Position control draft

.github/workflows/build.yml

@@ -10,29 +10,23 @@ on:
 jobs:
   build_linux:
     runs-on: ubuntu-latest
-    env:
-        ARDUINO_SKETCH_ALWAYS_EXPORT_BINARIES: 1
     steps:
     - uses: actions/checkout@v4
     - name: Install Arduino CLI
       run: curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=/usr/local/bin sh
-    - name: Build firmware for ESP32
+    - name: Build firmware
+      env:
+        ARDUINO_SKETCH_ALWAYS_EXPORT_BINARIES: 1
       run: make
-    - name: Build firmware for ESP32-C3
-      run: make BOARD=esp32:esp32:esp32c3
-    - name: Build firmware for ESP32-S3
-      run: make BOARD=esp32:esp32:esp32s3:CDCOnBoot=cdc
-    - name: Build firmware for ESP32-S3 with QSPI PSRAM
-      run: make BOARD=esp32:esp32:esp32s3:CDCOnBoot=cdc,PSRAM=enabled EXTRA=--output-dir=flix/build/esp32.esp32.esp32s3.qspi
-    - name: Build firmware for ESP32-S3 with OPI PSRAM
-      run: make BOARD=esp32:esp32:esp32s3:CDCOnBoot=cdc,PSRAM=opi EXTRA=--output-dir=flix/build/esp32.esp32.esp32s3.opi
-    - name: Build firmware for Flix2
-      run: make BOARD=esp32:esp32:esp32s3:FlashSize=4M,CDCOnBoot=cdc,PSRAM=opi FLAGS=-DFLIX2 EXTRA=--output-dir=flix/build/esp32.esp32.flix2
     - name: Upload binaries
       uses: actions/upload-artifact@v4
       with:
         name: firmware-binary
         path: flix/build
+    - name: Build firmware for ESP32-C3
+      run: make BOARD=esp32:esp32:esp32c3
+    - name: Build firmware for ESP32-S3
+      run: make BOARD=esp32:esp32:esp32s3
     - name: Build espnow-proxy
       run: arduino-cli compile --fqbn esp32:esp32:esp32 tools/espnow-proxy
     - name: Check c_cpp_properties.json
@@ -72,7 +66,7 @@ jobs:
         apt-get update
         DEBIAN_FRONTEND=noninteractive apt-get install -y curl wget build-essential cmake g++ pkg-config gnupg2 lsb-release sudo
     - name: Install Arduino CLI
-      run: curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=/usr/local/bin sh
+      uses: arduino/setup-arduino-cli@v1.1.1
     - uses: actions/checkout@v4
     - name: Install Gazebo
       run: |

.github/workflows/docs.yml

@@ -8,7 +8,6 @@ on:
 
 permissions:
   contents: read
-  actions: read
   pages: write
   id-token: write
 
@@ -25,50 +24,12 @@ jobs:
   build_book:
     runs-on: ubuntu-latest
     needs: markdownlint
-    env:
-      BINARIES: ${{ github.event_name == 'push' && (github.ref_name == 'master' || github.ref_name == 'dev') && github.repository == 'okalachev/flix' }}
     steps:
     - uses: actions/checkout@v4
     - name: Install mdBook
       run: cargo install mdbook --vers 0.4.43 --locked
     - name: Build book
       run: cd docs && mdbook build
-    - name: Wait for Build to complete
-      if: ${{ env.BINARIES }}
-      uses: lewagon/wait-on-check-action@v1.9.1
-      with:
-        ref: ${{ github.sha }}
-        check-name: build_linux
-        repo-token: ${{ secrets.GITHUB_TOKEN }}
-        wait-interval: 30
-    - name: Find firmware binaries
-      if: ${{ env.BINARIES }}
-      id: build_run
-      run: |
-        RUN_ID=$(gh api "repos/${{ github.repository }}/actions/workflows/build.yml/runs?head_sha=${{ github.sha }}&per_page=1" --jq '.workflow_runs[0].id')
-        echo "id=$RUN_ID" >> $GITHUB_OUTPUT
-      env:
-        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-    - name: Download firmware binaries
-      if: ${{ env.BINARIES }}
-      uses: actions/download-artifact@v4
-      with:
-        github-token: ${{ secrets.GITHUB_TOKEN }}
-        repository: ${{ github.repository }}
-        run-id: ${{ steps.build_run.outputs.id }}
-        name: firmware-binary
-        path: docs/build
-    - name: Create shortcuts for firmware binaries
-      if: ${{ env.BINARIES }}
-      working-directory: docs/build
-      run: |
-        for FQBN in esp32.esp32.*; do
-          zip -r $FQBN.zip $FQBN
-          BOARD="${FQBN#esp32.esp32.}"
-          ln -s "$FQBN/flix.ino.merged.bin" "flix.$BOARD.merged.bin"
-          ln -s "$FQBN/flix.ino.bin" "flix.$BOARD.bin"
-          ln -s "$FQBN/flix.ino.bootloader.bin" "flix.$BOARD.bootloader.bin"
-        done
     - name: Upload artifact
       uses: actions/upload-pages-artifact@v3
       with:

