Looking for a Better Image

February 1, 2016

Terry Costlow

As design teams work to continually improve operator efficiency and comfort, many are focusing on the critical role displays play in human-machine interfaces. HMIs are the link to the functions that actually do the work, so they play a central role as equipment suppliers race to help operators do more work in less time.

For years, development teams have made ergonomics a central focus when these user interfaces are being designed. This focus has expanded to flat panel displays, which are now a central factor in helping operators work longer at peak rates before fatigue sets in. That’s vital in commercial equipment.

“Ergonomics are critical in commercial and off-highway vehicles because drivers and operators are in the vehicle for long periods of time,” said Manuela Papadopol, Marketing Director at Elektrobit, which makes HMI design tools.

Many ergonomic efforts focus on mechanical aspects such as joysticks and seats, but displays must also be designed to maximize operator efficiency. Well-designed screens can have a huge role in reducing eyestrain that tires people out.

“Cabs use more and more glass and therefore displays must be very bright,” said Christiana Seethaler, Product Development Director at TTControl. “The displays of the HY-eVision2 family use an LCD with a luminosity of 500 cd/m2 and are therefore readable even under direct sunlight. A non-reflective surface of the glass front prevents disturbing reflections.”

Clearly better

Not all the techniques for reducing operator fatigue are obvious. The brightness levels in the cab can play a big role in keeping drivers alert and focused. Some designs change to respond to shifting ambient light conditions.

“An ambient light sensor enables automatic dimming to adapt the luminosity to the surrounding light conditions,” Seethaler said. “This enables different day and night designs for optimized ergonomics to avoid operator fatigue, thus maximizing safety and efficiency. Ergonomics can be further increased by using 3D and transparency effects due to hardware acceleration.”

The ability to create 3D graphics can be beneficial in the complex world of vehicle controls. It adds realism and separates some visuals from conventional 2D imagery. However, HMI specialists note that 2D and 3D components must be mixed in a meaningful way that’s understandable, not perplexing.

“Construction and farm equipment have very sophisticated mechanical components, like loading arms, pickers, tillers, dumpers, and robotic features,” said Mike Juran, CEO at Altia, a supplier of user-interface engineering tools. “These are best visualized and controlled with a 3D representation on the screen. On the other hand, menus, lists, and numeric information is best viewed in 2D. Using a 3D paradigm for these menu components is confusing, so the proper mix of 2D and 3D is critical.”

Display imagery also plays a central role in keeping operators focused and engaged with controls. That can be especially important when automated tasks are being performed. When cameras and well-designed graphics are available, it keeps operators involved so their attention doesn’t drift from the task at hand.

“Cameras that are typically attached to the display panel in the cabin allow the operator to supervise automated and repetitive tasks from a different perspective,” Seethaler said. “Overlay graphics offer the possibility to enhance the camera picture with graphic elements, e.g., to indicate the limits of the working area. Picture-in-picture functionality allows the display of other important information like alerts next to the camera image for increased safety.”

Pretty pictures

Flat panel displays continue to improve, letting HMI designers to get very creative with imagery. It’s getting easier and less expensive to show operators many different types of information that can be managed with a variety of input devices.

“You can easily create individual 2D and 3D components and overlay them, independently animate them, and independently control them with the touchscreen, button, knob, or joystick,” Juran said. “The visual components can even have a semi-transparent appearance so you can overlay the menus on top of the 3D representation when appropriate. Equally important, our code-generation tools can make these 3D/2D HMIs run on inexpensive microprocessors. That means you don’t need a $1000 gaming computer to run the HMI, you can do it on chips that cost tens of dollars.”

HMI developers are also using standard hardware and software modules to trim costs and shorten development time. For example, network connections can be easily designed using software that’s written to link to common architectures. Standardization also helps increase competition.

“Utilizing standard inter-device communication protocols helps ensure that customers have the freedom to choose from an assortment of vendors when selecting hardware that best meets their application needs,” said Evan Artis, Product Manager, Electronic Controls & Software, at Eaton’s Hydraulics Group. “Eaton’s software development tool, Pro-FX Control, comes with built-in support for J1939 and CANopen devices, two of the most prevalent communication protocols used in off-highway applications, particularly within the mobile hydraulics industry.”

It’s also becoming much simpler to leverage materials that are created for non-technical presentations such as marketing demos. Importing images and manipulating them using HMI design tools is no longer a challenge.

“Plug-ins like a visualization manager enable the application developer to position and rotate objects like PDFs, camera pictures, or graphics and combine them with transparency and overlay effects,” Seethaler said. “With the TTControl Image Container, it is easy to create animations for a digital dashboard or to visualize working functions in an intuitive way. Integrated font libraries allow a fast adaption to different languages like Unicode fonts such as Chinese characters. All these plug-ins give customers cost- and time-saving development of highly sophisticated visualizations resulting in a faster time-to-market.”

Though many design tools focus on displays and/or control, operators are more interested in the entirety of the cab. Some tools help OEMs see the big picture so they can figure out where to put things and how to size them while maintaining the company’s look and feel. For example, Altia’s tools let OEMs build the HMI for the entire cockpit on a PC, then pass sections to suppliers who will implement each component.

“The model-based approach allows for early testing on a PC or testing with hardware in the loop,” Juran said. “These capabilities help ensure that you start with a complete view and control of the cockpit, instead of relying on individual suppliers to build components in a vacuum, and thus not have the big picture in mind or having a common look, feel, and UI paradigm.”

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