Weight! (A continuation, sort of, of my Storm 4 review.)

[sakima]

[url]viewtopic.php?f=6&t=4585[/url]



Bman?
Just out of curiosity, how much do u weigh?

[Burgerman]

Dunno. But I am about 18 to 20 stone. 18 inch cushion. Size 12 feet.

And no its not true, or I would be 10 feet tall.

But it may make a front heavy chair feel worse, but it still nose heavy regardless of how light you are if it sits you too far forwards. As all modern chairs do. They have to do that because of silly regulations regarding stability when accelerating at full power up a slope.

The thing is, MANY different users of various rear drive chairs on this forum, and locally, including some that have driven here to my house for reprogramming, have done both things. Reprogrammed the chairs to turn, and stop turning and they were all mighty pleased with the results. Nobody ever wanted to put it back how it was, with one exception. And that was someone that didn't have the required joystick skills or hand capability.

Many people, including my neibour said they had no problem, and that it was steering great. Then for my own amusement, I reprogrammed her (their) chairs temporarily to remove all the delay, and the look on faces said it all. Most are amazed at how simple and intuitive and natural it suddenly became.

No more woolly feel, and total confidence at any speed through any gap. They THOUGHT it was good. They just didn't know how it can be.
You REALLY notice this badly if you are used to a properly set up controller. If you then try returning it to back to less than 100 percent on all 8 turn acc/dec settings. It just becomes hopeless.

Now while most wouldn't want a powerchair this tippy, I do! This is too extreme for most. But stock chairs are way to far the opposite way.

http://www.wheelchairdriver.com/gopro/wheelie.mp4

It allows you to drive on a completely flat caster tyre with no worries... Since there's almost no weight on the front. Maybe 10 percent.

It means I can hop up a curb with a quick wheelie. And the whole chair from anti tips to the end of the footplate is just 40 inches. So it turns and fits better in crowded places, vans, houses, pubs or allows me to turn around in a small toilet and come out forwards. Where your chair can barely fit in. And they are loaded less so sand isn't a problem and the fat rear tyres don't sink.

Here's Nandol in Thailand... Fat rear tyres, LIGHTLY loaded casters and sand, snow, mud no problem http://www.wheelchairdriver.com/BM3-con ... -TYRES.jpg

And my newer chair is a bit faster too. This is 12mph before I fixed the caster shake (listen carefully). It actually goes 16+mph... Great for outdoor use!
http://www.wheelchairdriver.com/BM3-con ... -12mph.mp4

http://www.wheelchairdriver.com/gopro/puncture.mp4

Moving the CG back just makes it more nimble, and puts the weight on the drive/steer tyres - giving less battery drain, better control, esp on uneven ground.
In the same way that most sport manual chair uses get to CHOOSE how "tippy" their chairs are. Most want it tippy because while that has disadvantages, the light steer, wheelie capability, and less energy wasted is a compromise that they want. In a powerchair we get no choice. Legislation means they all drive like oil tankers...

More BM3 stuff http://www.wheelchairdriver.com/BM3-construction/ Its designed and built pretty well too! In a bedroom with a budget of about 1/3rd a "real" powerchair like yours! You see I tried and tested a LOT of chairs over the years. And I know how to do better. And I don't just complain, but actually prove it.

With 45 miles bare minimum range? 16MPH, Tons of torque compared to a normal mobility offering, fat puncture proof Kevlar reinforced low pressure high floatation tyres, 2x 150Amp 45v Roboteq control system, with custom script for control (thanks Lenny!) 13.8kw of electrical power (3x that of the mobility industry best) 3.2kWh (also 3x better) hi rate lightweight 10 year minimum life 2000 cycle safe lithium ion phosphate battery system, Sand, snow, true outdoor capability. Tight small nimble indoor footprint, where you are sat over the drive wheels for control? Low pressure tyres that five a smoother vibration free ride? Wheelies? Better build quality? All there and more. Like graphing and monitoring of all battery and cell balance parameters, with a PC and Bluetooth control. Built in Radio Control, fast charging and charging in car. Etc. Data logging to PC of all controller, battery, motor, command and control info in real time as you drive.

This is among other chairs, what I am comparing your chair and stock mobility chairs to. This is why I can speak with the authority that I do. Because I know how it CAN be. If they tried.

[sakima]

I see what u mean, u do drive fast indoors. I just go at walking pace, besides which I could squash my cat!
Have u ever collided with your dog?

