Often a lever, or joystick motion, per function. And site plans can be input to bulldozers and excavators, and with precision sensing they do cool things like preventing operator from digging below grade. Those 'sticking pipe' in trenches, and those putting in landfill cells rave about it because it avoids rework. The old guys don't need it, but they are aging out of the workforce.

https://www.komatsu.eu/en/Komatsu-Intelligent-Machine-Contro...

Here's a modern piece of heavy equipment, a Ponsse tree harvester, with the operator showing how the machine is used.[1] One big joystick for each hand, and a lot of buttons on each joystick. The operator is guiding the beast, but once it grabs onto a tree, there's some automation to cut the tree into preset lengths. Notice how fluid the movements of the machine are.

It's nowhere near autonomous, but it's several times faster than total manual control would be.

[1] https://www.youtube.com/watch?v=OlvByJeAfv0

> It is usually one lever per hydraulic cylinder.

Not so much these days, but the general idea is correct.

Usually there are joysticks (one per hand) that provide control over one movement per axis. So for example the right hand joystick on a mini-excavator usually controls bucket curl (left/right) and boom movement (forward/back). Left hand does boom up/down and rotate left/right. There's an ISO standard for this UI. Old school tractor-loader-backhoe machines (what people in the US call "a backhoe") had one lever per cylinder, so more complicated to control and more levers. An old-style motor grader is the extreme example of lever confusion[1].

Operation of heavy machines relies (still) on the brain's capability to virtualize the movement of the machine in terms of the body's limbs. That's why you need some time training to become proficient. After a few hours you just think "I want the bucket over there" and your hands make the necessary movements without thinking.

There's already lots of automation available on high-end machines such as use of GPS to control cut/fill operations with bulldozers, and laser-transit-based automated dig depth control for excavators.

[1] https://www.cat.com/en_US/articles/for-owners/the-basics-of-...