Using an Ultrasonic Proximity Sensor to Control a Hydraulic Valve

Get rid of the operator on the tractor, and go with a fully autonomous vehicle. That way the speed can be as slow as necessary to process lot's of sensor data. And as it's weeding, can run 24/7 performing the task, with just a human needed to refuel and grease/maintain the works. Reduce the power needed also.

I've seen "precision farming" now for 35 years, and everyone is stuck in the paradigm of needing a full time operator. WHY?

So in this case, because there is an operator moving real fast, you have to time the sensor input, with processing delay, and mechanism inertia delay.

It won't look like a farm tractor when your done.

"how I can synchronize the speed of the hydraulic cylinder with the forward speed of the tractor?"

Walk in front of the tractor.

GPS with DGPS capable receiver

Modulate the carburetor, or more preferably a bypass valve in the hydraulic transmission, to regulate the driving speed automatically.

A manual override is sensible.

Hi

Tractors for many years have had the ability to do a speed/ground related control. However it depends on the make and model and no doubt age of your machine. On earlier machines it was very much a mechanical procedure but today with the complex electronics it will be more sophisticated and integrated with the control systems. Not easy to access.

You need to contact your dealer with model type and serial numbers and ask what can be done with your machine type.

If you wanted to do a DIY job you could do a wheel on the ground thro' a output device and relate this thro a control system to your solenoid valve but you would have to be good at your control engineering to make it work.

Regards

Oliver Dunthorne

Hydraulic Engineer (retired)

You have not included a method of measuring the distance between the weed being dealt with and the next plant that it is trying to avoid. Without this input automation of the system is not possible. If retraction of the cylinder to avoid plants is set extremely fast when it will always be clear of the plants regardless of any sensible tractor speed. After that it is down to tractor driver training.