wangp1283
Automotive
- Oct 19, 2004
- 56
Hi
I need to produce such a response to a load:
1.an constant acceleration of 0.5m/s^2 for 1/100 of a second.
2.The initial velocity is not important. What matters is that during that 1/100 second time interval, the acceleration is 0.5 m/s^2
I thought about using a cam to produce this response. Basically, a parabolic camshaft. (the type that produce a constant acceleration)
The problem is, the accuracy would be questionale, because the lobe would be practically non existant.
the distance traveled during a constant accleration would be (1/2)(acceleration)(time)^2, which would be (1/2)(0.5m/s^2)(1/100 sec)^2 = 1/40 mm (0.025mm). This is very small distance so a cam lobe is hard to manufacture.
My idea is to use a gear train via rack, pinions, and gears. I will "amplify" the acceleration by a factor or 25 at the cam lobe (so the parobolic lobe is steeper, this way the rate of change of slope is significant and may be more accurately machined), and then "bring it" down via a gear reduction.
I wonder if this is a way to do it? I think it should work since acceleration is the rate of change of speed. As long as the cam lobe is machined accurately, the speed at any instant should be accurately reflected by the gear train, and therefore, also the rate of change.
So I don't think there should be any loss of accuracy due to the "stepping down".
Thanks
I need to produce such a response to a load:
1.an constant acceleration of 0.5m/s^2 for 1/100 of a second.
2.The initial velocity is not important. What matters is that during that 1/100 second time interval, the acceleration is 0.5 m/s^2
I thought about using a cam to produce this response. Basically, a parabolic camshaft. (the type that produce a constant acceleration)
The problem is, the accuracy would be questionale, because the lobe would be practically non existant.
the distance traveled during a constant accleration would be (1/2)(acceleration)(time)^2, which would be (1/2)(0.5m/s^2)(1/100 sec)^2 = 1/40 mm (0.025mm). This is very small distance so a cam lobe is hard to manufacture.
My idea is to use a gear train via rack, pinions, and gears. I will "amplify" the acceleration by a factor or 25 at the cam lobe (so the parobolic lobe is steeper, this way the rate of change of slope is significant and may be more accurately machined), and then "bring it" down via a gear reduction.
I wonder if this is a way to do it? I think it should work since acceleration is the rate of change of speed. As long as the cam lobe is machined accurately, the speed at any instant should be accurately reflected by the gear train, and therefore, also the rate of change.
So I don't think there should be any loss of accuracy due to the "stepping down".
Thanks