There are not many pictures of powerchairs exactly side on, but what there are does show, just like MY Storm 4, that the seating position is just in front of the rear axle, with most of the body weight, based on Mr/Mrs average, towards the rear of the chair.
It seems all rwd wheelchairs are built this way, so they don't tip when u go up slopes and/or carry weight on the back. As u say, TIPPY wheelchairs are a bit extreme for most users and as u say again, heavier wheelchair users, would find this design worse and the heavier u are, the worse it becomes, putting more and more weight on the front wheels, so it becomes impossibly nose heavy and unresponsive.
The factory settings, so it would seem, are just set up to the weight of Mr/Mrs average.
That's probably why I get on with it cos I am lighter. (Alltho I do struggle with my weight!)

However, I am still a little overweight on some charts. (5' 9" n 12 stone) But I do 'scrape' in on this one;

bmi-chart.gif (46.63 KiB) Viewed 4858 times

so I have attached the list of chair settings to the next reply. Perhaps u could peruse them and make any recommendations where necessary;
(I am sure the current wheelchair engineers can make the adjustments.)

I am 12 stone.
I have minimal but steady use of my hand.
It is quite hilly round here.
So it is a lwb chair.
I am happy with the acceleration/de-acceleration.
I am also happy with the joystick 'throw.'
DON'T FORGET I find the current set up very precise and responsive.


An observation.
U say that this is the same chair that u tested. Was that, according to your post, in 2011?
If it was in 2011, then it couldn't have been the same, as it was re-designed in 2012.
Yes, it was a Storm 4, but it LOOKED different!

[sakima]

Attached..........................................

[Burgerman]

I would change almost all of the drive profile settings.

Everything is set to super delayed... And stock, and the same as all powerchairs I ever saw or tested. So trust me when I say it doesn't steer or is barely controllable.
The chairs I have played in were 2011 and 2012 and a few quite recently. I couldn't see or tell any difference whatsoever. They are all identical under the skin bar a bit of trim... I will mention a few obvious programming issues...

Turn acceleration (Yours 25) That is un-drivable to me and most others. Most chairs are set to 25 or 40. 40 is better but still abysmal and dangerous unless you have the patience of an old lady and go very carefully. Its super smooth, but begins to turn afterwards when it wants, not when you tell it, then speeds the turn up and does long after you wanted it to. It means you slam the stick fully left or right to make a correction and it gradually starts to accelerate into a turn over about 2 seconds period... The turn RATE increases as you wait. Yawn. Instant small accurate corrections are impossible. So you are heading for a door frame at speed, and no fast correction is possible. So in the panic at the lack of affect a few mm of stick had, you give it some more... Now the first bit starts to take affect (late) followed by the extra stick you also added in panic as nothing was happening... And the chair turns too much, too late. And then you cant STOP it turning because of:

Turn deceleration... This is a delay is STOPPING the turn. Once its going left nothing you do stops that. So you have turned too far due to the above, and so slam the stick the opposite way in panic. But it has no affect as decelaration delay makes sure that it cannot! So you now hit the opposite door frame to the first one you were scared of. This is followed by the chair lurching at the opposite side about 1 second later and you guessed it, you cant stop that either. Yours is set to 40. Also totally un-drivable - and worse than turn delay. You simply cannot drive in the sort of spirited accurate fashion that many want. It makes it plain dangerous unless you go slow.

My turn acceleration is set to 100. So it turns WHEN I say so. And by the amount I push the stick. Push it 3mm it instantly turns at a slow rate and continues to do so until I let go.
My turn deceleration is also set to 100. So when I am turning or made a high speed adjustment of say 2 degrees to hit a narrow gap at speed, and release the turn it instantly stops turning and goes straight.

There are also low speed turn acc and dec settings and these too need setting to 100 or you cant steer when going slow... And for what its worth I use just one high speed profile for everything. Once your chair steers properly you only need the one. You set the turn RATE separately, so after removing accelerations and decelerations, it will be too "sharp". So reduce this to taste.

I also have forward and reverse acc set to 100 too. So I can set of slowly or with the wheels in the air. I decide then by how MUCH stick I give it on how fast it turns, and how fast it accelerates, stops, or goes. But this needs normal hand and joystick skills and a hand on the side of the joystick for stability. If you don't have this than you will not be able to do this.

No I never hit the dog. Or anything in 17 years. And I wish you luck getting any "engineer" to change all the settings in the way I would.

[ex-Gooserider]

Don't underestimate the brains of your cat... (or dog) it may play "chicken" to see if it can make the stupid human stop, but if you nip it a time or two it will learn to get OUT of the way...

I also seem to remember BM saying that he has occasionally run over the dog's tail - but with the load distribution of the big tires, it doesn't do any lasting damage (at least not enough to create a long-term memory / learning experience....)

