Observer 4x4 Wheelchairs

Coming in at #6 of our top ten of Naidex 2013 is the Observer 4x4 Powerchair. The robust build, superb manoeuvrability and ability to climb stairs and slopes of up to 45 degrees made this an easy choice.

The RX model is ideal for use on high curbs, pebble and sandy beaches as well as in the snow. The 4-wheel drive and the auto-levelling seat make this the ideal chair for the adventurer.

For more information go to the Access4Wheelchairs website. 

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Permalink Reply by George Perfect on May 19, 2013 at 7:35

Video won't play - message appears "This video is private."

Permalink Reply by bespoken Team on May 19, 2013 at 10:17

Hi George, Apologies it's now set to public thanks for letting us know, kind regards Colin

Permalink Reply by George Perfect on May 19, 2013 at 7:47

I spoke with the Australian designer of this chair (which looks like a fabulous product, by the way). Among the stories she told of of users who had returned them for repair "under guarantee" (so they claimed) after

  • ploughing a field
  • mowing their lawn and ...
  • one lady who regularly and repeatedly used hers while she showered!! (the mind boggles)

she did say

  1. the company doesn't actually claim the chairs will climb stairs - that's something the UK importer has added. As the demo on the stand shows the facility is restricted to climbing steps ... don't go thinking this is going to do away with the need for a stairlift or wheelchair lift
  2. the seat does NOT self-level or auto-level ... the driver must adjust the seat angle relative to the chassis manually as needed

This chair is DEFINITELY an outdoor chair. None the worse for that - it would be great for outdoor pursuits (literally! :)), for those who live in the countryside or want to visit the beach or not get stuck in the house when it snows. It's the Land Rover of wheelchairs.

But it is not a chair that could be used indoors - at least in the average UK size home. I wouldn't want anyone (and I really wanted this chair to "do it all") to think this is a general purpose chair. It's great at what it does.

Like most chairs.

Permalink Reply by bespoken Team on May 19, 2013 at 10:23

Hi George,

Thanks for your post :-)

Just to clarify there are two models the RX comes with a self leveling seat and the LX doesn't sorry for the confusion

Regards

Colin

Permalink Reply by George Perfect on May 19, 2013 at 10:51

Hi Colin,

According to the lengthy chat Louise and I had with the designer, neither model auto- or self-levels. Both need to be adjusted manually. It would be quite a trick if they could do it automatically. The problems that arise with any such mechanism come down to the amount of hysterisis (or more simply, delay) that has to be built in.

If you make the automatic chair movement react too fast, the passenger will be tipped about violently whenever the chair travels over uneven ground - as it is clearly intended to do.

If you make the self-levelling reaction too slow, you risk hanging the passenger in a very unsafe position (eg; immediately on pitching down on to a steep slope) and making any upward climb initially unstable (the chair would start by being tipped backward, only positioning itself at level after some time set by the in-built hysterisis).

ANY setting for hysterisis is pure guesswork .. factors such as the speed the chair is travelling, the rate of surface angle change, the rate of climb, the length of the climb (eg; imagine a climb over a log where the front wheels first lift then quickly drop to the ground followed by the rear wheels starting to climb ... get the rate parameters wrong and you have just designed a modern 4WD trebuchet!)

Also, the levelling available on these chairs works only in one direction ... pitch. There's no lateral correction available for yaw. Why is this important? If you were to use the chair to traverse a slope or climb (steps or rocks) with only the wheels on one side of the vehicle rising, the chair will still be at a lateral angle and cannot be made vertical - any more than an "ordinary" wheelchair could.

Any useful and usable automatic self-levelling would have to use some form of ground surface sensing radar or laser to "predict" the relative surface angle the chair was about to encounter and then level the chair as the surface angle changed.

All entirely possible (search for "self driving cars" or "DARPA cross-country challenge" on Google to see just how far developed this technology is.)

Sadly, despite the high asking price, these chairs are not equipped with such technology.

I don't intend any of these remarks to take anything away from what seems an excellent product that I envisage many people would find extremely useful and liberating. But, as ever, it's best not to over-egg the capabilities of any device.

Permalink Reply by Alexander Thomas on May 19, 2013 at 15:29

Hi George, 

I am one of the directors selling this chair in the UK and I think you are talking about another chair. The RX Model does self-level and can climb steps up to 6" on a 25 degree angle. If you don't believe me, send me an email alex@access4wheelchairs.com and we can arrange to give you a free home demo so you can test it out for yourself.

Permalink Reply by George Perfect on May 20, 2013 at 13:06

Hi Alex,

Thanks for the correction - though your Australian colleague (who told us she designed the wheelchairs) was quite adamant that none of the chairs had automatic self-leveling - as it was one of the features that drew me to your stand you can imagine we had a fairly detailed, friendly and lengthy discussion.

Perhaps we are interpreting the function differently?

Thanks for the offer of a home demo. Tempted as I am, I'm not in the market just now for another large outdoor wheelchair. Maybe someone else here would like to take you up?

Permalink Reply by Alexander Thomas on May 20, 2013 at 13:31

Hi George,

Thanks for the quick response. There is no designer for our powerchairs in Australia. Our products were designed in Taiwan. However, we do have a distributor in Australia http://www.outandabouthealthcare.com.au/

I know which chair you are talking about, there is only one all terrain 4x4 wheelchair that is designed in Australia and sells in the UK. I won't post the name on here because I don't want this forum to end up in a debate :), but if you google all terrain wheelchairs, I am sure you will find it.

Permalink Reply by George Perfect on May 20, 2013 at 15:55

Hi Alex,

If I have mistaken you for another exhibitor, then I apologise - though the stand looked awfully like the one in the above video, complete with two chairs, stairs and a ramp.

So either you had an impostor on your stand or the young Australian lady (I owned a company with offices in Sydney - we even talked about where she lived!) wearing an exhibitor badge was very convincing about talking up her and her company's role and attitude to warranty claims!

Permalink Reply by Alexander Thomas on May 20, 2013 at 16:06

Hi George,

I am really sorry, but there were only 2 people on our stand, Clive and me. We both had light blue polo shirts on like you see in the video with our logo on them. Sounds like we did have an impostor on our stand :)

Permalink Reply by George Perfect on May 20, 2013 at 17:05

Hi Alex,

Spooky - the young lady was also in a light blue polo shirt!

Maybe my age is causing the confusion! I certainly can't blame beer-goggles ;>)

Anyway - reset - apologies if I have confused your company for another. Wish I had seen you. At some other time, it would be interesting to see how you have implemented the self-leveling in light of my earlier comments.

Ho hum ... time to take my medicine I think!

Permalink Reply by Alexander Thomas on May 20, 2013 at 17:51

Hi George,

For some reason I can't reply to the message bellow, we will be at the Mobility Roadshow stand B47 if you are attending, would be great to meet up for a chat.

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