When the control must follow a specific path to reach its starting point and stop point under load, the axis interpolation of the movement must be coordinated. There are 3 types of interpolation: linear, circular, and contoured.
Linear interpolation is the ability of a motion control system to move a load from one point to another in a straight line when having two or more axes. The motion controller must determine the speed of each axis in order to coordinate their movements. True linear interpolation requires modifying the axis acceleration of the motion controller, but some controllers program acceleration curves close to linear interpolation. The path can be on a plane or three-dimensional.
Circular interpolation motion control systems have the ability to move loads along a circular trajectory in two or more axes. During transport, it requires modifying the acceleration of the load with a motion controller. Similarly, a circle can be flat or three-dimensional.
Contour interpolation is the path followed in a load, tool, or end actuator under the coordinated control of two or more axes. The motion controller needs to vary the velocity on different axes in order to make its trajectory pass through a set of predefined points. The velocity of the load along the trajectory is determined and can be constant beyond the start and stop times.