increase adaptability and understandability of incremental incoder to

sail angle

keil_project/Services/IncrEncoder.c

@@ -7,13 +7,11 @@
 #include "stm32f1xx_ll_exti.h"
 #include "stm32f1xx_ll_tim.h"
 
-#define RESOLUTION 1
+#define ZERO_POSITION 0
-#define ANGLE_DEBUT 45
+#define TICKS_PER_REVOLUTION 360*4
-#define INCR_ENCODER_MID_VALUE 719
+#define DEGREE_PER_TICKS 0.25
-
 
 int index_passed = 0;
-int counts_per_revolution = 360;
 
 void INCR_ENCODER_Init(void){
 	
@@ -33,7 +31,7 @@ void INCR_ENCODER_Init(void){
 	LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_TIM3);
 	LL_TIM_InitTypeDef tim3_init_struct;
 	
-	tim3_init_struct.Autoreload= counts_per_revolution*4-1;
+	tim3_init_struct.Autoreload= TICKS_PER_REVOLUTION-1;
 	tim3_init_struct.Prescaler=0;
 	tim3_init_struct.ClockDivision=LL_TIM_CLOCKDIVISION_DIV1;
 	tim3_init_struct.CounterMode=LL_TIM_COUNTERMODE_UP;
@@ -101,17 +99,12 @@ int INCR_ENCODER_IsAbsolute(void)
 	return index_passed;
 };
 
-int INCR_ENCODER_GetAngle(void)
+float INCR_ENCODER_GetAngle(void)
 {
 	int counter_value = LL_TIM_ReadReg(TIM3, CNT);
-	float vabs = abs(counter_value-INCR_ENCODER_MID_VALUE);
+	// center
-	float vIEAngleDebut = INCR_ENCODER_MID_VALUE -(ANGLE_DEBUT*4);
+	int centered_counter_value = (counter_value - ZERO_POSITION) % TICKS_PER_REVOLUTION;
-	float nbIncrements = 90/RESOLUTION;
+	// translate ticks to angle
-	
+	float angle = centered_counter_value * DEGREE_PER_TICKS;
-	if(vabs > vIEAngleDebut)
+	return angle;
-	{
-		return 0;
-	}else{
-		return 90 - RESOLUTION*floor(vabs/(vIEAngleDebut/nbIncrements) ) ;
-	}
 };

keil_project/Services/IncrEncoder.h

@@ -6,6 +6,10 @@ void INCR_ENCODER_Init(void);
 
 int INCR_ENCODER_IsAbsolute(void);
 
-int INCR_ENCODER_GetAngle(void);
+/**
+  * @brief Returns the angle of the incremental encoder
+	* @retval -180 to 180 where 0 is the incremental encoder pointing towards the back of the boat
+  */
+float INCR_ENCODER_GetAngle(void);
 
 #endif

keil_project/Services/Sail.c

@@ -1,15 +1,32 @@
 #include "Sail.h"
-#include "Servo.h"
 
+#include "Servo.h"
+#include <stdlib.h>
+#include <math.h>
 
 #define SAIL_TRANSFER_FACTOR 1.0
 #define SAIL_TRANSFER_OFFSET 0
 
+#define ANGLE_DEBUT 45
+
 void SAIL_Init(void)
 {
 	SERVO_Init();
 }
 
+int SAIL_AngleFromGirouette(float girouette_value){
+	float vabs = fabs(girouette_value);
+
+	if(vabs < ANGLE_DEBUT)
+	{
+		return 0;
+	}else{
+		// map 45 to 180 -> 0 to 90 and floor it to get an integer
+		return floor((90 / (180 - ANGLE_DEBUT)) * (vabs - ANGLE_DEBUT));
+	}
+
+}
+
 void SAIL_SetAngle(float angle)
 {
 	float servo_angle = angle * SAIL_TRANSFER_FACTOR + SAIL_TRANSFER_OFFSET;

keil_project/Services/Sail.h

@@ -5,6 +5,7 @@
 
 void SAIL_Init(void);
 
+int SAIL_AngleFromGirouette(float girouette_value);
 // sets the opening angle of the sail
 void SAIL_SetAngle(float angle);
 

keil_project/Src/main.c

@@ -44,6 +44,7 @@ int angle_roulis_good = 0;
 int angle_sail = 0;
 int RF_Input_Duty = 0;
 int TX_Flag = 0, CONTROL_LOOP_Flag = 0;
+float angle_incr_encoder = 0;
 
 char wait_for_girouette[] = "En attente d'initialisation de la girouette\r\n";
 
@@ -79,8 +80,9 @@ int main(void)
 				SAIL_SetAngle(90);
 				DC_MOTOR_SetSpeed(0);
 			}else{
-				angle_sail = INCR_ENCODER_GetAngle();
+				angle_incr_encoder = INCR_ENCODER_GetAngle();
-				SAIL_SetAngle(angle_sail/2);
+				angle_sail = SAIL_AngleFromGirouette(angle_incr_encoder);
+				SAIL_SetAngle(angle_sail);
 				RF_Input_Duty = RF_INPUT_GetDutyTimeRelative();
 				DC_MOTOR_SetSpeed(RF_Input_Duty);
 			}