A couple weeks ago those nice folks at my local Chevy dealership replaced the electric power steering motor in my Cobalt due to a recall for high failure rate. If the motor had actually failed while driving, the existing rack and pinion mechanical linkage would still have allowed me some control of the vehicle.
Forget that with a joystick. Good for video games, but not in the real world.
I agree that a mechanical linkage between the driver and the steering wheel is an essential safety feature.
Only if a fully redundant backup system is available would I consider switching to a fly-by-wire clone in my car.
I shudder at the thought of driving along at highway speeds where a twitch or accidental nudge of a joystick could send my car careening off the road or into the oncoming lane. As novel and intuitive as those of the video-game generation would regard joystick steering, I think the steering wheel embodies several key aspects of tactile and visual feedback, as well as safe movement inertia, that would be very difficult to translate meaningfully to a joystick. Even after those problems are addressed, you still introduce a new layer of classification of driver training and licensing since I can't see a "wheel" taught driver drive a joystick car without additional training. That translates into more time and cost to the driver, a formidable barrier to the introduction of anything "new".
I get the sense the Ford exec was being somewhat toungue-in-cheek about the joystick for wheel swap; his underlying intent was probably a nod towards the benefits of drive-by-wire technology in the overall cost, fuel efficiency, and consumer acceptance of cars in the future. Drive-by-wire using a wheel can address the Left-hand/right-hand international market requirement without foisting onto drivers the joystick learning curve plus an extra layer of licensing process. It's up to engineers and designers like us to improve and reduce the cost and weight of the technology that makes drive-by-wire a reality.
"Are there other "it absolutely makes sense" consumer-product changes which you think about, and which our technology now allows, but haven't been adopted yet?"
How about get rid of the center console cup and CD holders, place a passenger seat on both right and left, and place the steering wheel and driver's seat in the middle. No more left/right issues and room for an extra passenger for car pooling. Might have to make the vehicle a few centimeters wider to give the driver elbow room.
Just wondering, does anyone know if the standard floor pedal and steering wheel arrangement was ever patented? Or were such things considered too obvious back then?
You don't find carbon fiber in critical systems (i.e. steering, suspension in particular) because there isn't a ductile mode failure, just sudden collapse. Sounds a lot like the silicon failure mode to me.
Fe all the way. I'm fine with Cu/Si as supplements.
By the way, as I understand it the most strenuous environments for products are: Aerospace due to extreme environment, but mitigated by expert operators and money available. Medical due to biocompatibility and usage requirements but mitigated by financial availability. And last, automotive due to environment and usage but exacerbated by inexpert operation and commodity pricing.
Everyday, so many pilots fly different aircraft machine at much higher speed with many more complex task. However, they are properly trianed for the system. Eventually, system will become more friendly and common person will quicly learn how to use it.
Aircraft have backup systems to compensate for failures.
It is not a question of "common person" learning how to use a joystick. It is a fact that silicon fails. Shorted or open, silicon fails without warning. I have replaced enough failed transistors to know this.
In airplanes, if you drift a few degrees left, you likely aren't going to smash into anything or fall into a ditch. Much different in a car.
That said, I could imagine an electronic "steering trim" control for long highway stretches, maybe tied to a vision system to follow lane markings...
This is exactly the point, planes are flown with a 1000m safety distance in X & Y, and something like 300m in Z. Our roads have as little as 50cm between vehicles. The additional risks associated with joysticks in planes are mitigated because of the 3D nature of flying. I have read news reports of drive by wire throttle control preventing a driver from stopping his vehicle for about 40km until he crashed it to end the nightmare.
The thought of a servo motor failure with a joystick controlled car should scare you. However, even with a steering wheel, drive by wire without a mechanical connection between steering wheel and steering rack, is on the way. Soon it won't matter if it's a joystick or wheel, the failure mode will be just as likely or unlikely and just as catastrophic.
I hate to disappoint all of you who think there is a direct, mechanical connection between the steering wheel and the car's wheels--but in many cars today, it's already drive by wire using a sensor/pickoff on the steering column. So whle we may feel that an all-mechanical system, aided by power assist, is more reliable, you don't have it in many cases, even if the look and feel makes you think you do.
This is really scary. Time to buy a bicycle.
Bill, what vehicles do you know of that do not have mechanical steering linkages? Let us know what to avoid. I do not ever want a shorted transistor to steer my vehicle into oncoming traffic without some sort of over-ride. Sort of like a separate button to shut off a runaway motor.
But we don't hate to disappoint you and your BOGUS claims. Please list which current automobiles and commercial vehicles have this Drive-By-Wire steering you claim so strongly.
Many cars today have electrically-assisted steering, and a few high-end have auto-parking. All of them retain mechanical linkage. Multiple manufacturers like Mazda, Chevy, Toyota have had recalls and advisories regarding the electric motors on their power-steering, but the reports always state that the worst failure is loss of Power Steering, not total loss of steering control. You just manhandle the steering wheel like you always did with your Dad's "classic" car.
