what motor an how would you suggest i get the position feedback so the motors could correct themselfs...... and what do u mean by arbitrary
By 'arbitrary' I mean a motor that you've chosen not because it is easy for the Arduino to work with. The Arduino can control various motors but it won't power them - you would need an external driver circuit to amplify the Arduino's puny logic signals up to something that will power the motor. How hard this will be would depend on the electrical characteristics of the motors. There are various shields commonly available for ordinary small electric motors that only need a few watts of power, but if the motor needs more than a few Amps or Volts then you will probably need to build your own driver circuit. Since your motor presumably doesn't provide any position control or sensing, you would have to attach your own position sensor and provide a means for the Arduino to read the position. For example that could be achieved using a potentiometer, or an encoder. Within the Arduino, you would use a closed loop feedback system to control the motors; your sketch would need to measure the current position of the motor, compare that with the position that you want it to be at, and power the motor in the right direction at the right speed to move it to that position. There is a control algorithm named PID (Proportional, Integral and Derivative Feedback) which is well suited to this sort of feedback loop. If you design the hardware so that the mechanism is self-supporting and does not need the motor to apply a force to keep it in position, this would work very well and I would anticipate you getting very nice smooth and well-damped movement.
