1 GENERAL

The origins of motion controllers were closely related to textile machine developments. In the very early history of such machines the control of position and velocity was accomplished by elaborate, expensive and time-consuming solutions comprising cams, gears and shuttles.

The automotive and machine tool industries were among those which saw the control of motion as a means of providing complex shapes and integrating complex operations. Being able to move heavy materials and process them in a repeatable and continuous manner added value and increased the productivity of their operations.

With the emergence of computers and microprocessor technology, other options became possible and modern motion controllers were born.

A position or motion controller can be considered as a system for providing an outer position or path control at the front end of a drive which traditionally may be considered to be a speed controller. This can be represented as shown in Figure 7.1.

Figure 7.1: Control loops within a position-control system

Although position control is frequently used in single axes, the generic motion-control system is most frequently associated with multiaxis applications. In such systems, the motion controller is often, but not always, used to coordinate the position or velocity of a number of drives. This form of application has been illustrated for a two-axis system in Figure 7.2.

Figure 7.2: Two-axis system with a motion controller

A more precise definition of a motion controller would be - the application of programmable hardware and software (in conjunction with input sensory...