CV [Constant Velocity] Inverse Crank is similar to the Y–Inverse Sinusoid Motion-Law. We urge you to use this motion-law in preference to the Y-Inverse Sinusoid. This segment can be used more than once in one machine cycle, whereas the Y-Inverse-Sinusoid can be used only one time. This segment is best explained by considering the X and Y motion components of a Point that is at the end of a rotating Part or Crank. When the Crank rotates with constant angular velocity, the horizontal* motion of a Point at the end of the Crank is 'Simple-Harmonic-Motion' [ a Sine function] When you apply the 'Constant-Velocity Inverse-Crank' segment to a Crank, the Point can be made to move with a constant linear horizontal* velocity for a portion of the crank's rotation. Thus, the crank can make a full rotation in each machine cycle, but it does not rotate at constant velocity. * Actually, the motion of a Point on a Crank projected on to any line is Simple-Harmonic-Motion. SEGMENT-EDITORIn the Segment Editor - see image below with Segment-Parameters You can set the:
If you use the Flexible-Polynomial Segment before and after this segment, you can:
![]() Segment-Parameters of the 'Constant-Velocity Inverse |
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![]() Schematic of Crank (green) made to give a constant linear velocity between the Start Angle(4) and End Angle(5). |
Segment Editor : Segment-ParametersNote: These angles are on the Y-axis of the motion. They are NOT angles on the X-axis. Minimum Velocity The angle, after the Base-Value The direction of the Constant-Velocity vector for Point *The Base-Value Rel. Start The angle, before from the Angle of Minimum Velocity Rel. End The angle, after the Angle of Minimum Velocity Note: Rel. Start is less than Min Vel, and Rel. End more than Min Vel, when the Crank rotates Counter-Clockwise. Rel. Start is more than Min Vel, and Rel. End less than Min Vel, when the Crank rotates Clockwise. |
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The velocity of the Point Start Angle = ...to... End Angle = The linear velocity and the length
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![]() Two CV Inverse-Velocity Segments in one Motion |
An example motion with four segments and two CV Inverse Crank Segment 1:
With these Parameters:
The Velocity, Acceleration and Jerk at the end of the Previous-Segment are made to match Start of this Segment. The Position at the end of the Previous-Segment (the end of the Motion) is usually = 'Position at Start + 360º' This makes sure the Crank rotates one time for each for each Machine Cycle Segment 2:
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Segment 3:
With these Parameters
Segment 4:
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