Four types of robot control
1. Point-to-point (PTP) control robot
2. Continuous-path (CP) control robot
3. Controlled-path robot
Point to Point Control Robot (PTP):
The PTP robot is capable of moving from one point to another point. The locations are recorded in the control memory.
PTP robots do not control the path to get from one point to the next point. Common applications include:
Machine loading and unloading
Continuous-Path Control Robot (CP):
The CP robot is capable of performing movements along the controlled path. With CP from one control, the robot can stop at any specified point along the controlled path.
All the points along the path must be stored explicitly in the robot's control memory. Applications Straight-line motion is the simplest example for this type of robot.
Some continuous-path controlled robots also have the capability to follow a smooth curve path that has been defined by the programmer.
In such cases the programmer manually moves the robot arm through the desired path and the controller unit stores a large number of individual point locations along the path in memory (teach-in).
Typical applications include:
Arc welding operations
In controlled-path robots, the control equipment can generate paths of different geometry such as straight lines, circles, and interpolated curves with a high degree of accuracy.
Good accuracy can be obtained at any point along the specified path.
Only the start and finish points and the path definition function must be stored in the robot's control memory.
It is important to mention that all controlled-path robots have a servo capability to correct their path.
It is open loop system
Position and velocity unknown to controller
On/off commands stored as valve states
End travel set by mechanical