A G is a G is a G. As a unit of acceleration, it doesn't matter what
vector that unit of acceleration takes. I flew fighters for the USAF
for years. I've pulled G's in just about any direction possible.
On 7/23/20 12:52 AM, John Dammeyer wrote:
I've asked a retired physics professor friend for some enlightenment.
Jon Elson has stated that with T = r x Fsin(theta) and F=ma that the acceleration is Gravity because it's equivalent to dropping the X axis table and letting the earth accelerate it.
But F=mg is the force due to gravity. I might well be that since we're dealing with horizontal motion here that the acceleration value is different so we're talking about F=ma.
We know the Force because we know the torque and the effective radius and that the force is perpendicular so sin(theta) is 1 and can be ignored. We know the mass.
When we set up MAX_VELOCITY and MAX_ACCELERATION in the ini file the velocity is in in/sec. The acceleration we don't know. We can keep trying values until the servo drive reports a following error because the step pulses have exceeded the encoder pulses by the preprogramed alarm point. Then back off until we are comfortable. And if the motor isn't connected then it spins up way faster than when it has to move the table.
But does the accel value in F=ma have to be gravity? And if not, what then?
John Dammeyer
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