Automotive

Extreme-terrain six-wheeler shows off in-wheel fluid drive motors

The Ferox Azaris was built to demonstrate the company's fluid drive technology
The Ferox Azaris was built to demonstrate the company's fluid drive technology
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The Ferox Azaris uses a reversed BMW R1200GS motor
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The Ferox Azaris uses a reversed BMW R1200GS motor
Ferox Azaris: front bodywork is very nicely done
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Ferox Azaris: front bodywork is very nicely done
Ferox Azaris: considerable effort has been put into the design of what is essentially a technology testbed
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Ferox Azaris: considerable effort has been put into the design of what is essentially a technology testbed
Ferox Azaris: named after Azurite, a blue-tinged mineral – might get awkward when they make a red one
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Ferox Azaris: named after Azurite, a blue-tinged mineral – might get awkward when they make a red one
Ferox Azaris: headlights
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Ferox Azaris: headlights
Ferox Azaris: rocker arms at the rear help isolate the chassis from road undulations
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Ferox Azaris: rocker arms at the rear help isolate the chassis from road undulations
Ferox Azaris: at the beach, but just for a photoshoot
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Ferox Azaris: at the beach, but just for a photoshoot
Ferox Azaris: four driven rear wheels. The team could've added drive to the front two wheels as well, but felt it wasn't necessary to demonstrate the tech
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Ferox Azaris: four driven rear wheels. The team could've added drive to the front two wheels as well, but felt it wasn't necessary to demonstrate the tech
Ferox Azaris: extreme terrain off-roader
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Ferox Azaris: extreme terrain off-roader
Ferox Azaris: the beach shots are cheating, it's being pulled by a 4WD. But the Azaris has been driven on bitumen, and the team is working towards off-road testing in the new year
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Ferox Azaris: the beach shots are cheating, it's being pulled by a 4WD. But the Azaris has been driven on bitumen, and the team is working towards off-road testing in the new year
Ferox Azaris: a blue-sky design from a company with big ambitions
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Ferox Azaris: a blue-sky design from a company with big ambitions
Ferox Azaris: cabin
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Ferox Azaris: cabin
Ferox Azaris: that back end looks super mean
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Ferox Azaris: that back end looks super mean
Ferox Azaris: all four rear wheels are driven on this bizarre six-wheeler
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Ferox Azaris: all four rear wheels are driven on this bizarre six-wheeler
Ferox Azaris: far better looking than a tech testbed needs to be
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Ferox Azaris: far better looking than a tech testbed needs to be
Ferox Azaris: rocker arms contain fluid channeling to send drive to the wheels
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Ferox Azaris: rocker arms contain fluid channeling to send drive to the wheels
Ferox Azaris: 4WD rocker suspension system would be a nightmare to execute with a traditional drivetrain
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Ferox Azaris: 4WD rocker suspension system would be a nightmare to execute with a traditional drivetrain
Ferox Azaris: all four rear wheels are driven
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Ferox Azaris: all four rear wheels are driven
Ferox Azaris: Wheeler says it handles far better than you might expect, due to the self-balancing nature of fluid systems, which gives the rear four wheels a natural differential effect
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Ferox Azaris: Wheeler says it handles far better than you might expect, due to the self-balancing nature of fluid systems, which gives the rear four wheels a natural differential effect
Ferox Azaris: right up the guts
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Ferox Azaris: right up the guts
The Ferox Azaris was built to demonstrate the company's fluid drive technology
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The Ferox Azaris was built to demonstrate the company's fluid drive technology
Ferox Azaris: rocker suspension and in-wheel motors
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Ferox Azaris: rocker suspension and in-wheel motors
Ferox Azaris: in-wheel motors are capable of putting down 500 lb-ft each. Now, to find an engine capable of that
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Ferox Azaris: in-wheel motors are capable of putting down 500 lb-ft each. Now, to find an engine capable of that
Ferox Azaris: top down
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Ferox Azaris: top down
Ferox Azaris: in-wheel motors weigh 11 kg – heavy for a rim, but very light for a powerful in-wheel motor
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Ferox Azaris: in-wheel motors weigh 11 kg – heavy for a rim, but very light for a powerful in-wheel motor
Ferox Azaris: an example of what's possible when you "liberate the wheel"
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Ferox Azaris: an example of what's possible when you "liberate the wheel"
Ferox is looking to the future, with the capability of building highly modular vehicles
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Ferox is looking to the future, with the capability of building highly modular vehicles
Ferox's in-wheel drive technology aims to open doors to a wide range of non-traditional vehicle and suspension possibilities
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Ferox's in-wheel drive technology aims to open doors to a wide range of non-traditional vehicle and suspension possibilities
Ferox is focusing on autonomy, agricultural and industrial robotics, and large-scale hauling to begin with
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Ferox is focusing on autonomy, agricultural and industrial robotics, and large-scale hauling to begin with
With in-wheel fluid drive technology, your drivetrain can look like whatever you want
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With in-wheel fluid drive technology, your drivetrain can look like whatever you want

