Parabolic Velocity

In the ParabolicVelocity profile, the axis will have a linearly changing acceleration and deceleration. The velocity curve will be parabolic-shaped. By adjusting the jerk ratio, part of the velocity curve during acceleration and deceleration can be changed to be linear.

The acceleration time and deceleration time are specified for this profile.

For the parabolic velocity profile, the Prohibit Overtravel parameter has the same effect when set to ChangeDeceleration or ChangeInitialVelocity.

This profile uses the following profile parameters:

Parameter	Description
Acceleration Time	Acceleration time in milliseconds
Deceleration Time	Deceleration time in milliseconds
Jerk Acc Ratio	Acceleration jerk ratio
Jerk Dec Ratio	Deceleration jerk ratio
Starting Velocity	Initial velocity
End Velocity	Final velocity

When the parabolic velocity profile is used for a velocity command or a jog command, the Deceleration Time and Jerk Dec Ratio parameters are ignored. In addition, the target velocity must be specified using the Velocity parameter.

When the Stop or Velocity::Stop function is called to stop an axis that is executing a parabolic velocity profile, the axis stops using the specified Acceleration Time.

The following plots show the position, velocity, and acceleration of a parabolic velocity profile with a jerk ratio of 0.75.

The following plots show the position, velocity, and acceleration of a parabolic profile with nonzero starting and end velocities. Three profiles are shown, each with a different target position.