Smart Motion Boosts Machine Productivity

Collaborative robotics, simplified machine design and other automation advances are helped in large part by intelligence in motion control.

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Distributed intelligence has made motion control a much more valuable aspect of automation technology. Motion advances that employ smart actuators—from collaborative robots that can move like humans to modular platforms that simplify machine design—enable OEMs to produce machines that are faster, more accurate and less prone to breakdowns.

“Industrial automation is moving in the same direction as smartphones, where a convergence of computing power, software and hardware is creating more powerful, more integrated platforms,” says Tom Geiger, Festo’s head of electric automation for the Americas. “Smarter devices are just the starting point.”

Low-cost processing power is enabling things that weren’t affordable previously, says John Kowal, director of business development for B&R Industrial Automation. “You can think about doing things a different way, which sparks innovation,” he says. “Servos, for example, are now replacing many mechanical devices. They apply very precise control, so you can automate and smooth out processes.”

Pressure to raise the minimum wage is also a driving factor in OEM and end-user demands for more intelligent motion control, according to Kowal. “Automation is inevitable; motion is at the heart of it,” he says. “At the same time, intelligent devices that make machines simpler to operate and processes more consistent also make it easier for less-educated people to have a job.”

Intelligence at the edge
“You can now afford to have a low-cost computer chip at the I/O slice, which reduces the distance between detection and reaction. It results in faster, more precise actions. In gluing applications, for example, distributed intelligence lets you achieve more accurate patterns, which improves holding power while using less material,” Kowal says. “Intelligent devices like drives can process information without going back to the PLC for instructions. As a result, one-second response rates for intelligent I/O and loop closure rates for drives of hundreds of microseconds are now common. This faster performance is critical in high-volume packaging equipment like labelers, heat sealers and stretch wrappers.”

B&R created a smart motion solution for Weiler Labeling Systems when it introduced a new glue-free labeling machine. Used to produce cut-and-stack labels for the pharmaceutical industry, the labeler uses an adhesive that is coated on the backs of labels during production and then activated by a water spray just before the label is attached to a container.

The motor-intensive process demands incredible speed and accuracy, as well as deterministic communications. The B&R system combines centralized machine control with distributed I/O and motion control that all communicate over Ethernet Powerlink. The cut-and-stack labeler features 12-24 stepper platforms on its turret, as well as servo motors that drive the feed screw, the turret and the machine’s cut-and-stack modules.

The servo and stepper motors must be synchronized with microsecond accuracy, along with the inline vision and printing equipment. Powerlink’s fast communication times and trigger accuracy, as well as product tracking capabilities, help solve many of the challenges associated with high-speed serialization coding and labeling.

“B&R’s stepper motors offer similar functionality to servo motors, while being both smaller and lower priced,” explains Philippe Maraval, Weiler’s vice president of sales and marketing. “As a result, we’re able to offer our customers pricing comparable to a traditional mechanical cam machine with the flexibility of a servo machine.”

Helping robots work with humans
Collaborative robotics is a fast-growing product category that leverages smart actuators. “Our Series Elastic Actuator technology is an example of an electronic actuator that enables a robot arm to adapt to variability in its environment the same way human arms do,” says Anthony Robson, hardware product manager for Rethink Robotics.

An operator programs a robot by moving its arms to demonstrate how to perform a task, which stops when physical contact is made with a human during a cycle. “This functionality enables collaborative robots to work in tandem on the factory floor and be reprogrammed limitlessly to perform a variety of tasks,” Robson explains. “Having a flexible robot arm with the ability to bend on contact, touch and interact with parts, fixtures and machinery designed for human operators creates a new, cost-effective way to automate production.”

In the past, the entire work cell had to be redesigned to accommodate rigid automation, Robson says. “Any misalignment with traditional robots could also be disastrous,” he adds. “A robot that can flex on contact and sense force can be trained to adapt to variability and move much the way human arms perform tasks such as accurate placement. This also allows companies to use their human workers for more valuable and complex tasks that require problem-solving.”

Intelligent actuators of all types are changing the way automation systems are being designed, Robson says. “Not only do these flexible new solutions support high-mix, short-run production needs more effectively than traditional automation, they also provide a window into what's happening in production. Equipped with sensors, they can feed data up to Big Data systems, where manufacturers can utilize artificial intelligence and advanced analytics to monitor for trends and insights on the production line, so you can adjust and optimize accordingly.”

Adapting in real time
One of the more important advances in motion technology is the introduction of independently controlled movers, particularly in conveyor applications. “With intelligence built in at the conveyor level, you can now individually control each product or box on a conveyor line. This allows the system to detect load and mechanical changes and alert the operator, providing an effective compensation tool,” explains Oliver Haya, a product manager for Rockwell Automation.

“Every box has a unique identifier, and each servo-controlled mover has a permanent magnet in it. Intelligent feedback allows the system to automatically detect the position of a box in relation to all the others on the line,” says Neil Bentley, MagneMotion product line manager for Rockwell Automation. “Independent mover control gives machine builders significant flexibility because they don’t have to add sensors or external devices to control the timing. Individual control means you only have to move one item at a time, so you can build smaller, more flexible machines with new capabilities not possible before.”

