For accurately detecting the rotor position, each servomotor is provided with a measuring device which determines the current position of the motor (e.g. the covered rotation angle with respect to the initial position). This measurement is carried out by means of a rotary encoder, for instance a resolver, an incremental encoder or an absolute encoder.
The electronic control system compares the signal of this encoder with a predetermined set point. If there is a discrepancy, the motor is turned in the direction that ensures a smaller traverse path to the set point. This means that the deviation is reduced. The procedure is repeated until the actual value is within the tolerance limits of the reference value either via increment or approximation. This is the simplest case, the position control. Alternatively, torque and speed can also be controlled by this principle. As a result, for example, uniform motion profiles with fluctuating loads are possible.
In the case of synchronous or asynchronous motors, a vector controller is usually installed below the position and speed controller to transmit the torque. We have created optimum conditions in our test field, in order to execute the repair works and subsequent checking and adjusting procedures safely and reliably.