04/26/2016 update, Fabrication

This semester we are fabricating the scaled model of the bogie aside from the failsafe mechanisms designed last semester. Also, our team is now in charge of propulsion for the model. Right now we have acquired most of the part we need for fabrication and are bringing everything together. This semester we have had to go over the details of the CAD model to make sure that everything will fit and hold the required loads. Also, we had to change the connections between the bogie and H-bar since now the model will run through an incline which requires the linkage to flex horizontally and vertically. This semester I have worked the most performing modifications to the CAD model and running FEA to the different parts and assemblies to make sure everything will work. Also, we have been helping Alex to fabricate the parts of the guideway as well as fabricating bogie parts.

Update 11/02/2015

In last class meeting we presented our ideas of a third bogie and anti rollback mechanism and the calculations and CAD performed for the two different fail-safe mechanisms we were working on. During our presentation we were told to focus in a mechanism that would avoid that the bogie fall from the track no matter what the failure is. Since last week I have been researching and going over different ideas to show and discuss them with the rest of fail-safe team members on our next team meeting.

Here is a link for our presentation number two:
https://docs.google.com/presentation/d/1lWFAE80qzSqN7ZtbFVaSHDX4EbZS058ueBsg3yqB-wE/edit?usp=sharing

Update 10/07

In last class session my sub team and other different sub teams made our presentations explaining our project goals, problems, background information, challenges and functional specifications that each team will be facing over the year. Also, we set up the individual responsibilities for each of the members of the fail safe team. Now, that we have done this, we are more organized and will be working on a more clear and efficient way.

Since last meeting, I have been researching more information on how roller coasters work and what safety mechanisms do they have. Also, I have been reading about safety in the Fundamentals of Personal Rapid Transit book and brainstorming some other fail safe ideas to discuss with the rest of the fail-safe sub team.

Work done since 09/16/2015

On last meeting on Wednesday 16^th, the whole bogie team got together to discuss about the research we did during the past week and what we had learned that could be relevant for the Spartan Superway. Also, we discussed some of our ideas and designs posted on our personal blogs so everyone understood them. Also, we were told that it was desired to work over the bogie already existent and to try to avoid major modifications such a complete redesign of it. Because of this, we decided that we are going to design a failsafe system applicable to the current bogie. It was also discussed the idea of adding a third wheel such as the one present on most roller coasters to make the bogie more stable since the track will have elevation changes. In addition, I have been searching on internet more information about different types of railways and designs that are already in use around the world, especially the ones from roller coasters since they are the most common using hanging designs.

Safety wheel addition

The current design of the boggie is lacking of safety features that would keep the boggie on the track during a failure on the main wheels or switching system. I was brainstorming some ideas on a simple “fail safe” mechanism to prevent the boggie from falling from the tracks in case that one of the main wheels fails. My idea is to add a safety wheel of smaller size between both main wheels on each side of the boggie. This extra wheel would be positioned slightly above the rail so it won’t be in contact with it during regular operation. If one of the main wheels falls from the boggie the weight will rest over the safety wheel. The advantage of having the safety wheel slightly above of the track is that the change in altitude of the whole boggie would be minimum keeping the guiding wheels attached to the rails and avoiding the boggie from tilting and falling off the tracks. Another advantage of having this safety wheel is that it will allow the boggie to be moved easily to the nearest station to unload the passengers and clear the tracks.

I think the safety wheel should be made of a hard rubber which would be able to hold the weight of the boggie while also absorbing the force of impact between it and the track. (Figure took and modified from Spartan Superway 2014-2015 Report).

Post 3

Now that I have decided to work on the bogie fail safe mechanism I have been going over the design of the bogie and the tracks to understand more on how they work. After reviewing the design, I think that the bogie is more prone to fail when switching rails since there are moving parts controlled by the electronic system that would have to make the switch in short periods of time. If this mechanism fails, the bogie can end not being attached to any of both guide rails and fall from the track. One way this could be avoided is by modifying the tracks to be enclosed with the bogie running inside as in the picture below. This would require a redesign of the tracks which I think can be avoided by designing our own safety mechanism based on our bogie and track system.

http://openprtspecs.blogspot.com/2010/01/about-that-angled-wheel-design.html

Post 2

On our last meeting I decided that I am going to work on the full scale model designing a fail safe mechanism for the bogie. I met other students that want to work in the same area as me and talked about our main safety concerns on the current model. Since then, I have been doing more research about the project and safety mechanisms being already used on other kind of bogies.