I will also add my agreement to the statement about fixing the programming - both the before and the after effects. I find it amazing that they can sell chairs that drive the way they do, as they could never sell a car that drove as badly...

However, to do the BM style programming setup DOES require precise incremental control skills - Since the chair goes exactly where you tell it, when you tell it, if you want to make a small turn adjustment, you need to be able to accurately move the joystick a small amount. Some disabilities leave a person without that ability to do precise movements, and for them, the stock setup works better. If all one can do is slam the stick to one side or the other, then it works to push all the way over, and wait for the chair to turn the desired amount, then go back to zero. Think of it as sort of a joystick equivalent of a sip & puff setup. For a person with this sort of disability, Burgerman type programming where the chair essentially turns as fast as the motors can drive it, would have the user doing snap spins, but not able to make small course corrections because the chair turns to quickly...

ex-Gooserider

[Burgerman]

Stolen from another thread:

3. This is VERY important - when showing them how to operate the chair, emphasize the need to keep their hand braced on the pod, and work the stick with a thumb or fingertips, so that they have a stable reference. Warn them that if they just grab the stick and move it, they will NOT be able to drive accurately as the chair moving under them will also move the stick and that will change where they are pointing it...

Quite. It may even spit you out. You MUST do this to have any chance of any semblance of accurate control. Even with good hand and joystick skills. You need a reference for your hand. Because once programmed as a instant linear proportional device (instead of a pudding stirrer with a time delay) it really will go exactly where you tell it immediately. You need to be millimetre perfect. Just like a computer mouse or my RC helicopter. I expect my chair to jump if I tell it to. Literally. And be smooth and slow if I am smooth and slow. It simply does exactly what I do. Wheels directly connected to joystick as if mechanically.

Watch 4 year old Justin's fingers on the control sticks here very carefully. He is flying a very lively helicopter smoothly. He is controlling 2 sticks simultaneously in very fine increments. He NEEDS his palms resting on the controllers case to have the fine 1 or 2mm movement skills required. Same with a properly programmed powerchair chair. But not quite as extreme.

http://www.youtube.com/watch?v=pLQhU1cKkx0 This is the EXACT same hand and hand rest skill that is essential.

P.S. You see where you put "its not" in red above? It doesn't matter. All the chairs are the same from the moment they started using the DX2 Dynamic controller. So all use the same industry standard pudding stirrer programming "overlay". And exactly as I expected. And so all drive equally crap. With the exception that the one referred to in red also has gyro steer help, and brushless motors. So those extra setting cannot actually be from your own chair. That sheet refers to the latest closed loop system. All manufacturers offer one. Called accutrack or some other variation. And you don't want that, its even worse as it removes any "feel" from the system as you negotiate terrain.

[sakima]

U say that it would be no good for you on those settings, OF COURSE NOT!
It would be no good to ANY ONE much over 12 stone.
It would seem those settings are just for the AVERAGE person of which I AM.

Everything is set to super delayed... And stock, and the same as all powerchairs I ever saw or tested. So trust me when I say it doesn't steer or is barely controllable. 
As u say “that I ever saw or tested.” The key word there is 'I'. They were not set-up for the heavier user.

I will ask again! U say that you tested the same chair. Is that pre 2012 or post?

Turn acceleration (Yours 25) That is un-drivable to me and most others.
Un-drivable to YOU and MOST others. It would be if YOU and MOST others were much over 12 stone.

Most chairs are set to 25 or 40. 40 is better but still abysmal and dangerous unless you have the patience of an old lady and go very carefully.
Again!
I do drive fast and it's in my review.

begins to turn afterwards when it wants, not when you tell it,  …..
 Instant small accurate corrections are impossible. 
 Just like a computer mouse or my RC helicopter. I expect my chair to jump if I tell it to. Literally. And be smooth and slow if I am smooth and slow. It simply does exactly what I do. Wheels directly connected to joystick as if mechanically. 
If I move the joystick just a tiny, tiny bit, the chair responds IMMEDIATLY. I don't get any lag at all. That's in my review

Turn deceleration... This is a delay is STOPPING the turn. Once its going left nothing you do stops that. So you have turned too far due to the above, and so slam the stick the opposite way in panic. But it has no affect as decelaration delay makes sure that it cannot! So you now hit the opposite door frame to the first one you were scared of. This is followed by the chair lurching at the opposite side about 1 second later and you guessed it, you cant stop that either.
I have already said, in MY review, which is based on MY weight. The steering is very, very sensitive. Don't forget that it is based on a 12 stone driver. Not 13, 14, 15, 16, 17 or 18+ BUT 12.

You simply cannot drive in the sort of spirited accurate fashion that many want. It makes it plain dangerous unless you go slow.
Again!
I DONT DRIVE SLOW!

