Engineering Rotation around fixed axis (robot arm), dynamics

AI Thread Summary
The discussion focuses on calculating the velocity and acceleration of point C on a robot arm driven by hydraulic cylinders, with point D rotating clockwise at 5 rad/s. The user initially miscalculated the distance from point D to C, realizing that only the radius perpendicular to the axis of rotation should be used. After consulting resources on rotational dynamics, the user found the solution but sought confirmation on the direction of the velocity vector at point C. The clarification indicated that the velocity vector should indeed point out of the paper, aligning with the clockwise rotation. The discussion emphasizes the importance of correctly identifying the relevant radius and vector directions in dynamics calculations.
Mech_LS24
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Homework Statement
The robot arm is driven by two hydraulic cilinders A and B which brings point D rotates CW. The gear in point D has a angular velocity of 5 rad/s. Calculate the velocity and acceleration of the part in point C.
Relevant Equations
Velocity = angular velocity * radius
Acceleration = angular velocity^2 * radius
Hello,

Given the figure below, and the following statement:
"The robot arm is driven by two hydraulic cilinders A and B which brings point D rotates CW. The gear in point D has a angular velocity of 5 rad/s. Calculate the velocity and acceleration of the part in point C."

First I determined the distance from point D to C as rc/d, this distance is used for the formula's. The answer doesn't correspond, what am I missing here??

Like to here! :)

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Last edited:
Thanks @Lnewqban . Found the solution :)

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@Lnewqban , just to be sure, could you verify the sketch below? I draw the velocity and acceleration vectors acting on point C, where V actually goes 'into' the paper.

1625397938237.png
 
If I understand it correctly, I believe that vector V should be pointing out of the paper, as the rotation of the gear has been said to be clockwise.
The rest of the diagram seems to be correct.
 
You are right, thanks! :biggrin:
 
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