Motion control is all about moving machine parts in an accurate, predefined manner and as such it is a sub-field of automation.
There are several typical components involved in controlling motion in machinery, of these the mains ones are motion controllers, energy amplifiers and actuators (the prime movers in charge of delivering the force required in order to generate the actual motion).
Open Loop and Closed Loop
In the past many systems involving controlled motion were open loop ones where the controller sends a signal which is amplified and delivered to the actuator (which could be a hydraulic pump, an electric motor, a servo, a linear actuator or any other kind of motion inducing device). In open loop systems there is no feedback regarding whether or not the desired motion occurred and in how precise a manner.
Today most motion control systems are closed loop ones. The controller is fed data from sensors or encoders regarding the position of the part the motion of which it is regulating. Such feedback allows for better positioning and far greater accuracy.
Components of Motion Control Systems
A typical closed loop motion control system includes some type of processor running specially designed and developed software, an encoder which electronically monitors the position of a rotating shaft, servo drives, motors (electrical or hydroulic), linear or any other type of actuators.
The different components of a motion control system must be linked to each other by cables which must be carefully designed and laid out in order to minimize wear and tear.