StepperMotor Module

This software module

1) Reads input from grapple dial to control the stepper motor

2) Controls the stepper motor

3) Keeps track of the number of steps which determines Tom Cruise's position

Public Functions:

initStepMotor(howManySteps)

Update all timing variables to the current time

Set the motor direction to raise Tom Cruise

Run the motor for a number of steps specified by the input howManySteps

Set the motor direction to lower Tom Cruise

Run the motor to a calibrated start position

Reset the internal count for motor position to zero

Read the grapple control dial position by calling readDial() which returns a number the ranges

from 0 to 1000

If the dial position is in the neutral position (about middle of the dial range)

Set a flag that indicates that the dial is in control of the motor

Else

Set a flag that the dial must first be in the neutral position before it is allowed to control

the motor

resetStepMotorStatus

If motor position is zero

Return MOTOR_NOT_IN_RANGE_STATUS

Else

Set the motor direction to raise Tom Cruise

Run the motor at a calibrated reset speed

Return MOTOR_RESETTING_STATUS

slowVictoryReset

If motor position is zero

Return MOTOR_NOT_IN_RANGE_STATUS

Else

Set the motor direction to raise Tom Cruise

Run the motor at a calibrated victory speed

Return MOTOR_RESETTING_STATUS

checkStepMotorStatus

Read in grapple control dial by calling readDial() which returns a value from 0 to 1000

Based on grapple control dial position, determine commanded grapple direction and speed

If flag indicates grapple control dial started not in the neutral position

Ignore grapple control dial input and assume it is reading neutral (not commanding a motor spd)

Else

Set a flag indicating that the grapple control dial is now in control of the motor

Calculate speed (which is actually commanded by a wait time)

Linearize between calibrated min and max wait times (corresponding to max and min speeds of the

motor) based off the relative position of the control dial from the neutral position

If motor is commanded to raise and motor position is greater than zero OR

motor is commanded to lower and motor position is less than the calibrated floor position

Run motor at commanded speed by calling runMotor(cmdWaitTime) which runs the motor at the

specified speed = 1/cmdWaitTime

If motor position is equal to calibrated floor position

Return MOTOR_HIT_FLOOR_STATUS

Else

If motor position is in the calibrated position window for the computer

Return MOTOR_IN_RANGE_STATUS

Else

Return MOTOR_NOT_IN_RANGE_STATUS

Module Functions:

runMotor(cmdWaitTime)

Filter input speed to prevent instantaneous accelerations of the stepper motor

If cmdWaitTime is greater than the current motor speed (which is actually expressed as a wait

time because all motor speeds are actually 1/motor wait times)

Set cmdWaitTime to be one step faster than the current motor speed

If cmdWaitTime is less than the current motor speed

Set cmdWaitTime to be one step slower than the current motor speed

Read the current time

If the current time minus the time when the last motor step was commanded

Command a step by calling pulseClock()

Save the current speed for future filtering

Update the timing variable with the current time

Update the motor position

readDial

Read in analog dial as number between 0 and 1023, store as myPos

If myPos is less than calibrated zero position on dial

Return 0

Else

If myPos is greater than the calibrated fully on position

Return 1000

Else

Linearize between two extreme calibrations in the following manner (to avoid floating point

math):

myTemp = (1000*((long)myPos-dialLO));

myCalc = (int)((myTemp)/((dialHI-dialLO)));

return myCalc;

setDir(dir)

If dir

Set stepper motor driver direction line to HI

Else

Set stepper motor driver direction line to LO

pulseClock

Set step command line to HI

Delay slightly to ensure CLOCK output stays HI for at least 10[us]

Set step command line to LO