There are many robotic swimming pool cleaners on the market and there are many pond vacuums.
The pool vacuums are all remote controlled and will pootle around on the bottom of the pool directed by the operator, sucking up water and filtering out small dirt particles and the occasional leaf before
returning the water to the pool.
The pond vacuums can suck up heavy duty muck, mud and leaves and get rid of it by discharging the dirty water to a container or on to the garden which means that you are required to do a large water change even if you do not want to. Some of them are also remote controlled.
I would like to see these two technologies combined and enhanced with robot turtle technology.
Just plop the pond turtle into your fishpond and it will autonomously plod along the bottom cleaning as it goes AND avoiding any planters or stones that it comes across. The large filtration bags sit on top of the unit and return the cleaned water to the pond (an extra hose attachment allows you to remove water if you so wish).
The robot turtle can sense when it's filtration bags are full or blocked and will return to the surface for maintenance (up a ramp to which the turtle is homed).
Depending on how clean you want the bottom of your pond (a bit of mud for rooting fish -> no mud) there are different timed settings.
This would be extremely useful for those times of year when leaves collect in the pond or for decorative Koi ponds. It is not advisable to use the Pond Turtle during spring when many animals and fish are spawning or when there are fry around.
(inspired by watching a swimming pool cleaner struggling to clean up an untimely poo).