Motion Control
Motion control is a sub-field of automation, in which the
position and/or velocity of machines are controlled using some type of device
such as a hydraulic pump, linear actuator, or an electric motor, generally a
servo. Motion control is an important part of robotics and CNC machine tools,
however it is more complex than in the use of specialized machines, where the
kinematics are usually simpler. The latter is often called General Motion
Control (GMC). Motion control is widely used in the packaging, printing,
textile and assembly industries.
Common control
functions include:
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Position (point-to-point) control. There are several methods for computing a
motion trajectory. These are often based on the velocity profiles of a move
such as a triangular profile, trapezoidal profile, or an S-curve profile.
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Pressure or Force control.
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Electronic gearing (or cam profiling). The position of a slave axis is
mathematically linked to the position of a master axis. A good example of this
would be in a system where two rotating drums turn at a given ration to each
other. A more advanced case of electronic gearing is electronic camming. With
electronic camming, a slave axis follows a profile that is a function of the
master position. This profile need not be linear, but it must be a mathematical
function.
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