Which type of stepper motor best suits my project?

[Win007]

Hi I'm Harish.
Currently i'm doing a project of integrating stepper motor along with PID controller programming for steering Automated Guided Vehicle (AGV).
And my project's main scope is to select and integrate stepper motor to replace the PMDC motor and control the same using PLC by a PID controller. Based on the magnetic sensor input error has to be calculated and accordingly stepper motor has to steer the steering set up.
Currently we are using 48VDc battery and BLDC motor and controller for driving AGV.
So can i know which type of stepper motor and the encoder best suits for my project?
Thanks!

[mparadis]

You will need to do some tests to determine how much torque you need in this application, either by finding the specifications of the motor you're replacing, or by measuring how much torque is required to turn the steering wheel. Once you have a number, you should get a motor with more torque than you think you'll need, so you won't have to worry about stalling out.

Steppers that have gearboxes have higher torque for the size of motor, but the gearbox can add a degree or two of slop due to the space between the gears. For this reason, applications that care about accuracy will often go for motors that don't have an attached gearbox. Our largest stepper motors don't come with gearboxes by default, but we do sell large worm gearboxes in our Mechanical/Transmission category.