Even the DARPA Challenge vehicles had mechanical steering linkages. The teams utilized either their own actuators to control the wheel, or took advantage of the steering assist, but the steering column remained.
Bill, actually have some real experience with this. I worked with a client that was helping with the software and electronic controls for a major auto maker is experimenting with joysticks, but they won't even be introduced for another 20 years... when our generation dies off. That's the reason.
Right now, we are raising up a generation that are used to joysticks and hand controllers (think of the PS3 controller in Men and Black 2), but they do not make up the majority of the market. The current majority still is more comfortable with a steering wheel and is actually unable to properly control autos equipped with joysticks. The costs of setting up manufacturing for both, right now, is a huge barrier. But once our generation is gone, the following gen will have the proper motor skiils to use the control systems. It is in the works, but we have a couple of decades before the driving populace is ready for them.
According to Car and Driver, here are the top 10 drive-by-wire cars on the market.
2010 Audi S4
2010 BMW 3-series / M3
2010 Cadillac CTS / CTS-V
2010 Ford Fusion Hybrid
2010 Honda Accord
2010 Honda Fit
2010 Mazda MX-5 Miata
2010 Mazda 3 / Mazdaspeed 3
2010 Porsche Boxster / Cayman
2010 Volkswagen GTI
According to the local Honda service manager, both the Fit and Accord have rack-and-pinion with electric assist option. He had to ask a mechanical technician.
Still waiting for a return call from the local Ford service manager. He also has to find a mechanical technician for the answer. I do expect the same, rack and pinion with electric assist.
Does anyone remember when a service manager got to that position by rising up through the ranks instead of learning how to answer a telephone?
True indeed. And to add to your point about failure mode, this failure was sudden, but far from catastrophic in the overall system impact. I just felt the frame drop a bit and suddenly get squishy and bouncy feeling.
If you've ever worked with radiation you know that it only takes one cosmic ray hit to change a flip-flop value. Sometimes it isn't even a cosmic ray--it can be an alpha particle emanating from the ceramic package of an IC. It doesn't happen often, but it does happen (kind of like the lottery). Check Altera/Xilinx/Micron app notes on radiation for statistics on how often it can occur.
How will your steering react to that changed flip-flop? Even radiation emanating from a nearby atom bomb explosion won't affect a mechanical steering wheel.
Yet another potential failure mode, never mind the possible effects of the vehicle beside you with a ham radio operator and a hundred watts of RF.
A nearby atomic bomb explosion will likely kill the solid-state ignition system, the intact steering mechanism will let you coast over onto the shoulder so that farmer in the 1930's pickup truck behind you (breaker points ignition) can get by.
Of course, being that close to the explosion nothing else would matter much anyway...
Do you realise airplane controls are fly by wire? And they are much more succeptible to particle bombardment related errors due to their height? This is not a valid argument.
Drivers of our generation arent ready for joysticks. Thats about it.
A "joystick" (which I presume means something fairly substantial, not a twig sticking out of a small box) would work well for vehicle control if the vehicle was largely autonomous. Indeed, for terminal control such as offroad or parking in non-standard areas a joystick would be fine, and allow much more space in the cabin with the large clunky round steering thing removed.
The classic 1DOF steering wheel has advantages until autonomous vehicles are available though. Either hand can operate the wheel easily, resistant to erroneous body inputs, familiarity (they used these on sailing ships for millennia after all, so there must be something to them), provides leverage and variable steering control...
No has yet to suggest more novel control methods, such as proprioception-- for instance, vehicle by shifting weight and dispensing with the monkey hands as control objects. Most modern monkeys probably can't master this though, at least not easily, but the experience weds the user much more closely with the environment. This method could be attractive if wedded to safe area semi-autonomy.
Long, long ago, when I was new to driving, I and my friends had to make due with beater cars that we could afford on our meager high school and college incomes. Control problems (brakes, steering, acceleration) were not at all uncommon. Most of these beater cars had between 80,000 and about 150,000 miles on them. That's hardly old at all for a modern car.
More than one of us had an accelerator return spring break. That's bad, but we all managed to survive. I know of at least two incidences of total hydraulic break failure. One in a car of mine and one in a friends car while I was towing him. Scary.
Another friend had an A-arm break on his pickup truck. I once had a needle and seat valve work its way loose. The float bowl filled up with gas and then it ended up spewing out on the engine. How that did not result in a fire, I'll never know.
Why am I droning on about failures past? The message is that the more electronic my vehicles have become, the more reliable they have become. Without a doubt, electronic cars have and will exhibit catastrophic failures. No question about that. However, the old pure mechanical cars did too.
We need to keep a close watch on the designers and regulators for these new systems, certainly. but I don't think we should fear them more or even as much as the old systems. I'd love to see some data comparing the per-capita failures of pure mechanical cars vs new electronic / mechatronic cars. My guess is that we'd find an order of magnitude fewer failures in the new cars. If anyone has access to such data, I'd love to see it.
