Hi Tony - so the rails are horizontal? The stroke is short so to size the motors it revolves around the acceleration and deceleration distance. The most distance is 150mm ie accel for 150mm then decel for 150mm then repeat. Or you may want it to accel in 20mm? More detail about what you are testing for is helpful. This potentially has very high accels (maybe that's what you are interested in?) Could be a shaker type table? Anyways once the accel distance is specified the motor size can be calculated . Peter
a 5mm pitch screw with 50Nm torque can apply 6403kgf which is a huge load. If the rails are horizontal the friction ratio for the load is 900x0.004=3.6kgf needed to move the 900kg load. So a tiny motor will move the load. Its the required acceleration of the load (translational inertia) and rotational inertia of a large 32mm ballscrew that needs to be calculated for. In high acceleration applications an belt is often used as the ballscrew can be 80% of the required torque. Whereas a belt is nearly negligible in the inertia. I once designed a belt system to fling a piano across the room in a Titanic experience in a theme park... That was fun.. Peter
your speed is 1min for the 300mm run which is slow I'd expect a crank arm mechanism would be easier and better than a ballscrew system. But is a harmonic motion suitable? Using the slowest acceleration ie over 150mm means to achieve 50mm/s the peak speed needs to be 100mm/s this gives an acceleration of 0-0.1m/s of 0.002m/s/s say. Thats 0.002/9.81=0.0002g which is tiny. Thinking about it a very small motor will do this job easily... unless your mass is being raised vertically then that's entirely different!! Sop specify your test a little better and I can figure out the motor size. Consider using a 150mm crank (ie 300mm stroke) very easy....
The ballscrew will require electronics and programming but the crank is completely mechanical just put a variable speed motor on it... and a cycle counter... plus your 35mm rail and cars are a bit oversized. A 20mm rail will take several tonnes...
Is this a one way test or a reciprocating test? if reciprocating the crank is definitely the go.