From 3eb483aef45951a21d4d3b548524b91e4a28bc24 Mon Sep 17 00:00:00 2001
From: Thomas Lambert <t.lambert@uliege.be>
Date: Tue, 22 Nov 2022 00:02:24 +0100
Subject: [PATCH] feat(calib, WIP): add calibration process
---
CHANGELOG.md | 1 +
README.md | 18 ++++-
controller/calibration.ino | 130 +++++++++++++++++++++++++++++++++++++
controller/controller.ino | 14 ++--
controller/sensors.ino | 4 +-
5 files changed, 159 insertions(+), 8 deletions(-)
create mode 100644 controller/calibration.ino
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fb7b6dc..9e29969 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ to [Semantic Versioning][sem_ver].
- **Controller**: Complete control over Serial
- **Acquisition**: Angle sensor acquisition
- **Acquisition**: PSU current and tension monitoring
+- **Calibration**: Wing angle automatic calibration
### Changed
diff --git a/README.md b/README.md
index 4f95109..1afb415 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,18 @@ A [_json_ configuration file](controller/mechaRaptor.json) is provided in order
to visualize the output stream in real time with [serial-studio]. This also
allows the automatic logging and retention of all data in _csv_ spreadsheets.
+### Angle calibration
+
+The flapping angle of each wing is measured using an absolute encoder. These
+sensors need to be 'calibrated' properly so the value they output corresponds to
+the actual wing angle.
+This calibration process be done automatically in Serial mode. At the end of the
+calibration, the Serial console will output the offset and the max angle values
+measured. This calibration is only necessary for the first run of the setup (or
+after a re-assembly). So the values measured during the calibration can be
+hard-coded in the code and the calibration functions can be by-passed by setting
+`gSKIP_CALIB = true`.
+
## Bill of Materials
| Device | Reference | Usage |
@@ -92,12 +104,14 @@ allows the automatic logging and retention of all data in _csv_ spreadsheets.
| **Potentiometer** | N/A | Manual control of RPM|
| **ON/OFF switch** | N/A | Switch between `Serial` and `Manual` control |
| **Resistors** | N/A | Voltage divider, noise reduction |
-| **Current sensor** | [Allegro SEN0098][SEN0098] | PSU current logging |
+| **Current sensor** | [Allegro SEN0098][SEN0098][^1] | PSU current logging |
## Schematics
To Do (ETA January 2023)
+[^1]: Using an ACS758 chip LCB050B-3370XAA-1044
+
[plettenberg]: <https://plettenbergmotors.com/>
[serial-studio]: <https://serial-studio.github.io/>
[jetispin]: <https://www.jetimodel.com/katalog/spin-75-pro-opto.htm>
@@ -105,4 +119,4 @@ To Do (ETA January 2023)
[arduino]: <https://store.arduino.cc/products/arduino-uno-rev3>
[elektro]: <https://elektroautomatik.de>
[AEAT612]: <https://docs.broadcom.com/doc/AV02-0188EN>
-[SEN0098]: https://www.allegromicro.com/~/media/Files/Datasheets/ACS758-Datasheet.ashx
+[SEN0098]: <https://www.allegromicro.com/~/media/Files/Datasheets/ACS758-Datasheet.ashx>
diff --git a/controller/calibration.ino b/controller/calibration.ino
new file mode 100644
index 0000000..afde8de
--- /dev/null
+++ b/controller/calibration.ino
@@ -0,0 +1,130 @@
+/*******************************************************************************
+Calibration
+
+'Calibrate' the wing absolute rotary encoders.
+First we unwrap the measured position by shifting the bits in order to avoid
+wrapping if this is needed.
+Then we determine the maximum position so we can make it match the maximum angle
+attainable.
+
+--------------------------------------------------------------------------------
+(c) Copyright 2022 University of Liege
+Author: Thomas Lambert <t.lambert@uliege.be>
+ULiege - Aeroelasticity and Experimental Aerodynamics
+MIT License
+Repo: https://gitlab.uliege.be/thlamb/mecharaptor-controller
+*******************************************************************************/
+
+void Calibrate() {
+ String input;
+
+ Serial.println("[INPUT]: Calibrate angles? (Y/n)");
+
+ while (Serial.available() == 0) {} // Wait for serial input
+ input = Serial.readString();
+
+ if (input.equalsIgnoreCase("n") or input.equalsIgnoreCase("no")) {
+ Serial.println("[INFO]: No calibration required. Using default values.");
+
+ } else {
+
+ Serial.println("[WARNING]: Setup will run for 8s to get the offset and maximum value.");
+ Serial.println("[INPUT]: Type 'Y' to begin.");
+
+ while (Serial.available() == 0) {} // Wait for serial input
+
+ if (input.equalsIgnoreCase("y")) {
+
+ // Run ESC at min value
+ gEsc1.write(40);
+ gEsc2.write(40);
+
+ GetAngleOffset();
+ GetMaxWingPos();
+
+ // Stop ESC
+ gEsc1.write(0);
+ gEsc2.write(0);
+
