9/21/2015

Last Wednesday (9/16) our group met during class and shared our ideas for the suspension design. We all tried to come up with our own take on how the suspension might work. Everyone had one or two different sketches , some were similar and others were completely thinking outside the box. We then discussed the pros and cons of each design. No signal design seemed to be perfect, yet each one had some positive aspects that could be incorporated into the final design. I think seeing everyone else's designs helped to spark ideas in the group and make each of us think about the problem in a different way. We all liked the idea of using the best parts of each design to come up with a comprehensive design that satisfies all of the requirements per the project scope.

Since last week, I have worked on revising my previous sketch and doing a bit more research on the particular suspension concept that I have been working on. I have been playing with the idea of using a cantilever style suspension, mainly because it has the potential to be packaged tightly above the cabin without sacrificing performance. I suspect that space will be at a premium with the entire Superway project, so being mindful about this possible restriction when designing seems like a good approach to me. With a cantilever suspension, there is a common fixed pivot point about which the cantilever arm rotates, however the distances from the dampers to the pivot and the cabin to the pivot need not be the same. Actually, it could be beneficial to design a 2:1 (or some other desirable ratio) cabin to shock displacement cantilever arm. Meaning, the damper moves 1 unit for ever 2 units of cabin displacement. With a design like this, a smaller damper (maybe a coil-over shock) can be used, which helps to keep the design more compact.

The last sketch I made had the fixed pivot and and push rod and an additional damper mounted to the top of the cabin. I eliminated the extra cabin mounted damper and moved it to the underside of the bogie. Also, I sort of inverted the orientation of the cantilever arm, this just seemed to look like a better setup. Instead of having two center mounted, side by side cantilever systems, I put them in-line front to back which seems like it may be more stable.

The major change I made, which was sparked by my group members' sketches, was to mount the suspension in-between the cabin and a platform, with actuators between the platform and the bogie. Now the entire actuator system and suspension system are isolated from each other. The actuator system is used to control the angle of the cabin with respect to ground when ascending and descending. The benefit of keeping these two systems separate is that the angle of the cabin can be changed without changing the geometry of the suspension system. The entire system would be supported by one or two pinned linkages, the angle of which would be controlled by the actuators.