Makefile

@@ -1,17 +1,13 @@
-BOARD = esp32:esp32:esp32
+BOARD = esp32:esp32:d1_mini32
 PORT := $(strip $(wildcard /dev/serial/by-id/usb-Silicon_Labs_CP21* /dev/serial/by-id/usb-1a86_USB_Single_Serial_* /dev/cu.usbserial-* /dev/cu.usbmodem*))
-VERSION = $(shell git describe --always --dirty)
 
 export ARDUINO_NETWORK_CONNECTION_TIMEOUT := 1h
 
 build: .core .libs
-	arduino-cli compile flix \
-		--fqbn $(BOARD) \
-		--build-property "build.core_debug_level=1" \
-		--build-property "compiler.cpp.extra_flags=-DVERSION=$(VERSION) $(FLAGS)" $(EXTRA)
+	arduino-cli compile --fqbn $(BOARD) --build-property "build.core_debug_level=1" flix
 
 upload: build
-	arduino-cli upload flix --fqbn $(BOARD) -p "$(PORT)"
+	arduino-cli upload --fqbn $(BOARD) -p "$(PORT)" flix
 
 erase:
 	arduino-cli burn-bootloader --fqbn $(BOARD) -p "$(PORT)" -P esptool
@@ -26,13 +22,13 @@ core .core:
 
 libs .libs:
 	arduino-cli lib update-index
-	ARDUINO_LIBRARY_ENABLE_UNSAFE_INSTALL=1 arduino-cli lib install --git-url 'https://github.com/okalachev/flixperiph.git#dev'
+	arduino-cli lib install "FlixPeriph"
 	arduino-cli lib install "MAVLink"@2.0.25
 	touch .libs
 
 upload_proxy: .core .libs
-	arduino-cli compile tools/espnow-proxy --fqbn $(BOARD)
-	arduino-cli upload tools/espnow-proxy --fqbn $(BOARD) -p "$(PORT)"
+	arduino-cli compile --fqbn $(BOARD) tools/espnow-proxy
+	arduino-cli upload --fqbn $(BOARD) -p "$(PORT)" tools/espnow-proxy
 
 gazebo/build cmake: gazebo/CMakeLists.txt
 	mkdir -p gazebo/build

README.md

@@ -55,12 +55,6 @@ Outdoor flights demo video of the current prototype:
 
 <a href="https://youtu.be/KXlNmvUTi4g"><img width=300 src="https://i3.ytimg.com/vi/KXlNmvUTi4g/maxresdefault.jpg"></a>
 
-### Position control
-
-The position control feature is in development. RoboCamp 2026 demo (using an overhead camera, [sources](https://github.com/xTimop/flix-poscontrol/compare/robolager2026...xTimop:flix-poscontrol:poscontrol)):
-
-<a href="https://youtu.be/369Xowm4HcU"><img width=300 src="https://i3.ytimg.com/vi/369Xowm4HcU/maxresdefault.jpg"></a>
-
 ## Simulation
 
 The simulator is implemented using Gazebo and runs the original Arduino code:

docs/usage.md

@@ -1,48 +1,20 @@
 # Usage: build, setup and flight
 
-To fly Flix quadcopter, you need to upload the firmware to the ESP32 board, and set up the drone for flight.
+To fly Flix quadcopter, you need to build the firmware, upload it to the ESP32 board, and set up the drone for flight.
 
-## Uploading the firmware
-
-You can either use the **prebuilt binaries** or **build the firmware** from sources — this will let you modify the firmware and add new features.
-
-### Prebuilt binaries (the easiest way)
-
-1. Download the latest firmware file using the following links:
-
-   <!-- markdownlint-disable MD044 -->
-   |Type|Boards|Link|
-   |-|-|-|
-   |ESP32|DevKit, D1 Mini|[`quadcopter.dev/flix.esp32.merged.bin`](https://quadcopter.dev/flix.esp32.merged.bin)|
-   |ESP32-S3|Most S3 based|[`quadcopter.dev/flix.esp32s3.merged.bin`](https://quadcopter.dev/flix.esp32s3.merged.bin)|
-   |ESP32-S3 (2MB PSRAM)|S3 Super Mini, S3 Zero (2MB PSRAM)|[`quadcopter.dev/flix.esp32s3.qspi.merged.bin`](https://quadcopter.dev/flix.esp32s3.qspi.merged.bin)|
-   |ESP32-S3 (8/16MB PSRAM)|S3 Zero (8MB PSRAM)|[`quadcopter.dev/flix.esp32s3.opi.merged.bin`](https://quadcopter.dev/flix.esp32s3.opi.merged.bin)|
-   |ESP32-C3|C3 Super Mini|[`quadcopter.dev/flix.esp32c3.merged.bin`](https://quadcopter.dev/flix.esp32c3.merged.bin)|
-   |Flix2|Flix2 board|[`quadcopter.dev/flix.flix2.merged.bin`](https://quadcopter.dev/flix.flix2.merged.bin)|
-   <!-- markdownlint-enable MD044 -->
-
-2. Flash your ESP32 board using [ESP32 Web Flasher](https://www.espboards.dev/tools/program/):
-
-   <img src="img/web-flasher.png" width="400">
-
-   * Connect the board to your computer, press *Connect to ESP*, choose the serial port.
-   * Go to the *Flash* tab.
-   * Choose the downloaded firmware file, set *Flash address* to *0* (important).
-   * Click *Program* button and wait until the process is finished.
-
-### Building from sources (flexible)
-
-You can build and upload the firmware using either **Arduino IDE** (easier for beginners) or **command line**.
-
-Get the sources using git:
+To get the firmware sources, clone the repository using git:
 
 ```bash
 git clone https://github.com/okalachev/flix.git && cd flix
 ```
 
