Types of Industrial Robot Control

Robots can be classified by the type of control that's used to move them. The types of control that are commonly used are point to point, continuous path, XYZ coordinates, and positive stop. The point-to-point system records a series of locations during the programming function and the robot moves to these points when the robot is in run mode. The continuous-path control is used where the robot must follow an exact path such as in welding or spray painting. Each location in the path is recorded when the robot is in teach mode, and then the robot will follow each path during playback or run mode. The XYZ control uses mathematical coordinates to determine each point in the program. All points in the program are identified by their X, Y, and Z coordinates and these points can be entered manually into the program or by moving the robot to the location and recording the location through a teach pendant.

The positive-stop control is used primarily with pneumatic robots where an air cylinder is extended or retracted until it reaches a stop. This type of robot control is also called bang-bang because of the noise the robot makes when it hits a stop. The robot motion is determined by a sequencer that energizes each cylinder at the appropriate time. The positions for this robot program are determined by the placement of each stop.