The obvious answer is that the steering wheel was developed to meet the needs of controlling the direction of the vehicle. Nothing else is as intuitive or as refined (yes even a joystick!). The left/right turning is directly associated with the wheel motion whereas how would that translate into a joystick? It seems weird to consider it, although there are many robots that use remote joysticks for control. The faster more car-like robots seem to use steering wheels (USB based of course), while crab/swerve drive robots most often use joysticks as that motion control more directly translates.
I agree with your asessment of the steering wheel. I think the main point of this dicussion thread is not joystick VS wheel, but mechanical linkage VS drive-by-wire. Good points raised by all on both sides of the debate.
The biggest reliability hazard by far, and most unreliable link in the chain is the human driver. The list of things that can cause a fatal mechanical or electronic failure pales in comparison to driver causes. An incident that comes to my mind is one that occured some years ago near the community I live in. A heart attack behind the wheel on a rural highway resulted in a horrific multi-fatality accident with a school bus. For those of you that fear the loss of direct mechanical steering control, I assume you also ensure that you are in the best of health, drive strictly by the rules of the road, and only drive roads where you are quite certain all the other drivers are as diligent as yourself. These steps would maybe somewhat minimize the huge disparity in failure probabilities between the vehicle's systems and the driver.
Perhaps this is somthing that drive-by-wire may actually improve. If coupled with smart, speed-context scaled safe auto-limiting to prevent sudden steering actions and intiate throttle release where sensors would predict a collision or loss of vehicle stability could otherwise result, new technology could actually make a significant dent in the failure probability of the driver. I'd personally feel much safer behind the wheel of such a car, particularly if all the other vehicles around me are similarly protected.
My apologies, I was wrong: there are apparently no standard cars using drive-by-wire steering, just electric or hydraulic power-assist. But why not steering? If you say "steering and safety and reliability" are the reason--what about that accelerator? That is certainly electronic and software controlled, and can lead to accidents just as steering failure can.
Why the accelerator and why not steering or breaking ? It's a matter of failure mode: whilst a failure of the 'gas pedal' is easily handled switching to "limp home mode" (=better slow than towed), there is no such way for steering. Electrical breaking seems to be under evaluation but I do not know what the failure reaction will look like.
The reason for a mechanical backup is, that mechanical
systems degrade in a predictable manner(assuming the
system passes through various inspection and tests).
Automotives are one, where irregular maintenance and
knowledge/skillfulness of the operator is not guaranteed.
Also the economy driven drive by wire systems found in
automotives are not very suitable for realtime duty.
High level design(not to mention the complexities of
realtime OS) coupled with failure in large electronic designs(not to be confused with the reliability of the LSI's itself), makes this even difficult, not to mention the rough operating env.
So, in essence the electronics in automotive that
are used in the critical realtime duty, will
be used in a backup mode to allow for graceful degradation in the event of a catastropic failure,
letting the mechanical sub system handle it in a
predictable but less effective manner.
I am not sure I am fully comfortable with all electronic/software control in cars (at least not yet). Does anyone remember the "sudden acceleration" problems of a few years ago? I am not sure how that all got resolved in the end but I do not yet have enough confidence in all electronic controls, as it is engines are highly automated and when working are great! If there is an issue it normally results in dead vehicle, with semi-mechanical controls there is the gradual decline in function/performance which allows the operator (their dad) to get it to the shop. Don't get me wrong, I love remote control, electronic based systems (robotics) but there are some limits to what we can and should do today. Perhaps I could be more comfortable with this if there was a way to design the new electronic systems with a gradual breakdown mechanism instead of: works, works, dead.
Back in the day (around 1960) Cornell University came up with the Cornell Safety Car. One feature was to put the driver in the center of the front seat (remember cars were wider then) for better visibility. Instead of a steering wheel there was an arrangement like a small bicycle handle bar that rotated perhaps through 90 degrees.
If you want a good background on electrical power steering systems, check out this feature: http://www.eetimes.com/design/automotive-design/4019429/A-Matter-of-Torque-Electric-power-steering-systems.
My guess is that before Joysticks become commonplace, there will be a huge change in the way cars are controlled. They'd have to have sensors that keep them in the lane and check back and front for other vehicles and obstacles. If you tried to change lane or turn, the electronics wouldn't let you unless it found it safe to do so. In any case, by that time the electronics of the car would be integrated with the GPS and you'd just punch in (or, more probably, speak) your destination, and the electronics would select the route, taking into account traffic conditions. I'd agree this will be quite a way off, but anyone care to say it'll never happen??
IMHO, there is nothing in a joystick that gives anything like the potential for initiating both tiny movements and major swings with the control that a wheel gives. Even with power steering, the ability to shift your grip on a wheel gives much finer control.
What if the next generation car has 4 independently controlled electric motors in the wheel hubs? Using a (fault tolerant controller) one can then emulate the traditional car. But we can do a lot more. E.g. each wheel has independent traction control (not just braking) and directional control. This allows a very high degree of manoeuvrability and active safety. However, this means the controller executes what the driver intends the vehicle to do, not the driver himself as he won't have hands enough. Rather than a steering wheel or a joy-stick, he might have two handles like in a tank that can move forward, backwards, but also sideways.
