2019 Modification for the code and problem analysis for the bogie This week, we ran the program from previous year on both if the bogie to find out that bug that was mentioned form the previous report. We found out that for the switching mechanism, the stepper motor only turns one way. We download the code and ran diagnose to find out the bug, and able to fix it at the end of the day. For the bogies, the switching mechanism on both bogie were not working, and one of the gear on the main motor slipped. One of the bogie can run on the track but switching mechanism is not working, the other one is not functioning well. We decided to take apart the bogie that’s not functioning well to figure out where the problems are and will do modification on some parts to keep gears or piece in position. We are planing to insert keys for the wheels and the gears, so that they will be locked in position instead of slipping off. We are also thinking redesign the switching mechanism and ch
Gantt Chart for ME195-A Half-Scale Team For our timeline, the next two weeks will be crucial (9/28/19-10/9/19) as each of us would be working on the CAD prototypes for each of the respective mechanical systems. After that, we would be doing inventory checks and basic testings on the motors, Arduino boards and gears as carried on by previous Half-Scale teams. After that, we would be implementing our CAD designs and constructing our sectional model for each of the systems which, if successful, would be carried into ME195-B and used be used as our prototypes.
We have conducted trial runs of the bogie system to analyze its functionality and have found several problems with the gearing, switching mechanism and the track layout. In order to correct these issues, we have decided to redesign the switching mechanism and add additional gears to the drive system as it tends to separate from the teeth of the drive motor. The switching mechanism is only partially functional and must also be redesigned due to structural weaknesses in the pin that holds the rocker, which lowers the factor of safety substantially. As the the Half-scale team, we have chosen to redesign the switching mechanism by removing the 'rocker style' arm that is currently being used and replacing it with a 'T-shaped' bar with a wheel attached. By these redesigns along with modifications to the track, we will be able to navigate the track with full functionality.