My turn acceleration is set to 100. So it turns WHEN I say so. And by the amount I push the stick. Push it 3mm it instantly turns at a slow rate and continues to do so until I let go. 
My turn deceleration is also set to 100.
I also have forward and reverse acc set to 100 too.
There are also low speed turn acc and dec settings and these too need setting to 100 or you cant steer when going slow
You need the acceleration and de-acceleration on a100 because you are a heavier driver.
If you get a driver of half your weight, they would need this set very, very, very low. I, therefore, need a much lower setting than you.
CAN YOU NOT SEE that different user weights require different settings? That's why they are there.
You are heavier and therefore require more substantial settings. As you say “you need” these settings to make the chair responsive.

So when I am turning or made a high speed adjustment of say 2 degrees to hit a narrow gap at speed, and release the turn it instantly stops turning and goes straight.
I do that on the current settings. But those same settings would be NO GOOD to a heavier user.

But this needs normal hand and joystick skills and a hand on the side of the joystick for stability. If you don't have this than you will not be able to do this.
Even with good hand and joystick skills. You need a reference for your hand.
 He NEEDS his palms resting on the controllers case to have the fine 1 or 2mm movement skills required. Same with a properly programmed powerchair chair. 
I have told you that I have minimal but steady use of my hand.
I rest my hand on the control, because the steering IS so very sensitive.

[Burgerman]

Weight has an affect on many things. It doesn't have ANY affect on any of the steering delays and accelerations. So every comment about your weight is plain meaningless.
You can watch the delay on a graph or computer screen, with no actual power chair connected. Or a scope like my fluke trend meter. You watch it build or decline gradually after you move the stick. Your weight simply doesn't enter into it.

>>> If I move the joystick just a tiny, tiny bit, the chair responds IMMEDIATLY. I don't get any lag at all. That's in my review

With those settings, you do. And a lot of it. You get a SMALL instant response which then accelerates (builds ever faster) to catch up with the amount of stick you initially
gave it, later on. That IS what those setting actually do, no matter how many times you tell me otherwise.

Also I have driven 2010, 2013, chairs, and they all drive and even look much the same. Programming has not changed at all. On ANY mainstream manufacturers chair.

You will never get it, until you actually try it. Then you will come back and go:

Ah... I see.

You really have no idea, simply because you do not have anything to compare it to.

[Burgerman]

I will also add my agreement to the statement about fixing the programming - both the before and the after effects. I find it amazing that they can sell chairs that drive the way they do, as they could never sell a car that drove as badly...

However, to do the BM style programming setup DOES require precise incremental control skills - Since the chair goes exactly where you tell it, when you tell it, if you want to make a small turn adjustment, you need to be able to accurately move the joystick a small amount. Some disabilities leave a person without that ability to do precise movements, and for them, the stock setup works better. If all one can do is slam the stick to one side or the other, then it works to push all the way over, and wait for the chair to turn the desired amount, then go back to zero. Think of it as sort of a joystick equivalent of a sip & puff setup. For a person with this sort of disability, Burgerman type programming where the chair essentially turns as fast as the motors can drive it, would have the user doing snap spins, but not able to make small course corrections because the chair turns to quickly...

ex-Gooserider

This is ONE user that listened.

There are a lot on here. Another is ex pilot Mark, who is on the Quadcopter thread at the moment who came here with the same programming choices you have, for me to fix. It doesn't matter what chair, the driving parameters are all much the same. Once set the same, all chairs feel the same. And directly as the programming says. As a pilot he was used to a joystick that did as asked, proportionally and when you asked it. He too found it abysmal and impossible to get any accurate control. 3 mins later total relief! PM him and ask.

[sakima]

Weight has an affect on many things. It doesn't have ANY affect on any of the steering delays and accelerations. So every comment about your weight is plain meaningless.
Erm weight does have an affect on steering and accelerations, ask any HGV driver. (That's why crawler lanes exist!) It is called WEIGHT TRANSFER. There are 1000's of articles on the internet;
https://www.google.co.uk/search?num=100&site=webhp&q=weight+transfer&oq=weight+transfer&gs_l=serp.12..0i20j0l9.48488.68333.0.79267.42.21.0.2.2.0.509.3695.0j1j12j0j1j1.15.0....0...1c.1.58.serp..26.16.3200.0.tRelIZSuOZE

With those settings, you do. And a lot of it. You get a SMALL instant response which then accelerates (builds ever faster) to catch up with the amount of stick you initially
gave it, later on. That IS what those setting actually do, no matter how many times you tell me otherwise.
If I move the stick a little, the chair responds IMMEDIATELY a little.
If I move the stick a lot, the chair responds IMMEDIATELY a lot.
Basically, the chair does what I tell it IMMEDIATELY.

