- #1
samee
- 60
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Please see uploaded image...
So the question is, what is Hg(dot) ?
so I know that I need w1 in rad/sec, so 1800*(2(pi)/60)=188 rad/sec
I want to establish a set of moving axes at the center of the rotating disk on the saw that is parallel to the stationary axis. My w is then,
w=w1k+w2J : Always
Now I want to have my w in terms of my moving axes, so
w=w1k+rw2j : Instantaneously
Where r is the distance from my moving axes origin to the stationary x-axis.
w(dot)=α={w1(dot)k+w1k(dot)}+{rw2(dot)J+rw2J(dot)}
Since w2 is a constant angular velocity, w2(dot)=0
Jdot=0
α=w1(dot)k+w1[wxk]
wxk=(w1k+rw2j)xk=0+rw2i
α=2w1w2i+w1(dot)k
Okay- so now I need to determine my Inertial products and moments. This is where I'm getting stuck, though... I know that;
HG(dot)=(Ixxαx-Ixyαy-Ixzαz)i+(Iyyαy-Ixyαx-Iyzαz)j+(Izzαz-Ixzαx-Iyzαy)k
and since αy doesn't exist,
HG(dot)=(Ixxαx-Ixzαz)i+(Ixyαx-Iyzαz)j+(Izzαz-Ixzαx)k
but I don't understand how to find Ixx, Izz, Ixz, Ixy, or Iyz. I know that Ixy, Ixz, and Iyz are the mass products of intertia and that Izz and Ixx are the mass moments of inertia. But I don't know how to use these equations to solve for the components of I...
Also- the answer to the whole problem is
HG(dot)=-0.366i lb-ft
So the question is, what is Hg(dot) ?
so I know that I need w1 in rad/sec, so 1800*(2(pi)/60)=188 rad/sec
I want to establish a set of moving axes at the center of the rotating disk on the saw that is parallel to the stationary axis. My w is then,
w=w1k+w2J : Always
Now I want to have my w in terms of my moving axes, so
w=w1k+rw2j : Instantaneously
Where r is the distance from my moving axes origin to the stationary x-axis.
w(dot)=α={w1(dot)k+w1k(dot)}+{rw2(dot)J+rw2J(dot)}
Since w2 is a constant angular velocity, w2(dot)=0
Jdot=0
α=w1(dot)k+w1[wxk]
wxk=(w1k+rw2j)xk=0+rw2i
α=2w1w2i+w1(dot)k
Okay- so now I need to determine my Inertial products and moments. This is where I'm getting stuck, though... I know that;
HG(dot)=(Ixxαx-Ixyαy-Ixzαz)i+(Iyyαy-Ixyαx-Iyzαz)j+(Izzαz-Ixzαx-Iyzαy)k
and since αy doesn't exist,
HG(dot)=(Ixxαx-Ixzαz)i+(Ixyαx-Iyzαz)j+(Izzαz-Ixzαx)k
but I don't understand how to find Ixx, Izz, Ixz, Ixy, or Iyz. I know that Ixy, Ixz, and Iyz are the mass products of intertia and that Izz and Ixx are the mass moments of inertia. But I don't know how to use these equations to solve for the components of I...
Also- the answer to the whole problem is
HG(dot)=-0.366i lb-ft