Machine Ergonomics Enhance Efficiency

The term “ergonomically designed” conjures up images of delicate instruments, pristine laboratories and highly sensitive gadgetry. But in the often harsh world of construction equipment, ergonomics is more than just another pretty face. It's a subtle, sometimes unseen, ingredient that makes man and machine more productive.

“Before ergonomics took center stage, for example, access ladders were usually completely vertical, making it difficult for operators to climb into a large machine without slipping,” says Bruce Michael Dayton, sales engineer, articulated haulers and wheel loaders for Volvo Construction Equipment.

Today's Volvo's F-Series wheel loader has ergonomic design elements such as egress ladders that are sloped for easy movement into and out of the cab, he says, and the door handle is positioned at 45 degrees.

“When you put your hand on it, it's a natural movement,” says Dayton. “You don't have to twist or turn your shoulder to grasp the handle.”

In addition, the steps are slip-resistant—similar to serrated metal—and grab handles are located so operators can reach them from ground level.

Inside, the cab's interior is 4 inches wider and 2 inches deeper than on previous models to accommodate today's operators who prefer to have more room. The cab also has more glass for better forward visibility—22 percent better.

One of the more obvious changes ergonomics has brought about in construction equipment is replacement of steering wheels with joysticks. In 2005, Komatsu's WA600-6 wheel loader was introduced without a steering wheel.

“With that model, Komatsu eliminated the steering wheel and went to a joystick steering control as standard equipment,” says Rob Warden, product manager for wheel loaders, Komatsu America.

According to Warden, initially the company was concerned they would have a hard time selling the idea to more-experienced operators. As it turned out, it wasn't a problem.

“As we demonstrated the equipment across the country, the reaction was, 'Wow this is easy to use,'” he says. “Once they had experienced the quickness and responsiveness of the loader's joystick, it was easier for them to accept the change.”

Many Volvo products are also joystick converts.

“Across the board, Volvo's products—excavators, wheel loaders, compacters, etc.—have joystick controls,” says Dayton. “This allows for boom and bucket control with one joystick instead of two levers.”

Although the joystick controls are still hydraulic-servo, the next evolution in operator controls will be the “electro-hydraulic” boom and bucket levers, according to Dayton.

“With electro-hydraulic controls, electronics activate the hydraulics,” he says. ”The controls don't require a lot of force from the hand or wrist to activate them. It's all electrical, rather than mechanical.”

These controls will allow the operator to adjust boom height and bucket angle stops without leaving the cab. Another advantage to the improved control system is that it enhances heat dissipation inside the cab because no hoses enter it.

Deere machines have also moved to new types of controls.

“We're trying to reduce hand motions and repetitive movement by the operator,” says Chris Johnson, engineering manager for cabs at John Deere Construction and Forestry Division. “You see some of that in joysticks that have multiple functions. They have pistol grips with auxiliary function buttons on top and other design features that help reduce motion. Low-speed machines are using joysticks for steering.”

On Deere skid-steer loaders, functions are combined.

“You have a choice of machine control and bucket and boom functions in the hand controls,” says Johnson.

But joysticks aren't for everyone.

“The joystick-only steering system works well on larger quarry or mining machines,” says Komatsu's Warden. “But smaller machines in a sand and gravel operation with trucks probably wouldn't use joysticks. Those machines have more than one application and have to be adaptable to many situations. By comparison, larger machines typically are single-purpose units that don't require as much flexibility.”

Even machines that still rely on steering wheels have been redesigned to require less effort to operate them.

“With Volvo's Comfort Control Drive, for example, an operator can make steering and directional changes from the control system bolted to the side of the seat,” says Dayton. “This eliminates static muscle strain from constant steering and places controls in the operator's fingertips. The steering wheel is still in front of the operator in case of an emergency.”

At Caterpillar, too, control systems are an area of significant research and development.

”Our new motor grader is a good example,” says Bernard M. Meegan, manager of Caterpillar's ergonomics section of machine research. “It went from having a steering wheel and 25 mechanically operated levers to using just two joysticks. That change resulted in a 75-percent reduction in operator hand motions inside the cab.”

Ergonomic development has eliminated “one-size-fits-all” seating in off-road equipment and many seats are now pneumatic.

“A pneumatic operator's seat is like sitting on an air cushion,” says Volvo's Dayton. “They adjust for a more comfortable ride. The lumbar area is adjustable and there are options now that have multiple adjustments enabling the operator to work from a custom seat, one that fits him regardless of height, size or weight.”

In cold climates, a heated seat option is often available.

“Ergonomic studies have shown that the more comfortable an operator is and the easier it is for him to operate the machine, the more effective he will be,” says Dayton.

On some machines, it takes more than an adjustable seat to keep the operator comfortable.

“Our wheel loaders have an option called boom suspension,” says Dayton. “In layman's terms, boom suspension actually puts a shock absorber on the boom itself. If the operator has a bucket full of gravel and is driving across a bumpy jobsite, the boom—not the machine and operator—absorbs most of the forces generated by machine bounce. The operator never feels the vibration and stress coming from a bouncing load.”

At Komatsu, an entire design group is dedicated strictly to developing cab environments.

