Precise Automation Through Real-Time Functions
Using SoftTorque and PartTrack, two new functions incorporated into Wittmann’s R8 robot control system, the ejector now pushes the parts to be removed only "approximately" into the robot’s grippers. At the same time, the arm of the robot moves while applying minimal force. To achieve this, the robot controls switch to a torque control mode, reacting immediately to externally introduced forces and compensating for them by applying a force in the opposite direction.
Techniques employed previously for such applications permitted only deactivation of individual servo axes and possibly the opening of any existing brakes to allow passive "retraction" of the axis in the automatic mode. Thanks to the SoftTorque function, overloading of the mechanical components and possible damage to the surface of the part being removed are prevented completely. The function compensates automatically for varying ejector strokes and speeds.
A second function with the designation PartTrack permits tracking the position of moving objects, especially on a conveyor belt. The PartTrack function relies on an Incremental encoder interface to transmit the speed of the conveyor belt to the robot’s control system. A sensor gives the start signal to track the desired object. As an alternative, a camera system that evaluates various orientations of the object simultaneously can be employed.
The PartTrack function permits parts to be tracked over the entire permissible speed range of the particular robot axis and adjusts automatically to changes in operating conditions and speeds. For instance, PartTrack can be used to "peel" packaging items from thermoforming machines. It is also possible to stack finished parts in moving containers. In this case, the conveyor belt can have any orientation and assume any angle with respect to the robot axes.