View Full Version : [Question(s)] I need advice

09-14-2009, 04:49 PM
I have a brand new pride quantum 600 powerchair and i have removed the chair but left the platfirm of the seat. THis plat form has the ability to raise up a foot and tilt almost 90 degress. now for the plans for this expensive equpitment. i want to add a laptop computer to the chair along with three camera two for the front and one for the back. i would like to be able to control the robot via another laptop, desktop or iphone. after i can control the robot i will add things like an arm, sensors and maybe the ability to run atutonomously. but that is the future. let foucus on the present. i have a great base, new computers, the servos and stepperr motors ect. my question(s); should i use motors or servo to control the joystick or digitaly control it? (the joystick computer has speed controlers power regulators and batter gague really want to keep it). now for my big problem no matter if i do it analog or digital how to i make the computer communicate with the robot. computer to computer communication can be achieved via remote desktop, right? so if you havent figured out i ambitious but this is my first robot that involves a computer. all others have been simple switches or old parts salvaged from r/c cars so can anyone help? fyi i have two powerchairs i plan to start with the older on just incase i mess up its not exspensive the q600 will be final project. thanks for the help.:veryhappy:

09-14-2009, 05:03 PM
Welcome to the forum!

You could remote into the other machine over a wifi connection. Personally, I'd write a client/server application to do it. You didn't mention if you have any programming experience - and honestly, you're not going to get far without learning to program.

You could interface a microcontroller to the joystick control box replacing the physical joystick, and then the microcontroller interfaces to your onboard PC. Again - programming required.

09-14-2009, 08:39 PM
Great project! I've been working on a robotic telepresence system that I've connected wheelchair robots to also. Strange coincidence in that my first one was a Quantum chair also. Here's a blog entry describing some of the details of how it works:

Interfacing with the electronics of the chair will really take advantage of the solid motor controllers that come with the chair, but you can also bypass these completely if you wish too. I tried another system where I wired directly to the wheelchair motors using a separate controller as well.

If you're looking to make some of the networking a bit easier. The server I'm using for my own robot is designed to interface with all kinds of devices. I've used both a low-cost EEE PC to drive my robot as well as an inexpensive Arduino processor w/ ethernet shield for an even lower-cost connection to the internet. Then you can either drive the robot via a webpage, or even via an internet-connected hardware joystick (like this one which I connected to an arduino also: YouTube - Internet connected joystick ) to drive your robot from afar too!

Be great to connect and I'd love to share more about my project and hear about yours too!


09-15-2009, 05:35 PM
One possibility that I have not tried, but might work. Use a pair of servos to simply move the joystick you already have. It would require a good linkage, one that uses a bracket to move the joystick front to back, and another bracket to move the joystick left to right.

This might be the only way to be none-invasive and maintain the normal functions of the powerchair.

I've recently acquired an Invacare Ranger II, however I believe the normal joystick is not operational, so will be attempting to use a couple OSMC h-bridges to drive the motors, control to be determined.

09-16-2009, 06:53 AM
Firt let me say thanks for posting. to answer some questions. i havent programmed in a long time but i have microsoft robotic studios and net frames. i have toyed with the idea of by passing the physical joystick and doing everything digital again this is my first robot that is going to have a computer on it and the first on that is going to require a computer program. now for the ideas. and the wheelchair cost over ten thousand so i am going to try analog hardware first then move on to digital. servos were a good idea and i was thinking about using two "u" shaped peices that over lap each other forming a cross. each one will have a channel in the middle allowing 360 rotation with the two. and it would require only a base and two motors. i was talking to an old friend of mine about microcontrollers and motor controllers and he suggested that i disassemble an old printer, considering i have more than enough computer junk around. if i take the serial port and chip out of a printer this will allow me to operate more than one motor simply by changing voltage out put. it leaves room for expansion and its free! so if i use the printer motor controller and serial port what would be a good program to use to write for it and good websites for this info?

09-16-2009, 07:56 AM
given im not very good at explaing what i mean i've provided a picture. lol. instead of sensors though i want motors to control the joystick so i guess i have to build it.

09-16-2009, 04:05 PM
The mechanism you've drawn is somewhat like what I had in mind, seems like it would be effective. However I would still use a pair or RC servos, like some HiTec HS-645MG (http://www.trossenrobotics.com/store/p/3292-Hitec-HS-645MG-high-performance-hobby-servo.aspx)s some use here, rather than trying to hack printer parts.

Most any micro should be able to control 2 servos, while accepting commands from a laptop or other micro. One recent device I've been playing with is the Arduino (http://www.trossenrobotics.com/p/arduino-duemilanove.aspx). In addition to the 2 servos running the joystick, another 2 could be used to pan and tilt a camera on the bot, all controlled by the Arduino.

09-16-2009, 07:12 PM
Yeah, the Arduino is an easy choice for that.

The 645 is a good servo - probably overkill. You could probably just embed a couple microservos.

09-18-2009, 10:28 PM
Servos seem like a great way to get started with no risk to the electronics of the chair. Never tried it, but I've read about others doing it that way. I'd also highly recommend using the arduino for servo control or for just about any electronics project. I've tried using arduinos for both servo control, and the for the control of my chair itself (I can connect to the Internet by adding an ethernet shield to the arduino and then control the robot remotely from a web page), and it's really easy to use. Happy to share the code for the arduino if you're interested. I've also used phidgets (see phidgets.com, but Trossen Robotics sells them too) for robot control, and they work pretty well also.

Also, next week I'm taking some time off to work on my wheelchair robot. I'm hoping to (with the help of a friend) get inside the controller and figure out how to directly "wire into" the joystick electronically. Most of the chairs I have use Penny + Giles (P&G) joystick controllers. So if anyone else has P&G joysticks or motor controllers let me know, and I can share the findings.

Last, I'm working with another friend to get an inexpensive (but large) robot arm that I can attach to the wheelchair. That project is going very well too, so I should have more to share on that next week.

10-06-2009, 02:06 PM
I am also trying to figure out some kind of linkage to control the wheelchair joystick with 2 rc servos any thought would be appreciated

10-06-2009, 02:12 PM
Look into ball joint linkages. Something like this may do the job:

08-23-2011, 07:11 PM
So I had some personal things to deal with and I am ready to get back to my project. I have taken some robotics classes and have decided that PBasic\Stamp is the language that I plan to program in. I have a board of education robot and I plan to use it's processor as the brain hooked up to a nice laptop. From there I am going to use a client server or blue-tooth to run it. The boe-bot is from parallax and I am pretty good at writing the programs. I still plan to use the wheelchair but want to scrap the analog control. It is too damn complicated lol. The few designs I had lacked the proper control. I am now looking for motor controls that will work with the boe-bot. I am really liking the HB-25. Though I do not know the horse power rating on the wheelchair. I am sure it can't be more than a half horse power right? and the controllers say they're rated for twelve volts which is good.I have been on the parallax forum and know one seems to know if the controllers will hold up to the motors. Has anyone used the HB-25 for motors other than parallax's motors?