Guidance on a large rc rover

Hi Everyone,
I'm new to arduino and large amounts of programing but the purpose of this project is to help me learn. I was wondering if someone would be willing to guide me with this project. I basically would like to be able to control a 2' by 3' robot with and arduino. Heres the control process I would like to use: Gamepad -> Computer -> Wifi -> Wifi Router -> Arduino ethernet shield -> Arduino -> Arduino motor controller -> 2 motors. Is this easily possible? I would like to use a game with 2 joysticks on the input controller.

Hope someone can help,
GeekGuy96

I am trying a similar task, although starting with a physically smaller robot, which makes little difference. I have been looking for software to run on a laptop computer to read one or more USB Joysticks, process the analog values and switches read from them, and generate motor commands to send over a serial link to an Arduino or other microcontroller. I am still looking. I think a nice package for someone to write is a simple driver station app, written preferably in C or C++ that can be compiled by a common compiler (gcc?) that will drive a robot in tank mode (differential drive on each side), and Ackerman (like) with servo controlling the steering angle of one or two wheels that pivot and drive speed on two fixed wheels. It should also be easy to modify the code on the robot to handle the same inputs but control a hexapod or other multilegged robot. I am not sure, but even a two legged, standing upright robot could probably use the same input stream to control speed and direction, but you would rapidly want to use additional inputs to control gate, stepping up or down, stance, and other anthropomorphic functions.

Basically, we need a laptop drive station app.

Also, I would consider using the Xbee shields instead of Wifi -> Wifi router -> Ethernet Shield unless you want the extra bandwidth for an IP digital camera signal coming back. The Xbee will be MUCH cheaper, and possibly simpler to interface.

Mike

Its possible - certainly - working on something that size myself (platform is a PowerWheels H2) - see my website if you want details.

Just realize that your motor controller isn't going to be cheap (unless you go with an h-bridge made of relays). Everything else is certainly possible. My plan is to use the Arduino for control of the steering and drive motors, and to relay commands to a Pololu servo controller for a pan/tilt platform for a camera. The Arduino will be running a custom command control software for this (with built-in heartbeat and dead-man checks in case of failure to perform system shutdown). On the backend I plan to control it with a custom Ubuntu server running a LAMP stack (though the serial comms will probably be done in Python). It's a Mini-ITX box with an 802.11g AP. Hit it with any browser (using WEP and MAC address limits for security, along with https), and control it from there.

Lately, though - I've been a bit of bum when it comes to working on the project - so many other things taking my time every weekend (joys of home ownership!)...

:slight_smile:

I'm only looking at 1.5 x 2 ft at the moment, but this thread intrigues me. I could see somebody converting a powerwheels over to tank-drive...

magnethead794:
I'm only looking at 1.5 x 2 ft at the moment, but this thread intrigues me. I could see somebody converting a powerwheels over to tank-drive...

Yeah, you probably could. Most of the larger 12VDC Powerwheels use two separate motors on the rear axle. They're run in series for "low speed" and in parallel for "high speed" (I think - I may have that backwards?). The "gear shifter" switch is a pretty ingenious arrangement of a couple of heavy-duty DPDT (or a DPDT and a DPST - or something like that) switches; low engages one, high engages the other in turn.

I could see setting up the motors to turn sprockets or something to rotate treads. Whether the gearing would hold up or not, though - I don't know. A lot of the secret behind the ruggedness of the toy is the fact that there's so much slip with the hard plastic wheels. I'm actually planning on putting some 10 inch pneumatic tires on mine when I get to that point, to increase the traction and add a bit of "suspension".

I'm also planning on experimenting with creating some form of electronic differential - I have this idea that you might be able to perform "differential skid steering" with the back wheels while steering normally (Akermann) with the front wheels - and possibly get a tighter turn radius as a result. Also, with an electronic diff, if you monitor the speed and/or current flow in the motors, you can potentially do things that you can't with a regular or even limit-slip diff (if you were using one). That's in the future though.

The step after the Powerwheels will likely be to use a dual-motor powerchair transaxle I bought off Ebay to build a diff-steered multi-wheeled platform (thinking 6-wheels), possibly as a hybrid powered (gas-electric genset) machine. Then maybe - just maybe - progressing to a Polaris-type ORV (big dreams, I know - and if I wasn't such a bum on all of this, I'd probably be there already)...

:slight_smile:

If you want to build a body that is 2’ by 3’, look at the FRC robots build in the thousands each year for FIRST.org robotics. They use CIM motors, gear boxes and chain drives, Victor or Jaguar high current H-bridge motor drivers, and other items that would work well for your size robot. To buy parts, look at AndyMark.com and BaneBots.com as starting points.

Mike