-Beginners can [download the sources as a ZIP archive](https://github.com/okalachev/flix/archive/refs/heads/master.zip).
+Beginners can [download the source code as a ZIP archive](https://github.com/okalachev/flix/archive/refs/heads/master.zip).
 
-#### Arduino IDE (Windows, Linux, macOS)
+## Building the firmware
+
+You can build and upload the firmware using either **Arduino IDE** (easier for beginners) or **command line**.
+
+### Arduino IDE (Windows, Linux, macOS)
 
 <img src="img/arduino-ide.png" width="400" alt="Flix firmware open in Arduino IDE">
 
@@ -57,7 +29,7 @@ Beginners can [download the sources as a ZIP archive](https://github.com/okalach
 7. Set *Tools* ⇒ *Core Debug Level* to *Error* to see the errors in the serial console. Set *Tools* ⇒ *USB CDC on Boot* to *Enabled* for ESP32-S3/ESP32-C3 boards.
 8. [Build and upload](https://docs.arduino.cc/software/ide-v2/tutorials/getting-started/ide-v2-uploading-a-sketch) the firmware using Arduino IDE.
 
-#### Command line (Windows, Linux, macOS)
+### Command line (Windows, Linux, macOS)
 
 1. [Install Arduino CLI](https://arduino.github.io/arduino-cli/installation/).
 
@@ -99,6 +71,32 @@ See other available Make commands in [Makefile](../Makefile).
 
 ## Before first flight
 
+### Choose the IMU model
+
+In case if using different IMU model than MPU9250, change `imu` variable declaration in the `imu.ino`:
+
+```cpp
+ICM20948 imu(SPI);  // For ICM-20948 via SPI
+// or
+MPU6050 imu(Wire);  // For MPU-6050 via I2C
+```
+
+If using non-default SPI pins, pass SCK, MISO, and MOSI pin numbers to `SPI.begin` call and SS pin to `imu` constructor like that:
+
+```cpp
+ICM20948(SPI, <SS>);
+// ...
+SPI.begin(<SCK>, <MISO>, <MOSI>);
+imu.begin();
+```
+
+If using non-default I2C pins, pass SDA and SCL pin numbers to `Wire.setPins` call like that:
+
+```cpp
+Wire.begin(<SDA>, <SCL>);
+imu.begin();
+```
+
 ### Connect using QGroundControl
 
 QGroundControl is a ground control station software that can be used to monitor and control the drone.
@@ -139,17 +137,6 @@ The drone is configured using parameters. To access and modify them, go to the Q
 
 You can also work with parameters using `p` command in the console. Parameter names are case-insensitive.
 
-### Configure the IMU
-
-1. Configure the following parameters for the IMU:
-   * `IMU_MODEL` — IMU model (1 for MPU-9250/MPU-6500, 2 for ICM-20948, 3 for MPU-6050, 4 for ICM-40609-D).
-   * `IMU_BUS` — communication bus (0 for SPI, 1 for I²C).
-   * `IMU_PIN_SCK`, `IMU_PIN_MISO`, `IMU_PIN_MOSI`, `IMU_PIN_CS` — SPI pin numbers.
-   * `IMU_PIN_SCL`, `IMU_PIN_SDA` — I²C pin numbers.
-   * `IMU_PIN_INT` — IMU data ready pin number (-1 if not used).
-2. Reboot the drone.
-3. Check the IMU is working using `imu` command in the console (should print `status: OK`).
-
 ### Define IMU orientation
 
 The IMU orientation (relative to the drone's axes) is defined using the parameters: `IMU_ROT_ROLL`, `IMU_ROT_PITCH`, and `IMU_ROT_YAW`.
@@ -178,9 +165,9 @@ Before flight you need to calibrate the accelerometer:
 
 If using non-default motor pins, set the pin numbers using the parameters: `MOTOR_PIN_FL`, `MOTOR_PIN_FR`, `MOTOR_PIN_RL`, `MOTOR_PIN_RR` (front-left, front-right, rear-left, rear-right respectively).
 