Benefits to the customer include more reliable machine performance with fewer things to fail, and also the ability to process multiple products on the same conveyor line, Bentley adds.

An improved operator experience is another advantage of independent mover control, Haya says. “Since timing is less rigid, there’s less need for an operator to interact with the machine,” he says. “He’s also more likely to be able to prevent jams from ever happening since he has more information on the machine’s operation before a problem can occur.”

Rockwell Automation’s iTrak technology made it possible for machine builder Cama Group to design a cartoning machine with a completely new layout and functionality. The modular, scalable motion control system independently controls multiple magnetically propelled movers on a track. Its servo transport engine is completely programmable for deceleration, speed and positioning.

Cama’s cartoning machine offers multiple benefits to the end user: optimized format changeover, reduced footprint, lower maintenance needs and energy savings. The automatic changeover doesn’t require manual intervention and is key to the machine’s improved performance.

In terms of overall machine productivity, there’s one other important benefit from the redesign: In case of an emergency stop, there’s no need to restart the system. “In traditional packaging systems, motors need some seconds to find their home position in case of restart, says Riccardo Panepinto, operations director at Cama. “The absolute encoders set on each iTrak mover retain position data during loss of power and allow the machine to restart immediately.”

Integrated for efficiency
Though most OEMs still buy drives and motors separately, the demand by end users for more efficient and productive machines is driving greater market acceptance of integrated drives and motors for many applications. “In fact, some actual applications, such as fans and pumps, are being integrated with the motor/drive and sold as one device,” says Rick Kirkpatrick, product manager for AC variable-speed motors at Baldor Electric. “This is particularly true for ECM [electronically commutated motor] motors and drives. The driving factors for this trend are reduced installation costs and the associated efficiency gains.”

By machine-mounting the integrated unit, OEMs don’t have to set aside panel space for drives. There’s also no need to install large or force-vented or air-conditioned panels for many small power applications. In addition to smaller control panels, machine builders also reduce labor costs because there’s only one unit to install.

These devices can sit directly on the I/O communications structure of the programmable logic controller (PLC) or other controller, so there’s no need for a remote I/O rack in the vicinity of the drive or hardwiring of the I/O to the drives. Integrated drives/motors also support both industrial fieldbuses and building automation communication links.

“These integrated devices enable OEMs to provide their customers with a lower total cost of ownership solution, which is a real competitive advantage in today’s business environment,” Kirkpatrick adds.

Pneumatics are evolving
Pneumatic technology suppliers like Aventics are working to integrate advanced capabilities, such as condition monitoring, diagnostics features and integrated proportional valves, on valve components. By using feedback loops similar to those used in electric drive systems, these advanced devices improve the ability of machines designers and end users to have all the performance data they need to manage machine productivity, throughput and quality.

Pneumatics-driven systems can move products through machine sequences at high speeds. Typical systems can support motion sequences of up to 5 m/s using standard components, with higher speeds possible in specially engineered applications. These rates satisfy a significant percentage of the throughput rates found in packaging machine applications, such as pick-and-place systems.

Along with more sophisticated control and integration of digital intelligence and communications capabilities in pneumatic architectures, the valves that control the distribution and sequencing of the pressurized air that drives individual actuators are also becoming more compact and modular. High-grade polymers are being used to reduce valve weight, which is key to keeping the valve as close as possible to the actuators it controls.

Minimizing the distance from the valve to the components helps reduce installation and connection costs. More importantly, it improves overall pneumatic energy efficiency. Air is considered an expensive commodity in many operations. If you can mount a compact, lightweight manifold close to the cylinders it is driving—even mount it on the end effector itself—the lighter weight enables the machine designer to use smaller actuators. Lighter weight plus smaller cylinders add up to less energy needed to supply the requisite pneumatic flow.

Benchmarking with virtual machines
If smarter devices are just a starting point in this new world of machine design, as Geiger says, imagine if you could design and test a virtual machine long before the real machine is built or installed. The convergence of hardware and software, such as Festo’s CPX modular automation platform, is making that possible.

“Unlike traditional fixed automation hardware, this seventh-generation valve terminal platform makes it easy to add and configure modules for valves, sensors, control inputs/outputs and any other devices needed for a particular machine,” Geiger says. “These building blocks create a cyber-physical system that combines function, process, hardware and software in the design stage and serve as a bridge between virtual and real machines.”

A virtual machine establishes a theoretical baseline for how the machine should ideally function, and enables it to be designed to work at a specific level of functionality, Geiger explains. “This gives you a benchmark against how the machine actually functions in the real world, allowing you to adjust or optimize the actual equipment during its years of operation.”

Trying out a design in a computer-aided design (CAD) environment leads to shorter design cycles and greater ability to customize a machine for a customer’s exact needs, Geiger says. “While it’s still very early days in this higher level of convergence, the pieces are starting to come together and will drive innovation to the next level,” he says. “Customers will benefit by getting products to market faster, achieving greater flexibility in their product mix or packaging approach, and gaining insights they can use to optimize a machine’s operations.”

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