Velocity,Acceleration,Angle

Question

Sachith Wijayanayaka 2020-6-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/550014-velocity-acceleration-angle

评论： Sachith Wijayanayaka 2020-6-18

采纳的回答： James Tursa

How do I find plots for

velocity of link3 vs angle of link1 Acceleration of link3 vs angle of link1.

5 个评论
显示 3更早的评论隐藏 3更早的评论

James Tursa 2020-6-17

And I don't know how to view the image.

James Tursa 2020-6-17

I see the image below, but that doesn't change my comment above. You simply need to take the derivative of the L3 equation I gave you above and then plug in the phi1 derivatives to get your answer. Do you know how to take the derivatives?

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

James Tursa 2020-6-17

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/550014-velocity-acceleration-angle#answer_452775

This is a dynamics class. Dynamics involves derivatives. How can you be in a dynamics class without knowing calculus and how to take derivatives? All you have to do is know how to take the derivative of sqrt and trig functions and apply some chain rule stuff to get your answer. E.g., if you had the following for the x-coordinate of point B with respect to point A:

Bx = L1 * cos(phi1)

And you were asked to find the velocity of the x-coordinate of point B, then the derivative of Bx with respect to time would be

d(Bx)/dt = -L1 * sin(phi1) * d(phi1)/dt

And since they told you that phi1 is changing with constant angular rate w1, you get

d(Bx)/dt = -L1 * sin(phi1) * w1 <-- Velocity of Bx

If you were asked about the acceleration of Bx, then take another derivative:

d2(Bx)/dt^2 = -L1 * cos(phi1) * d(phi1)/dt * w1

And again knowing that d(phi1)/dt is the constant w1 you get

d2(Bx)/dt^2 = -L1 * cos(phi1) * w1^2 <-- Acceleration of Bx

This is simple calculus. You have to know this stuff to get by in a dynamics class. Just apply this method to the L3 equation I gave you above.