Some also mentioned that this is standard in airplanes, but let's not forget that driving a car has a lot less temporal room for corrections. Driving on a highway at 120 km/hr between two trucks is cm-work executed in sub-second intervals.
I point out that a great deal of time and effort (MONEY) is spent on the airplane control systems that use joy sticks. That does not mix well with the design philosophy of automotive manufacturers.
Drive by wire is fraught with potential for disaster (just ask Toyota).
Also, how do you get feedback to the driver with a joy stick.
Fly by wire technology is good if there is some centralized system over all the motor-able roads to monitor the health of the control electronic in a car and take over-riding measures to bring the car safely to the curb without disturbing the other vehicles on the road. With wireless technology this is possible. The dependability of drive-by-wire systems can be increased many fold if such monitoring systems are in place. With such systems in place not only the steering wheels but even the drivers can be made redundant someday.
If my car had a middle name, it would be "intermittent computer problem", so would my previous car, and the one before it. I dread the idea of yet another "feature" running on a computer. I had a steering motor failure which was no big deal at all. Didn't even notice it above 20 mph. But my Body Control Module computer now fails to start the car about 1% of the time. Of course, when brought to the shop ( seven times now, and counting) it works perfectly. My vote is for more mechanical linkage, less computer.
Would it be correct to presume that your BCM is still under warranty and cannot be replaced unless the shop can return a proven bad unit to the manufacturer? In this case a little bit of assistance could help, such as current-limited reverse polarity applied to the 12 volt input (with the unit out of the vehicle of course). Do not apply 120VAC since the damage would be too obvious.
Been there where a shop that will quickly "shotgun" out-of-warranty at the customer's expense will not repair intermittent problems under warranty.
If not under warranty try resoldering all components with a small tipped soldering iron designed for surface mount work. Do not bridge solder across fine pitch IC pins. I had to do this to a Dodge Neon dashboard pcb, several solder joints had cracked. (That's one of many reasons I never buy Dodge/Chrysler any more).
Now imagine this scenario as applied to an intermittent steering joystick: "Sorry Sir, we cannot replace your intermittent Steering Control Module until it fails permanently and you actually run head-on into a truck."
There is a valid reason for having a steering wheel, inertia. when your driver's side tire hits an obstacle this unbalanced force can cause the steering angle to change. the forces restraining this are due mostly to the inertia from the steering wheel. this inertia is due to the fact that 1 turn of the steering wheel produces perhaps 1/8 of a turn of the tire about it's steering axis. this 8 to 1 advantage is squared to get the unit correct, so the steering wheel comes out with the majority of inertia. without this wheel the electric power steering would need to generate greater correcting force.
If you folks think that the older drivers can not handle a vehicle with a joy stick, then you should drop by a Senior Center with assisted living. Lots of the scooters and power chairs are controlled by joy sticks and these seniors are doing pretty well with them.
Drive By Wire (DBW) to reduce weight and cost are fine. But the more DBW, then the more required yearly inspections we will need to ensure vehicle safety - especially on older cars. We already have emission inspections. If we have more DBW then we will have to mandate DBW inspections as well. Not a big deal if we have it at the same time as the yearly emission inspection. Of course the car makers will need to provide test portals and procedures so that the inspectors can thoroughly test the safety critical DBW elements.
The trouble with this is that a yearly inspection will not catch a silicon junction that is about to fail. Unlike mechanical wear (such as ball joints) silicon is packaged where it cannot be seen, and a transistor will fail instantaneously and without warning.
Analogy: Predict when a light bulb will fail.
I think one point most of you are forgetting is the tactile feedback of the wheel. It lets me know how hard I am turning. There is none of that in a DBW system. Its one of the reasons fans of racing games always go back to the steering wheel. Its just more robust(tolerant to noise if you will) I know I won't use a joystick for a car it just wouldn't feel as controlled.
I was quite reminded of this last night, where I was driving in a heavy rainstorm in a badly rutted road. Every once in a while one wheel would hydroplane, pulling the wheel towards the side that wasn't. It was easy to tell via wheel feedback. They would have to greatly improve haptic feedback to get a joystick to do that.
My experience in vehicle development is littered with electronic "assist" systems that endanger the driver and passengers by causing the car to behave in an unexpected way. For example, the traction control system of the 5th generation Corvette nearly killed me. Went to pull into traffic where there was a little loose gravel. TC saw a bit of wheel slip and simply shut down the power, leaving us dead in the path of an approaching truck. Common situation that would have posed no threat ordinarily- made nearly lethal by the assumption of an electronic system. Similarly, during developoment of the Prowler, the auto-stick tried repeatedly to wreck us. Downshifted approaching the S-curves at the tech center. Tranny won't shift, won't shift... Finally I have to get into the brakes -late. Entering the curve, the computer decides to downshift, of course snaps the rear end out, putting us sideways. In this case, simply a little extra fun- correct & verify on the next lap. Never had the ppportunity to drive a production unit. Can't say if it was ever corrected. My point is that these systems cause a car to behave unpredictably in the hands of an engaged, skilled drive. As a veteran automotive electronics engineer and skilled driver, first thing I do is turn off any computer assistance that can be turned off. I'll trust 850,000 miles of safe experience. Unfortunately, far too many "drivers" only want an appliance. When we can put them into a fully automated car, or better yet mass transit, then I'll feel safer...
