Spring 2016 Updates

Since the last semester, the Fail-Safe team has made a significant amount of progress. During the time from the last post, the team has taken on the role of motor for propulsion. Other changes that has occurred involved the team working to together to reduce the cost of the bogie.

Cassie has taken lead in the fabrication due to her having the best schedule to work with the tech shop. She has already fabricated most of the parts. The cost to waterjet the plates ourselves was the same cost as having another party help except doing it ourselves would allow us to work on our own schedule. However, we do have an issue do the the limitation of machine time we have access to.


Figure 1. This is an image of the side plate of the bogie being waterjet cut. 

Christopher has taken lead in finding the right motor for the bogie and will also take lead in controls. The motor he found most appropriate for our parameters is the Crystalyte SAW400-series motor with the 4825 Controller, as shown in Figure 2.

 
Figure 2. Image of Crystalite SAW400-Series Motor

Lastly the rest of the team is working on helping with finalizing designs to mount the motor and he appropriate wheels for the bogie. The design is for the bogie is slowly being modified as other groups are making modifications which require us to change our design due to the fact the the bogie will house all of the other teams projects. We are also helping Alex with working on the guideway. The team is working well with the intention to finish by Maker's Fair.

Week 7 Update - Second Presentations

During this week we had more presentations during the class session. For our project, my group has done more research into the ratchet system. We also analyzed the impact of a third redundant component. Research has shown that redundant components are often used as a fail-safe and help increase reliability. On the redundant components, we can potentially implement an emergency brake and the ratchet system onto that system. However, after our presentation, it seems that we need to implement a "catch" for the cabin in case it were to fall. The group will be compiling ideas and bringing it to our group meetings the following Tuesday, November 3.

10/22 Update

Over the last weeks, we had presentations where groups spent 15 minutes to go through the introduction of their projects. This covered initial problems or obstacles, why their project is important or relevant, and etc. Groups were able to learn about other sections and see where other groups were at in their project.

My group has finalized designs and start working with the steering and brake group we both affect each other. Our group will start to implement designs onto CAD and use it to get analysis. With all the information at hand, the group will be prepared for the next presentation

Project Update

Since the last update, my group has met twice to help prepare for presentations.  The two meetings allowed every member to have an opportunity to attend a group meeting due to the difference in availability.  While we only met twice in preparation for the presentations, there were online conversations delivered through emails or group chats.

The last class meeting was utilized by having students present their projects proposals.  Half of the class presented their project by telling the class general background information and some research conducted.  These presentations are useful to allow other groups to know where the project is at and allow information to be exchanged.

The fail-safe mechanism group has created a list of issues that could occur for the Spartan Superway and decided to focus on the issue of the cabin derailing.  Solutions to this issue will be discussed during our next meeting.

Spartan Superway Update Assignment #3

Since the last assignment, I spent some time looking over the designs and concept ideas the team has created involving the fail-safe mechanism. From looking at the team's personal assessment, it appears the team have similar thoughts on how to make the cabin safer. Although there are various details that differ, a primary concern that threatens the cabin is the possibility of the cabin falling from the tracks.

A common idea the team had involved adding a secondary wheel as a safety precaution. To implement the secondary wheel the designs reconfigured the guide-way. While this decision is unavoidable, it will raise the cost production for the guide-way. The secondary wheel to help reinforce the bogie was also installed which would help provide extra support while giving the bogie a way for the cabin to be properly transported if the bogie malfunctions.

A specific sketch that caught my attention was Jeffrey Chau due to the detail and concept. His steering mechanism utilizes the guide-way to with control the direction. While the original bogie already does this, the design created also provides extra support to relieve some stress from the other portions of the wheel. His second design involves a drastic change in the guide-way. While that probably isn't recommended for the project, he gave the guide-way additional tracks to help guide the bogie and provide direction. After some clarification, altercations to the guide-ways is recommended instead of reinventing the bogie or guide-way.

Initial Thoughts on Bogie Design

A primary concern for many riders will be if the bogie will be able to support the full weight of the cabin. Or people would be concern about getting stranded somewhere if the mechanism fails.  While looking at the design created by the previous year, I noticed a lot of the functionality is centered around the large two wheels located around the center of the bogie. If these were to fail, the cabin would face a large predicament. By making the turning mechanism on the bogie into two separate parts, we can have an operator input commands into the outer lower wheels in case the larger ones fail.  By allowing the outer lower wheels to rest on the railway, it can take some of the weight relieving the larger midsection wheels.  This design should still work like the previous years design in turning. This design is a little bulkier but should be able to be optimized to be smaller and more cost efficient.  The new railway design is more complex meaning it would also cost more but would provide more options in case of failure. 

Further Research into Different Safety Mechanisms

A major concern many people will probably have upon seeing the Automated Transit Network (ATN) is "What if something breaks? Will the cabin fall?".  While the current design of the bogie mechanism lacks a fail safe mechanism, studying other safety systems could provide the team with insight on how to approach the problem.

I started by reading about the differences between supported and hanging vehicles off a report found in the INIST Library. The report discussed how it is better to focus on the one-way guide-way system due to having half the amount of bulk as a two-way guide-way which means the cost is lower.  For the supported-vehicle system, super-elevation in curves reduces the curve radii. Super-elevation is the defined as the difference in which the outer edge of a curve is banked above the inner edge in reference to roads or railroads.  The hanging-vehicle system has more freedom to swing which would eliminate the need for super-elevation.  The hanging-vehicle system is less complex and cheaper because it does not need the super-elevation.

A safety measure used for elevators is a hydraulic or gas spring buffer found at the bottom to help reduce the impact. Another safety measure found while digging could be borrowed from the trains. I came across an article where they reported people dying due to a train traveling at high speeds and derailing. The technology used is called positive train control (PTC) which uses digital airwaves and GPS to detect curves and slow down the vehicle accordingly to help prevent more derailment issues. This technology also prevents collisions and helps control the speed of the vehicle in required areas.

The diagram above shows how the train control system would operate. The center of this system that allows the information to be exchanged is the Radio Network which enables the on-board PTC systems, wayside interfacing unit and the PTC Back Office server to communicate.  The Wayside Interfacing Unit helps monitor the overall status of the train and reports back to the office servers. And the on-board system provides more control over the vehicle by controlling the speed and braking  with a stronger communication system. The sharing of information makes this system efficient and and able to prevent accidents.  This technology would be great to incorporate into the Spartan Superway because it has yet to have these kind of features.

Works Cited:

Anderson, J.E. "Tradeoff between Internal Combustion Engined Vehicles and Electric Vehicles in Hong Kong." (n.d.): n. pag. INIST Library. Web.

Glenza, Jessica. "Amtrak Crash: Safety Mechanism to Slow Speeding Trains Was Close to Operational." Theguardian. N.p., n.d. Web.

"Positive Train Control (PTC)." Tech Mahindra. N.p., n.d. Web.