Also I have driven 2010, 2013, chairs, and they all drive and even look much the same.
You still haven't said when you drove the Storm 4? Was it post or pre the new design?


You really have no idea, simply because you do not have anything to compare it to.
Their you go again!

[rover220]

This thread is funny.

Sakima, the storm 4 is an ok chair as stock but it can be vastly improved with some small programming tweaks despite what you want to believe.

[rover220]

No need to pm me.

I'm not a chair user however am well experienced and have factory training in both dynamics and Curtis programming so do know what I'm on about.

[Burgerman]

He is an owner. Wants to think its "good" as it is, no matter what.
Will not listen or learn, from those of us that know much more or know better. Or that have experienced the huge difference it can make.

It has NOTHING whatever to do with weight.
COMPLETELY EMPTY chairs driven by RC respond exactly the same and are also unsteerable in comparison. I have a lot of experience of driving chairs by RC...
http://www.wheelchairdriver.com/gopro/rc2.mp4
http://www.wheelchairdriver.com/gopro/rc.mp4
http://www.wheelchairdriver.com/gopro/RC-BM3.mp4
I know this because I test MANY chairs empty. Mine and other peoples.

When I try to drive badly programmed ones like yours, that I haven't yet fixed, they make me *very* nervous...

Its like the difference between a cheap burger and a fillet steak. Only *much* more so. If you never tried the steak you think the burger is "good"...

One goes where its told and one simply doesn't... The difference is night and day.

So I am no longer wasting any more time here. You cannot help some people! Enjoy your oil tanker.

[Burgerman]

Back from pub. Developed some more patience for one last possibly futile attempt.

Lets take just ONE of the 4 important turn related settings. As a simple example. So you can SEE WHY your chair isn't really controllable. TURN DECELERATION.

Bear with me.
First you need to know what TURN RATE does. Looking from above at the powerchair out of a high window, it simply controls the rate that the chair rotates in a circle on the spot. Like the hand on a clock. So at FULL RIGHT STICK it goes 360 degrees and more and will continue to rotate until you let go. Around and around. This TURN RATE, simply says how fast it does this continual ROTATION. Or right turn. Its the RATE at which it rotates.

Set to 1 it will rotate at a super slow speed that will make you fall asleep before you do a full circle. Super slow. Set to 100, and it will rotate so fast - maybe 1 revolution per second - that your legs will fall off the footplate and stick straight out due to centrifugal forces! You do not want that.
So 40 or 45% is about right here from experience. Gives about 2 seconds per revolution at full stick. THIS is the TURN RATE at full stick. Continually.

Now TURN DECELERATION. This is ONE problem... (We already set turn RATE correctly above).

Lets say that we set 10% TURN DECELERATION. We are ALREADY rotating as seen from above at a sensible max turn rate, with full right stick. Around and around... And you then suddenly zero the stick. Let go. Now. at a 10% TURN DECELERATION setting, it takes approx. 4 full seconds before the turn command dies off to zero. You rotate maybe another full revolution or so. It does not stop rotating as seen from the window, instantly, as you release the stick but it slows down gradually over 4 seconds to a stop. But it isn't now pointing the same way as when you released the stick. In a perfect world it would stop dead the moment you released the right turn.

Now rotate on the spot again (at full right stick). With TURN DECELERATION set to 100% and then release the stick. The chair stops rotating as seen from above ALMOST INSTANTLY in approx. 0.2 of a second in fact. Fast enough to give you a sudden jolt. It stops. (If you are heavier MOTOR COMPENSATION corrects for this and the deceleration remains equally fast or slow. So weight has little to no actual affect on this)

Now, imagine you are at full speed along a curved footpath, you are turning on the curve so you have some "turn" stick held in too. And now need to stop turning and go dead straight instead for an instant. To miss a pot hole, someone that steps out in your way, or to hit a narrow doorway opening. You have a fraction of a second to do this.

You want it to STOP TURNING right NOW. You do not want a further 4 seconds of turning that begins to reduce then gradually decreases until it goes straight. Because you will hit something. You will now tell me that your chair DOES stop turning. It does not, it BEGINS to turn less, the rate of turn decreases instantly, but ALL of the turning still takes a few seconds to cease altogether. That's why its called turn deceleration. Because its not instant.

Now your chair isn't that extreme. It has 40 TURN DECELERATION set, (rather than 10 above). But to make it stop turning WHEN YOU CHOOSE this has got to be set to 100. Or SOME turn continues after you let go. Making steering accurately (or in fact stop turning instantly) impossible. It will continue turning for a short time after you zero the stick...