+ Serial.println("[INFO]: Calibration done.");
+ Serial.println("Maxium wing posiions are: ");
+ for (int i = 0; i < sizeof(gCSN_PINS); i++) {
+ Serial.print(gMaxWingPos[i]);
+ if (i < sizeof(gCSN_PINS)-1){
+ Serial.print(", ");
+ }
+ Serial.println("Offsets are: ");
+ for (int i = 0; i < sizeof(gCSN_PINS); i++) {
+ Serial.print(gAngleOffset[i]);
+ if (i < sizeof(gCSN_PINS)-1){
+ Serial.print(", ");
+ }
+ }
+
+ } else {
+ Serial.println("[INFO]: Calibration aborted. Using default values.");
+ }
+ }
+
+ // Flush Serial before continuing
+ while(Serial.available()){Serial.read();}
+}
+
+// Determine if wing position needs to be offset to prevent wrap-around
+void GetAngleOffset() {
+
+ uint16_t calibTime = 4000;
+
+ unsigned int maxPos[4];
+ unsigned int minPos[4];
+ unsigned int newPos;
+
+ for (uint32_t tStart = millis(); (millis()-tStart) < calibTime; ) {
+
+ // Find max and min wing position
+ for (int i = 0; i < sizeof(gCSN_PINS); i++) {
+ newPos = ReadSensor(gCSN_PINS[i], gENC_ORIENT[i], 0);
+ if (i == 0) {
+ maxPos[i] = newPos;
+ minPos[i] = newPos;
+ }
+ else {
+ if (newPos > maxPos[i]) {
+ maxPos[i] = newPos;
+ }
+ else if (newPos < minPos[i]) {
+ minPos[i] = newPos;
+ }
+ }
+ }
+ }
+
+ // Determine if offset is needed
+ for (int i = 0; i < sizeof(gCSN_PINS); i++) {
+ else if (maxPos[i] - minPos[i] > ENC_PRECISION/2) {
+ gAngleOffset[i] = 1;
+ }
+ }
+}
+
+
+unsigned int GetMaxWingPos() {
+
+ uint16_t calibTime = 4000;
+
+ unsigned int maxPos[4];
+ unsigned int minPos[4];
+ unsigned int newPos;
+
+ for (uint32_t tStart = millis(); (millis()-tStart) < calibTime; ) {
+
+ // Find max and min wing position
+ for (int i = 0; i < sizeof(gCSN_PINS); i++) {
+ newPos = ReadSensor(gCSN_PINS[i], gENC_ORIENT[i], gAngleOffset[i]);
+ if (newPos > maxPos[i]) {
+ gMaxWingPos[i] = newPos;
+ }
+ }
+ }
+
+}
diff --git a/controller/controller.ino b/controller/controller.ino
index d95f95f..4317a67 100644
--- a/controller/controller.ino
+++ b/controller/controller.ino
@@ -64,6 +64,8 @@ Repo: https://gitlab.uliege.be/thlamb/mecharaptor-controller
Globals (for things that I can change manually)
*******************************************************************************/
+const boolean gSKIP_CALIB = true; // Skip calibration or not
+
// Constant values that can be tweaked here or in the ESC before run
const uint16_t gMAX_SIG = 2000; // Max signal to the ESC [ms]
const uint16_t gMIN_SIG = 1000; // Min signal to the ESC [ms]
@@ -84,7 +86,9 @@ 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 max_wing_pos[] = MAX_WING_POS; // Encoder maximum recorder position
+uint16_t gAngleOffset[] = {0, 0, 0, 0}; // Encoder offset (prevent wrap-around)
+uint16_t gMaxWingPos[] = MAX_WING_POS; // Encoder maximum recorder position
+
/*******************************************************************************
@@ -129,7 +133,9 @@ void setup() {
}
// Calibrate angle sensors
- // SetupCalibration();
+ if (!gSKIP_CALIB) {
+ SetupCalibration();
+ }
Serial.println("[INFO]: Setup OK, starting now...");
delay(1000); // Ensure all is properly initialized
@@ -168,7 +174,7 @@ void loop() {
// Read value from rotary encoders
for (int i = 0; i < sizeof(gCSN_PINS); i++) {
- wing_angles[i] = ReadSensor(gCSN_PINS[i], gENC_ORIENT[i]);
+ wing_angles[i] = ReadSensor(gCSN_PINS[i], gENC_ORIENT[i], gAngleOffset[i]);
}
// Read tension and current from PSU
@@ -260,7 +266,7 @@ void SerialPrint(String mode, int potent, int esc_val, unsigned int wing_angles[
Serial.print(freq);
for (int i = 0; i < sizeof(gCSN_PINS); i++) {
Serial.print(",");
- Serial.print(PosToDeg(wing_angles[i])-max_wing_pos[i] + TRUE_MAX_ANGLE);
+ Serial.print(PosToDeg(wing_angles[i])-gMaxWingPos[i] + TRUE_MAX_ANGLE);
}
for (int i = 0; i < sizeof(psu_vol); i++) {
Serial.print(",");
diff --git a/controller/sensors.ino b/controller/sensors.ino
index f847951..dfa641e 100644
--- a/controller/sensors.ino
+++ b/controller/sensors.ino
@@ -12,7 +12,7 @@ Repo: https://gitlab.uliege.be/thlamb/mecharaptor-controller
*******************************************************************************/
//Read 12-bit rotary encoder (RobinL modified by linarism on forum.arduino.cc)
-unsigned int ReadSensor(uint8_t csn, int8_t orient) {
+unsigned int ReadSensor(uint8_t csn, int8_t orient, int8_t offset) {
unsigned int ret = 0;
digitalWrite(csn, LOW);
@@ -28,7 +28,7 @@ unsigned int ReadSensor(uint8_t csn, int8_t orient) {
}
digitalWrite(csn, HIGH); //deselects the encoder from reading
- return (1-orient)/2 * ENC_PRECISION + orient*ret;
+ return (1-orient)/2 * ENC_PRECISION + orient*ret - offset * ENC_PRECISION/2;
}
// Get the tension and current of a PSU
--
GitLab