Joy stick control is enjoyable in place of the steering wheel.Initially a joystick and a steering wheel which could be retracted a touch of a button in the joy stick can be provided.In case if the joystick fails the steering wheel will come out and the user can control with the steering wheel.
Safety critical subsystems (steering and brakes) should always have manual overrides of some sort.
Also why do we need DBW acceleration control? The old traditional acceleration control doesn't add much weight or cost.
Only add DBW for fuel savings, power windows, etc. Items where they do not cause safety problems.
My vote is as follows:
DBW: Fuel saving, power windows, door locks, handless phone service, handless music/stereo control, tire pressure monitor, fluid monitors (fuel, oil, hydraulic, radiator, etc.). Any other function that does not directly or immediately affect safety.
No DBW (or at least manual overrides): Steering, Brakes, Accelerator control
You can't make a locomotive that goes faster than 25 miles an hour because the air will be moving so fast that a human won't be able to breath and will die.
I'm never going to fly an airplane without a propeller. I don't trust anything without one.
Microwave? I really don't believe anything without flame or a glowing burner can cook, and the rays will kill us.
How can you possibly trust one of those carriages that is pulled by a motor instead of a horse. What if you run out of fuel? They break down all of the time. With my horse, I can keep going as long as there's grass and water.
Bar codes will never work for pricing because a lot of items are sold by weight and are measured out in the store. You can't design and print a bar code on the fly like that.
You can't put continuous feed forms and labels through a laser printer so we can't use one in our office.
I'm sorry, but where is the spirit of innovation and thirst for discovery and problem solving here in this thread? We all know what the problems will be when the steering wheel is replaced by a joystick or some other drive-by-wire set up. Pointing out the problems is the easy part.
How about instead of being skeptics because we don't believe it will work, how about we think about solutions? The reliability scares you. How can we make it not scare you? Instant-failure terrifying. How can we make it fail gracefully? Don't think something will work. How can we make it work?
Somebody's going to solve these problems. Why not us? We can look at all of the fears and worries as engineering challenges and solve them, or we can fade silently into the night as the rest of the world moves on ahead of us.
I do agree with the need for the innovavative spirit. I see the biggest hurdle in case of Automotives is the cost perceived by the manufacturer.
Is the premium increase, worth the added feature(in this case a high reliable drive by wire system). How much of the safety premium will reduce the accident probability that already exists?
In this case, we are addressing just
the driver error introduced by the
drive by wire system, compared to
In order to see a high reliability system for the above application, we
need a paradigm shift, where the reliability factor should become a commodity(fly by wire systems in Airplanes use high amount of redundancy,
and overdesign, which results in a substantial increase in the cost-justifying the multi million dollar
Well said Duane. For a bunch of engineers most of the comments are fairly luddite-ish.
That said, I'm a bit of a luddite myself. Like Zeeglen, I wouldn't trust a joystick in my current car, but how DO you do it mechanically on a car with a motor per wheel? And as someone else pointed out, look at the seniors with joystick controlled scooters.
And who says you can't do DBW with a wheel? There's no rule that says it has to be a joystick. And there's no rule which says you can't give it some tactile feedback as well.
derF above gave some good examples of what happens when we get it wrong. But Engineers should be able to think round these issues. For example on the traction control issue on gravel - disable the traction control when the driver gives full accellerator. As soon as his foot is off full, enable the traction control again. And if the car can sense what's in front and what's coming up behind, use that information as well.
Another comment noted the need for centimetre control when on a highway between two trucks at 70Mph (rats, mixing units) and the much larger range of control to turn a corner. So make the control range dependent on the speed, and make it non-linear so that larger movements produce a proportionally larger effect. Computer mice have this already....
I'd agree with derF: "When we can put them into a fully automated car, or better yet mass transit, then I'll feel safer...". Too true. A driver gets information from many sources - vision, hearing, touch, etc. Only when cars can do this as well can they overcome these problems. The traction control issue was due to only one source of information driving it. As Emmsys says below: "Am I totally against more computers and less mechanical in a car? If done properly, no."
I'll freely admit that I have nowhere near the skills to implement these solutions, but there are lots of guys (and gals, SallyF below!) here that can - so c'mon, think outside the box...
Totally Agree with Duane, above. I too think this thread got a little hijacked by the 'reliability'conerns, while there is no data to support the fact that mechanical assemblies wouldnt fail as much as the electronics fail. We know that semiconductor devices fail, but let us not forget that the ones getting designed into autos are special grade which are rigorously tested and their chances of failure approach to zero. Most of the public transport - Railways, Airplanes have their controls based on electronics alone. With the number of passengers and the speed/environmental conditions that a train or an airplane encounters, it should atleast settle the argument regarding the reliability of ICs. I am sure an entire system could be worked out for cars as well, which would be as reliable and safe as our trains and airplanes are.
