Truck/Research Development

Overview

 * It should be as modular as possible. I'm thinking more of a collection of parts for building a vehicle than a vehicle that can accept alterations.
 * The focus on hydraulics should be applied here as much as possible. That implies a lot of design choices and also opens up some interesting avenues for experimentation and synergy. For example, can hydraulic actuators be used as shock absorbers by letting the fluid be pushed out and resisting the flow with a generator that would capture the energy, then letting the cylinder fill back up from the reservoir? Additionally, would that allow the ride height to be adjusted on the fly?
 * There are already good examples of hydraulic hybrid transmissions being used to great effect in terms of performance and efficiency. They don't weigh more than a regular transmission, but they can operate more efficiently (braking/suspension recapture) and they can provide hp bursts that far exceed any engine the vehicle could practically carry. Perhaps the Power Cube can simply be augmented with an accumulator.
 * I wonder how wide a range of applications can be met with a single set of parts. Can you use four "wheel units" and one Power Cube to make a 4-wheeler, then use 6 "wheel units" and several Power Cubes to make a pickup truck, then use X "wheel units" and X Power Cubes to make a dump truck?
 * Along those lines, a nice flexible way to load different "mission units" into the vehicle could satisfy a number of flexibility requirements. The roll-off truck concept seems applicable. Not only could it load standard open-top dumpsters, it could be used as a dump truck by holding the dumpster in place. Additionally, since the dumpster can be secured well enough for driving over rough terrain, anything that fits in the space of a dumpster could be integrated into the vehicle. Like a large passenger cabin, or a flat bed, or a pickup bed, or a trash compactor with robotic arm, or farming equipment, etc.
 * The "mission units" could be loaded/unloaded onto/from the vehicle with a hydraulic winch. Then, once they're secured in place, the winch could be used for whatever else you need a winch to do.
 * "Wheel units" that function identically would be the most straight forward to mass produce. That would mean that every wheel unit was independently suspended and steerable. The "crew cab unit" could have a control panel that allowed the driver to select which combination of "wheel units" they wanted to activate with each control. So they could switch between a "two front wheel steering" mode and "all wheel steering" mode, or anything in between.
 * If hydraulic actuators could be used as shock absorbers then a damaged or flat tire could be forced to lift up and off of the ground. That would not only mean it wasn't dragging during driving, but also that you wouldn't need an external jack to change tires.
 * The upper wishbone of the "wheel units" (assuming they use double wishbone) could be made out of threaded rod and turnbuckles. That would allow the relative dimensions of the suspension in the "wheel unit" to vary between equal length wishbones (long travel off road) and unequal length (short travel on road) by bringing the upper wishbone frame mounting points closer to the wheel.
 * Each "wheel unit" could have a hydraulic motor mounted on a pivot point with a spline shaft and a universal joint providing torque to the wheel hub.
 * The "wheel unit" could easily be changed from fixed to steerable by swapping out a turnbuckle for a small hydraulic actuator. If two "wheel units" are going to be steered together than an alternative would be connecting them across the body of the vehicle via a shared steering mechanism. Steering them separately would be more expensive, but would allow on-the-fly Ackerman steering. It would also allow 4 wheel steering, which has a number of important advantages.

NOTE: it has been pointed out that if a vehicle is going to drive on public streets it needs title/registration/license/insurance/etc and that stuff only applies to one vehicle. If the vehicle is taken apart and used to make one or more other vehicles those will need their own paperwork. Thus, the modularity idea works best for farm/industry vehicles that won't drive on public roads. All-in-all that's not a particularly significant change since it's probably a better idea to just buy a used or broken commercial vehicle and maintain/fix it with your machine shop (so you can drive on public roads) than to build a vehicle from scratch and go through the process of getting all the paperwork.

Research

 * Rheinmetall GEFAS
 * Operational Utility Vehicle System comparison featureing the GEFAS