Make a square of tensioned cable (or rigid rail) boxing in some area of garden/food forest/farmland at a height above the plants. Have 4 modules which maintain position on opposite sides and holds a tensioned wire between them, making a tensioned wire along the x and a tensioned wire along the y. At the intersection of these wires there is a powered doohicky that can act like a spider and drop down onto the plants below and do its work. The power to the doohicky could be cable from either axis.
Following the other comment re: power being king, what if we used a hub-and-spoke model where small drones with cameras (for sensing) and simple arms w/ clampers (for manipulating) perform 'bursts' of energy intensive activity and aggregate their sensory inputs into one composite report on the health of the plants? They do their thing (maybe for 10 - 15 mins or however long their battery lasts) and then fly back to the hub to charge. The hub itself could rely on a hybrid combo of guaranteed external power and solar panels.
Ofc, it'd be cool to see a cost analysis of how expensive this solution is (from both technical and financial standpoints) versus simpler, more energy-efficient human inputs (aka walk around your garden and prune trees that need it and pick berries that are ripe).
This technology has existed for a long time now (see cable robots, or cable-suspended cameras)
I work in this industry (contributing architect of https://nelsonirrigation.com/products/twig-wireless-controls...).
We dream of lots of fun things. And even try some of them. But not a few days go by that we don’t once again mutter “power is king” To each other. Everything we do revolves around the constraint of power budgets.