@Christopher_Milner, @Yuri_Rage, @ktrussell I am in the planning stages for a small all electric mower project I want to do and I have some questions. I have been involved in building several of the large gasoline powered ArduRover mowers and I have had success with these mowers. I am now considering building my first battery powered small (4WD 21 inch variety mower) that I want to use for mowing in small spaces and to use to mow closer to things. I have used motor controllers for DC motors in the past but I think I want brushless motors for this project for efficiency and durability. Right now I am looking at using a 18-24v motor Husqvarna designed for many of its automowers because of it’s torque, lower speed, durability against dirt, and availability.
My questions are centered around controlling this motor properly taking advantage of the hall sensors built in so I can get smooth efficient operation.
Husqvarna 18-24V High Torque Automower Brushless Gear Motor Drive Wheel Motor Husqvarna Automower Drive Wheel Motor DC 18V 24V Brushless Lawn Mower Gear Motor | eBay
@Christopher_Milner@Yuri_Rage Will the VESC-6-75 control that motor? I don’t really know the wattage of that motor but I would estimate it to be less than a 200W. I have a lot to learn about the high tech motor control world.
In my opinion it’s almost certain that the Vesc-6-75 will handle that motor. You will connect the 3 motor leads from the vesc to the U, V, W on the motor. (there is no “right” way to connect the motor leads; the only impact of connecting them one way or another is that the motor will turn in the opposite direction, and if it does, you can just switch any 2 of the 3 wires, or, alternatively, you can just change the motor direction in software). The other 5 wires are hall sensors and you can connect them to the controller, or, you can try to run the controller in sensorless mode (which I am doing with my motors). Of course you need one for each wheel. There are cheaper speed controllers which would likely also work, basically knock-offs from the vesc, at Flipsky. You need to think about how your autopilot will command the speed controller, basically your choices are PWM or CAN. If you use PWM you need an isolator (generally an optoisolator) to avoid creating a ground loop which can fry your $300 vesc in an instant. If your autopilot hardware supports CAN then I suggest you use CAN as you don’t need an isolator; just connect CANH and CANL to the autopilot and speed controller and off you go. If your autopilot hardware doesn’t support CAN then my recommendation is … to get an autopilot that supports CAN.
The flipsky claims to have similar capabilities; there’s spirited debate especially on the DIY electric skateboard forums on that topic. For my (250kg) rover I stuck with the trampa vescs for the traction drive (it’s skid steer so I needed only two per rover) and went with cheaper flipsky vescs for the deck blade motors. (I run the flipskys pretty hot, about 1.5-3 kw continuous, and I do fry them every 10-20 hours of operation, hopefully I can improve heat dissipation from the flipskys to eliminate that problem). You’re probably safe starting with the 75100 but I’d recommend the Pro because it has phase filters which, as I understand it, can marginally improve the firmware’s ability to operate in sensorless mode. I’m notice those motors don’t have a temperature sensor. The vesc firmware’s sensorless mode will use motor temp, if available, to improve performance. If it were me I’d probably consider adding a standard 10K NTC thermistor, mounted on the motors, as close as possible to the coils, and wired to the controller (both vesc and trampa have + and - wires for temp sensor)…
