Demand for products, supply chains, and worker demographics are all changing, as are working conditions. Motion control is evolving in response to these problems, whether it is creating new or superior technology or expanding the usage of already-existing technologies. Divide the market into two classes to get the greatest perspective on some of these trends:
Motion control within the equipment that is typically portable but not always mobile is known as embedded motion. Think of reconfigurable production lines and AGVs as examples.
Large-frame, high-power fixed equipment for industrial automation
Because each class has its unique set of needs, the following trends have emerged:
Motion Embedded
In embedded motion, controllers, drive electronics, actuators, and even motors are incorporated into a single integrated module. Applications include satellites, where decreasing the size and weight is crucial, as well as instruments like DNA sequencers or ultracompact medical devices. For many of these applications, SWaP, or size, weight, and power consumption, is the magic phrase. Vendors are approaching the issue from many directions to reduce the impact of all these elements.
Miniaturization
A continual push for downsizing and greater levels of functionality is taking place in the embedded motion space (see Figure 1). The entire device architecture must be rethought in order to accomplish this goal. For instance, is it possible to get rid of extra circuitry? Bus capacitors and rectifiers are not typically required for mobile equipment because it typically operates on DC power. The endeavour might centre on reorganising system partitions or discovering a technique to supply functionality using just one subassembly rather than the two or three that were previously required.
The end result is a smaller, lighter device with fewer parts. The number of certification requirements has decreased, which is positive for the aerospace and medical industries. On the negative side, making gadgets can be more challenging. Very small conductors and insulators are frequently patterned, and layered designs are frequently used. Micron-level tolerances are required for pick-and-place assembly. However, businesses are overcoming these difficulties with highly successful solutions.
These gadgets can carry out complicated, multi-axis positioning with a small footprint. As opposed to requiring closed-loop control to be carried out elsewhere, with all the additional wire and separate electronic assemblies, taking care of integration at the device itself has become a more and more popular approach, according to David Henderson, founder and CEO of New Scale Robotics. “The device’s control is within. It only requires DC power and a digital command to move to a certain area.
A plug-and-play system called a “all-in-one system” might combine the CPU, the controller, and the amplifier to make setup and maintenance easier. An alternative would be for a drive to have a generic CPU, allowing users to write their own software to gather data, preprocess it, and then package it. According to Prabhakar Gowrisankaran, vice president of engineering and strategy at Performance Motion Devices, “especially for satellite applications with bandwidth limits, the more they can accomplish on board locally and employ to make intelligent judgments, the better.” For applications where space is at a premium, these types of all-in-one drives are becoming more popular.
Time-to-market can be greatly accelerated by the availability of an integrated solution that provides not only hardware but also code libraries and software development kits (SDKs). Using a commercially available FPGA or DSP to create a solution from scratch may initially appear to be a cost-effective strategy, but the procedure is often more difficult than it appears. In reality, adds Gowrisankaran, “they start with a set of minimal criteria but then features keep getting added. “They understand how difficult the work is. They still have the ability to complete the task, but it will take nine to twelve months now. If they purchase an integrated chip, all current control, control algorithms, and profiles are already built into it. Then you have access to the SDK, which means that 50 to 70 percent of the job is already done. That’s the main value claim.
Without emphasising that smaller isn’t always better, we should end our discussion of miniaturisation. High levels of miniaturisation need customization and can reduce output power after a certain point. Serving the application should be the main priority at all times. It’s important to get the component that will fit into the cavity and complete the work at hand rather than the smallest component that will fit.
Not all embedded motion involves parts that are extremely small. It can also take the shape of an integrated subassembly, such as a propeller-integrated drone motor or a pump used for intravenous medication. The OEM’s primary area of expertise is frequently in the field of medical treatments or diagnostics, especially in the case of medical devices. The application requires motion control, although it may be outside of their area of expertise. Integrated subassemblies outsource their supply chain as well as their automation needs.
The bill of materials for these systems is incredibly lengthy and complex, according to Carsten Horn, maxon’s applications engineering manager. “This prompts customers to inquire about items other than just the motor. They may request that the provider install a full pump mechanism, complete with encoders and electronics. Suppliers who previously only offered components are now much more similar to system suppliers. We note that as a significant trend.