-#### Brushless motors
+Certain ESP32 models (such as ESP32-S3 and ESP32-C3) support a lower maximum PWM frequency; on these boards the parameter `MOT_PWM_FREQ` should be set to 38000 Hz.
 
-If using brushless motors with ESCs:
+If using brushless motors and ESCs:
 
 1. Set the appropriate PWM using the parameters: `MOT_PWM_STOP`, `MOT_PWM_MIN`, and `MOT_PWM_MAX` (1000, 1000, and 2000 is typical).
 2. Decrease the PWM frequency using the `MOT_PWM_FREQ` parameter (400 is typical).
@@ -188,7 +175,7 @@ If using brushless motors with ESCs:
 > [!CAUTION]
 > **Remove the props when configuring the motors!** If improperly configured, you may not be able to stop them.
 
-### Battery voltage monitoring (optional)
+### Battery voltage monitoring
 
 ESP32 ADC can measure only up to 3.3 V, so you need to use a voltage divider to monitor the battery voltage. To enable voltage measurement, set the following parameters:
 
@@ -385,7 +372,7 @@ To setup ESP-NOW communication:
 5. Click *Save*, click *Connect*. QGroundControl should connect to the drone using ESP-NOW and begin showing the telemetry.
 
 > [!TIP]
-> Make sure Arduino IDE is not running when using ESP-NOW proxy board, as it may block the serial port.
+> Make sure Arduino IDE is not running when using ESP-NOW proxy board, as it may block it.
 
 ## Flight log
 

docs/user.md

@@ -4,15 +4,6 @@ This page contains user-built drones based on the Flix project. Publish your pro
 
 ---
 
-Author: [Oleg1405](https://t.me/Oleg1405).<br>
-Description: ESP32 Mini, MPU-6500 IMU, boost converter, BT2.0 power connector, 65 mm props, BetaFPV ELRS Lite Receiver, Radiomaster Pocket + Mavlink Joystick (Android) control.
-
-<img src="img/user/oleg1405/1.jpg" height=300>
-
-[Flight video](https://www.youtube.com/shorts/rbXV4sHbpso).
-
----
-
 Author: Alican Erüst.<br>
 Description: QX95 mm frame, 55 mm propellers, 3.7 V 25C 1050 mAh LiPo battery, MPU6050 IMU, Logitech F310 gamepad controller, with a total quadcopter weight of 66 g.
 

flix/cli.ino

@@ -9,7 +9,7 @@
 #include "filter.h"
 
 extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
-extern const int RAW, ACRO, STAB, AUTO;
+extern const int RAW, ACRO, STAB, AUTO, POS;
 extern const int W_AP, W_STA, W_ESPNOW;
 extern float t, dt, loopRate;
 extern uint16_t channels[16];
@@ -134,6 +134,8 @@ void doCommand(String str, bool echo = false) {
 		mode = ACRO;
 	} else if (command == "auto") {
 		mode = AUTO;
+	} else if (command == "pos") {
+		mode = POS;
 	} else if (command == "rc") {
 		print("channels: ");
 		for (int i = 0; i < 16; i++) {
@@ -191,10 +193,7 @@ void doCommand(String str, bool echo = false) {
 		print("Free heap: %d KB\n", ESP.getFreeHeap() / 1024);
 		print("PSRAM: %d KB\n", ESP.getPsramSize() / 1024);
 		print("Free PSRAM: %d KB\n", ESP.getFreePsram() / 1024);
-#ifdef VERSION
-		print("Version: %s\n", STRINGIFY(VERSION));
-#endif
-		print("Build date: " __DATE__ " " __TIME__ "\n");
+		print("Firmware: " __DATE__ " " __TIME__ "\n");
 		// Print tasks table
 		print("Num  Task                MinSt  Prio  Core  CPU%%\n");
 		int taskCount = uxTaskGetNumberOfTasks();

flix/config.h

@@ -1,27 +0,0 @@
-// Copyright (c) 2026 Oleg Kalachev <okalachev@gmail.com>
-// Repository: https://github.com/okalachev/flix
-
-// Parameter defaults
-
-#pragma once
-
-void setDefaults() {
-	// Set defaults here
-
-	#if defined(CONFIG_IDF_TARGET_ESP32S3) || defined(CONFIG_IDF_TARGET_ESP32C3)
-		pwmFrequency = 38000;
-	#endif
-
-	#ifdef FLIX2
-		imuModel = 4; // ICM-40609-D
-		imuIntPin = 10;
-		imuCsPin = 14;
-
-		motorPins[MOTOR_REAR_LEFT] = 41;
-		motorPins[MOTOR_REAR_RIGHT] = 7;
-		motorPins[MOTOR_FRONT_RIGHT] = 18;
-		motorPins[MOTOR_FRONT_LEFT] = 38;
-
-		voltagePin = 3;
-	#endif
-}

flix/control.ino

@@ -9,28 +9,54 @@
 #include "filter.h"
 #include "util.h"
 
