From: Kai-Mikael Jää-Aro Subject: Re: HUMAN-FACTORS: SIDs & HMDs Date: Tue, 29 Oct 1996 10:08:54 +0100 Message-ID: <3275C9A6.2428@nada.kth.se> Organization: Royal Institute of Technology [I have set followups to comp.human-factors, as I think that is the more proper forum.] John Draper wrote: > > Kai-Mikael Jää-Aro wrote: > > > > John Draper wrote: > > > > > To say that something is better than another thing HF-wise, you must > > > really specify what the mission of the thing is. Good HF requires > > > designing for the mission, not in the abstract. A joystick is superior > > > HF-wise for fighter planes, but not for automobiles, for (trivial) > > > example. > > > > Not necessarily, the experiments SAAB has done with a > > joystick-controlled car seems to me to indicate that a steering wheel is > > more of a historical accident that remains for no good (HF) reason... > > This is a good example of what I'm talking about. Of course you can > control a car with a joystick, and driver performance with the joystick > is probably just as good as for a steering wheel. There may be good > reasons for using a joystick in, for example, a Formula 1 racer. However, > when you look at putting the joystick into the family automobile, some > other issues crop up. These are all very good questions, and I admit that I (and possibly not the responsible people at SAAB either :-) had not thought about most of them. I can fill in what I know though. > (1) Does the joystick need to be in a position analagous to an arm > rest? Yes, the pictures I have seen indicate that the joystick is (right-side) side-mounted for comfortable usage. > If so, is it more prone to accidental activation if, say, > a 3-year-old drops his teddy bear out of his child restraint seat > or the user reaches for a map in the glove compartment? Well, the driver is presumably holding on to the joystick while driving, so any falling objects would probably end up in the lap of the driver. (My son was very proficient at fiddling with the gear stick at an early age, so my brother, who often drove us, soon took to always having a hand on the gear stick.) My stern opinion is that the driver should *never* reach for anything in the glove compartment while the car is in motion - ask any front-seat passenger or stop the car first. > Does the joystick limit seating by preventing the 3 abreast arrangement? Yes, lorries might be an issue. We wouldn't want incompatible systems between different sizes of cars... > (3) Do you mount the joystick on a pedestal between the driver's legs? You would not want to do this, since having a stick in front of your stomach would probably increase, rather than decrease as intended, crash injuries. > (4) Can you make a joystick that provides the same amount of haptic > feedback to the driver that a steering wheel does? Is this > important? As I have understood it, it was actually considered a benefit that jolts in the road were *not* propagated to the hand. I am myself a bit wary about this, but since joysticks in aircraft can do this it should not be impossible to do so for cars, if required. > (6) How much wrist support do you need to provide? How much does this > reduce useful cabin volume? How fatiguing is it to drive for hours > without support? The space taken up is the console where handbrake and gearstick usually go, so I don't see it taking up passenger space. (Where the handbrake and gearstick have ended up, I do not know.) It would seem to me that it is more comfortable resting your arm here than having to hang them off a steering wheel. Any F16-pilots around that can tell us more? ;-) > (7) Is the joystick equally useable for left-handed and right-handed > people, as steering wheels seem to be? This is a very important point. It could be argued that lefthanded people manage to operate the gearstick etc in conventional cars, but this is of course a much more intermittent activity and possibly not even as demanding of fine-motor skills. -- Kai-Mikael J-Aro email: kai@nada.kth.se "Don't win, don't lose." IPLab voice: +46 8 790 62 79 -- Yoshigasaki-sensei NADA, KTH fax: +46 8 790 09 30 S-100 44 Stockholm telex: 812 6154 1156 SICS SWEDEN teletex:2401-812 6154 1156=SICS