NEW RELEASE: Wheelchair multi-node CANbus and analog hardware and software

I have just posted a new release of the wheelcair CANbus system for Roboteq as well as the analog-only script at drive.google.com/open?id=0B3svXvyPGRgral9FU2lJZlpHdFU . There are a number of significant improvements since the last release and I've tried to make the Manual more complete.

CONTENTS

WHY BUILD YOUR OWN CONTROL SYSTEM? 2
OVERVIEW 3
DRIVING THE WHEELCHAIR 6
SYSTEM DESIGN
I. System Modules 9
II. Software Design 12
III. Some Suggestions for Tuning User Settings 26
IV. Hardware 28


Although the bulk of the Manual covers the CANbus system, much of the software description is relevant for the analog version as well. In particular, whether using one version or the other I do recommend reading the Roboteq MOTOR CONTROLLER subsection (beginning on p. 21) of "Software Design" as well as "Some Suggestions for Tuning User Settings" (starting at p. 26).

Please note that the CANbus version of the Roboteq script has been real-world tested and is in daily use in my daughter Rachele's chair, but that the analog version of the Roboteq script has only been bench tested with dummy loads. If you use the analog version of the Roboteq script, PLEASE BE CAREFUL, and, of course, post back your results. The user settings in the release for both the CANbus and analog systems are not the ones actually in Rachi's chair, but more conservative ones for safety's sake.

Hey, this is great! Thanks for sharing this! Just for clarification, is there a license that you are releasing this work under?

This is intended to be open source and open hardware & there are no licensing conditions as far as I'm concerned. Some of the Arduino programs do carry open source verbiage for code from others that require a copy of the license information - look at the top of the files to see these. Of course, I would appreciate crediting of my work when it is used and, even more important, feedback about how it's being used and about any bugs or improvements.

I'll add. The manual does have a copyright notice and I'd appreciate that it be respected, though it's almost certainly not enforceable.

Thanks for the clarification!

As noted in above, I am not set up to real-world test the analog version of the Roboteq script, and a couple people using it have now reported bugs. While I am attempting to squash them, doing this "long distance" is a frustrating task. I am also nervous about doing this because I consider the CAN implementation a much safer way to control a wheelchair, as well as having much simpler chair wiring. I don't want anyone to be hurt because of me.

The CANbus system does require a lot more electronics, including SMD soldering several circuit boards, and no one has yet said that they have tried to build one. I have therefore gotten a quote for commercial PCB assembly to see if I can encourage others to go CAN by reducing the amount of work needed.

The complete set of boards contains 4 CAN boards, 2 DC-DC converter boards that turn on when the CAN bus is live, 1 DC-DC converter board that handles ON/OFF/Sleep for the whole system (all quite small and moderate component density), and 2 different larger power distribution boards that handle Roboteq on/off, high-current relay, brakes, lights, current sensors, and two linear actuators. Even using an off-shore assembly house, PCB assembly is not inexpensive and I can not afford it unless there are others interested in covering the cost for several sets. Assembly of five sets would cost about $1,125 (U.S. dollars - $250 per set); somewhat less per set if more were ordered.

GABRIEL: If you'd like to move this thread to the new User Applications section, that does seem a good place for it.

Do realize that there would be other costs and plenty of work needed even with pre-assembled boards. But those costs and that work would be about the same as for an analog setup: joystick, contactor relay and current sensor breakout boards (optional) to mount on the power distribution boards, boxes, Arduino Nano-equivalent boards, display screen (if desired), internal wiring and connectors and so on. No long multi-conductor cables, however. If four or more people tell me that they are interested, I will go ahead and place an order and send out sets after I have wired and tested one system that I'd keep for myself.

Lastly, I have no experience laying out boards for production rather than hand assembly. If there are any volunteers, I would certainly appreciate having others look over my designs and suggest changes that might reduce cost or improve reliability or safety.

Wow. Thanks for sharing this information. Very helpful for learning about Roboteq!

SCRIPT RELEASE 108

The Roboteq script bugs found by two testers, one with brushed and one with brushless motors, have now been thoroughly SQUASHED so a new release has been uploaded to Google Drive. Testing now looks good on three wheelchairs: CANbus and brushed motors, analog with brushed motors and analog with brushless motors.

Hey Lenny, thanks again for releasing this. Have you considered releasing this project on Github ? I would be happy to contribute to it and report issues that any customers experience if it was hosted on a Git Repository.

I really wanted to avoid having to learn another interface, but a lot of people do like github, so I've put this in a repository at:
CANbus github repository
under a GPL-3.0 license.