-const int RAW = 0, ACRO = 1, STAB = 2, AUTO = 3; // flight modes
+#define PITCHRATE_P 0.05
+#define PITCHRATE_I 0.2
+#define PITCHRATE_D 0.001
+#define PITCHRATE_I_LIM 0.3
+#define ROLLRATE_P PITCHRATE_P
+#define ROLLRATE_I PITCHRATE_I
+#define ROLLRATE_D PITCHRATE_D
+#define ROLLRATE_I_LIM PITCHRATE_I_LIM
+#define YAWRATE_P 0.3
+#define YAWRATE_I 0.0
+#define YAWRATE_D 0.0
+#define YAWRATE_I_LIM 0.3
+#define ROLL_P 6
+#define ROLL_I 0
+#define ROLL_D 0
+#define PITCH_P ROLL_P
+#define PITCH_I ROLL_I
+#define PITCH_D ROLL_D
+#define YAW_P 3
+#define PITCHRATE_MAX radians(360)
+#define ROLLRATE_MAX radians(360)
+#define YAWRATE_MAX radians(300)
+#define TILT_MAX radians(30)
+#define RATES_D_LPF_ALPHA 0.2 // cutoff frequency ~ 40 Hz
+
+const int RAW = 0, ACRO = 1, STAB = 2, AUTO = 3, POS = 4;
 int mode = STAB;
 bool armed = false;
 
 Quaternion attitudeTarget;
 Vector ratesTarget;
 Vector ratesExtra; // feedforward rates
-Vector torqueTarget; // 0 - no torque, 1 - maximum torque
+Vector torqueTarget;
 float thrustTarget;
 
-PID rollRatePID(0.05, 0.2, 0.001, 0.3, 0.2);
-PID pitchRatePID(0.05, 0.2, 0.001, 0.3, 0.2);
-PID yawRatePID(0.3, 0, 0, 0.3);
-PID rollPID(6);
-PID pitchPID(6);
-PID yawPID(3);
-Vector maxRate(radians(360), radians(360), radians(360));
-float tiltMax = radians(30);
+PID rollRatePID(ROLLRATE_P, ROLLRATE_I, ROLLRATE_D, ROLLRATE_I_LIM, RATES_D_LPF_ALPHA);
+PID pitchRatePID(PITCHRATE_P, PITCHRATE_I, PITCHRATE_D, PITCHRATE_I_LIM, RATES_D_LPF_ALPHA);
+PID yawRatePID(YAWRATE_P, YAWRATE_I, YAWRATE_D);
+PID rollPID(ROLL_P, ROLL_I, ROLL_D);
+PID pitchPID(PITCH_P, PITCH_I, PITCH_D);
+PID yawPID(YAW_P, 0, 0);
+Vector maxRate(ROLLRATE_MAX, PITCHRATE_MAX, YAWRATE_MAX);
+float tiltMax = TILT_MAX;
 int flightModes[] = {STAB, STAB, STAB}; // map for rc mode switch
 
 extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
 extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlMode;
+extern Vector position, positionTarget;
 
 void control() {
 	interpretControls();
@@ -54,7 +80,18 @@ void interpretControls() {
 
 	thrustTarget = controlThrottle;
 
-	if (mode == STAB) {
+	if (mode == POS) {
+		if (controlRoll != 0 || controlPitch != 0) {
+			positionTarget.x = NAN;
+			positionTarget.y = NAN;
+		} else if (invalid(positionTarget.x) || invalid(positionTarget.y)) {
+			// reset position target
+			positionTarget.x = position.x;
+			positionTarget.y = position.y;
+		}
+	}
+
+	if (mode == STAB || (mode == POS && invalid(positionTarget.x))) {
 		float yawTarget = attitudeTarget.getYaw();
 		if (!armed || invalid(yawTarget) || controlYaw != 0) yawTarget = attitude.getYaw(); // reset yaw target
 		attitudeTarget = Quaternion::fromEuler(Vector(controlRoll * tiltMax, controlPitch * tiltMax, yawTarget));

flix/estimate.ino

@@ -15,7 +15,7 @@ bool landed;
 float accWeight = 0.003;
 float levelWeight = 0.0002;
 LowPassFilter<Vector> ratesFilter(0.2); // cutoff frequency ~ 40 Hz
-NotchFilter<Vector> ratesNotch(382, 40);
+NotchFilter<Vector> ratesNotch(382, 0);
 
 void setupEstimate() {
 	print("Setup estimation\n");
@@ -26,6 +26,7 @@ void estimate() {
 	applyGyro();
 	applyAcc();
 	applyLevel();
+	estimatePosition();
 }
 
 void applyGyro() {

flix/imu.ino

@@ -4,17 +4,12 @@
 // Work with the IMU sensor
 
 #include <SPI.h>
-#include <Wire.h>
 #include <FlixPeriph.h>
 #include "vector.h"
 #include "filter.h"
 #include "util.h"
 
