Fix fading: correctly use different accel, decel ramps

- Change fading algorithm to handle Acceleration and Deceleration for
  forward and reverse separately (4 different cases)

- rename variables to make fading direction more obvious
  e.g. msFadeUp -> msFadeAccel  or  dutyIncrementDon -> dutyIncrementDecel

TODO: fading needs optimization

main/config.cpp

@@ -29,8 +29,8 @@ single100a_config_t configDriverRight = {
 
 //--- configure motor contol ---
 motorctl_config_t configMotorControl = {
-    .msFadeUp = 1500,
-    .msFadeDown = 1000,
+    .msFadeAccel = 5000, //acceleration of the motor (ms it takes from 0% to 100%)
+    .msFadeDecel = 3000, //deceleration of the motor (ms it takes from 100% to 0%)
     .currentMax = 10
 };
 

main/motorctl.cpp

@@ -27,6 +27,26 @@ void controlledMotor::init(){
 
 
 
+//----------------
+//----- fade -----
+//----------------
+//local function that fades a variable
+//- increments a variable (pointer) by given value
+//- sets to target if already closer than increment
+//TODO this needs testing
+void fade(float * dutyNow, float dutyTarget, float dutyIncrement){
+    float dutyDelta = dutyTarget - *dutyNow; 
+    if ( fabs(dutyDelta) > fabs(dutyIncrement) ) { //check if already close to target
+        *dutyNow = *dutyNow + dutyIncrement;
+    }
+    //already closer to target than increment
+    else {
+        *dutyNow = dutyTarget;
+    }
+}
+
+
+
 //==============================
 //=========== handle ===========
 //==============================
@@ -65,16 +85,17 @@ void controlledMotor::handle(){
         }
     }
 
+
     //--- calculate increment ---
     //calculate increment for fading UP with passed time since last run and configured fade time
     int64_t usPassed = esp_timer_get_time() - timestampLastRunUs;
-    dutyIncrementUp = ( usPassed / ((float)config.msFadeUp * 1000) ) * 100; //TODO define maximum increment - first run after startup (or long) pause can cause a very large increment
+    dutyIncrementAccel = ( usPassed / ((float)config.msFadeAccel * 1000) ) * 100; //TODO define maximum increment - first run after startup (or long) pause can cause a very large increment
 
     //calculate increment for fading DOWN with passed time since last run and configured fade time
-    if (config.msFadeDown > 0){
-        dutyIncrementDown = ( usPassed / ((float)config.msFadeDown * 1000) ) * 100; 
+    if (config.msFadeDecel > 0){
+        dutyIncrementDecel = ( usPassed / ((float)config.msFadeDecel * 1000) ) * 100; 
     } else {
-        dutyIncrementDown = 100;
+        dutyIncrementDecel = 100;
     }
 
     
@@ -93,28 +114,55 @@ void controlledMotor::handle(){
     //positive: need to increase by that value
     //negative: need to decrease
 
-    //--- fade up ---
-    //dutyDelta is higher than IncrementUp -> fade up
-    if(dutyDelta > dutyIncrementUp){
-        ESP_LOGV(TAG, "*fading up*: target=%.2f%% - previous=%.2f%% - increment=%.6f%% - usSinceLastRun=%d", dutyTarget, dutyNow, dutyIncrementUp, (int)usPassed);
-        dutyNow += dutyIncrementUp; //increase duty by increment
+
+
+    //--- fade duty to target (up and down) ---
+    //TODO: this needs optimization (can be more clear and/or simpler)
+    if (dutyDelta > 0) { //difference positive -> increasing duty (-100 -> 100)
+        if (dutyNow < 0) { //reverse, decelerating
+            fade(&dutyNow, dutyTarget, dutyIncrementDecel);
+        }
+        else if (dutyNow > 0) { //forward, accelerating
+            fade(&dutyNow, dutyTarget, dutyIncrementAccel);
+        }
+    }
+    else if (dutyDelta < 0) { //difference negative -> decreasing duty (100 -> -100)
+        if (dutyNow < 0) { //reverse, accelerating
+            fade(&dutyNow, dutyTarget, - dutyIncrementAccel);
+
+        }
+        else if (&dutyNow > 0) { //forward, decelerating
+            fade(&dutyNow, dutyTarget, - dutyIncrementDecel);
+        }
     }
 
-    //--- fade down ---
-    //dutyDelta is more negative than -IncrementDown -> fade down
-    else if (dutyDelta < -dutyIncrementDown){
-        ESP_LOGV(TAG, "*fading down*: target=%.2f%% - previous=%.2f%% - increment=%.6f%% - usSinceLastRun=%d", dutyTarget, dutyNow, dutyIncrementDown, (int)usPassed);
-        dutyNow -= dutyIncrementDown; //decrease duty by increment
-    }
 
-    //--- set to target ---
-    //duty is already very close to target (closer than IncrementUp or IncrementDown)
-    else{ 
-        //immediately set to target duty
-        dutyNow = dutyTarget;
-    }
+
+    //previous approach: (resulted in bug where accel/decel fade is swaped in reverse)
+//    //--- fade up ---
+//    //dutyDelta is higher than IncrementUp -> fade up
+//    if(dutyDelta > dutyIncrementUp){
+//        ESP_LOGV(TAG, "*fading up*: target=%.2f%% - previous=%.2f%% - increment=%.6f%% - usSinceLastRun=%d", dutyTarget, dutyNow, dutyIncrementUp, (int)usPassed);
+//        dutyNow += dutyIncrementUp; //increase duty by increment
+//    }
+//
+//    //--- fade down ---
+//    //dutyDelta is more negative than -IncrementDown -> fade down
+//    else if (dutyDelta < -dutyIncrementDown){
+//        ESP_LOGV(TAG, "*fading down*: target=%.2f%% - previous=%.2f%% - increment=%.6f%% - usSinceLastRun=%d", dutyTarget, dutyNow, dutyIncrementDown, (int)usPassed);
+//
+//        dutyNow -= dutyIncrementDown; //decrease duty by increment
+//    }
+//
+//    //--- set to target ---
+//    //duty is already very close to target (closer than IncrementUp or IncrementDown)
+//    else{ 
+//        //immediately set to target duty
+//        dutyNow = dutyTarget;
+//    }
     
 
+
     //define motorstate from converted duty -100 to 100
     //apply target duty and state to motor driver
     //forward

main/motorctl.hpp

@@ -30,8 +30,8 @@ typedef struct motorCommands_t {
 
 //struct with all config parameters for a motor regarding ramp and current limit
 typedef struct motorctl_config_t {
-    uint32_t msFadeUp; //acceleration of the motor (ms it should take from 0% to 100%)
-    uint32_t msFadeDown; //acceleration of the motor (ms it should take from 100% to 0%)
+    uint32_t msFadeAccel; //acceleration of the motor (ms it takes from 0% to 100%)
+    uint32_t msFadeDecel; //deceleration of the motor (ms it takes from 100% to 0%)
     float currentMax;
 } motorctl_config_t;
 
@@ -68,8 +68,8 @@ class controlledMotor {
 
         float dutyTarget;
         float dutyNow;
-        float dutyIncrementUp;
-        float dutyIncrementDown;
+        float dutyIncrementAccel;
+        float dutyIncrementDecel;
         float dutyDelta;
 
         uint32_t ramp;