From c41a98ba13cf6e384a62d2e5d24aa2f8fa9f0343 Mon Sep 17 00:00:00 2001
From: Thomas Lambert <t.lambert@uliege.be>
Date: Thu, 13 Jul 2023 22:06:04 +0200
Subject: [PATCH] fix(encoders): multiple issues with encoders
- Issue with interger overlow is no longer a problem. I tried to work it
out, but as the sensors are all within range for the Q3 2023 campaign,
I have not gone deeper into it.
- Issue with conversion between bit value and degrees properly solved.
Other changes concern calibration value to display data properly for the
Q3 2023 test campaign.
---
controller/calibration.ino | 9 ++++++++-
controller/controller.ino | 10 +++++-----
controller/sensors.ino | 20 ++++++++++++++++++--
controller/utils.ino | 4 ++--
4 files changed, 33 insertions(+), 10 deletions(-)
diff --git a/controller/calibration.ino b/controller/calibration.ino
index 7386153..db8f683 100644
--- a/controller/calibration.ino
+++ b/controller/calibration.ino
@@ -7,8 +7,11 @@
Then we determine the maximum position so we can make it match the maximum
angle attainable.
+ WARNING: Not sure if this function is working properly or not. The second test
+ campaign (Q3 2023) did not require any special offset as all encoders were
+ staying within 12 bit without overflowing.
-------------------------------------------------------------------------------
- (c) Copyright 2022 University of Liege
+ (c) Copyright 2022-2023 University of Liege
Author: Thomas Lambert <t.lambert@uliege.be>
ULiege - Aeroelasticity and Experimental Aerodynamics
MIT License
@@ -96,6 +99,10 @@ void GetAngleOffset(uint32_t calibTime) {
}
// Determine if offset is needed
+ // We know that the overall amplitude is approx 60deg -> ENC_PREICSION / 6
+ // If we measure a difference between the min and max that is more than the
+ // preicsion/2, we are sure that we have an over/under flow somewhere.
+ // Therefore, we conclude that we need to offset everything.
for (int i = 0; i < sizeof(gCSN_PINS); i++) {
if (maxPos[i] - minPos[i] > ENC_PRECISION / 2) {
gAngleOffset[i] = 1;
diff --git a/controller/controller.ino b/controller/controller.ino
index 8850336..d6288c7 100644
--- a/controller/controller.ino
+++ b/controller/controller.ino
@@ -7,7 +7,7 @@
wings flap at the same frequency. The phase between the two sets will be
adjusted manually by setting their initial positions as desired.
------------------------------------------------------------------------------
- (c) Copyright 2022 University of Liege
+ (c) Copyright 2022-2023 University of Liege
Author: Thomas Lambert <t.lambert@uliege.be>
ULiege - Aeroelasticity and Experimental Aerodynamics
MIT License
@@ -56,9 +56,9 @@
// Calibration of encoders
#define ENC_PRECISION 4096 // 12-Bits encoders (nb of points per rot)
#define ENC_ORIENT \
- { 1, -1, 1, -1 } // Encoder orientation
+ { 1, -1, -1, 1 } // Encoder orientation
#define MAX_WING_POS \
- { 4095, 1317, 0, 1494 } // Maximum wing angle (returned by encoder value)
+ { 3166, 2374, 1290, 1135 } // Maximum wing angle (returned by encoder value)
#define TRUE_MAX_ANGLE 38.07 // Maximum wing angle (measured on setup)
@@ -89,7 +89,7 @@ Servo gEsc2; // ESC for aft motor
uint8_t gEsc_val = 0; // ESC angle (to use with the Servo library) [0-180]
String gMode; // Mode of operation
-uint16_t gAngleOffset[] = { 0, 0, 1, 0 }; // Encoder offset (prevent wrap-around)
+uint16_t gAngleOffset[] = { 0, 0, 0, 0 }; // Encoder offset (prevent wrap-around)
uint16_t gMaxWingPos[] = MAX_WING_POS; // Encoder maximum recorder position
int gStartTime; // Loop start time
@@ -275,7 +275,7 @@ void SerialPrint(String mode, int potent, int esc_val, unsigned int wing_angles[
}
for (int i = 0; i < sizeof(gCSN_PINS); i++) {
Serial.print(",");
- Serial.print(PosToDeg((wing_angles[i] - gMaxWingPos[i]) % ENC_PRECISION) + TRUE_MAX_ANGLE - 360);
+ Serial.print(PosToDeg(int(wing_angles[i]) - int(gMaxWingPos[i])) + TRUE_MAX_ANGLE);
}
for (int i = 0; i < 2; i++) {
Serial.print(",");
diff --git a/controller/sensors.ino b/controller/sensors.ino
index 5fb742d..d150649 100644
--- a/controller/sensors.ino
+++ b/controller/sensors.ino
@@ -3,8 +3,12 @@
Functions for sensors and acquisition.
+ WARNING: Not sure if the application of an offset to prevent integer overflow
+ is working properly or not. The second test campaign (Q3 2023) did not require
+ any special offset as all encoders were staying within 12 bit without
+ overflowing.
------------------------------------------------------------------------------
- (c) Copyright 2022 University of Liege
+ (c) Copyright 2022-2023 University of Liege
Author: Thomas Lambert <t.lambert@uliege.be>
ULiege - Aeroelasticity and Experimental Aerodynamics
MIT License
@@ -30,7 +34,19 @@ unsigned int ReadSensor(uint8_t csn, int8_t orient, int8_t offset) {
digitalWrite(csn, HIGH); //deselects the encoder from reading
- return (1 - orient) / 2 * ENC_PRECISION + orient * ret - (offset * ENC_PRECISION / 2);
+ // Flip the function if needed
+ ret = (1 - orient) / 2 * ENC_PRECISION + orient * ret;
+
+ // Apply offset to prevent overflow if needed
+ // FIXME: Check. It is probably not correct
+ if (offset == 1) {
+ if (ret >= 0 and ret < ENC_PRECISION / 2) {
+ ret = ret + ENC_PRECISION / 2;
+ } else {
+ ret = ret - ENC_PRECISION / 2;
+ }
+ }
+ return ret;
}
// Get the tension and current of a PSU
diff --git a/controller/utils.ino b/controller/utils.ino
index d902aa5..f3fb116 100644
--- a/controller/utils.ino
+++ b/controller/utils.ino
@@ -3,7 +3,7 @@
Miscellaneous utilities.
------------------------------------------------------------------------------
- (c) Copyright 2022 University of Liege
+ (c) Copyright 2022-2023 University of Liege
Author: Thomas Lambert <t.lambert@uliege.be>
ULiege - Aeroelasticity and Experimental Aerodynamics
MIT License
@@ -32,7 +32,7 @@ float RpmToFreq(int rpm) {
// Convert encoder position to degree
-float PosToDeg(unsigned int pos) {
+float PosToDeg(int pos) {
return pos * 360.0 / ENC_PRECISION;
}
--
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