Hi chris,

first of all i'd like to tell u that motion control is in my veins.
i realized so many projects in this feild of control systems.
in order to help u i need to know what kind of servo u're trying to
design? is it for stepper, dc or ac motors? what do u mean by quadruple servo?
do u mean that u need to synchronize the motion of 4 actuators to describe
a certain 3 dimensional trajectory?
if so microcontrollers are not the best technological choice. asic's or dsp's are more suited for such designs.
however, it is possible to use mcu's but u need to chose the right ones.
i made an attempt not long ago to design a programmable motion controller for 3 steppers using mcu.
it actually worked out pretty well, but i did use the 89C51RD+ which contains a programmable counter array.
that actually dramatically reduces software complexity, offered great timing flexibility and a very elegant
timer interrupt handling.
i also used external ram and i2c serila eeprom for trajectory data storage and made the whole system work on a common i2c bus.
i'm willing to exchange more info on this subject.

mourad