The Ferox Azaris is a work of art to look at, and should offer some awesome rough terrain capabilities – but at its heart, it's a test bed and demonstrator for a new in-wheel motor with a volumetric efficiency of up to 98 percent, with a highly responsive fluid drive system that Ferox hopes will enable some pretty crazy future vehicle architectures.

The Azaris is a beautifully designed side-by-side ATV. It makes around 100 hp, thanks to a BMW R1200GS motor, and rides on six wheels, the rear four of which are driven, and which sit on a rocker-style suspension system similar to the one used on the Mars Rover.

Ferox Azaris: right up the guts
Ferox Azaris: right up the guts

That rocker suspension delivers a very nice ride, keeping the rear swinging arms, and indeed the cabin, isolated from a lot of up and down movement. But the suspension system - and the Azaris itself - aren't the real story here.

Perth company Ferox chose to build this extreme-terrain vehicle, using that suspension system, for one main reason: it can't be done with a conventional powertrain. Getting drive to four wheels rocking on two independent swingarms would be a nightmare to accomplish with anything but in-wheel motors, and Ferox's unique fluid drivetrain is exactly what this vehicle has been built to demonstrate.

Ferox Azaris: far better looking than a tech testbed needs to be
Ferox Azaris: far better looking than a tech testbed needs to be

The Ferox fluid drivetrain

As it's implemented in the Azaris, the drivetrain breaks down like this: the R1200GS motor is mounted backwards in the frame, with its shaft drive unit intact. Where the wheel would normally be mounted, Ferox has mounted a pump unit instead, so the motorcycle motor is entirely devoted to driving that pump.

The pump is linked, using fluid piping and channeling through the swinging arms, down through the point where the rocker pivots, and right out to each wheel.

The wheel hubs contain what could crudely be described as paddle wheels within them - as water is forced through them, the outer housing starts to rotate, and that's where your drive comes from. The low-pressure water feed then exits the wheel and makes its way back up toward the pump. Fluid controls can allow the wheel to rotate forward or in reverse, and the drive can even be used as a form of braking.

Ferox Azaris: rocker arms at the rear help isolate the chassis from road undulations
Ferox Azaris: rocker arms at the rear help isolate the chassis from road undulations

The system, Ferox CEO Troy Wheeler tells us over Skype from his Perth office, can handle insanely high torques. The motors in the Azaris could handle up to 500 lb-ft (678 Nm) per wheel if they were attached to a motor that could put that kind of torque out, and they've got bigger units tested up to 850 lb-ft (1,152 Nm). Four of those would happily drive your average giant Haulpak mining truck.

They're also incredibly efficient, the pump and motors each operate at an impressive volumetric efficiency of up to 98 percent without running the high pressures or temperatures traditionally associated with hydraulic drive systems.

Ferox Azaris: rocker suspension and in-wheel motors
Ferox Azaris: rocker suspension and in-wheel motors

"Hydraulics have a bit of a bad name," says Wheeler, "probably because of where they've ended up: high pressure, inefficient, hot, jerky … we use 95 percent water, with 5 percent of additives in there. It's a completely different system and completely different pressures too. We're talking 200-1,500 psi versus 3,000 to 15,000 psi.

"The whole system is incredibly responsive - and that's a big difference to traditional hydraulics. Usually they're quite jerky. But our system has a high startup torque, similar to an electric motor. As you start to accelerate, the system immediately receives that and is able to respond, and smoothly accelerate with the engine."