Next time you fly on a 777 or similar Airbus keep in mind the pilot has no mechanical link to move the primary surfaces. All those passengers are relying on Fly-By-Wire whether they know it or not. To me it is not an issue of eventually dealing with the safety / redundancy requirements. The only issue I see is the precision and upset characteristics of whatever the steer by wire control is - joystick or something else?
Actually, I remember reading that the WWII B-17 used electrically operated flight-control surfaces instead of hydraulics, in part because it's harder to shoot a hole in a wire than in a hydraulic hose. Those were some tough planes!
Media catchphrase of the day is "crowd souring". I'd be glad to design a steering system for automobiles with benefits of weight, space, and cost reduction, while at the same time offering high reliability, fail safe, and human factors considerations. But not for free - send me a contract proposal.
Joystick stering is in fact available today as a handicap adaptation. See one man's story about modification of a van with a commercial joystick steering system at tetraplegicliving.com/disabled-driving-disability-info
Part of the major commercial airliners initial flight test involved review of what are called 'flight squawks'. This is a list of complaints the pilots made.
First squawk on a program I worked on. 'Joy stick is missing'. Chief engineer's response. Ha Ha Ha.
In terms of steering, I imagine there will always be a mechanical link in the background. What if the main fuse blows while your driving your DBW-only vehicle? I owned a BMW so I can attest to critical things like that happening at the worst possible times.
As for DBW throttle, that's been around for a while. My BMW had it and it became obvious that it was there when coolant shorted the ECU right at the throttle position sensor pins. The car launched forward a couple of meters before I put the car in neutral and let it coast to a stop. The engine RPMS were bouncing everywhere (there was no brake/accelerator error check) despite not pressing on the gas pedal.
Am I totally against more computers and less mechanical in a car? If done properly, no. However my experience is that cars have become sensitive because of sensors failing, which often completely disables the car. People have become more lazy with respect to driving and vehicle maintenance because they rely on sensors to keep them from sleeping at the wheel and from visually inspecting their tires.
In a car the driver may move. Vibrations, inertia... are transmitted to the driver. And the driver "secures" himself/herself by "catching" the steering wheel. That is, the vibrations... into the steering wheel do not affect the steering functionality (at least in a "normal" case).
It is not this case with a joystick. You will see, whenever a joystick is used, that either the driver suffers no vibrations or inertia, or the driver is securely "fixed" to the seat. If we accept a more "secure fixing" to our seats, then a joystick could start to be a possibility.
I think the risk of a bad driver is far higher than that of faulty electronics. And Toyota is a good example for that.
Frankly speaking any electronics that controls the average sloppy uninterested driver will increase safety and not decrease it.
And it doesnt't matter if it is a joystick or an electric steering wheel. Both can be easily pushed in the wrong direction if drivers grab a cup of coffee or turn to their kids while traveling at 70 mph. The trick is that electronics would be able to detect this and prevent the accident.
With two handed driving, the driver's input is much like a balanced line so that anything that affects both inputs (hands) like a sneeze has minimal to no effect on the direction of the vehicle. Would a single joystick react the same or would two joysticks be required? I'm certain DBW could mimic the wheel functionality but it may raise the complexity of the joystick system.
As for drawing parallels to the joystick in aircraft, how much flying is done manually with a joystick and not on autopilot? Would a better comparison be operating construction equipment or lift trucks with joystick controls?
I recall that a project was published in magazine (Popular Science?) in the 1960's or maybe early 1970's that changed the steering wheel system. The dash mounted wheel was removed and wheels were installed beside the driver's seat on both sides. The added wheels were parallel to the tires. The driver turned the car by turning one wheel forward and the other wheel back. I don't recall any more about the project other than is was not suitable for bench seats. Maybe a reader recalls the article or can find it.
There is an intrinsic fault with steer-by-wire, which is that it uses a computer in the loop, at least in almost all of the versions that I have seen recently, which means that there will be software that will not be able to handle unusual conditions. The software will be set up to protect a 16 year old beginning driver on city streets. That alone is a show-stopper. The FBW systems on aircraft are multiply redundant and usually set up to work with a very well trained pilot. Besides that, they are far more carefully maintained than even most race cars. One final thing is that we all see a wide spread of failures in our current vehicles. Who would wish to add steering to that list? As for the assertion that vehicle electronics is becoming more reliable, it is clear that the individual is in sales of vehicle electronics.
Bill Schweber's original question was why hasn't the steering wheel gone away? Well it's pretty darn clear, in this blog alone, why is hasn't, people are not mentally ready to turn loose of that control, just that simple. Most comments center around something going wrong and causing an accident. Any engineer worth their salt should know there are ways around ALL of the design related issues listed here.
Cars applying brakes if they sense an imminent collision were unheard of a few years ago but they are on their way to becoming standard. There are brake by wire (BBW) cars and in fact some of the naysayers posting here may have driven one without even knowing it. DBW is just the next step.
Will there be an occasional failure resulting in a crash and possible death? I can guarantee it. It has been and will continue to be the risk of being transported by something weighting thousands of pounds and going much faster than you can walk or run.