The same exact issue applies to the other 3 important turn settings too. TURN ACC, MIN TURN ACC, MIN TURN DEC. So this delay or acc is actually added to every turn start, and turn stop command all of the time. It makes your chair drive like its got a mind of its own compared to what is actually possible. (That's the steak...)

Now all control systems are alike. It doesn't matter what chair is, what "version" or update, or even what manufacturer. The very same settings affect all the very same way. And all have very similar default settings. Including Invacare chairs.

PLEASE read this about 6 times.

[greybeard]

Very nicely explained, BM. Even a child would understand.

[steves1977uk]

Even I can tell the difference between a piss-poor programmed chair and a PROPERLY programmed one and I'm about 10 stone.

I had an Invacare Spectra that had stock programming and that was about as good as a Skoda. Once I'd whack every setting up to 100 it became usable and I drive my chair with my right foot.

Seriously sakima, you need to try a PROPERLY programmed chair and you'd notice the difference night and day.

Steve

[fuzzy logic]

Once you have driven a responsive chair it's frightening going back (if you have never seen riches you can live with been poor) waiting for it to stop or guess when it might actually start moving definitely oil tanker steering fitted as standard.

[popschief]

First power chair I owned was a new Shoprider midwheel ($400 from a yard-sale) and we use it from bed to bed in the house only. It's programming has not been altered and I proceed down the hallway like a drunken sailor so we call it our Exxon Valdez.
bp

[Burgerman]

Heres another...

viewtopic.php?f=2&t=4614&p=61787#p61779

[sakima]

I really didn't want to shoot you down in flames, but you leave me no choice, so here is a video for you and the other doubting Thomases out there;
http://www.timsstroke.co.uk/#/blank-page/4587264903

Why you just didn't believe me in the first place is beyond me!

You can see that it is not super delayed, nor does it steer like an oil tanker, nor does it drive like a drunken sailor.
That video proves, beyond doubt, that all I said is true. You cannot argue with proof!
When you zero the joystick the chair stops immediately, it doesn't gradually stop as you suggest, but stops immediately.
If I go along a curved pavement and I need to straighten or swerve, the chair responds immediately.
I did say:

This is MY review, based on MY weight and life-style and terrain and is therefore, MY opinion.


This forum is great and you are very, very clever to have built your own wheelchairs and most of your knowledge surrounding wheelchair stuff is undisputed.
However, I did say 'most'.

My life is so, so funny now, even aspects of my disability I find funny. But some of the stuff you say and some of the stuff on the main site are utterly hilarious!
Of course weight effects a wheelchair, it affects practically everything;
http://www.explainthatstuff.com/motion.html
(“A car is a heavy lump of metal and it takes a lot of force to get it moving, speed it up, slow it down, or turn it round. The heavier something is, the more force it takes to accelerate. That's why trucks take longer to accelerate than cars, even though they have much bigger engines”.)
https://www.youtube.com/watch?v=Wf2nI1Fz7l0
I think that has something to do with a bloke called Sir Isacc Newton. But then what does he know!
A little kid who has pushed a trolley around a supermarket will tell you that the more items you put in, the heavier the trolley will get and it makes it harder to push and steer.
I watch a lot of F1 and the more fuel they burn off, (weight) the faster they go!
Topgear are constantly referring to the weight of a car.
An unladen lorry will go a lot quicker than a laden lorry. Especially up a hill.
If you and I had a drag race in a Storm 4, I would win because I would reach the top speed quicker, because your chair would have more weight to move.
If we had a race up a hill, again in a Storm 4. I would accelerate quicker than you and achieve a higher speed. (Weight again!)
Wait a sec...................................................................................................................
thought so.
You have referred to 'weight' a couple of times in this thread and a few times on the main site;

Max user weight:

Unknown, I am about 20 stone see notes about range. 25 stone wouldn't hurt it but batteries would suffer... There can never be a real "range" figure on any powerchair. Too many variables involved making such claims meaningless.


Incline capacity:

More than 15 degrees. Probably 18 is safe if you can lean forwards.. Unknown max depends on user weight and seating position. Power isn't an issue here no matter how steep.
If you can stay in the seat it would reverse up very steep slopes. More but requires user skill and control like a manual wheelchair going forwards. Safe in reverse on VERY steep ramps if you don't fall out of the front! But tips back going forwards if its too steep. Requires some user skills like a sport manual chair... Not for old ladies. It has the power for steep angles even with my considerable weight in it. If not the stability! If you want manoeuvrability, and a machine that wheelies easily then it tips back easily. Its a user adjustment choice much like a manual wheelchair.