Commercial Automation
Industrial automation is the term for traditional automation, which includes not only factory machinery but also facilities like dockside cranes. In industrial automation, larger motors, heavier loads, larger drives, and more complicated controls are typical. In general, they are cost conscious and use more turnkey solutions. Trends in the industry focus on these issues.
Cheaper Absolute Encoders
The backbone of the industrial world has traditionally been incremental encoders. They are straightforward and affordable, but they have one drawback: they have to be relocated when they first start up or if there is a power outage. Rehoming after a defect can, at best, take some time. Worst-case scenarios include product quality issues or equipment damage. When the power goes off and the computer restarts, absolute encoders keep their absolute position. Switching to absolute feedback can have an impact on applications with an OEE focus, whether that be better throughput or more quality output.
The expense of absolute encoders has been one of the main obstacles, which has limited their use to high-performance applications. That circumstance has changed in recent times. In the past, an absolute encoder might cost up to a factor of ten more than an incremental encoder. That cost differential is more than doubled or even cut in half now. Scott Evans, Kollmorgen’s vice president of strategy, asserts that if price drops persist, even less expensive machines will be able to fully benefit from the decreased cost.
According to Jeff Smoot, vice president of engineering at CUI Devices, “absolute encoders have been gaining underlying momentum for the last four to five years, but adoption has been relatively gradual.” We’ve noticed a significant increase in design work during the past 12 to 18 months. A concerted attempt to flatten the learning curve through education and code libraries has contributed to this in part. Although incremental encoders need a lot of wire, there is a significant ecosystem of controllers and drives that are compatible with the technology. Smoot claims that the absolute encoder supply chain is catching up. And unlike analogue absolute encoders, which needed two wires for every bit, digital ones are now available that greatly simplify and lower the cost of wiring. The industrial automation market is reacting to this.
“I don’t think it’s yet appropriate to forecast ubiquity. “Temperature and vibration limits still need to be addressed,” adds Evans. They don’t yet have that type of traction, but I predict they will in around five years.
Driven Directly
Some of these trends are being accelerated by the shifting technical employee demographic. The machine whisperers are leaving their positions and taking their extensive knowledge with them. Predictive maintenance has become increasingly important as a result, as is well-known. Additionally, the hardware options are evolving. There are various advantages to direct-drive motors. They can be used to produce more compact, lighter, and cutting-edge designs because they are frameless motors that are shipped as separate rotor and stator assemblies and incorporated into the machine. They can also be found in hollow-bore, contained forms. Finally, there are so-called cartridge variants, which have direct drive webs and conveyors and include a rotor that doubles as a conveyor roller (see Figure 2).
Couplings and gearboxes, two components that might cause early failure, are not required with direct-drive motors. They frequently replace the requirement for bearings, which can likewise be maintenance-intensive and prone to malfunction.
Embedded motion systems combine motion mechanisms, controls, and piezoelectric motors.
Piezoelectric motor, controls, and motion mechanisms are all integrated in Figure 1’s embedded motion system. (With thanks to New Scale Technologies)
As with these rollers, the rotor in cartridge-type direct-drive motors can serve as the motion component, obviating the requirement for couplings and gearboxes.
Figure 2: By acting as the motion element in cartridge-type direct-drive motors, as with these rollers, couplings and gearboxes are no longer necessary. (Credit: Kollmorgen)
Direct-drive motors have been reserved for high-performance systems for many years. Direct-drive motors are being considered more often as a more reliable strategy that offers a cheaper total cost of ownership due to their reduced maintenance capability, according to Evans (TCO). Therefore, Evans notes, “you are beginning to see a movement back toward direct drive in applications that were previously not,” merely motivated by cost. “But they are beginning to understand that, once again, if I am an OEM, I own the uptime of the machine, and I have to choose components that are going to survive,” the author said. OEMs are now beginning to recognize the advantages of direct drive, even though they haven’t in the past.
Direct-drive motors do have restrictions, as do other technologies. The amount of torque they can produce decreases with size, even if they can be useful for applications like surgical robots, for instance.
Dispersed Control
It’s not new, but the idea of incorporating intelligence into the push for allowing decentralized governance is gathering momentum. Decentralized control can minimize cabinet footprint and cabling for industrial automation applications with very high axis counts.