Posters talk about single point failures that could occur without warning causing loss of control, think tires! Try a having a blow out while negotiating a decreasing radius turn (like an off ramp) and see how much control you have. Funny thing about control, you think you have it until you don't.
I drive a '71 VW bus not because I'm afraid of technology but because it's fun, cheap and I have been known to fix it in a parking lot with a swiss army knife. So I'm very familiar with old vs new technologies. Bottom line, with cars generally getting safer each year I would happily drive a properly engineered DBW/BBW vehicle and have more real and less illusionary safety and control.
The question or point isn't that a steering wheel could be replaced by something; of course it could. But the question should be WHY do you want to replace it? Other than design and manufacturability improvements by having wires instead of a linkage, is there some actual shortcoming or problem with the steering wheel that someone is trying to address??
Don't brand the folks here as Luddites (or -ish) for being skeptical. There has to be, first off, a good reason to change something, and second, the replacement has to meet or exceed all of the performance of the original and solve some additional problems.
The thread is quite long, so I'm sorry if I missed someone pointing out the problems, but it's a waste of time to talk about insufficient and unneeded solutions to problems that don't exist.
"There has to be, first off, a good reason to change something...."
The manufacturers have a good reason - they could design the front so that the controls can be placed either side without rearranging the whold car....
Ref my luddite comment...as I said I am one myself. Until vehicles have as much input as I get while driving, I wouldn't trust a DBW system either.
And I agree ref the steering wheel..Don't reinvent the wheel, it's done a good job for reasons many posters have outlined, and a wheel is as good as anything as a man-machine interface. And some vehicles already have self-steering into parking spaces.
I think (and I kind of hope) that a completely DBW vehicle won't happen anytime soon, but as I said above... anyone care to tell me it will never happen?
A few thoughts to Bill's original question:
One big problem with anything new in the car is the variation between manufacturers. Look at the trouble Audi had in the 1980's, primarily chalked up to the pedal cluster placement being shifted a bit relative to big American cars... and that's even with basically the same control system. It's daunting to imagine the problems people will have with several variations on the theme among different models, esp. in rental cars. Anything unexpected/unintuitive in emergency situations will make outcomes worse.
Any changes here will have to go though some sort of standardization process. That alone could be a big enough barrier to stall progress.
Reliability, for me, is the main barrier though. I've had a few older cars and when problems arose with mechanical things the situation was minor and with a lot of warning (e.g. seepage around the steering rack gasket). Most of the problems related to electronics - and not the devices as much as the connectors failing. By and large the mechanical systems hold up pretty well for 20 years even in extreme heat (south Florida).
You bring up some great points. Just look at how the keyless start system on newer cars causes confusion to most drivers. By most I mean the average driver that only thinks of a car as an appliance that takes you from A to B. On many cars you need to hold the "Start" button down a few seconds to shut the engine off. With the standard key you just need to turn it counterclockwise which can take less than a second. One method is cool and "new", while the other is old but much more natural.
When I wrote earlier about my BMW launching itself when coolant shorted the throttle position sensor pins on the ECU, no one would ever imagine that that would happen. And evidently BMW didn't expect anything to ever go wrong with the throttle position input so there was no safety check against pressing the brake and accelerator at the same time. Thankfully I instinctively threw the shiter into neutral but how many people would have done the same thing when a 282HP V8 all of a sudden decides to go wide-open-throttle by itself? Now this was a "mechanical failure" (the coolant temperature sensor failed resulting in the coolant to enter the wiring harness) that resulted in a software failure. We can add as many MCU or MPUs on a car as we want but we really need to factor in failsafe systems. Losing steering control on a car is much worse than the lighter fuse blowing out.
As for reliability, my father has a 1971 Corvette (All-original) that starts right up even in -25degreesC weather every single time. On the other hand, my BMW had an air pump whose only purpose was to blow cold air onto the O2 sensors on startup to avoid a check-engine-light from appearing. That's right...on startup only. Of course the pump died and it cost $500+ for a replacement...all this just to trick the O2 sensors for a brief period of time!
Technology is great, that's why many of us became engineers but sometimes there are solutions proposed without a problem.
First thing I did in the test drive last year when I found I couldn't get a new pickup truck without power brakes and power steering was run it up to 15 MPH, turn off the key, and demonstrate that I could steer it and stop it. After a few years designing burner safety controls, where the overriding design consideration is ironclad proof that every physically possible component failure leads to a safe condition, I'm far more concerned with failure mode effects than failure probabilities. As for stuff like power windows, it's just more crap to break. What ever happened to KISS?
A steering wheel is "Roughly Speaking" a "2D" device - you move it "To the Left" or "To the Right" and the car "Follows" it. But more importantly, when you do NOT move it to the Right or Left, the car stays on the course that it is already on, (Whether that be on a curve or straiht ahead).
A Joy Stick, (If you disregard its "North/South" movement, which, you could well argue could be used for accelerating, ("Up"), or for Braking, ("Down"), does not have a "Rest" position and you would be forced to "Hold it in position" all the time.
