On the Verge of the Digital Age

Increasingly connected electrohydraulic systems and machine controls allow the high degree of controllability that’s essential for automated operations.

Proactive Dozing Control logic from Komatsu opens up application possibilities for machine control technology, like allowing operators to use automation for general site clean-up and backfilling trenches.

An intense focus on connectivity and the digitalization of seemingly every aspect of off-highway vehicles not surprisingly is impacting mobile hydraulics and machine controls as well. Increasingly advanced solutions are being revealed at every machine redesign.

For example, Komatsu America recently introduced its Proactive Dozing Control logic, a fully-integrated control system that allows operators to perform auto-stripping, auto-spreading and high production dozing, as well as finish grading. Built on the company’s existing intelligent machine control, the system uses global navigation satellite system (GNSS) positioning in conjunction with an inertial measurement unit (IMU) to calculate precise position. The control system communicates with the dozer’s hydraulic controllers, engine controllers and the machine controller.

Lift and tilt settings in CASE F Series wheel loaders can now be adjusted with two new 3-way rocker switches (high, medium, low), allowing operators to adjust the responsiveness of the loader lift arms independently of the attachment tilt functions.

“Traditionally, GPS machine control focused on finish grade, which meant operators only used the technology approximately 10 to 20% of the time. Proactive Dozing Control logic now lets operators use automation any time, whether for general site clean-up, backfilling trenches and more,” said Derek Morris, product marketing manager, Intelligent Machine Control and Smart Construction for Komatsu, in a statement.

A key differentiator of Komatsu’s system is that it collects data at the tracks—not at the blade—allowing the system to make calculated decisions based on the current terrain around the machine. “By collecting data at the track level, we’ve created machine control that is far more advanced, offering an entirely new level of efficiency,” Morris said.

An electrohydraulic drivetrain is a good first step to electrification since most of the hydraulic systems can be kept on the machine and has a lower impact on the overall machine design. A Poclain setup is shown.

Another recent example, CASE Construction Equipment announced in September that its F Series compact wheel loaders have been upgraded with new electrohydraulic controls. The adjustable controls provide operators with advanced bucket lift and tilt functionality, a new inching pedal with electronically-controlled valve for greater control at slow speeds, and automated bucket metering for more precise movement while metering or sifting material.

Electrohydraulic (EH) systems can be a convenient first step to electrification since most of the hydraulic systems can be kept on the machine, lessening the impact to overall machine design.

Cascade Drives, developer of heavy-duty electric linear drives, believes electromechanical actuators are well suited for automated operations due to the high degree of controllability and available motor data they offer.

“The trend to electrohydraulic transmissions for battery-powered off-highway vehicles will speed up the development of connected machines and digitalization,” said Jean Heren, engineering manager – Electro-Mobility Program at Poclain Hydraulics.

With the development of decentralized electrohydraulic systems to improve energy consumption and machine range, the main challenge will be to develop the appropriate management systems of these interacting systems and technologies while ensuring vehicle functional safety, according to Heren.

Efficiency opportunities

Electric actuation is becoming a more popular solution as vehicles become increasingly electrified, but experts agree that there are still many applications where hydraulic actuation makes the most sense. In these cases, companies are working to make hydraulics more efficient.

Taking a system-wide approach to efficiency is key, according to Astrid Mozes, VP of Power & Motion Controls, Eaton.

“Instead of looking at one component over another, our engineers are using embedded sensors and software to connect components, creating intelligent sub-systems that can dynamically adapt and respond to changing conditions in the field,” Mozes explained. “This intelligence at the component and subsystem level makes machines easier to use, more precise and improves efficiency. We are also looking at ways to reduce hydraulic losses and regenerate energy through novel products.” He offered Eaton’s independent metering mobile valve, CMA, as one example.

Digital tools play a big part at Bosch Rexroth in developing and testing code that works on the controller.

Downsizing components and optimizing functionality are other significant trends. Gary Gotting, product manager at Sun Hydraulics, rattled off a list of pathways to improve the efficiency of hydraulic systems: “Lower power usage (watts), reduced pressure drops, reduced heat generation, and multiple functions in one valve to reduce package size and weight.”

Poclain also has developed products that maximize output with downsized components. But using an e-motor to drive the hydraulic pump offers possibilities to further optimize energy usage, according to Heren.

“E-motor can work four quadrants such as the typical close-circuit hydrostatic drive (forward, reverse, traction, retardation). This means capability to recover kinetic and potential energy that was not possible with the IC engine alone,” he explained. “Hydrostatic also brings the benefit of a variable transmission ratio, through adjustment of pump displacement. This feature helps electric components working into their sweet spot and offset their efficiency drop at high torque low speed of operation.”

