There's been a lot of work on the WEEDINATOR mechanics this week, mostly trying to tune the motor upgrade from steppers to 750 watt AC servos. It took me a couple of days to work out that most of the attention needed to be focused on the steering algorithm rather than the motors themselves - the machine worked fine when moving in a straight line, with adequate power and plenty of speed, but threw up current overload errors when negotiating tight turns.

The drive now uses two of these motor and driver kits, bought from Fasttobuy, China:

Leadshine ACM8008L2H + L5 750, NEMA32 0.75KW 220V High Speed CNC Servo Control 2.4NM
2500line AC Servo Motor and Driver L5 750 + cables

I would have preferred to use brushless DC servos but I could not find anything affordable above 400 watts. One of the advantages of using DC power is that there would be less strain on the generator due to fluctuating power demands as small batteries can be used as 'capacitors' to provide extra amps during heavy demand. I might try temporarily swapping in the 400 watt Nema 23 motors that I'm currently using on the CNC, just to see how they behave.

The CNC mechanism uses this motor and driver kit, from the same Chinese supplier:

Leadshine Brushless ACS806 + ACM604V60-30-2500, 20-80V DC 400W servo motor + drive + cables

The following video shows some of the success achieved with the CNC mechanism and a more in depth description of the drive motor and steering tuning issues with proposed solutions: