As Industry 4.0 initiatives bring more and more industrial axes of motion into the realm of automation, the need for cost-effective control across them grows as well. Advances in robotics, connectivity, cloud computing, artificial intelligence, data analysis, mobility, and numerous other areas are converging to push global industry to new plateaus of operational efficiency and creating roles for automated actuators in places previously thought impractical.
Enabling actuators to play a central role in Industry 4.0 initiatives has been the integration of microelectronics into what were previously mechanical systems. The use of just a few wires to connect power sources and networks improves actuator controllability and design flexibility for machine builders, while simplifying installation, diagnostics, and maintenance for end users. These factors combine to enable automation on previously manually operated axes, which can contribute to increased efficiencies in plants, vehicles, and buildings. The most important benefits a design engineer can expect from this new generation of smart actuators include:
Low-level power switching (PLC compatible). Traditional actuators often rely on large, power-inefficient relays or independent controllers to extend, retract, or stop the extension tube. Onboard electronics implement H-bridge-type switching inside the actuators, making them easier to control with low-level power signals from external sources. This enables programming of the embedded electronics without the need for complex bus communications while reducing electrical shock hazards. Low-level power switching also simplifies design by allowing the use of lower-rated control components and puts less stress on system batteries and charging systems. Managing power with onboard electronics can reduce current at the switches or contacts from 20A to less than 22mA, enabling a more efficient and less expensive system design.
Dynamic braking. Once the power is cut to an actuator, it could take between 5 and 10 mm of coast before the actuator arrives at a full stop, depending on how the actuator is mounted. The dynamic braking feature reduces this coasting to about half a millimeter by electronically forcing a short between the motor leads inside the actuator. This improves repeatability and positioning capability.
End-of-stroke indication. Confirmation that an actuator reached either end of its stroke is important for safety and performance, especially in connected operations. It can provide, for example, an inter-loop function between two mechanisms. Or, if the actuator is used to lock a device into place, a simple LED light triggered by the output can confirm that it is locked, protecting the operator from unsafe conditions while extending the working life of the actuator.
Improved position feedback. Knowing exactly where the actuator is at every point of the stroke is a major benefit of integrated electronics. This can be accomplished by embedding a potentiometer, which would deliver absolute position feedback immediately, or by embedding an encoder that would provide incremental feedback indirectly by counting and reporting on pulses. Such advanced position control enables programming of the drive to perform with an infinite number of movement profiles and custom motion strategies; for example, users can program the actuator to seek forward a few millimeters or make a small set of movements back and forth to reach a desired position. And because the system knows what it is supposed to do and monitors performance in real time, it can flag potential variances and trigger advanced algorithms to manage alarms, corrections, or shutdown.
Condition monitoring. Smart actuators can also monitor their own health, providing a safety net for actuator operation. They can monitor temperature and shut down at anything that indicates an overload — both in extension and retraction — which provides consistent fulfillment over the life of the actuator. The electronics know whether the system is receiving enough voltage for the job at hand and can adjust accordingly. They can accumulate data on the number of cycles performed and pace of operation across shifts. Having such timely fault detection is increasingly critical as larger, integrated automation schemes become more dependent upon actuators.
Real-time communications. Key to many Industry 4.0 projects is the ability of smart actuators to communicate across a network. The position feedback, end-of-stroke indication, condition monitoring, and diagnostics can be shared across a J1939 CAN bus, PROFINET, Ethernet/ IP, or other industrial network protocols, integrating operations and improving maintenance efficiency. Previously manual activities can now integrate with larger and more complicated control schemes and workflow strategies.
Through such networks, smart actuators are currently delivering solutions in four main areas: industrial automation, operation of off-road vehicles, structural automation, and patient care.
Industry 4.0 in the Plant
In industrial settings, smart actuators are used in applications requiring maximum controllability and connectivity, including material handling, intermittent load management, robotics, automated guided vehicles (AGVs), and synchronized load management.