-IMU *imu;
-int imuModel = -1; // 1 - MPU9250, 2 - ICM20948, 3 - MPU6050, 4 - ICM40609D
-int imuBus = 0; // 0 - SPI, 1 - I2C
-int imuSckPin = SCK, imuMisoPin = MISO, imuMosiPin = MOSI, imuCsPin = SS, imuIntPin = -1;
-int imuSdaPin = SDA, imuSclPin = SCL;
+MPU9250 imu(SPI);
 Vector imuRotation(0, 0, PI / 2); // imu orientation as Euler angles
 
 Vector gyro; // gyroscope output, rad/s
@@ -28,35 +23,22 @@ LowPassFilter<Vector> gyroBiasFilter(0.001);
 
 void setupIMU() {
 	print("Setup IMU\n");
-	free(imu);
-	if (imuModel == 3) imuBus = 1; // MPU6050 is I2C only
-
-	if (imuBus == 0) {
-		// SPI connection
-		SPI.begin(imuSckPin, imuMisoPin, imuMosiPin);
-		imu = IMU::create(imuModel, SPI, imuCsPin, imuIntPin);
-	} else {
-		// I2C connection
-		Wire.setPins(imuSdaPin, imuSclPin);
-		imu = IMU::create(imuModel, Wire, imuIntPin);
-	}
-
-	imu->begin();
+	imu.begin();
 	configureIMU();
 }
 
 void configureIMU() {
-	imu->setAccelRange(IMU::ACCEL_RANGE_4G);
-	imu->setGyroRange(IMU::GYRO_RANGE_2000DPS);
-	imu->setDLPF(IMU::DLPF_MAX);
-	imu->setRate(IMU::RATE_1KHZ_APPROX);
-	imu->setupInterrupt();
+	imu.setAccelRange(imu.ACCEL_RANGE_4G);
+	imu.setGyroRange(imu.GYRO_RANGE_2000DPS);
+	imu.setDLPF(imu.DLPF_MAX);
+	imu.setRate(imu.RATE_1KHZ_APPROX);
+	imu.setupInterrupt();
 }
 
 void readIMU() {
-	imu->waitForData();
-	imu->getGyro(gyro.x, gyro.y, gyro.z);
-	imu->getAccel(acc.x, acc.y, acc.z);
+	imu.waitForData();
+	imu.getGyro(gyro.x, gyro.y, gyro.z);
+	imu.getAccel(acc.x, acc.y, acc.z);
 	calibrateGyroOnce();
 
 	// Apply scale and bias
@@ -78,7 +60,7 @@ void calibrateGyroOnce() {
 
 void calibrateAccel() {
 	print("Calibrating accelerometer\n");
-	imu->setAccelRange(IMU::ACCEL_RANGE_2G); // the most sensitive mode
+	imu.setAccelRange(imu.ACCEL_RANGE_2G); // the most sensitive mode
 
 	print("1/6 Place level [8 sec]\n");
 	pause(8);
@@ -112,9 +94,9 @@ void calibrateAccelOnce() {
 	// Compute the average of the accelerometer readings
 	acc = Vector(0, 0, 0);
 	for (int i = 0; i < samples; i++) {
-		imu->waitForData();
+		imu.waitForData();
 		Vector sample;
-		imu->getAccel(sample.x, sample.y, sample.z);
+		imu.getAccel(sample.x, sample.y, sample.z);
 		acc = acc + sample;
 	}
 	acc = acc / samples;
@@ -139,18 +121,17 @@ void printIMUCalibration() {
 }
 
 void printIMUInfo() {
-	imu->status() ? print("status: ERROR %d\n", imu->status()) : print("status: OK\n");
-	print("model: %s\n", imu->getModel());
-	print("who am I: 0x%02X\n", imu->whoAmI());
+	imu.status() ? print("status: ERROR %d\n", imu.status()) : print("status: OK\n");
+	print("model: %s\n", imu.getModel());
+	print("who am I: 0x%02X\n", imu.whoAmI());
 	print("rate: %.0f\n", loopRate);
-	print("interrupt mode: %s\n", imuIntPin != -1 ? "pin" : "timer");
-	print("temperature: %.1f °C\n", imu->getTemp());
+	print("temperature: %.1f °C\n", imu.getTemp());
 	print("gyro: %f %f %f\n", gyro.x, gyro.y, gyro.z);
 	print("acc: %f %f %f\n", acc.x, acc.y, acc.z);
-	imu->waitForData();
+	imu.waitForData();
 	Vector rawGyro, rawAcc;
-	imu->getGyro(rawGyro.x, rawGyro.y, rawGyro.z);
-	imu->getAccel(rawAcc.x, rawAcc.y, rawAcc.z);
+	imu.getGyro(rawGyro.x, rawGyro.y, rawGyro.z);
+	imu.getAccel(rawAcc.x, rawAcc.y, rawAcc.z);
 	print("raw gyro: %f %f %f\n", rawGyro.x, rawGyro.y, rawGyro.z);
 	print("raw acc: %f %f %f\n", rawAcc.x, rawAcc.y, rawAcc.z);
 }

flix/log.ino

@@ -6,7 +6,7 @@
 #include "vector.h"
 #include "util.h"
 