Electrifying machines

For off-highway applications, hydraulics has always been the obvious choice, not only for its proven robustness but also because it’s an inexpensive solution. “With electrified powertrains, the strive for improved battery range is driving the development of high-efficiency linear drives,” said Kristian Floresjö, CEO of Cascade Drives, a Swedish company that develops electric linear drives for heavy-duty applications. He noted that the use of electromechanical actuators (EMC) are likely to increase in the mining industry—where electrified and automated machines have been employed for quite some time — because of safety (risk of fire) and controllability aspects.

Cascade’s technology is based on a rack-and-pinon principle, but it uses multiple pinions on a double-sided rack, keeping size and inertia low, according to Floresjö. Applications for its products include material handling, construction equipment and mining, as well as industrial uses like presses and pressure boosters.

Eaton’s boom stability control system uses the company’s CMA advanced control valve (shown) equipped with an algorithm that stabilizes the operation of a machine with a flexible boom.

Another area in which electrification is making significant inroads is smaller machines working in urban environments, where tougher legislation on emissions requires use of highly efficient and less-noisy equipment.

“Here is the next opportunity,” Floresjö said. “Those are all features proven by EMCs. From a product development point, it also fits well starting off with smaller machines.”

Sun’s Gotting says that compact hydraulics like SICV (screw-in cartridge valve) are well placed to be relevant in this arena. He provided a glimpse into what we can expect related to hydraulics and controls in the coming years: “Higher pressures, smaller hoses/connections, leak free, and embedded controls that are semi-autonomous to speed up the central processor and decide default conditions in emergencies, etc.”

Small machines can be challenging when it comes to space and weight limitations. “Heavy-duty hydraulic solutions offer compact solutions, such as wheel motors, for example,” said Poclain’s Heren. “This helps saving space and reorganize components in order to increase the size of the battery pack for a longer machine range.”

Terry Hershberger, product manager for Mobile Hydraulics at Bosch Rexroth, noted that the concept of functional movement on the machine is essentially the same, whether it’s electrics or hydraulics doing the work. “It could be an electric motor that’s driving a gear pump or load-sense pump through a valve out to the cylinder, or maybe we even start to talk in the future about an electric motor driving a small gear pump that’s on the cylinder itself and we control it that way,” he said. “In either case, when we start to talk about larger electric motors, the functions of movement on the machine are still known—the kinematics, those sorts of things are known. It’s just what the methodology is to drive the electric motor or the hydraulic pump or hydraulic valve.”

As machines begin to use more electric power, there are certain services where it makes sense to switch from hydraulic to electric actuation, according to Mozes. “However, in the many cases where hydraulic actuation makes the most sense, we are working to make hydraulics more efficient,” he said, adding that the Hydraulics Group works with Eaton’s new eMobility business to develop optimized solutions that manage hydraulic and electrical power for off-road equipment.

Going digital

So, are hydraulics in the “digital age” yet? According to Gotting, the simple answer is “No.”

“Connectivity is an issue. Wires are the weakest link,” he shared, adding that the pathway ahead must rely on robust wireless comms, possibly a mesh network like Zigbee. He believes this is achievable within the next decade.

Still, the trend toward increasingly digital solutions has been under way for several years, led by early adopters in niche markets, Heren noted. “Nowadays, IOT solutions enable [us] to get precise machine on-field duty cycle, representative of their exact utilization. Such data collected via the cloud brings valuable information to optimize the sizing of the solution, but also development and validation of the controls,” he explained.

Advances also are required to achieve greater levels of automated operation in off-highway vehicles.

“Finer, more repeatable controllability is needed and demanded for smooth operation,” said Gotting.

Floresjö agrees: “High controllability is essential for future autonomous vehicles.”

Digitalization and connectivity are the keys to enabling the extraction of operational data that can generate optimization possibilities, Floresjö stressed. “Electromechanical actuators are well suited for the task due to the high degree of controllability and available motor data. Achieving an equal degree of controllability with hydraulics requires complex and expensive components,” he said.

The EH movement has allowed fleets to see what’s going on with their machines, like monitoring the engine and fluid levels. Taking this a step further— updating various aspects of machines via flash over-the-air—requires more intelligence and data security, said Bosch Rexroth’s Hershberger.

“The bigger question is, how is the controller able to handle the functional safety requirements that are on the machine?” Hershberger said. “Just observing information is one thing but doing something remotely, it’s really important that the machine performs at the level it’s designed to. The intensity of what has to be done on the controller itself is much more than in the past.”

Hydraulic equipment—controls included—will look totally different as automation advances, according to Eaton’s Mozes.

“To be able to achieve the levels of performance, flexibility, and automation customers are demanding, the hydraulics systems and components will have to be digitally controlled with the capabilities of tuning behavior through software,” Mozes explained. “This digital foundation also provides the ability to provide improved diagnostics and health monitoring, which is also in high demand. The continuous improvements in microcontrollers, sensors and data analytics will be key enablers of the growth of the ‘digital age.’”