“We design all our cabs—no matter what the product is—so that the features that control the functions of the machine are easily reached and accessible at any time during the operation,” says Warden. “The operator generally doesn't have to bend forward or reach far to either side. We try to position the controls within the normal working reach of the operator.”

The result is that when an operator moves from a smaller machine to a bigger machine, or vice versa, the switches, levers and functions are in the same general location.

“Operators can go from a small 2-cubic-yard machine to an 8-cubic-yard one—which is a huge jump in size—and when they step inside the cab, they'll find themselves in familiar surroundings,” says Warden.

Putting creature comforts on earthmoving machines isn't simply to pamper the operator; it has a direct impact on productivity.

“When an operator is in a more comfortable cabin—better seat, better working environment, etc.—that operator is more productive,” says Warden. “If the seat is bad and the armrest is in the wrong position and hard to adjust, the operator is continually fidgeting rather than working. With an ergonomically designed cab, the operator can dedicate that time and energy to production and the task at hand.”

Caterpillar enhances operator comfort by designing more ergonomic control systems and seating combined with visibility improvements and other dynamics that enable an operator to work more comfortably and more productively.

”Physical degradation over time results in fatigue and fatigue hurts performance,” says Caterpillar's Meegan. “How well an operator performs impacts productivity.”

At the same time, the health, safety and comfort of employees has become paramount.

“What we do in the ergonomics arena reduces the negative health impact while improving safety and productivity,” says Meegan. That's a good reason for fleet managers to invest in machines that are more ergonomic. When an operator is more comfortable, he's more productive and that goes right to the bottom line.”

Other machine changes that will improve productivity are the rear-view camera and rear obstacle-detection systems that are being introduced on Deere's K-Series loaders.

“They are big improvements and will result in increased productivity at the jobsite,” says Johnson.

Another benefit of ergonomic design changes is the reaction of operators.

“Good ergonomics can help retain your work force,” says Meegan.

Another plus, he says, is that some insurance companies consider ergonomic investment a reason for lower premiums.

“Highly skilled operators are now a prime commodity and if you can keep them your business will profit from that,” says Warden.

Ergonomics has also impacted machine serviceability.

“We make sure filters are easy to reach, fluid fills are in the same location on similar machines, and when operators do service checks at the start of the day, they open a door and everything is right there,” says Jonathan E. Drum, vehicle ergonomics engineer for John Deere Construction and Forestry Division. “In the shop, technicians also have easy access and can make repairs faster.”

Industry-wide, ergonomic advances are occurring more rapidly. Surprisingly, one reason is the current round of emissions regulations.

“Prior to tiered emissions regulations that must be met by specific dates, the more popular OEM machines were updated more frequently than low-volume units,” says Warden. “If you sold a lot of one model, that model got more upgrades and updates. Today, emissions regulations deadlines apply to all models so all models are upgraded at the same time.”

Clearly, ergonomics are continuing to improve the health, safety and productivity of both man and machine, but at what price? And what is the return on investment?

“You'd like to think there is a quantifiable ROI with ergonomics, but the ROI for the fleet owner isn't going to be something he can see,” says Warden. ”It's not that you're paying x dollars for the seat or the armrest. You're paying for a Tier 3 machine that includes the ergonomics.”

According to Johnson, Deere doesn't approach ergonomics in terms of a dollar amount.

“You can't quantify ergonomics in terms of ROI,” he says, “but we look at how we provide fleet managers with products that help them in their businesses.”

What lies ahead in ergonomics remains to be seen. However, certain trends in ergonomic design offer a few hints.

“I don't think we're going to see anything truly outrageous,” says Komatsu's Warden. “The trend is to improve and simplify operator's compartments to make it very easy for any operator to sit down and make adjustments quickly.”

Upcoming improvements may not even be visible to the operator.

“We try to make it seamless,” says Warden. “When an operator comes off a Tier 2 machine and moves into a Tier 3 machine, he eventually notices that the levers are easier to use compared to the old ones and that the cab is a lot more comfortable.”

One trend that's coming is tunable controls, says Deere's Drum.

“That is, if the operator is aggressive, the controls can be aggressive,” he says. “If he likes the controls to lag a little bit, they will.”

Another important trend is hybrids.

“Earlier this year, Volvo unveiled a hybrid diesel wheel loader that will be available in 2009 to certain key customers,” says Dayton. “The hybrid loader gives fleet managers a dramatic reduction in fuel costs.”

Meegan foresees the addition of more features that enhance the skills of the operator. For example, one Caterpillar backhoe-loader has an automated dig function that allows the operator to set up a control dig depth and maintain that depth to within a couple of millimeters.

“To encourage new construction industry workers, we'll need to have some sort of automated features to enhance operator skills,” says Meegan.

Ergonomically designed cabs, joystick controls and machines that enhance an operator's skills make an impressive list, but in the final analysis, does it mean a generation of X-Boxers and other video gamers can adapt more easily to future construction equipment?

No one knows for sure, but they are certainly a different breed.

“At ConExpo-Con/Agg, we brought in a motor grader simulator,” says Drum. “When the younger operators, got into it and found themselves in a virtual environment, they immediately adapted to the alternative reality with no noticeable performance decrease. Some of the more experienced operators, however, were still a little wary of something that was that radically different, even though the controls looked familiar.”