inertiamotor A stepping motor is used to drive a leadscrew a

inertia,motor

A stepping motor is used to drive a leadscrew and a table as shown below. The motor step angle is 2 degrees per step. The leadscrew pitch is 3 rev/in. The table is moving from rest to the maximum velocity of 4 inches/sec in 0.5 seconds. The efficiency of the leadscrew is 0.65. a) What is the motor speed (steps/sec) when the table reaches the max speed? b) If the inertia of the motor and drive system (including the leadscrew) is 0.3 oz-in-sec and the inertia of the load is 1 oz-in-sec2, what is the minimum torque required from the motor to inertia of the load is 1 oz-in-sec, what is the minimum torque required from the motor to accelerate the table to maximum velocity? Table tep motor Leadcrew The figure below shows a typical move profile for a motor driving a load. During ti the load is driven to its terminal velocity. During t2 and ts the motor moves the load at terminal velocity. During t4 the motor decelerates to zero velocity. For the example of Question 2, if the frictional forces opposing motion of the lead screw is 300 oz., a) What is the torque required by the motor during t2 and t3?

Solution

a) Max velocity = 4 in /s

   Lead of screw = 0.65 * 1/3   in/rev

   Rotation of lead screw   =   4 / (0.65 * 1/3)   = 18.46154 rev/s

   motor step angle = 1/180 rev/step

   motor speed    = 18.46154 / (1/180)   = 3323.077 steps/sec

b) Torque = (1 + 0.3) * alpha

     Torque = 1.3 * 4 / 0.5   = 10.4 oz-in