Fixed Errors with Stepper Motor Control

Input Capture Module #4 is used to monitor the number of pulses sent to the stepper motor via the PWM Module #2.  This count is used to know when the user has moved the stepper too far in one direction and prevents further motion in that direction.

Fixed various issues (like changing Pin A2 unnecessarily and several incorrect if statements in the IC Module #4 Interrupt) that was causing the PIC to send inappropriate signals to the stepper motor, which caused it to malfunction.

Dependencies/Input Capture/InputCapture.c

@@ -306,9 +306,12 @@ void __attribute__ ((__interrupt__, auto_psv)) _IC4Interrupt(void)
 {
     if (LATAbits.LATA2 == 0)
     {
-        IC4_Buffer.numberOfCounts--;
+        if (IC4_Buffer.numberOfCounts > -200)
+        {
+            IC4_Buffer.numberOfCounts--;
+        }
     }
-    else
+    else if (IC4_Buffer.numberOfCounts < 200)
     {
         IC4_Buffer.numberOfCounts++;
     }
@@ -320,7 +323,11 @@ void IC4_Initialize(Count_Monitor* IC4_Module)
 {
     IC4CON1 = 0x0000;
 
+    IC4_Buffer.numberOfCounts = 0;
+
     IC4_Module->numberOfCounts = 0;
+    IC4_Module->allowClockwiseMotion = 1;
+    IC4_Module->allowCounterClockwiseMotion = 1;
 
 	TRISBbits.TRISB7 = 1;
 	Nop();
@@ -350,7 +357,23 @@ void IC4_Initialize(Count_Monitor* IC4_Module)
 
 void IC4_Update(Count_Monitor* IC4_Module)
 {
-
+	IC4_Module->numberOfCounts = IC4_Buffer.numberOfCounts;
+
+    if (IC4_Buffer.numberOfCounts <= -200)
+    {
+        IC4_Module->allowClockwiseMotion = 0;
+        IC4_Module->allowCounterClockwiseMotion = 1;
+    }
+    else if (IC4_Buffer.numberOfCounts >= 200)
+    {
+        IC4_Module->allowClockwiseMotion = 1;
+        IC4_Module->allowCounterClockwiseMotion = 0;
+    }
+    else
+    {
+        IC4_Module->allowClockwiseMotion = 1;
+        IC4_Module->allowCounterClockwiseMotion = 1;
+    }
 }
 
 

Dependencies/Input Capture/InputCapture.h

@@ -45,6 +45,11 @@ struct Count_Monitor
     //stepper motor.  Negative values are CW, positive values are CCW.
     int numberOfCounts;
 
+    int allowClockwiseMotion;
+    int allowCounterClockwiseMotion;
+
+    int brakeEngaged;
+
     void (*Initialize)(Count_Monitor*);
 	void (*Update)(Count_Monitor*);
 };

Finalized Design/Final Project/main_driver.c

@@ -46,7 +46,7 @@ void PIC_Initialization(void)
     Nop();
 }
 
-void IC_Module_Initialize(IC_Module* kill_switch_input, IC_Module* propulsion_throttle_servo_input, IC_Module* propulsion_direction_motor_input)
+void IC_Module_Initialize(IC_Module* kill_switch_input, IC_Module* propulsion_throttle_servo_input, IC_Module* propulsion_direction_motor_input, Count_Monitor* stepper_motor_counter_input)
 {
     kill_switch_input->Initialize = IC1_Initialize;
     kill_switch_input->Update = IC1_Update;
@@ -56,6 +56,9 @@ void IC_Module_Initialize(IC_Module* kill_switch_input, IC_Module* propulsion_th
 
 	propulsion_direction_motor_input->Initialize = IC3_Initialize;
 	propulsion_direction_motor_input->Update = IC3_Update;
+
+    stepper_motor_counter_input->Initialize = IC4_Initialize;
+    stepper_motor_counter_input->Update = IC4_Update;
 }
 