Why are you now contradicting yourself?

Oh! you know you say that you pull wheelies easily when going up a slope or ramp or just when you pull away? That is the centre of gravity/mass (weight) going back beyond the drive wheels, causing you to tip. But you knew that, right?

The C of G makes a HUGE difference to how the powerchair handles, steers, performs and even has a drastic effect on range or battery longevity.

(That's weight transfer!)

I think some bloke called Einstein discussed gravity. But, again, what does he know!

https://archive.org/details/CIL-10004

Do a little experiment to show how your WEIGHT moves.
Tie an object, on a length of string, on your wheelchair so it is free to swing.
As you accelerate forward, the object will swing back. Showing that more of your weight has moved back. That's weight transfer!
If you decelerate, the object will swing forward. More of your weight has moved forward. That's weight transfer.
As you go round a corner your object will swing the opposite way to the corner and so does your weight move. That's weight transfer!
Weight is such an important factor in wheelchairs.

When you test wheelchairs, do you get them to change the suspension to accommodate your weight? Because the suspension fitted as standard is only for the average weight person!
If the suspension was not changed for your weight, then you would squash the tyres more, thus making more rubber connect with the floor, thus creating more friction and that would make the chair work harder and thus make it feel delayed, mushy and unresponsive.
I am guessing, but it seems like you are doing all your tests, on wheelchairs that have not been adjusted for your weight and the wheelchairs you have built, are built with your weight in mind.

Here is an email from an independent wheelchair supplier concerning the settings;

Hello Tim , the reason for the delay in answering your email is because I see it as a pointless argument and ***** Disability Centre wouldn’t want to get involved. If you are asking me about your chair I would say that it has been set up for Mr Average and that setting suits most people . If you are not happy with the drive then we can adjust those settings if you want , not many people would want them set to max. The way I see it is that we are all individuals with different needs and thats why these chairs are programable , your posture, 
C O G, the terrain where you live , your weight , tyres, all have an effect on the way the chair drives. Invacare , Sunrise Medical, Handicare, Otto Bock, Pride, You Q, Permobil, Balder, none of these manufacturers would send a chair out with all the settings set to max
Have they all got it wrong?????

David

(Do you think people would buy them if they are, as you make out, so crap!)

You know I said that I find life incredibly funny?
Well, that is very true, but I am a little unhappy with how you have made me look a 'simpleton' by saying, twice, “that I know no better” when I clearly do and the fact that you have contradicted everything I say, insinuating that I am a liar.

You missed your true vocation in life, you should have become a politician!
3 times I asked you, specifically, about whether you have tested this design of Storm 4 and 3 times you have dodged the question!
I take it then, that you haven't tested this design?

You do realize that 97% of people that see this thread will give you support, coz they don't wish to offend you. But, in the back of their mind they will be thinking, “hmmm that 'sakima' could be right. I will check it out.”
Then in future they will take your advice, if it involves common sense, with a 'pinch of salt.'

[Burgerman]

The 1st video shows almost nothing but a blurred joystick that you barely move about. And you are turning and changing direction so slowly that even if the camera was in a sensible position that showed the scenery too, that it still wouldn't show any delay. Because you are moving and manoevering / turning way to slowly and gently to show up any delay or accelerations...

2nd video shows much the same but I see the difficulty in accuracy that you have negotiating the door/threshold. And there are moments when you do actually move it about albeit super slowly that I can see turn acc and deceleration happening. But you are going to need to turn things up at least 6 notches before it becomes visible or even noticeable. If you really manoeuvre about as slow as that all the time then there's no point changing it.

As for are they all wrong? YES!!! That's the point.

Sit on one spot. Give it instant full left stick. I mean bang it left. And hold it there and let it rotate. Does it turn at full speed in around .3 of a sec and then continue? That's no good if you need to turn instantly to hit a doorway at 6mph. As it begins to turn it should jolt your legs/knees sideways.

Then as it rotates on the spot, let go of the stick instantly. It should stop turning left or right almost INSTANTLY.
Moving the stick a couple of mm around the centre shows nothing. And it will turn instantly. Because you are not turning hard enough to show anything... And in fact do not really understand what you are trying to show. Suspension settings have no affect on this. CG does and overall mass does but only slightly.

[Burgerman]

So that you can actually get a clue about what I am talking about, I did you a new video.

Yes it includes wheelies and full 6.2mph all over the house. But it also includes a door that is 28 inches wide, and a wheelchair that's 26...

And importantly it shows what I mean by turn acc and deceleration.

It isn't how soon "it responds" they all do that instantly. Its how soon it reaches the max turn rate, and how soon it STOPS turning when you let go.

