With its integrated servo motors, STXI Motion wants to pave new paths in high-end applications that were previously unsuitable for decentralized drives. – Image: STXI Motion Ltd.
Decentralized Drive Technology
The Trend Towards Cabinet-free Machines
Decentralized drive technology is a rapidly growing trend that is interesting for a wide range of machine builders and OEMs – from those developing more compact and cost-effective machines to those wanting to improve the modularity of their existing machines. Users of decentralized drive solutions can benefit from various advantages, such as more freedom in design, more flexibility, and more efficiency, in contrast to reduced installation and cabling effort and less space required for the machine.
The market for decentralized drive technology traditionally divides into two different segments: on one hand, motors with integrated servo controllers and on the other hand, decentralized servo controllers placed near the motor they drive. The main difference between an integrated motor and a decentralized servo controller is that in the former, the control electronics are physically integrated on the top or back of the motors, while the decentralized servo controller is mounted near the motor. In the latter case, additional power and encoder cables are required to connect the motor to the servo controller, while in the former, these connections are made within the integrated motor. Mounting the control electronics directly on the driven motors and axes or nearby can significantly reduce cabling effort and eliminate the need for a control cabinet.
Decentralized drive technology is becoming increasingly important for OEMs under strong pressure to reduce the footprint of their machines and costs. For some, integrated motors are essentially the standard option when considering a cabinet-free machine design.
Examining the trends prompting OEMs and machine builders towards decentralization helps better understand the potential benefits and challenges that integrated motors offer in various industries and applications.
The Future of Decentralized Drive Technology
The outlook for the market of decentralized drive technology is positive: forecasts predict that the sector’s share of the overall market for servo drives will increase from 2 to 5 percent between 2021 and 2026, thus growing significantly faster than the overall market. The latest figures from the global market research firm Interact Analysis predict a cumulative annual growth rate of 12 percent for the market of decentralized drive technology in the same five-year period. In comparison, a cumulative annual growth rate of 6 to 8 percent is forecast for all other segments of the servo market between 2021 and 2026, with multi-axis servo drives at the higher end of this forecast and standard servo motors at the lower end.
According to Tim Dawson, Senior Research Director and Head of Motion Control at Interact Analysis, the market for decentralized drives reached a value of 381 million US dollars in 2021 and is expected to grow to almost 700 million US dollars by 2026. Future growth in the market for decentralized drive technology is particularly strong in industries such as packaging, intralogistics, and food and beverage processing. These are industries where more complex machines with advanced drive technology and many servo axes are used, and therefore a modular concept is advantageous. “It should be noted that the packaging industry, in particular, is a growth industry where companies often revise their concepts more frequently than in other industries, allowing trends and innovations to take hold more quickly,” Dawson says. He also refers to the increasing demand for low-voltage products (<100V) in certain industries that require a safe voltage range, including packaging, intralogistics, medical and laboratory equipment, semiconductor and electronics manufacturing, as well as collaborative and mobile robots.
US Market Grows Particularly Fast
In Europe, decentralized solutions have long been popular as saving space in factories has always been a crucial concern for end customers due to high land costs. Increasingly, US customers now also desire more compact decentralized machines. “In the past, demand in North and South America was lower because the American market is dominated by the USA, where space and areas are less limited, so factories are often larger,” Dawson explains. “It should be noted that the packaging industry itself is a growth industry where companies often revise their concepts more frequently than in other industries, allowing trends and innovations to take hold more quickly,” Dawson says. Due to the historically limited presence of decentralized machine architecture in the US market, modularization is leading to particularly rapid growth there.
Moreover, decision-makers are increasingly demanding cost reductions wherever possible in response to inflation and economic pressure caused by ongoing supply chain issues and a weakening economy. This pressure for cost reduction makes the move towards decentralized drive and the associated lower manufacturing and operating costs more important than ever.
Motion Control without a Control Cabinet
A key trend in the market for decentralized drives is that customers are moving towards decentralizing the main servo axes of machines. Initially, the focus of decentralization was mainly on a range of less demanding basic applications, such as auxiliary and service axes, where drives with smaller power and lower performance were sufficient. However, as the demand for higher power increases, modern decentralized drives are being developed to meet these requirements.
The area of cabinet-free machines is developing similarly to the entire machine construction sector, where technical requirements are becoming increasingly demanding as customers insist on more powerful decentralized drives. OEMs are increasingly demanding decentralized drives that support various fieldbuses and offer modern functional safety features. Ultimately, market demand will dictate that the safety technology and functions offered today in cabinet drives are also made available in decentralized drives – from Safe Stop 1 (SS1) to Safely Limited Speed (SLS). Modern integrated servo motors, as developed by STXI Motion, open up new possibilities for high-end applications that were traditionally unsuitable for decentralized drives – especially by providing higher power and performance to both auxiliary and main servo axes.
Conventional control cabinet construction today requires a high proportion of manual labor, representing a significant cost factor and potential source of error. Centralized control cabinets require time-consuming manual installations and cabling, including laying long cables through the machine, which take up a lot of space and increase susceptibility to interference. This often leads to expensive machine designs and high production costs.
The decision for decentralized rather than central solutions typically depends on the machine builder’s design philosophy. Nonetheless, there are two main reasons why decentralization can be financially and technically sensible. First, for machines with a large number of axes, which are usually long and used in industries like intralogistics, packaging, printing, wood processing, or textile industry. The decentralized arrangement of the drive with multiple axes in long machines offers the greatest savings in installation, wiring, and cabling; it reduces machine installation by up to 40 percent while simultaneously reducing the space requirements and design constraints of the machine.
Second, for applications where the motor is mounted directly on the axis it moves, such as a rotary table or a cartesian system, where the motor is mounted on a moving axis. If the motor moves, the cables must also move, increasing the complexity of the mechanics (e.g., cable carriers or slip rings) and the likelihood of material wear and fatigue. Using integrated motors in these applications significantly reduces complexity as the number of cables, energy chains, and slip rings can be greatly reduced. Consequently, with fewer power and signal cables, the space requirements and sources of error are reduced.
Furthermore, the use of plastic parts and cable insulations in cleanrooms, where the concentration of airborne particles is controlled, is problematic. The advantage of a decentralized solution in this scenario is that it requires significantly less cabling effort compared to all other possible solutions.
The most obvious reason for switching to a decentralized drive is cost reduction. The profitability of a decentralized drive technology solution is best considered in terms of total operating costs.
A solution with decentralized drive technology saves money from the beginning of the design process through the production cycle to the operating costs at the end customer. Material and labor costs decrease due to simplified cabling and the reduction of time- and cost-intensive control cabinet installation, especially stripping, setting ferrules, and clamping. In addition, the machine’s operating costs are reduced, e.g., by eliminating the need to cool the control cabinet with energy-intensive air conditioning units. Beyond the direct financial savings, additional benefits arise, such as saving production area due to a smaller footprint and the ability to design modular machines more easily.
As more OEMs decentralize the main machine axes and demand for modularly designed machines continues to rise, the need for modern decentralized solutions is growing significantly. On its website, STXI provides detailed information on how decentralized, integrated motors can improve the design of modern machines and have a positive impact on total operating costs.
Image: STXI Motion Ltd.