I am planning to create a kinetic sculpture like the one in this video,
but it will have less balls (i.e 144 balls). I am planning to have stepper motors in this project. Is it possible to control the movement of 144 balls by 6 Maesto 24-channel servo controller by an Arduino? Is it possible to control the stepper motors precisely, quickly, and smoothly by 6 pieces of Maesto 24-channel servo controller? How many pulses can I send to stepper motors in one second?
I am also open to your suggestions. What kind of motors and motor drives should I use for this project?
You could use the Maestro to control a stepper motor driver which in turn drives stepper motors, but you might lose some precision and speed. Also, you would need 2 I/O lines to drive each stepper motor driver which means you would need twice as many Maestros as you proposed. If you are going to use stepper motors, I recommend directly driving the stepper motor drivers from the Arduino. I also suggest getting started by getting one stepper motor to move and then duplicating the system to get what you want. Which stepper motor and driver you use depends on your specific application and something you would have to determine yourself.
I have been working on this same type of sculpture for a while now. If you are interested, I can help and describe some of the pitfalls and challenges in creating this project.