THAT is what I need to see. Or even a movie showing you driving about in the same spirited fashion I do in a confined space at full speed. With complete confidence.

And yes I nearly hit the dog! I had to shove his head out of the way with my hand, as I went through a doorway while purposely steering and lowering the front wheels and with a camera in my hand... All pretty easy if your chair STEERS properly.

Watch this, and show me something similar regarding turn acceleration and stop turning speed. ON THE SPOT.

Remember this is with a 20 stone guy, old ruined batteries and an old tired chair. That deadens the response a bit. That's all it does. Weight, suspension etc and the exact chair model all make ALMOST NO DIFFERENCE to the programming issue we are discussing. That is an electronically introduced delay. Which yours has. And most of your post (and bad grasp of physics) is not remotely relevant here.

We are talking about speed of achieving FULL EFFECT not the speed it responds. IE how fast it achieves FULL TURN RATE and how fast it stops turning from full turn rate. NOT HOW QUICKLY IT DOES "SOMETHING". The problem after watching your vids is that you don't move around aggressively enough to ever know what it does...

http://www.wheelchairdriver.com/gopro/control.mp4

[garriew]

Your dog has that, "Oh shit" look.

You have a nice looking home. Is there an elevator?

[Burgerman]

No.

There is a bathroom and 2 bedrooms up there that I paid to have decorated, carpeted but have never seen in 17 years!

I don't need upstairs, I have a large downstairs with a lot of space and 2 more bedrooms, workshop, kitchen that you saw, etc. Enough to get to 6mph at least. And wheelies.

The dog is used to that, I have been driving that way indoors for 17 years... And no I never hit him yet. He hears me and reverses fast! Close though!

[calabash]

Poor dog looks like "he is not happy"! (BM not the dog)

I have been folowing this since it was first posted and need to put my bit in and agree with "BM".
The first chair I had came from a friend who used to work for the chair supplier and it was all set up like a dream, so I thought "what are they talking about", but I did'nt know that the chair had already been adusted by the place she worked for!

My second chair (a Groove) was crap, I thought it was going to be like the first, not a chance. So I got a programmer and the differance is------ well, HUGE. I still have some tweeking to do but until you drive one with all set to 100 and it tweeked you will never know, so you can say it does what you want which is great, if it fits your driving style why worry, BUT it can be so much better, and the ONLY way to tell is to drive one that has been tweeked.

If your happy with it "as is" then why worry? Enjoy it.

[Burgerman]

I can see from the vids that he doesn't move or steer anywhere near fast enough to really understand the difference which is where the problem arises. Possibly due to his specific disability. Or lack of confidence in control. Or some of each. Which is where the difference lies. But that chair wouldn't be usable as it is by many of us here. No way I can do this in ANY stock powerchair. Because all come with the same daft settings. http://www.wheelchairdriver.com/gopro/control.mp4

Although I can just see a little of this bad steer confidence issue where he is trying to cross that threshold slowly. I genuinely wouldn't notice that. I just gun it and go. Exactly where I expect to. Because I can correct it fast on the fly without thinking about it.

But he is going to need to move a lot faster than that to show that it steers properly. He moves the stick almost slower than the acc/dec so disguises it. But he has no urgent need to change it if he only moves about slowly as shown in the video. But even at those speeds it will "feel" more accurate and give more user confidence if set to 100 or even 90.

You get this sort of denial with the pro Canon/Nikon camera users. Each will not hear of their own cameras flaws. Or Yamaha/Honda/Suzuki/Kawasaki bikers. There's is the best... They fight to prove it regardless of the facts.

I love my Nikon D800E and its definitely better than any Canon

Sensor ratings. Scroll down the list and try and spot the first Canon! http://www.dxomark.com/Cameras/Ratings You will find the best one is 31st in the list behind even entry level Nikons, Sony, etc. They got left behind about 6 years ago.

[sakima]

HAHAHAHA! You are sooooooooooooooooo funny!

Of course weight effects a wheelchairs handling and you DO have different suspension setups for different weights of user. (Ask any manufacturer.)

Are you saying that you know better than Newton or Einstein?

I would go to Specsavers if I were you.

If I go hard left or right, on the spot and then zero the stick, the chair stops completely and immediately as soon as the stick is released.

Just remember, you are speaking from the perspective of a 20 stone man!

[Burgerman]

Weight makes a massive difference to many things.
It however makes zero difference to the controlled delay which is time based, that is the turn acc and deceleration.

So, show me it turn on the spot with instant full stick.
And then once full rotation speed is achieved, let go.

[sakima]

I will do another video for you, so that you cannot argue anymore.

Seriously though, I would go and get your eyes tested!