Kevin - robotics platform

After reviving my robotics platform I encountered some serious problems with the durability of the system. The motors are very powerful but they are slow and the wheel mounting isn't very good, the motor shaft attaches to the wheel with a pin which is shearing under very high loads.

With these fundamental problems with the platform I have decided to build a new system. The new platform will be powered by 4 wheelchair motors and have a stronger welded frame, I have also decided to call it Kevin! (for no particular reason).
The wheelchair motors will give it the power and strength to move its own weight along with hopefully a person sitting on top! It should also travel at 5 to 10 mph much faster than the 3mph of the existing system.

This is the start of the frame, it will form the core of the robot and will have a motor will be mounted in each of the corners.
In addition to the motors this center frame will also hold the batteries and motor controllers, these components together will provide the minimum needed to get the platform moving.