Skid Steer Mows Airport Grass Autonomously

Sure, mowing the lawn is a hassle. No one really wants to spend their time and money growing a crop that doesn’t produce food, but we do it anyway. If you’re taking care of a quarter acre in the suburbs it’s not that much of a time sink, but if you’re taking care of as much grass as [Roby], you’d probably build something similar to his autonomous skid-steer mower, too.

This thing isn’t a normal push mower outfitted with some random electronics, either. This is a serious mower that is essentially a tractor with blades attached to it. Since it’s a skid steer, it turns by means of two handles that control the speed of the left or right drive wheels. Fabricating up some servo linkages to attach them to specialized servos takes care of the steering portion, and the brain is ArduPilot hooked up to a host of radios, GPS, and a compass to allow it to drive all around the runways at the airport without interfering with any aircraft.

This is a serious build and goes into a lot of detail about how servos and linkages should behave, how all the software works, and the issues of actually mounting everything to the mower. The entire project is open source too, so even if you don’t have a whole airport runway to mow you might be able to find something in there to help with your little patch of grass.

Thanks to [Vincent] for the tip!

32 thoughts on “Skid Steer Mows Airport Grass Autonomously

    1. Elefant in the room? Why waste energy and pollute to have a grassed area?
      Why not let nature provide with wild flowers and let nature provide cover for small animals and reptiles?

      1. I didn’t mow my property and now it’s full of deer ticks and poison oak. Nature doesn’t necessarily go the way that appeals to mammalian life.

        What I should have done is planted native grasses that could have promoted predator insects instead of allowing volunteer plants to come in. (in my case I should have grabbed seeds for California Buckwheat, field sedge, splitawn sedge, California buttercup,Bolander’s sunflower, California sunflower, Mendocino Reed Grass, etc)

  1. That’s a zero turn mower, not a skid steer. Skid steers don’t have pivoting wheels and literally turn by skidding the tires when the speed of the left and right pairs are different. The also have a hydraulic lifting arm for a bucket or other attachments (which might include a hydraulic mower attachment)

    1. That be said…. Impressive build. I think I’d focus more on kill switches or Deadman bars than on making the servos overridable by humans….the mower decks on those mowers are vicious and I wouldn’t want to approach one with the blades spinning to try and control the lever arms

  2. Sorry but you can’t legally operate this within 1000 feet of an airport in the US. (at least not within 1000 feet off the ends) ICAO also has a similar rule. There is an area called the Runway Safety Area that is tightly restricted that extends hundreds of feet to the side of the runway and 1000 feet off the ends where no operations, equipment, vehicles, hobby robots, etc are permitted. (FAA AC 150/5300-13A also see figure 3-5.) When mowing there is a requirement for trained and tested personnel with aviation band radios with direct on equipment control who are required to stop operations when a runway is supporting active aircraft traffic.
    I don’t know why everyone wants to take their hobby projects out to the airports. There was another one who wanted to take a drone with a Killer Ray radio transmitter to chase down other drones.
    Airports are highly regulated and no place to go testing hobby projects.
    Now on the other hand, a golf course…

      1. You are right. The regulation for Runway Safety Areas is under the FAR 14 C.F.R. section 139.309 Safety Areas : subsection
        (c)” FAA Advisory Circulars contain methods and procedures for the configuration and maintenance of safety areas acceptable to the Administrator. ”
        The advisory circular is not the regulation. The ACs are the guidance by the FAA of how to legally comply with the FAA Code of Federal Regulations. If you doubt this, try getting caught flying a plane in violation of an Advisory Circular. If it is an unregulated private landing strip then it really isn’t an airport.

        1. Of course it’s an airport.

          The word Airport is defined in CFR Section 1.1 – Airport means an area of land or water that is used or intended to be used for the landing and takeoff of aircraft, and includes its buildings and facilities, if any.

          Section 139.1…


          (a) This part prescribes rules governing the certification and operation of airports in any State of the United States, the District of Columbia, or any territory or possession of the United States serving any –

          (1) Scheduled passenger-carrying operations of an air carrier operating aircraft configured for more than 9 passenger seats, as determined by the regulations under which the operation is conducted or the aircraft type certificate issued by a competent civil aviation authority; and

          (2) Unscheduled passenger-carrying operations of an air carrier operating aircraft configured for at least 31 passenger seats, as determined by the regulations under which the operation is conducted or the aircraft type certificate issued by a competent civil aviation authority.

          Section 139 doesn’t apply to the vast majority of airports in the U.S.

          1. Once again, you are right. Of course an unregulated airport doesn’t have regulations.
            If this is at a private airport which doesn’t support public use, you can do anything you want to do. Park an 18 wheeler on the runway, etc. Sorry for saying that they aren’t airports, it’s just they aren’t airports in the sense they have required safety standards like airports which serve the public. By definition, any piece of land or patch of water could be a private airport.