In industrial applications, decentralized control is becoming more and more common, according to Evans. In his observation, he notes that “more OEMs are seeking to get drives out onto the machines, especially if the machines have a longer process.” Examples include corrugating equipment, rubber and steel, and virtually any application involving physically long machines or numerous machines closely coupled in series. According to Evans, a common trend with this kind of equipment is toward decentralization and removing at least the amplifier portion of the drives from the cabinet. These drives are becoming more intelligent as a result of their connection to the upstream power supply, which then transmits the information to the control system.
OEMs who are working with pre-existing machine designs might still favor making small adjustments, such as replacing a drive in the panel, as opposed to making significant adjustments to the automation architecture. The (di/dt & dv/dt) issue with carrying a PWM signal through a 100-m cable while switching the motor power at, let’s say, 20kHz, is EMI/RFI: Even a well-shielded cable has the potential to behave like an antenna, disrupting the delicate equipment that is increasingly employed in industrial settings. There is far less radiated noise if you send DC electricity (or even 50 Hz or 60 Hz AC down to those drives and maybe Ethernet communication using CAT 5 or CAT 7 cable. This is because the cables from the drive to the motor are now considerably shorter.
In general, distributed control has a sweet spot with fewer axes or lower levels of synchronization, as was mentioned in the recent drives post. Discuss the best strategy for your application with your vendors.
Greater Control Strength
On the other hand, some highly synchronized, computationally demanding applications, like machine tools, demand very potent centralized controllers. In machine tools, both the component and the cutting tool revolve simultaneously. Due to differences induced in the mounting procedure, particularly if the tool changes are performed manually, tool length varies from machine to machine or even within the same machine. A certain angle may need to be maintained between the tool and the surface, which may be curved.
It is only the beginning of the process to programme the tool with a curve defined by even a million points. A poor part finish will occur from moving the tool from one place to another. The device must simultaneously find a balance between accuracy and speed. The controller must do a regression to create a polynomial that will be used to move the tool, and the operation must be completed in real time. Particularly as part complexity rises, the procedure requires a lot of processing power.
According to Tiansu Jing, Product Manager for Siemens’ Sinumerik CNC product line, “the calculating capability demanded for CNC machine tools are greater and higher.” However, he sees it as a component of a wider tendency. “I believe it is analogous to factory automation, where many motion control functions are now being performed by PLCs rather than just logic control. You need to give the customer more flexibility and do more calculations in the controller itself if you want it to be more adaptable. This is the necessary calculating power, in my opinion, as a key trend.
Modularization
The pandemic’s revelation of supply-chain weaknesses has forced businesses up and down the food chain to reconsider not only their suppliers but also the designs of the goods they are acquiring. There is still room for labour and cost savings in application-specific subsystems like traction drives for AGVs. Recent disruptions have demonstrated the potential for serious issues with higher-level integration that is dependent on particular ICs.
When necessary, a move toward a more modular design has been made in response. “ “Everyone is beginning to question their single-sourcing decisions and whether they still should. The tendency toward modularization is evident if the response to that question is “probably not,” according to Evans. The objective is to simplify customization while simultaneously avoiding the risk of single sourcing. The current situation was brought about by a generational epidemic, but firms have always needed to arrange their sourcing and products to be ready for disruption.
Evans continues, “Companies are starting to restructure the central computational engine of their IPCs, controls, and drives into its own module. Nothing the customer can access. Nothing can be switched out in the field, but if their existing supplier suddenly is unable or unwilling to deliver components to them, they could switch, for instance, from an Intel to an AMD.
The industrial automation slide shows a stronger tendency toward modularization than the embedded motion control presentation. The pinouts commonly vary from IC to IC, making it difficult to just drop in a replacement chip. Swapping out a chip is not as simple as it may appear. Industrial devices are more likely to have the additional space necessary to accommodate this level of modularity, and a modular design may require some sort of mezzanine board to facilitate quick changeover. Applications requiring embedded motion are typically more price, weight, and size conscious. They may not be able to concentrate as intensely on modular designs because higher-level integration is a key component of their value proposition.
Technology used for motion control is naturally flexible to varying motion requirements as well as to demands from the market, the economy, and the environment. Delivering technologies that increase performance and reliability is not the only goal. The motion-control ecosystem is aware of the fact that assisting OEMs and end-users in bringing better products to market more quickly is the primary function of their technology. To that aim, efforts are still being made to make these technologies more user-friendly and better suited to the client base. Many items have drawn-out design cycles. The moment has come to begin looking into choices.