Robotics 2
Stepper Motors
Quiz
Question 10: Suppose you have a stepper with 0.36 degrees per step and you are delaying 0.1ms between steps.  How fast is the motor turning in rpm?  Round your answer to two decimal places.
Question 4:  Why do we consider a stepper motor a type of 'open-loop' actuator, while servo motors are considered a type of 'closed-loop' actuator?
Question 3: True or false: One of the benefits of a stepper motor is that it doesn't require a sensor providing feedback in order to control position.
Question 1:  True or false: One of the benefits of a stepper motor is that it is often more accurate at positioning than servo motors.
True
False
Question 5:  Why do we refer to a stepper motor as a type of 'digital' actuator, while servo motors are referred to as a type of 'analog' actuator?
Stepper motors rely on feedback from a digital sensor that is attached to the shaft.
Question 6:  When we turn off one pole of the stepper and turn on the next pole, how far does the motor rotate?
A stepper motor cannot rotate to any angle, but only to certain angles that are multiples of the 'steps'.
A stepper motor is controlled by a PWM signal, which is a type of digital signal, while servos are controlled by an analog voltage.
Question 8: Suppose you are selecting a stepper motor for an application where your stepper motor is attached to a belt drive, and you know that the belt moves 20mm in one revolution of the motor.  You want to be able to position the thing attached to the belt with a precision of 0.1mm.  What is the minimum number of teeth that the stepper motor needs to have?  Your answer should be an integer.
Stepper motors do not need a sensor in order to achieve position control.
Stepper motors have an internal sensor that is used to achieve position control.
Stepper motors can't achieve position control, they can only be used for velocity control.
Stepper motors can only rotate to certain positions that are multiples of the 'steps'.
Question 7:  Suppose you have a stepper motor with 300 teeth (150 in the north pole disk and 150 in the south pole disk).  How many degrees will the shaft of the motor rotate in one step?  Round your answer to two decimal places.
1 tooth width
10 tooth widths
1/2 the tooth width
2 tooth widths
True
False
True
False
Question 2:  True or false: One of the benefits of a stepper motor is that it is able to reject disturbances, while servo motors are not.
Question 9: Suppose you have a stepper motor that rotates 0.9 degrees per step, and you want the motor to rotate at 120 revolutions per minute.  How long of a delay, in milliseconds, should you have between steps?  Round your answer to two decimal places.