4 Linkage system: velocity calculation

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vsarnaud
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Homework Statement
I want to calculate the x-vector velocity of the middle leg of the walking machine. This requires two angular velocities. The one from the leg (which I've calculated), and the one from the driver (which I've set to a value, see below).

I can't seem to figure out what the total velocity of this leg is. The program shows me a value (see below) but I can't seem to find an appropriate formula to add both angular velocities together.
Relevant Equations
You could compare this problem to a trebuchet, golfswing or a folded arm that stretches. Where you have two seperate angular velocities resulting in one larger angular velocity.

R1 - R2 - R3 - R4 = 0 (see screenshots)
For the attempt at a solution view the Excel screenshots (1).

A screenshot with all the lengths is provided (2).

The 4-linkage system is shown in screenshot (3).

The problem is shown in screenshot (4).

A screenshot from the whole assembly is also provided to add some insights (5).

Thanks for the help!

(I did not create this 3D model, I chose this project to do calculations for one of my lectures)
 
Attachments
  • Screenshot of a spreadsheet and calculation sheets for a four-bar linkage: a parameter table with link lengths R1 to R4 and angles, followed by vector loop and angular velocity equations and a velocity result of 163,272 mm/s.
    1_Gegevens_Hoeken_Snelheden.PNG
    33.4 KB · Views: 394
  • Diagram of a linkage mechanism with dimensions: links labelled 120 mm, 104 mm, 102.9563 mm and 85 mm, a pivot radius R4 and a radius R6, plus a 15 mm wheel and gear.
    2_Gegevens2.PNG
    22.8 KB · Views: 397
  • Diagram of a four-bar linkage from a 3D assembly, with links labelled R1 (blue), R2, R3 and R4 (orange) joining pivot points, next to a gear and a frame member.
    3_Links.PNG
    30.4 KB · Views: 358
  • Diagram of a four-bar linkage in a mechanism with angular velocity annotations: red arrow labelled 4,974 rad/s, blue arrow labelled 0,641 rad/s, and a green arrow labelled ...mm/s pointing left at the bottom.
    4_Help.PNG
    20.1 KB · Views: 408
  • 3D CAD rendering of a six-legged walking mechanism with a yellow-and-green gear train and wooden-looking linkage legs, with green labels such as 3_LinksVoor and 4_2_RechtsVoor naming the parts.
    5_WalkingMachine.PNG
    33.7 KB · Views: 374
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Nevermind... I accidently entered the value for θ4 = 0°, but it is equal to 90°...

Sorry for wasting time! :oops:

Kind regards!
 
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