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The iBOT 4000 Powerchair tested in
its normal mode and its problems explained...
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7. normal mode This is the main problem with this
chair still. First a picture. Ignore my fat gut.
Look at the wheels. The rear drive wheel is very far
back. The centre wheels are raised up a few inches.
This makes for a
very nose heavy, "long" vehicle with a very large amount of
weight over the front castor wheels. It takes a lot of power
to turn, and feels unwieldy indoors the very place you HAVE
to use this mode..
It is I do think
SLIGHTLY better in this respect than the original iBOT 3000
was from what I can remember. But its still far too
nose heavy.
The result of this
is that when turning indoors it feels like its turning from
a long way behind you and you have to allow for this when
turning corners and aiming for doorways etc. It also
seems to make it more sluggish to steer, and of course
requires more battery power to achieve, so shortens range.
In short it is improved but not cured.
Its a strange
feeling to me as my own Powerchair is very short and light
to manoeuvre. Now this heavy front end runs on SMALL
harsh front castors (6 inch) which transfers all the cracks
and other surface imperfections and real world shocks
to your chair directly! I suffered lots more muscle spasm
because of this than usual and its vibration is very
tiring. The other problem with the castors is their
shape!
 They
have decided to use a "Tweel" for the castor wheel.
Made by Michelin. see their
site
here
Now they are very flat and square in profile. see picture
>>>
Now these are both
very heavily loaded, and only 6 inch diameter. Imagine
what happens if one comes across a slightly raised
longitudinal paving slab, or anything with a square raised
edge over say 1/2 inch.
Well in case you
cant I will describe it! It bounces off the edge about
20 times, while oscillating about and gives the occupant a
rough ride! And it effects steering.
Then depending on
how high it eventually jams up or jumps up to the higher
slab. Its the same if you run over a slightly raised curb or
drain cover at a slight angle. They are both too small
in diameter for the street, and have the wrong profile.
It seems the
marketing departments enthusiasm for "high tech "TWEELS" has
won over the engineers common sense! These things are
great on cars, but totally useless on castors!!!
Just how exactly DO they come to daft decisions like this? A
victory for the marketing department over the engineers...
They do have the advantage that they will not puncture
though. Unlike the fragile rear tyres. (More later!)
Also the real
world happens to be full of pot holes, 1 or 2 inch jumps on
the start of ramps in the street uneven surfaces etc.
These castors, are far too small and hard with too much
weight on them to negotiate these things without an awful
lot of care! You could use 4 wheel drive mode, in
straight lines, but that takes time to engage and set up and
turning is a real issue. I tend to move pretty fast!
It wouldn't work for me. I would spend at least as
much time going from one mode to the other without actually
driving, as it took me to get there in my own modified
chair!
Next the
programming. Just as most powerchairs arrive with
dismal programming for the control system, this one does
too. The difference here is that you cant just buy a
programmer from say Penny and Giles, and fix it! They
will neither do it for you or allow you to change anything
yourself.
As it arrives, it
has lots of turn acceleration, and turn deceleration. This
is like most other powerchairs are, akin to steering your
car with a rubber band. You choose to add a little
correction say to stop it heading towards a wall.
You add say 1/8th
inch of right stick while travelling at a good speed along
the pavement. It appears to not be working. So you add a
little more. Or you do it progressively.
Now because of the
delay caused by the damned turn acceleration, the FIRST part
of the stick correction kicks in. It was enough after
all!
But now the next
adjustment you added because of no or little initial
response also kicks in! You suddenly realise that
"you" over controlled the chair. (It really wasn't
your fault but due to an initial lack of response.)
So now to stop it
going violently the opposite way to the wall you originally
corrected for (right in this case), you add some left stick.
But because of the
turn DECELERATION it only slowly reacts to the initial right
turn condition and keeps turning for x time period to the
right!. Making your original error worse.
So you feel its
not responding (again - because its not!) and of course keep adding more left!
Suddenly all your left input begins to work, too well!
And off we go
again towards the wall only now its worse because you try to
correct it again! This oscillation, which happens with
most standard powerchairs is caused purely by the dummies
that set it up adding acceleration and deceleration to to
the steering!
When will these idiots learn! I
reprogram lots of powerchairs for others, and every time I
remove ALL the turn acceleration, and deceleration they are
amazed at how easy and accurate their Powerchair then
becomes! EVERY TIME. Turn acc and
deceleration is ALWAYS BAD!
Also it has an
almost embarrassingly slow reverse max speed (about 0.5mph),
and also very sluggish forward acceleration. The programming
for forward acceleration rate feels like its set to about
35% Its just TOOOO slow It needs to reach full speed in
about 2 seconds IF I WANT IT TO! Just like a throttle
on a car you don't have to use it all...
It goes 7.2mph
eventually, but it takes ages to get there due to the above
setting.
All of these
settings together make it cumbersome and difficult to
accurately manoeuvre in say a pub or when doing your average
23 point turns (35 with those awful footplates) in a corridor.
OK last
programming bug! Every time you release the stick, at
any speed no matter how carefully, it stops as fast as
possible. The tyres squeal, I slide out of the seat.
Its both tiring, and uncomfortable, and dangerous!
When you release the stick it SHOULD slow, but it should do
so at a reasonable rate. Say 4 to 5 seconds from flat out.
If you need to stop faster in emergency set it up so it
gives you the max braking as you pull the stick right back
like other powerchairs! Also because of this instant
max braking, it can start to oscillate as you slow down and
the stick gets to the point where the braking comes in. It
starts jerking and oscillating between low power and stop -
very uncomfortable.! Partly due to the wobbly arms on
the ill thought out armrest system.
THIS LOT NEEDS
FIXING! iBOT engineers - are you listening? I want to
buy one but THIS is the one thing on this chair that I
cannot repair myself.
Summary of normal
mode.
As it is, I could
not use this chair on a daily basis, because the unbalanced
controls, (programming) incorrectly chosen castor wheels and
nose heavy layout make it too slow and hard work compared to
my own modified F55s chair.
When I leave for
the pub say at night I Fly through the house missing
obstacles by inches, diving through doorways, swerving
around the dog, and go! This iBOT 4000 chair isn't
capable of this at the moment. I would need to
be very slow and deliberate to avoid hitting things.
Then I get
outside. Here I nail it flat out, (7 or 8 mph
(slow...) all the way to the pub about half a mile away. I
don't slow. There are big roads to cross, ramps,
uneven paving, sunken drain covers, small curbs, pot holes,
funny cambers, broken glass, etc. I get there smoothly
in one mode and fast.
In the iBOT you
couldn't use 4 wheel drive mode because you cant turn more
than a few degrees without ripping the tyres off
Couldn't use balance mode because the pavements and roads
around here are simply not flat enough.
I could use Normal
mode, which I did. But its handling problems, small castors,
and inability to run over say a 2 inch curb make it much
less comfortable and slower. All of these things could
easily be fixed. But they don't seem interested.
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