Velocity control device

A velocity control device for controlling a velocity of a controlled object, said control device comprising:

• means for obtaining a velocity profile in which the velocity of the controlled object is proportional to a square root of a distance from a present position of the controlled object to a desired position of the controlled object;
• means for obtaining a feedforward signal in accordance with -.eta./(2 .omega..sub.u) wherein .eta. is a ratio of a position sensing coefficient and a velocity sensing coefficient, and .omega..sub.u is a unity gain frequency of said velocity servo loop, said position sensing coefficient being provided for transforming a present position of the controlled object to a signal used for the control of the velocity control device, said velocity sensing coefficient being provided for transforming the present position of the controlled object to a signal corresponding to an actual velocity of the controlled object;
• means for forming a velocity servo loop for controlling the velocity of the controlled object so that the velocity of the controlled object substantially matches said velocity profile;
• and
• means for applying a feedforward signal to said velocity servo loop so that the velocity of the controlled object is more precisely matched with said velocity profile than when controlled by said velocity servo loop alone, said feedforward signal having a constant value.

A velocity control device for controlling a velocity of a controlled object, said control device comprising:

• means for obtaining a velocity profile in which the velocity of the controlled object is proportional to a square root of a distance from a present position of the controlled object to a desired position of the controlled object;
• means for forming a velocity servo loop for controlling the velocity of the controlled object so that the velocity of the controlled object substantially matches said velocity profile;
• and
• means for applying a feedforward signal to said velocity servo loop so that the velocity of the controlled object is more precisely matched with said velocity profile than when controlled by said velocity servo loop alone, said feedforward signal having a value corresponding to a differential value obtained by differentiating said velocity profile by time and said feedforward signal being obtained by multiplying said differential value by Kf=1/.omega..sub.u, wherein .omega..sub.u is a unity gain frequency of said velocity servo loop.

A device for controlling a velocity of a controlled object, comprising:

• means for obtaining a velocity profile in which the velocity of the controlled object is proportional to a square root of a distance from a present position at which the controlled object is positioned to a desired position to which the controlled object is to be moved;
• a velocity servo loop for controlling the controlled object to be moved in accordance with said velocity profile;
• and
• means for applying a feedforward signal to said velocity servo loop so that the velocity of the controlled object substantially coincides with said velocity profile, said feedforward signal being supplied to said velocity servo loop so that the controlled object is subjected to a constant acceleration in a direction opposite to a direction of movement of the controlled object, said feedforward signal being applied to said velocity servo loop only while the controlled object is decelerating.

A device for controlling a velocity of a controlled object, comprising:

• means for obtaining a velocity profile in which the velocity of the controlled object is proportional to a square root of a distance from a present position at which the controlled object is positioned to a desired position to which the controlled object is to be moved;
• a velocity servo loop for controlling the controlled object to be moved in accordance with said velocity profile;
• and
• means for applying a feedforward signal to said velocity servo loop so that the velocity of the controlled object substantially coincides with said velocity profile, said feedforward signal being generated by a direct current source and applied to said velocity servo loop only when the controlled object is decelerating.