Material handling. Manufacturers of logistics trains are increasingly deploying smart actuators to help increase load capacity, regulate operations, and reduce maintenance. Low-level switching (PLC-compatible), verified positioning, and end-of-stroke shutoff are among the features frequently applied in these applications.
Intermittent load handling. Industrial tasks such as raising or lowering a conveyor to handle cartons of various sizes can be handled cost efficiently with smart actuators. If such adjustments are needed only a few times a day, automation with conventional technology would be difficult to justify. Because smart actuators have minimal external infrastructure requirements, they can be deployed cost effectively. Furthermore, the use of smart actuators also might enable analysis of data, which could improve the process by optimizing the frequency of adjustments.
AGVs/robotics. AGVs that move around the plant, receiving goods from conveying stations and transporting them to other stages of production or delivery, can benefit from smart actuators. As the AGV approaches a conveyor, for example, it could signal an actuator to open a hatch and select goods from that hatch using image recognition technology. Once filled to capacity, the AGV moves to the next station. Such integration likely would not have been feasible — or even considered — prior to Industry 4.0 innovation. Smart actuators are also being used in automated valet parking systems in which patrons use their smartphones to signal that they are ready to pick up their cars, and an actuator-driven, robotic assembly delivers their car to them.
Synchronized load balancing. For large work platforms, smart actuators can be synchronized to self-correct as loads shift. For assembly stations, they can provide similar ergonomic lift support for off-center or awkward loads. For lift gates, they can enable smoother handling without the complexity and maintenance requirements of a traditional hydraulic solution. For industrial logistics trains, they can automatically correct imbalances between the front and backend loads. And for doors on ovens and large processing equipment, they can enable smoother, safer opening and closing.
Industry 4.0 Off-Highway
Smart actuators are also supporting innovation in the mobile off-highway (MOH) market on agricultural and construction vehicles, marine vessels, and even public transportation. End users are seeking improved efficiency and simplified wiring.
Ergonomics. Standard operating protocol of some MOH vehicles requires raising the hood to check engine compartments before each run; however, as a trend toward larger engine compartments requires heavier hoods, these are becoming more difficult to handle. Deploying an actuator on either side of the hood might help raise and lower it, but larger hoods can buckle. Deploying an actuator on both sides of the hood and synchronizing them across a vehicle network, however, results in more ergonomic, safer, and better maintained equipment.
Integrated control for construction and agricultural equipment. Large equipment often features multiple functions that have traditionally been isolated or dependent upon multiple external structures such as switches and cables. Today, combine manufacturers can use J1939 networking capability to synchronize control of actuators across more than 20 axes, including those controlling a rock trap door, gate latch, ladder, grain tank, and auger.
Industry 4.0 in Facility Automation
In structural automation and patient care, smart actuators are providing ease of control, improved safety, and sometimes quieter operation.
Louver control. Actuators can be timed to regulate the entry or obstruction of sunlight into a building at various points throughout the day.
Solar energy optimization. To store maximum energy, solar panels must move in synchrony with the Sun. One solar panel manufacturer accomplished this by using the J1939 CAN bus protocol to synchronize operation of large solar panels as they track the Sun's position, minimizing impact of wind shear and reducing the need for specialized supports.
Patient care. With patient-handling equipment in health facilities, synchronization can improve the quality of care by controlling operation of lift tables and columns, and stair lifts.
Connecting the Future
Many of today's Industry 4.0 applications involve actuators connecting with other actuators in intelligent ways, but we are well on the brink of something much bigger. Given their controllability and communications capabilities, it is not difficult to imagine extending the reach of smart actuators for increased integration with other similarly enhanced sensors, data acquisition devices, and production equipment. These advancements have set the stage for production and automation engineers to define the actuator applications that will shape the next generation of industrial innovation.
This article was written by Håkan Persson, Global Product Line Director – Actuators, at Thomson Industries, Radford, VA. For more information, visit here.