Actuators are the basic components carrying out the actual actions in production. Power electronics ensure they move with maximum precision and efficiency. Sensors, microprocessors and communications interfaces turn smart drives into miniature so-called cyber-physical units.
Actuators, or drives, provide the movement in a factory – driving conveyor belts, opening valves, and lifting robot arms, for example. They have conventionally received the necessary commands by way of separate control units. With the decentralisation of control engineering, similarly to the trend in sensor technology, that intelligence is shifting into the drives themselves. State-of-the-art drive units incorporate both the control system and the motor. Open interfaces enable direct access to all the drive parameters, meaning drives can be integrated directly into networks without the need for switch cabinets. If a sensor is then also integrated into the drive unit, miniature autonomous systems are created which need no higher-level control.
This opens up the possibility of creating a conveyor line, for example, on which a workpiece logs on to the motor autonomously and is identified by the integrated sensor. The first drive unit passes on the signal to the downstream drives, which then all together ensure that the workpiece is transported to where it is needed.
More efficiency with electronic speed control
The numbers of actuators being used in production environments are rising as automation becomes more widespread. To minimise power consumption throughout the production process despite this growth, drives featuring electronic speed control have been increasingly used in recent years. Their speeds can be precisely adjusted to the changing demands of the line, so saving energy. The drives are also highly precise, positioning to within micrometre accuracy. That is one of the key prerequisites in assuring efficient processes and high quality in production.
Power electronics as an integral element
Power electronics in speed-controlled drives ensure that the electric power is converted into the required form with maximum efficiency. This is done using special semiconductor components such as MOSFETS (Metal-Oxide Semiconductor Field-Effect Transistors) or high-efficiency IGBT (Insulated-Gate Bipolar Transistor) modules. As automation becomes more widespread, and the trend towards autonomous, self- controlling units advances, these power semiconductors will have to meet the highest demands in terms of reliability and robustness.
With their sensors and microprocessors, these smart drives are essentially autonomous cyber-physical systems in their own right, and represent the “muscles” of Industry 4.0.