We are wondering what type of micro controller would be the best choice for making a robot with 3 actuators and two motors, also we are running a 24V system, would we need a voltage step down to power the board?
Uno can do that. Will need external components or modules to drive the actuators (which are solenoids?) and motors.
Can recommend better with more specifics.
Board needs 7.5-9V at the barrel jack to power it, no more than 12V.
We have two 12V batteries we are going to wire in series with 3 linear actuators and 2DC motors, as of right now two actuators will be on the mechanical arm, one on a dumping mechanism and the two D.C. Motors will power the main wheels.
Got links to the actuator and motor? Do they need to move in two directions, and at variable speeds?
Take a feed from between the two batteries to give 12V to power the Arduino. Yes, that means the batteries will not be drained at perfectly equal rate, but you won't notice the difference.