Active Suspension Ideas: Cantilever Sketch

One idea that I had last week for the active suspension was to implement a cantilever type suspension system. This is an appealing option be cause of the variety of different ways a cantilever suspension can be designed. Considering the Spartan Superway as a whole, designing each component with efficiency in mind is crucial.  The idea is to mount a spring and shock (coilover) in a horizontal orientation creating a compact system, still allowing the damper to operate in compression.

This preliminary sketch shows the principle of a cantilever suspension system, and could obviously be designed to be much more compact and refined (this is side view, imagine another set of shocks and cantilever behind/into the page). One of the criteria for the active suspension is the ability to maintain a level position on a 17 degree slope. This requirement could be fulfilled using an actuator mounted vertically at the end of the cantilever arm. When the bogie and cabin begin to descend down the slope, the actuator will extend, keeping the cabin in a horizontal plane. The actuator would retract when the bogie begins to ascend back up the track. 

While this system has a lot of versatility, it also is a bit more complicated and unorthodox compared to just mounting dampers vertically above the cabin. One thing that would need to be incorporated into this design is a method of controlling the ride height when the cabin arrives at the platform and passengers load/unload. This could possibly be accomplished by the actuator mounted as shown, but some 3D motion analysis would be needed to really understand how this system would behave. Another idea that I had (not shown in sketch) was to incorporate a sway-bar across the two cantilever arms to limit the roll of the cabin around turns.

I still need to run this sketch by my group members and get their input. We had discussed some other suspension ideas that were simple and to the point, but may lack some refinement and adaptability. This cantilever approach definitely is not the most straight forward, but with some brainstorming and refinement, it may offer the best active control of the cabin's movement.