CV Inverse Crank

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CV Inverse Crank

Constant-Velocity Inverse Crank

Motion-Description

This segment is best explained by considering a Point at the end of a Crank when its motion is projected onto a Line.

When a Crank rotates with Constant angular velocity, the projected-motion of the Point along the Line is Simple-Harmonic-Motion.

When you use CV-Inverse-Crank, the projected-motion of the Point along the Line is Constant Linear Velocity.

Motion-Values

Position at the Start - defined by the three Segment-Parameters - see below.

Position at the End - defined by the three Segment-Parameters - see below.

You CANNOT specify the:

Velocity at the Start or End

Acceleration at the Start or End

Jerk at the Start or End

The actual velocity, acceleration, jerk values, and the distance the Point moves along the Line is a function of the:

Segment-Width

Length of the Rocker/Crank

Segment-Parameters

Segment Parameters

Typical Segment-Parameters

Typical Segment-Parameters

Schematic of Crank made to give a constant linear velocity from Angle(4) (defined by Start-Position(1), to Angle(5), defined by the End-Position(2).

Svhematic to help you understand how to use the CV-Crank motion-law.

You can set the:

Min VelRed-14-2 (Minimum Velocity)

the Angle we add to the Base-ValueRed-14-1b angle defined by the Motion-Dimension FB

Rel StartRed-14-4 (Relative Start)

Direction angle relative to the angle defined by Min VelRed-14-2 at which PointRed-14-3 starts to move along the Orange Line with Constant-Velocity.

Rel EndRed-14-5 (Relative End)

Directional angle relative to the angle defined by Min Vel Red-14-2 at which PointRed-14-3 ends moving along the Orange Line with Constant-Velocity.

Note:

The Crank rotates Counter-Clockwise when Rel. Start is a Negative and Rel. End is a Positive.

The Crank rotates Clockwise when Rel. Start is a Positive and Rel. End is a Negative.

Segment-Range

Start-Range

End- Range

0 ≤ Start-Range < End-Range ≤ 1


CV Inverse-Crank2 x 

CV Inverse-Crank2 x 

EXAMPLE Motion with two CV Inverse Crank segments.

Segment 1: Constant-Velocity Inverse-Crank

X-axis : 0 to 90º

Segment Parameters are:

Angle of Minimum Velocity = 90º

Relative Start Angle = -30º

Relative End = 30º

With these Parameters:

When X-axis = 0º ; Y–axis = 60º.

When X-axis =90 ; Y–axis = 120º

Segment 2: Flexible-Polynomial

X-axis : 90 to 180º

Y-axis at Start P=120. V, A, J flow from the end of the Constant-Crank-Velocity Segment.

Y-axis at End 240º

Segment 3: Constant-Velocity Inverse-Crank

X-axis : 180 to 270º

Segment Parameters are:

Angle of Minimum Velocity = 270º

Relative Start Angle = -30º

Relative End = 30º

With these Parameters:

When X-axis = 180º ; Y–axis = 240º

When X-axis =270 ; Y–axis = 300º

Segment 4: Flexible-Polynomial

X-axis : 90 to 180º

Y-axis P at Start = 300º. V, A, J flow from the end of the Constant-Crank-Velocity Segment.

Y=axis at End = 420º.