Now if you could "Spring Load" it back to its neutral position, I might buy that.
The advantage of a rotary control for steering (and also for radio volume) is the decoupling of the desired action (changing direction/volume) from the variable inertial forces of a non-uniform driving surface. Consider the radio volume control while driving on a bumpy road: You grab the knob with your hand and rotate to the correct volume, with any road-bump accelerations to your arm being ignored as your hand position is stabilized by the knob supports. Now, consider a vertically mounted slide-pot: You grab the slider and begin to position for the new volume setting, whil a road bump causes your arm to make violent changes to the position.
I have been playing video games with joysticks since I was a pre-teen which makes that over 30 years ... Yes, that is how long video games have been around!
Could a joystick be used to effectively "pilot" a vehicle?
Need to consider that steering is a closed loop system. Decide where I want to go, turn the wheel, see if I am going where I want to go, make adjustments. While there is speed sensitive steering that adjusts the turns ratio between the steering wheel and the real wheels, for the most part in any given situation, there is a level of linearity (or at least piecewise linearity). There is also a fairly significant movement arm, i.e. the radius of the steering wheel multiplied the required angle to turn. That allows fairly small corrections with fairly gross movements.
A joystick is not able to easily replicate this relationship between human input and what happens at the wheels.
When a joystick is incorporated part of that closed loop control system MUST be taken out of the control of the human and put into the car. That has nothing to do with age, experience, what you are familiar with, etc. That is just the reality of replacing what we could call a low gain input, the steering wheel, with a high gain input, i.e. the joystick.
Do I think there are some inherent safety advantages with the current mechanical linkage? Within the confines of a car: cost sensitive, questionable maintenance, etc. that for the foreseeable future, the mechanical linkage is an acceptable and perhaps cost effective redundant system. Is that likely to be the case always? Highly unlikely.
Do I expect that driving over time will be taken somewhat out of the hands of the driver? ... That is an absolute, 100% given, at first on major highways and then perhaps to major secondary roads, though perhaps a long time till it hits the local roads. Don't believe that? Imagine being able to rush along on crowded highways during rush hour at 120+kph (75mph) because your computer controlled vehicle is only sitting 3 metres (10 feet) from the car in front of you ... just like the one directly behind you. Impossible with driver input, viable if computer controlled. 3-5x the number of cars on the same amount of road and less fuel usage due to drafting. Of course, maybe our vehicles will just be pulled along by magnets, etc.
To someone's point, progress is progress. It has its hiccups. Almost impossible to "work" on my car anymore, but since it keeps going and going with minimal maintenance, who cares. I don't use the "DOS" prompt much any more either, but again, I don't have to.
Many years ago I designed-in a joystick from Flight Link Controls Ltd (now owned by PWT). The joystick used a differential inductive transducer principle which sounds tricksy but used only a handful of R,C,TR discretes to give a contactless, failsafe design, whatever component or connection failed.
The reason for this post is that if you can get a copy of the schematic you will one of the most cunning, elegant and well-thought-out analog designs you will ever meet.
These joysticks had a very good track record, and were/are often fitted to wheelchairs etc for users who often could not have manipulated a wheel anyway.
One thing that I think some people may be missing is thinking of a "joystick" a small, video-game sized joystick.
Small linear motions, very sensetive - true, there's not much motion difference between a small nudge and full scale.
A joystick used to control something like a car could be such a device, or could be a much different shaped stick, with a larger range of motion - both small wiggle movements, and a large sweeping motion that would be hard to mistakenly execute.
Or it could just be a 4"X4" touch pad.
Not that any of these are necessarily "better" than a wheel, which does have some pretty good merits as a steering control device.
Why? Well, when professionals do it (racing drivers) it might be accepted. Racing teams have seven figure budgets, and they haven't thought about it. We'll see something like this AFTER we see it in the INDY 500! Not before!
Make everything DBW as desired.
However, give me an independent
backup system (DBW also if desired)
for steering and brakes with their own independant power supplies.
It is extremely unlikely two independant
safety critical systems will fail.
Why would anybody advocate an all-electronic control of the steering on a car? There must *always* be a mechanical fail safe for steering (and brakes). Case closed.
Is the ostensible reason to save money? You still need to steer the wheels. That involves a mechanical linkage, a gearbox, tie rods, everything that has been there on every car ever made. The only item you would be saving money on is the steering wheel itself. And replacing that with, what, an electronic gizmo that has to operate over the automotive temperature range? I don't see the savings.
Even if there were a cost savings, is that sufficient reason to put the occupants' safety at risk?
And how about this? Hacking a car through bluetooth... not easy apparently, but possible.... scary....
The day we use something like Microsoft Windows to control our new cars is the day I go out to the junkyard to buy and retrofit an old car.
Even in more "robust" RTOS operating systems I find glitches and problems that require reboots to clear problems.
For the amount and cost of oil we'll have in 20 years I'm betting most of it will be saved for flights and trucks and such and most of us will be walking, biking or taking trains...that's my guess anyway.
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