-int logMemory = 0; // 0 - RAM, 1 - PSRAM, -1 - disabled
+int logMemory = -1; // 0 - RAM, 1 - PSRAM, -1 - disabled
 float logUsage = 0.5; // fraction of free memory to use for log
 
 struct LogValue {
@@ -68,6 +68,11 @@ LogTopic logTopics[] = {
 		{"attitude.pitch", []() { return attitude.getPitch(); }},
 		{"attitude.yaw", []() { return attitude.getYaw(); }}),
 
+	LogTopic(50,
+		{"position.x", &position.x},
+		{"position.y", &position.y},
+		{"position.z", &position.z}),
+
 	// rc
 	LogTopic(10,
 		{"controlTime", &controlTime, false}, // trigger value
@@ -100,7 +105,7 @@ LogTopic logTopics[] = {
 	LogTopic(5,
 		{"voltage", &voltage},
 		{"temp", &temperatureRead},
-		{"imuTemp", []() { return imu->getTemp(); }}),
+		{"imuTemp", []() { return imu.getTemp(); }}),
 };
 
 void *logBuffer; // buffer for log data

flix/mavlink.ino

@@ -18,7 +18,7 @@ Rate telemetryMotors(10);
 Rate telemetryIMU(15);
 Rate telemetryTopic(10);
 
-float mavlinkTime = NAN; // time of last received message
+bool mavlinkConnected = false;
 String mavlinkPrintBuffer;
 
 void processMavlink() {
@@ -41,7 +41,7 @@ void sendMavlink() {
 		sendMessage(&msg);
 	}
 
-	if (!valid(mavlinkTime)) return; // send only heartbeat until connected
+	if (!mavlinkConnected) return; // send only heartbeat until connected
 
 	if (telemetrySlow) {
 		mavlink_msg_extended_sys_state_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
@@ -128,7 +128,7 @@ void receiveMavlink() {
 	mavlink_status_t status;
 	for (int i = 0; i < len; i++) {
 		if (mavlink_parse_char(MAVLINK_COMM_0, buf[i], &msg, &status)) {
-			mavlinkTime = t;
+			mavlinkConnected = true;
 			handleMavlink(&msg);
 		}
 	}
@@ -196,6 +196,13 @@ void handleMavlink(const void *_msg) {
 		sendMessage(&msg);
 	}
 
+	if (msg.msgid == MAVLINK_MSG_ID_VISION_POSITION_ESTIMATE) {
+		mavlink_vision_position_estimate_t m;
+		mavlink_msg_vision_position_estimate_decode(&msg, &m);
+		Vector pos(m.x, m.y, m.z);
+		correctPosition(pos);
+	}
+
 	if (msg.msgid == MAVLINK_MSG_ID_MISSION_REQUEST_LIST) { // handle to make qgc happy
 		mavlink_mission_request_list_t m;
 		mavlink_msg_mission_request_list_decode(&msg, &m);

flix/motors.ino

@@ -7,7 +7,7 @@
 
 float motors[4]; // normalized motor thrusts in range [0..1]
 
-int motorPins[4] = {12, 13, 14, 15}; // default pin numbers
+int motorPins[4] = {-1, -1, -1, -1}; // default pin numbers
 int pwmFrequency = 78000;
 int pwmResolution = 10;
 int pwmStop = 0;

flix/parameters.ino

@@ -5,16 +5,16 @@
 
 #include <Preferences.h>
 #include "util.h"
+#include "pid.h"
 
 extern int channelZero[16], channelMax[16];
 extern int rollChannel, pitchChannel, throttleChannel, yawChannel, armedChannel, modeChannel;
 extern int rcRxPin, voltagePin;
-extern int wifiMode, wifiLongRange, wifiBroadcast, udpLocalPort, udpRemotePort, espnowChannel;
+extern int wifiMode, wifiLongRange, udpLocalPort, udpRemotePort, espnowChannel;
 extern float rcLossTimeout, descendTime, disarmTilt;
 extern float voltageScale;
 extern LowPassFilter<float> voltageFilter;
-
-#include "config.h"
+extern PID posX_PID, posY_PID;
 
 Preferences storage;
 