      1. – I’d be curious too… especially if you’ve got WDT enabled and some failsafe setups, I don’t really see a big deal. It’s not like you’re mass producing these or marketing for residential use. – I’d give it an ‘acceptable risk’, given the use case/circumstances (without having looked closely at the setup or programming).

        1. I doubt in your life time you will ever see a commercial product that is based on Arduino. There is a reason for that. The Arduino tool chain is for toys not real products. Its a total kludge hack of so many sources trying to work together to support so many products. Its just begging for trouble.

          1. I really don’t understand this attitude. Sure, the Arduino IDE and libraries may be a bit of a mess, but the fact that there are better options out there for skilled developers and big companies doesn’t nobody’s ever made a commercial product based on it.

            For one thing, there are commercial drones based on the same ardupilot hardware & software that’s driving this mower! Not to mention most FDM 3D printers, including commercially mass-produced ones, have been built on Arduino-derived boards and arduino-based firmware. Same with GRBL for hobbyist CNC machines. These are all machines with potentially dangerous failure modes, yet they’re still based on Arduino and literally *millions* have been produced and sold, people are happily using them.

            Would someone build an autopilot system for a passenger plane or a control system for a nuclear power plant using the Arduino IDE and/or hardware? Obviously not.

            Is *this* project safe? Quite possibly no.

            Does the fact that this guy uses ardupilot rather than another autonomous vehicle solution have a significant impact on its safety? not really.

            Building safe systems is primarily a matter of *understanding possible failure modes* and mitigating the consequences of those failures. You ASSUME the systems will fail. You can build with the least reliable hardware in the world as long as it fails in a way that doesn’t hurt anybody.

          2. If the Arduino IDE is the only thing preventing you from developing for the Arduino, VisualMicro is a Visual Studio plugin the allows you to program for any Arduino-compatible micro-controller.

    1. Although ArduPilot autopilot software stack has an ”Ardu” in it’s name, it is completely different from Arduino framework nowadays. It is running on ChibiOS RTOS and has very realiable and tested core software. The name ”ArduPilot” came from it’s early days when it was actually run on Arduino framework.

      Hardware on this project might not be the most reliable, but the the software side is well covered. ArduPilot is trusted by many big name companies and used on their unmanned vehicles and aircrafts.

  3. What i don’t understand is why the guy kept following it, Just sit the seat if you want to monitor it. Should it ever go crazy, your never going to catch it by trying to hop on it with a spinning mower deck. Some people just have no sense.

    1. Probably because if he sat in the seat people would act like it isn’t autonomous or something. Those things don’t go so fast and out of control that you can’t somehow get control over it again. Maybe he had a failsafe in place too, so give the guy a break.

    2. I don’t have the ability to RTFA at the moment, but perhaps he has a wireless failsafe emergency stop such as the ones sold by FORT Robotics (Formerly Humanistic Robotics) and BWI Eagle?

  4. I would really have expected an E-stop crash bar all around the sides of this thing. It’s a pretty impressive build, but as a pilot I would not really want anything like this operating anywhere near a runway I’m using. As an engineer, I wouldn’t want to work anywhere near it, as the idea of “being able to grab a control lever” for safety is wholly inadequate and very little thought seems to have been given to safety issues in general

  5. I feel like my thunder has been stolen… I’m working on my “Cybergoat” tele-operated weed trimmer. It’s currently designed around using an RC FPV headset, RC BLDC’s & ESC’s (reversible!) and some cheapy Walmart hedge trimmer. Add-ons include the Baphomet goat head and audio to proselytize to the neighbor’s horses, goats, and dogs. It’s almost 3 acres of rough terrain, semi-arid SoCal environment, and it’s been hot, so f*ck walking the lot with a weed whacker. That and the rattlesnake I found by my mini-lathe, tele-op it is.

  6. If you are referring to the way it steers it’s called differential steering not skid steering. If you are referring to what it is, it’s a zero turn mower and not a skid steer with a mower. An autonomous skid steer mower is an even worse idea than this zero turn in terms of safety…God help you if that goes out of control. I have a zero turn and the ability to build this, but I would not even consider it…it seems a lawsuit waiting to happen.

  7. A few very negative wannabe “aviation experts” here!
    Robo! Awesome build!

    Congratulations on applying the world’s leading autopilot firmware to this mower!

    As mentioned above “Ardu” is a nod to our past, “Ardupilot” is a professional project that has maintained its open source status, it is flying hundreds of thousands of unmanned aircraft around the world, many now certified by the EU, CASA, FAA for seriously professional operations.

    I’m obviously biased as the lead hardware designer for the project, but we are very proud of our hardware, and very proud of Ardupilot and the highly professional team that develops it.

    The best bit about Ardupilot, is that it’s still FREE!

    Oh, and as far as using this at an airport, there are many Ardupilot drones flying daily at airports around the world, doing inspections of aircraft, runway inspections, to scare birds away, and perimeter security.

    Mowing the grass with a proven system with active Geofencing, and active E-Stop is a very safe operation, and awesome application of the technology.

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