 void PWM_Module_Initialize(PWM_Module* propulsion_thrust_servo_output, PWM_Module* duration_to_turn_propulsion_engine_output)
@@ -96,7 +99,8 @@ int main(void)
     IC_Module kill_switch_input;
     IC_Module propulsion_throttle_servo_input;
 	IC_Module propulsion_direction_motor_input;
-    IC_Module_Initialize(&kill_switch_input, &propulsion_throttle_servo_input, &propulsion_direction_motor_input);
+    Count_Monitor stepper_motor_counter_input;
+    IC_Module_Initialize(&kill_switch_input, &propulsion_throttle_servo_input, &propulsion_direction_motor_input, &stepper_motor_counter_input);
 
     PWM_Module propulsion_throttle_servo_output;
     PWM_Module turn_propulsion_engine_output;
@@ -105,6 +109,7 @@ int main(void)
     kill_switch_input.Initialize(&kill_switch_input);
     propulsion_throttle_servo_input.Initialize(&propulsion_throttle_servo_input);
     propulsion_direction_motor_input.Initialize(&propulsion_direction_motor_input);
+    stepper_motor_counter_input.Initialize(&stepper_motor_counter_input);
 
     propulsion_throttle_servo_output.Initialize(&propulsion_throttle_servo_output);
     turn_propulsion_engine_output.Initialize(&turn_propulsion_engine_output);
@@ -159,28 +164,28 @@ int main(void)
         //this will allow for smooth movement of the stepper motor
         //if PWM frequency * counts per trigger > 800 * RPS, then the user input will experience a delay in controlling the stepper motor
         //if PWM frequency * counts per trigger < 800 * RPS, then the user input will cause jerking in the stepper motor response
-        if (propulsion_direction_motor_input.dutyCyclePercentage < MIDPOINT_INPUT_SIGNAL_DUTY_CYCLE - DEAD_ZONE_OFFSET)
+        stepper_motor_counter_input.Update(&stepper_motor_counter_input);
+        if (propulsion_direction_motor_input.dutyCyclePercentage < MIDPOINT_INPUT_SIGNAL_DUTY_CYCLE - DEAD_ZONE_OFFSET && stepper_motor_counter_input.allowClockwiseMotion == 1)
         {
 			//This is the enable bit for the stepper motor responsible for turning the propulsion engine to control direction
             LATAbits.LATA2 = 0;
 
-            turn_propulsion_engine_output.dutyCyclePercentage = 5;
+            turn_propulsion_engine_output.dutyCyclePercentage = 10;
             turn_propulsion_engine_output.UpdateDutyCycle(&turn_propulsion_engine_output);
         }
         //represents a rightward turn of the propulsion engine
-        else if (propulsion_direction_motor_input.dutyCyclePercentage >= MIDPOINT_INPUT_SIGNAL_DUTY_CYCLE + DEAD_ZONE_OFFSET)
+
+        else if (propulsion_direction_motor_input.dutyCyclePercentage >= MIDPOINT_INPUT_SIGNAL_DUTY_CYCLE + DEAD_ZONE_OFFSET && stepper_motor_counter_input.allowCounterClockwiseMotion == 1)
         {
             //This is the enable bit for the stepper motor responsible for turning the propulsion engine to control direction
             LATAbits.LATA2 = 1;
 
-            turn_propulsion_engine_output.dutyCyclePercentage = 5;
+            turn_propulsion_engine_output.dutyCyclePercentage = 10;
             turn_propulsion_engine_output.UpdateDutyCycle(&turn_propulsion_engine_output);
         }
         //the motor holds its position
         else
         {
-            LATAbits.LATA2 = 0;
-
             turn_propulsion_engine_output.dutyCyclePercentage = 100;
             turn_propulsion_engine_output.UpdateDutyCycle(&turn_propulsion_engine_output);
         }