Wheeler tells us the primary reasoning behind the fluid drive system is to "liberate the wheel," removing the restrictions on how and where driven wheels can be placed on future vehicles, and what sorts of suspension systems can be used. To do that, you've got to make the drivetrain extremely flexible, as well as highly efficient.

"You can do that electrically," says Wheeler, "or you can do it with fluids. I don't know of any other method. Electrics have some issues, because of their native format, the weight that they are, and some other component elements. We think the path forward right now is with fluids. One of the advantages with fluids is that you can print the fluid channels within the chassis and the components that link the whole system together, if you're doing 3D printing and things like that."

Ferox Azaris: four driven rear wheels. The team could've added drive to the front two wheels as well, but felt it wasn't necessary to demonstrate the tech
Ferox Azaris: four driven rear wheels. The team could've added drive to the front two wheels as well, but felt it wasn't necessary to demonstrate the tech

Another advantage is weight. Each of Ferox's in-wheel motors weighs around 11 kg (24.2 lb) - which is certainly hefty for a rim, but Wheeler says electric hub drives of comparable capability are coming in around 30 kg (66 lb).

Like electric motors, Wheeler says, you end up with a highly responsive drivetrain and virtually no lag - particularly if you put the valving and flow control components down close to the wheels. Indeed, the team feels the system would mate even better with an electric motor than with its current motorcycle powerplant.

The natural tendency of fluids to self-balance also kicks in to give the Azaris drivetrain a natural differential effect. "When we drive it outside here on the bitumen," says Wheeler, "it maneuvers very well for what you'd expect from a six-wheeled vehicle."

Ferox Azaris: the beach shots are cheating, it's being pulled by a 4WD. But the Azaris has been driven on bitumen, and the team is working towards off-road testing in the new year
Ferox Azaris: the beach shots are cheating, it's being pulled by a 4WD. But the Azaris has been driven on bitumen, and the team is working towards off-road testing in the new year

The path forward for fluid drive technology

The Azaris prototype hasn't been fully tested off-road as yet - these beach shots, for example, were taken several months ago before the vehicle was finished, with the six-wheeler being towed by a 4WD. But the team has been driving it on bitumen and around a local quarry, and is moving to tougher off-road testing in the next month or two, promising some video of the Azaris on the move in the new year.

For something that was created as a technology demonstrator, it certainly seems to be a hit. Wheeler laughs when asked if people can buy an Azaris. "A few people have been asking about that! Look, in all honesty I would do a limited run. I have looked at building some, I've had some discussions. I would do a version two, maybe build 100 of them, where no two are finished the same in terms of color and trim. We could sell them almost as a moving art piece, a collector's item. It would come with some interesting elements of being able to test and play with the tech in that transaction."

But Ferox is thinking much bigger than recreational off-roading with this technology. Wheeler sees its true value being expressed in autonomous agricultural robots, in modular heavy vehicles and haulers that can click on extra driven wheels and moving functional parts when needed, all driven off a single main powerplant.

Ferox is looking to the future, with the capability of building highly modular vehicles
Ferox is looking to the future, with the capability of building highly modular vehicles

Also in military applications, where the fluid system can be used as a unique defense against electronic weapons. "These things aren't in there yet," says Wheeler, "but things like fluidics - basically allowing you to send computer style electronic message using fluids, so you don't need an electrical system. Defense likes them, because, for instance, if you get an EMP that blows out your electronics, you still have control functionality through fluid logic control. It's not too relevant right now, but that's tech that will be interesting to apply because of the fluid transmission system we'll have in these vehicles."

Ferox's in-wheel drive technology aims to open doors to a wide range of non-traditional vehicle and suspension possibilities
Ferox's in-wheel drive technology aims to open doors to a wide range of non-traditional vehicle and suspension possibilities

So really, the Azaris ATV is really more of a signal that Ferox is open for business than anything else. With this extraordinary prototype concept, the company is hoping to capture the imagination of potential partners, investors and innovators to take things to the next level. "There's a broad mix of potential candidates," says Wheeler. "The technology will evolve with whoever we partner with."

For a technology testbed, this thing looks almost like a fully finished vehicle. It's a remarkable public debut and an impressive first achievement for an Australian company that's thinking big, and looking far into the future. We wish these guys all the best, and hope to see a lot more from them as things develop.

