Intro...and other stuff eg Interested in a Powerchair tiller

You dont have to, but its interesting!

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Intro...and other stuff eg Interested in a Powerchair tiller

Postby Tanjarine » 25 Apr 2015, 16:12

Hi everyone,

I have joined here for a few different reasons; one of them to get to know other wheelchair users and the other to find out if anyone has knowledge or info of converting a powerchair joystick into a tiller/handlebar. Anyone know if there's a way? I find the joystick too challenging to use so am trying to sell my powerchair, however It may make more financial sense if I can find a way to get the joystick action altered so to work with a tiller/scooter style handlebar. Haha...I'm not able to do this myself due to lack of engineering mindset however I have the imagination and need. Alternatively I'll keep looking to swap or sell my power chair for an off road scooter.

I am in the process of getting a Tailwind...final stages of the delivery now. So this will be great to have.

I'm looking for inspiration and maybe support in adapting to trying to get out and about without my own transport.

Other than that info...I'm a part time wheelchair user at the mo, however this varies greatly from day to day needs. I'm currently based in the East Midlands. It'll be cool to get to know other wheelchair users with similar interests. Mine are...photography, creativity, resourcefulness, gardening, design, chilling out, countryside, geocaching...
Tanjarine
 

Re: Intro...and other stuff eg Interested in a Powerchair ti

Postby LROBBINS » 25 Apr 2015, 22:18

Can you describe what you find difficult about the joystick? As delivered, chairs routinely have programming that makes it very hard to drive with any precision, but that can be fixed - on Burgerman's main WheelchairDriver pages he describes an excellent starting point for this. What he describes is great for those with good fine motor skills, but might need some changing if you have a tremor, or muscle weakness, or other ???

Also, how do you hold the joystick? Are your hand and wrist well supported when you try to drive? Is your seated position stable?

If it's the actual gripping or motion of the joystick that's the problem, there are lots of alternate handles available, and alternative controls as well - such as proportional or switch head operated controls, sip and puff controls, chin activated joystick, foot operated etc. If I lived anywhere near you, I'd come over and take a look. Though not a pro at this sort of thing, my daughter's been using a chair for most all of her 29 years and fitting and modifying it for her has been my job. However, I live in Italy, which is rather too far from East Midlands to be of much use. Perhaps someone else on this forum does live near enough, or can suggest some source of help in your area.

I have no experience with scooters, but fitting a tiller bar to a chair would be quite a project, and, because a chair steers by applying different power to the two motors instead of direct, auto or bicycle-like steering, even if you did so, you might well experience the same problems as with the joystick.

Ciao,
Lenny
LROBBINS
 
Posts: 4537
Joined: 27 Aug 2010, 09:36
Location: Siena, Italy

Re: Intro...and other stuff eg Interested in a Powerchair ti

Postby Tanjarine » 27 Apr 2015, 19:48

Hey Lenny,

Thank you sooo much for taking the time and effort to write back. And thank you for the offer to help...yep, lol, Italy being a bit far.

I have cognitive brain damage and so have difficulties working out the steering using a joystick...so it's not instinctive for me to use. I tend to hold the joystick with thumb and finger, and for long distances I rest my hand on the bit between the armrest and the actual joystick. I've not been able to use my powerchair for so long due to the steering trouble I have. I wondered if by changing the sensitivity of the joystick response, if this will help me with steering the powerchair, by enabling a slower joystick response to match my slow cognition response...if this makes sense. The seat seems stable.

It's a Days Volt powerchair...with a Dynamic Shark Series Control.

I understand (very roughly) what you say about the scooter differences with steering mechanics and electrics.

Thank you,
Tanjarine
Tanjarine
 

Re: Intro...and other stuff eg Interested in a Powerchair ti

Postby LROBBINS » 27 Apr 2015, 22:43

To adjust the joystick response, you will have to find someone with the Dynamic software, computer dongle (a gadget that plugs into a PC and contains the license for using the software) and a programming cable. The dongles come in different "flavors", the most common, a dealer level dongle, doesn't let one adjust everything, the harder-to-get OEM level dongle lets you adjust everything. There are quite a few parameters that affect joystick response, but usually a slow response (reduced turn acceleration and deceleration) leads to worse control - the chair will not start to turn when you move the stick, and will continue to turn after you center the stick. Banging into doorways is the common result.

More precise control is achieved if you set turn acceleration and deceleration as high as possible, but set turn rate way down - this will give slower turns, but better response. You may also want to turn down speeds as well until you get used to things, or if your controller has a speed pot turn it way down. There are other, less important, settings that are sometimes pretty useful - tremor damping if your hand isn't steady, deadband so nothing happens until the stick is moved some distance from center, and others. A very important one is motor compensation, but you should only adjust that after your really understand what it does and why it has to be adjusted in very small steps - if it's too little, the chair can be very sluggish, if too much the chair can be very jittery, and if really too much the chair can run away and be COMPLETELY uncontrollable. Adjusting that needs a lot of caution.

I strongly recommend that you download all of the manuals for the Shark from the Dynamic web site - you will have to register as some kind of professional (but no one checks on your credentials). Once you've done that you can get all of the installation, operation, programming and user manuals. I have only worked with Dynamic DX controllers and not the Shark so I can't be any more specific, but the manuals are quite detailed. One or more of them will contain a list, with descriptions, of all of the programming parameters. Warning though, the explanations are sometimes less than crystal clear (at least if the Shark manuals are like the DX manuals that I'm actually familiar with). Burgerman has a good walk through of programming on the main WheelchairDriver pages - it refers the the parameters used in P&G controllers, so they're not exactly the same as on Dynamic controllers, but not all that different either.

If you don't feel up to doing that yourself, you will have to find someone to help you with this, but re-programming the controller really can make a world of difference.

I'm glad that you say you rest your arm on something solid. One of the things that often leads to poor control is trying to move the stick with your hand not supported. If you do that, every little bump will make the stick move. I like to rest the heel of my hand on the joystick housing and use index and middle finger on one side of the stick and thumb on the other and usually make very small movements. Steering a chair is very different from steering a car - it's much more like using a joystick for computer games. You are not pointing the joystick where you want to go. You're not commanding "where" you want to turn to, but how fast you want to be turning and the chair really needs to be programmed so that when you command x turn rate for y time it then gets you to z angle. At that point you center the stick and the turning should stop right then and there. Most chairs out of the factory are not programmed that way.

Consider posting on the Everything Powerchair part of this forum and asking if there's anyone in your area who could help you with programming the Shark, or could point you toward a tech who actually knows how to do this - rather few do. It might also help to put your location in your "profile" (look for a button that, I think, says "User control panel").

Ciao,
Lenny
LROBBINS
 
Posts: 4537
Joined: 27 Aug 2010, 09:36
Location: Siena, Italy

Re: Intro...and other stuff eg Interested in a Powerchair ti

Postby Tanjarine » 28 Apr 2015, 08:25

Wow, thanks for all of your explanations. Having read all of your helpful directions and guidance, it's safe to say that the technical side is way over my head. I'll have a further think about whether to keep it or find a scooter to transfer to. It's all for off-road use so they'll be no doorways etc to avoid however I have always been crap at joystick gaming!
Thank you
Tanjarine
 


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