It was one of my dream to build a remote controlled ground rover or robot ever since I started tinkering with electronics. I hadn't got enough time and money to build one until for my college project. So I built a four wheel rover for my VANET project. It is what you see above. I'm talking only about the rover design and build but not about the motor driver or the radio remote controller because I have them in an another post here. You can also find this project at Instructables and Hackster.io.
I used an old amplifier box as the chassis of the rover. It had holes underneath which made fixing the motor clamps easy. The right angled motor clamps have six screw holes each. The whole setup was not that sturdy but okay for holding all the weight of batteries etc. The motors can be attached to the clamps by using the nuts provided with the DC geared motors. The motor shaft has threaded hole for attaching the wheels.
I bought the motors from Matha Electronics, Ernakulam. They are low torque 300 RPM motors with plastic gear box and are not good for heavy loads. I prefer Johnson geared motors to them, though costly.
Like I said, the chassis was not so strong, so there was a problem with this design.
The clamps along with motors and the wheels tend to swing outwards when there is weight on the chassis. This will reduce the area of contact between the wheels and floor which will then make it difficult to steer left or right as I'm using differential drive which requires the maximum friction between the tyres and the floor. The solution for this problem is to use a strong chassis and clamps or use a completely different design may be with shock absorbers.
The finished rover looked like this before painting and wiring.
After painting and adding other stuff.
You can see in the below image how I installed two 6V 5Ah lead-acid batteries and the boards inside. The circuit board on the top is actually a VANET module and underneath is the L298 motor driver board with an RF receiver.
I have a plan to build a new rover in the future; a six wheeled one with off-road tyres, high torque Johnson geared motors, aluminium chassis, LiPo batteries etc. I just wonder when that'll be possible!
And here's a video of my rover.