Week 8

This week is the last week of the internship. The team decides to stay their complete 8 weeks. For the team members that came in late; they will stay a full 8 weeks. One member decides to stay until Tuesday, and the others decide to stay at least until Friday or next Tuesday in order to fulfill the 8 weeks.

Week 7

This week, we drilled new holes and cut copper rails for the left side of the track. We were able to finish one side of the track with the ends missing. There are a few problems that happen, which took the rails longer than expected to finish. The copper rails broke in half, and that made us redrill new holes and remake the copper rails.  We also briefly discussed with the bogie team about how a track change would occur.  We plan to have a shovel-like guide, made of wood, that would guide a derailed pair of shoe collectors into the PVC pipe.  A 3D printed part will be printed to prevent a pair of derailed shoe collectors to not dangle freely.

Week 6

We have implemented finished copper railed onto the wayside. Previous week, we drilled holes and cut the copper rail into the shape wanted for a better connection. This week we started to put up the copper rails.  Our initial plan was to carve out a rectangular section in the inside of the pvc so that the copper backing that holds two joining copper rails together would be flush with pvc pipe.  However, we realized that this design was way to time-consuming.  Instead, we decided to not carve or cut any of the insides of the pvc pipes.  We just screwed the rectangular copper joint to the other side of the pipe.  This rectagular copper piece is needed to ensure that the copper sections are always connected electrically even if they are not visibly touching.  It takes awhile to put up the copper rails because of unexpected flaws. There are usually problems that occur while working on the rail.

Week 5

We ordered a few items to improve the rail. We ordered an 8 gauge and 10 gauge wire for better connection of electricity. The previous wires on the solar controller were gauge 12 which does not allow as much current. We also got more screws and nuts that is a good fit. The previous screws were difficult to find matching nuts.

The copper rails were also all removed from the PVC pipes.  We decided to redesign the way that the copper rails were joined to each other.  Last week, we simply unscrewed each joining copper rail and overlapped them such that the current collector would drop from one copper rail to another as it rides through separate copper rails.  This puts too much unnecessary stress on the current collector.  In addition, the shoes also got stuck at some points along the track.  So we just took out all the rails and cut each end at a 40 degree angle.  To connect two rails, we match the angled cuts together like a puzzle and also add a copper backing to hold the two rails together with screws.  We used a slightly bigger drill bit as a countersink to redrill the holes in the copper to make it flush with the copper rails.

Week 4

We put our final touches on the collector shoes and continued to fix the power rails.  After our group presentation, Dr. Furman and Claude suggested that we come up with a way to connect the copper rails without any overlapping.  Most likely this would mean we will have to take apart all the rails from the track.  It will be worth the effort because without a good power rail, the bogie will not run.  In addition, it may be best to redrill each of the holes in the copper with a countersink.  The countersink will make screws flush with the surface of the copper.  We also did a little brainstorming of how to get the collector shoes to derail and rerail during a track change.  We decided that it may be required to have the bogie operate using on-board battery power during the time of the track change.

We also figured out that the solar panels will not charge the batteries. The solar charge controller have a blown fuse, which will act as an open circuit and prevent the current going to the batteries. We will have to reorder a fuse that is made for the charge controller. The fuse claims that it is a 250V 0.5A fuse. This means the previous team surpassed the limits. Voltages from a 90-degree sunlight with four solar panels will receive about 100V.

Week 3

We were able to find several mistakes with the previous designs and find solutions to them. We found that the tubes that were design had several problems. The tubes were too large for the collector shoes. The tubes were made from PVC pipes that are circular, which does not fit the collector shoes. The PVC pipes are too large for the collector shoes, which can cause slipping and lose contact with the copper railings.  In addition, we have to ensure that the copper rails are overlapped propperly at the junctions, where two sections of rail are joined together.  The copper has to be overlapped such that the collector shoe glides from a higher elevation to a lower elevation to avoid hitting against a rail.

The shoes must be touching the copper railings at all times. We were able to find a way to fix the problem. Instead of changing the tubing to rectangular shaped that will fit the collector shoes in the first place; we decided to redesign the collector shoes. Changing all the tubings and gluing all the copper railings will take weeks. We change increased the width of the collector shoes by adding more copper to the shoes. Making the shoes wider will increase being in contact with the railings. We added two copper strips to each side, which made the shoes wider as shown in Figure 1. The problem with that is getting stuck on a nail in the copper railing. We were able to design the shoes with a slight ramp that will go over the nails smoothly as shown in Figure 2.  This was simply done by cutting a small strip of copper and bending it before hot-gluing it at each end of the modified collector shoe to cover up the screws.  We glided each collector shoes across multiple screws on the power rails using more force than it will be subjected to, to ensuere that the hot glue is strong enough to hold the copper peice together.

Figure 1. Increased width in collector shoes            Figure 2. Final design on collector shoes 

                      

Week 2

There are two batteries that are available for us to use for storing the solar energy.  These two batteries, the GMET TS116 2014/04/21 as shown in Figure 1, are supposedly identical according to their data sheets.  However, we obtained significantly different voltage measurements from each battery.  We suspect that one of the batteries are damaged.  We tried to hook up the Anada PV60 charge controller to three Solopower SFX1-i70 solar panels to charge the battery that had an unexpectedly low voltage.  However, we noticed that the charge controller always indicated that the batteries were "ready", or fully charged.  It even indicated the batteries were full when the batteries were not connected.

Figure 1.  Battery with the case opened.

The wayside track also had a problem. The wayside on the track did not have fully connected copper railings. The tubings on the track were not connected either. We believe that the track was designed unevenly which caused the tubings to be forcefully bent. This caused the wayside tubes to deform. Since the tubes were deformed and took a lot of force to put them back in place, we decided to remove the sections that were not connected and put new tubings in. In order to put the tubings on the track, we screwed in a wood block to hold together the tubes as shown in Figure 2.


Figure 2.  Fixing the tubings on the wayside track