A-frame ALLGO

grabcad

GENERAL IDEA:A design with 4 equally-distanced legs will make moving on lunar surface more difficult and makes the gantry less stable. So is about designs with 3 legs. On the other hand, in some cases, it's more difficult to place such a 4-leg frame in good position relative to payload.So I used the shape of conventional gantries to eliminate those problems.RIGIDITY:While inflated, gas pressure wants to make the curved shape planar, but the cables will go under tension and will not allow the curved shape to "unfold". This pre-stress makes this design more stable.CHASSIS:I tried to design it as light as possible. It holds the batteries and gas tank in place and connects the frame to suspension links. Connection to frame is provided using holes on chassis and corresponding bosses on frame which fit into each other.SUSPENSION:I used Curiosity Mars rover's wheels, here:Wheel- NASA-JPL Curiosity Rover WheelAll 4 wheels have 330 degree steering capability. Motors are hub-mounted brushless. Arms that attach the wheels to body can be controlled using a step motor. In case of failure of these step motors, a rubber damper will prevent the arm from damaging chassis, while allowing the system to continue to perform.HOIST:An aluminum "cap" is attached to top of frame which provides the place for mounting hoist and distributes the load on surface to prevent stress concentration. Those holes on the cap are there for weight reduction, also 4 of holes serve as places to mount the cap on frame.hook file:Hook 5 tonsI changed its dimensions and added holes for weight reduction. POWER SUPPLY:Adding solar arrays will make the gantry heavier and bulkier while they provide little power compared to their size. Instead we can add more batteries. The batteries can be recharged by being connected to an RTG (Radioisotope thermoelectric generator) or any other power sources.Mack R file: Mack R seriesI will add more photos and description.