Source: Ferox via CarAdvice.

17 comments
guzmanchinky
Wow, that is pushing the envelope. I don't see a downside except for leaks? But current systems have plenty of failure points as well. I would LOVE to someday have a silent side by side to go exploring the forest. Each wheel individually controlled with tons of torque and a soft ride.
notarichman
hmm, i wonder about using the system in mud and snow. if one wheel loses traction; then does it spin fast and the other wheels lose power? same question with extreme valleys and bumps that make one or more wheels lose traction, such as Moab rock climbing.
amazed W1
Once again the competition in drives between electrics and hydraulics. In the past the electrics have always won, but the locked rotor or runaway rotor problem is easier to deal with by hydraulics? Also the overall efficiency, i.c. motor to wheels looks better, so guessing, the electrical version is better for battery sourced vehicles with a good recharging grid but the hydraulic version is better where the range needs to be much greater, as in the deserts of OZ.
paul314
200-1500 psi isn't much compared to regular hydraulics, but things will still get interesting if there are any leaks or dings.
Malatrope
We've had this kind of drive in agricultural equipment since 5the 50's. It has some serious advantages, but also disadvantages (like leaks).
Koko The Talking Ape
Fantastic! I have some questions. Like others, I wonder how pressure will be distributed to the various wheels to control traction, etc. I believe both ICE and electric motor vehicles use mechanical clutches, which work pretty well. Electric hub motors are heavy, as the article points out, but they allow fly-by-wire control of each motor, even when used for regenerative braking. The devices that allow that are solid-state (I believe) and hence super-reliable, and easily controlled by the car computer. Second, I wonder if the pump will always be able to maintain pressure under momentary high loads. In an electric car, lithium batteries maintain "pressure" (voltage) fairly steadily until they are depleted. The same is true, in effect, for ICE. Third, I wonder how well the hydraulic motors stall. If the wheels simply can't turn, there should be some kind of valve or throttle so that pressure doesn't build uncontrollably. That would be another mechanical component that could fail. I also wonder about "gears." Like propellors or wind turbines, I imagine these hydraulic motors are most efficient at a certain rotational speed. What if you need different speed? Is there friction? Turbulence? Cavitation? Does the fluid heat up? The fluid might heat up, and in fact the pump might have to work harder, non-intuitively, like when the vehicle is cruising at low speed, or at high speed. As a side note, it occurs to me that this kind of rocker suspension (I have also heard it called a "bogie" suspension) prevents squat or lift when the vehicle accelerates, because torque around each hub is cancelled out. Also, the rocker arm may have to pivot exactly between the two wheel hubs, or else the rocker arm would tilt one way or the other under acceleration, because of unbalanced torque. It also occurs to me that you could tiny hydraulic motors inside the joints of the arms, to help counter the torque effects from the hub motors.
Plaw
Two wheel drive motorcycles?
MzunguMkubwa
If the weight advantages really are there, and design intent could factor in other means to achieve it (such as material selection), could this tech find application in aviation? It seems like it could really be effective in distributing the weight desirably: allowing a centrally located power unit to "feed" remote motor/propeller units. The tech should also allow these units to pivot easily, making VTOL and multi-copter like flight achievable, assuming the individual motors could be independently controlled effectively to maintain the needed in-flight balance. Very cool proto, tho!
jd_dunerider
I'm with Plaw, 2wd motorcycles! Both front and rear driven by this, with no chains for drive shafts. That could make for a sweet bike. Really it would be pretty amazing on a ton of different vehicles. Offroading without a drive shaft, diffs, axles, you'd have clearance for days allowing the vehicle body to sit lower. I hope this goes places.
Grunchy
It's funny they never mention "hydrostatic drive" in the story, I wonder why that is. Probably because hydrostatic drive is known to be highly inefficient for power transmission. They may be able to fudge numbers to "prove" 98% efficiency at the pump, but there's a lot of friction in the hoses that they seem to be curiously silent about. Hydrostatic is excellent for low speed (low flow) drives for machines like tractors, and best of all at zero speed (starting) torque. Any application that requires high flow rate suffers crippling inefficiency that just kills the performance. I wouldn't make any production units - customers will be disappointed.
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