Conventional actuators usually rely on bulky, inefficient relays or separate control units to extend, retract or hold a load. In contrast, the use of integrated electronics reduces the current required at the switches or contacts from 20 A to less than 22 mA, enabling a much simpler and more cost-effective system design. This allows operators to switch the actuator on and off using a simple control unit.

Imagine a factory floor where employees move heavy components and often have to stretch and bend down. If their work surface were adjustable using actuators with low-current switching, they could set the height individually. The result would be less fatigue and more productivity.

Although conventional actuator assemblies also offer such adjustment options, an external motor circuit is required - including higher power consumption and manual operation. In contrast, with electronic control, switching takes place directly in the actuator housing, which also enables a tidy solution without external wiring. Automated switching of the motor also offers safety-related advantages. An actuator draws 20 to 40 A, depending on the load. Reduced exposure to this current during installation and operation allows for more ergonomic control and reduces the risk of electric shock from high-current relays.

Digital position feedback

Smart electric actuators not only allow position adjustment with millimeter precision, but also provide real-time feedback on the effect of the adjustment. They can report the position of the load over the entire stroke. In the example of a work table, they could record data on the position of the load and compare it with the preset parameters.

Digital position feedback is supplemented by the ability to measure and control speed. For example, when opening or closing a heavy door that shields a specific machine or separates areas from each other. The microcontroller could receive pulse counts from an encoder and calculate the travel distance and speed based on the number of pulses received in a time interval. Applied to the example of a heavy door, the speed could be reduced as the door approaches the end position so that the door cannot slam shut before the operator has left the opening.

Digital position feedback is one of the simplest methods of measuring the adjustment speed. But it is not easy to program, as it does not remember the reported positions after a power failure or shutdown. Smart actuators equipped with analog potentiometers, on the other hand, can receive exact position information from the potentiometers installed in the actuator's gearbox. The transmitted voltage signals report the actuator speed and direction over the entire stroke path. They also save this position so that the device does not have to be moved to the starting position and then reset, even in the event of a power failure.

Reliable position storage allows the development of systems that store the ergonomic settings for each user. This means that the workstation can be individualized for any number of people using factors such as working height, stored work processes or user preferences.

Synchronization

The ergonomic benefits of smart electric actuators become even clearer when several of these actuators are used. For example, the actuators can be set up so that they automatically adapt to loads that are moving. In aircraft construction, for example, where five to ten people work on fuselage assembly at the same time, a work platform is required for work at height. As the fitters move around on the platform, the weight keeps shifting, which can even lead to dangerous tilted positions in extreme cases. Smart actuators distributed at several points under the platform solve the problem by balancing themselves each time the load shifts during a synchronized movement.

The compensating movements on these shifted loads are realized by means of speed control coupled with position feedback. The actuators communicate via an internal network, read the speeds among themselves via the position feedback and adjust their own movements accordingly.

However, if digital feedback is used for this purpose, this results in a stuttering step. Developers can avoid this by integrating both the position and the speed into the control loop and making the adjustment based on both variables. This offers an ergonomic advantage that gently lifts a shifted load over several points.

Controlling multiple conventional actuators is also possible, but results in an imprecise, time-consuming and labor-intensive process that subjects the actuators to additional stress, which ultimately leads to jamming or other malfunctions. In contrast, the synchronization of smart actuators eliminates any uncertainties and results in a balanced, smooth and true-to-position movement.

Real-time monitoring

Smart electric actuators are able to continuously provide monitoring information regarding temperature, current draw, speed, voltage and other variables, enabling advanced condition monitoring, diagnostics and error handling. If the actuator detects a problem, it can either stop mid-stroke or complete its programmed movement and send an error message to the computer.

Based on such feedback, users can check their operations for certain patterns of use, speed and position in order to achieve greater ergonomics, safety and efficiency. This is particularly important in production automation scenarios where multiple devices are integrated. The data collected shows, for example, how often a workstation has been raised and lowered or a door opened and closed. This information can then be compared with previous values or ideal processes in order to optimize the layout of a processing cell. In addition, the recorded operating data can be compared with accident reports, which may result in the need for further ergonomic investigations. For example, if an actuator that operates a crimping tool repeatedly reports an overload, it can show the frequency of errors and indicate in which cell this occurs more frequently and at what time.

Success through diversification

The wide range of functions offered by smart electric actuators allows users to design their systems with simplicity in mind. The ability to control the actuators via digital systems, implement digital or analogue feedback, synchronize multiple actuators or monitor key figures in real time offers the entire range of instruments in one package. So if users want to implement a specific application, they can offer an automation solution that goes far beyond the basic function of a simple linear movement. Smart actuators enable automated processes without the complexity of other automation technologies such as hydraulic or pneumatic cylinders.

The more closely these control capabilities are integrated into the device, the less they stand between users and the added value they expect. The added value manifests itself in the form of employee satisfaction, occupational health and safety and productivity, which ultimately benefits the entire value chain.