@@ -46,7 +46,6 @@ Parameter parameters[] = {
 	{"CTL_Y_RATE_P", &yawRatePID.p},
 	{"CTL_Y_RATE_I", &yawRatePID.i},
 	{"CTL_Y_RATE_D", &yawRatePID.d},
-	{"CTL_Y_RATE_WU", &yawRatePID.windup},
 	{"CTL_Y_RATE_D_A", &yawRatePID.lpf.alpha},
 	{"CTL_R_P", &rollPID.p},
 	{"CTL_R_I", &rollPID.i},
@@ -62,16 +61,13 @@ Parameter parameters[] = {
 	{"CTL_FLT_MODE_0", &flightModes[0]},
 	{"CTL_FLT_MODE_1", &flightModes[1]},
 	{"CTL_FLT_MODE_2", &flightModes[2]},
+	// position
+	{"POS_XY_P", &posX_PID.p, setupPosition},
+	{"POS_XY_I", &posX_PID.i, setupPosition},
+	{"POS_XY_D", &posX_PID.d, setupPosition},
+	{"POS_XY_WU", &posX_PID.windup, setupPosition},
+	{"POS_XY_D_A", &posX_PID.lpf.alpha, setupPosition},
 	// imu
-	{"IMU_MODEL", &imuModel},
-	{"IMU_BUS", &imuBus},
-	{"IMU_PIN_SCK", &imuSckPin},
-	{"IMU_PIN_MISO", &imuMisoPin},
-	{"IMU_PIN_MOSI", &imuMosiPin},
-	{"IMU_PIN_CS", &imuCsPin},
-	{"IMU_PIN_SDA", &imuSdaPin},
-	{"IMU_PIN_SCL", &imuSclPin},
-	{"IMU_PIN_INT", &imuIntPin},
 	{"IMU_ROT_ROLL", &imuRotation.x},
 	{"IMU_ROT_PITCH", &imuRotation.y},
 	{"IMU_ROT_YAW", &imuRotation.z},
@@ -126,7 +122,6 @@ Parameter parameters[] = {
 	{"WIFI_PORT_LOC", &udpLocalPort},
 	{"WIFI_PORT_REM", &udpRemotePort},
 	{"WIFI_LONG_RANGE", &wifiLongRange},
-	{"WIFI_BROADCAST", &wifiBroadcast},
 	// espnow
 	{"ESPNOW_CHANNEL", &espnowChannel},
 	// mavlink
@@ -159,12 +154,11 @@ Parameter parameters[] = {
 	// safety
 	{"SF_RC_LOSS_TIME", &rcLossTimeout},
 	{"SF_DESCEND_TIME", &descendTime},
-	{"SF_DISARM_TILT", &disarmTilt},
+	{"SF_DISARM_TILT", &disarmTilt}
 };
 
 void setupParameters() {
 	print("Setup parameters\n");
-	setDefaults();
 	storage.begin("flix");
 	// Read parameters from storage
 	for (auto &parameter : parameters) {

flix/pid.h

@@ -18,7 +18,7 @@ public:
 
 	LowPassFilter<float> lpf; // low pass filter for derivative term
 
-	PID(float p, float i = 0, float d = 0, float windup = 0, float dAlpha = 1, float dtMax = 0.1) :
+	PID(float p, float i, float d, float windup = 0, float dAlpha = 1, float dtMax = 0.1) :
 		p(p), i(i), d(d), windup(windup), lpf(dAlpha), dtMax(dtMax) {}
 
 	float update(float error) {

flix/position.ino

@@ -0,0 +1,95 @@
+#include "vector.h"
+#include "quaternion.h"
+#include "pid.h"
+#include "util.h"
+
+float mass = 0.065;
+float motorThrust = 0.031 * ONE_G;
+float positionWeight = 0.9;
+float velocityWeight = 0.9;
+
+PID velX_PID(1.0, 0.0, 0.02);
+PID velY_PID(1.0, 0.0, 0.02);
+PID velZ_PID(1.0, 0.0, 0.02);
+
+// PID posX_PID(1.0, 0.0, 0.0);
+// PID posY_PID(1.0, 0.0, 0.0);
+// PID posZ_PID(1.0, 0.0, 0.0);
+
+PID posX_PID(0.1, 0.0, 0.0);
+PID posY_PID(0.1, 0.0, 0.0);
+PID posZ_PID(0.1, 0.0, 0.0);
+
+Vector acceleration;
+Vector velocity;
+Vector position;
+Vector velocityTarget(NAN, NAN, NAN);
+Vector positionTarget(NAN, NAN, NAN);
+
+extern Quaternion attitudeTarget;
+extern float thrustTarget;
+
+void setupPosition() {
+	// TODO: posY_PID = posX_PID;
+	// posX_PID.copy(posY_PID);
+	posY_PID.p = posX_PID.p;
+	posY_PID.i = posX_PID.i;
+	posY_PID.d = posX_PID.d;
+}
+
+void estimatePosition() {
+	acceleration = Quaternion::rotateVector(acceleration, attitude) + Vector(0, 0, -ONE_G);
+	velocity += acceleration * dt;
+	position += velocity * dt;
+}
+
+void correctPosition(Vector& pos) {
+	// position += (pos - position) * positionWeight;
+	position = pos;
+	// positionUpdated = true;
+
+	if (invalid(positionTarget.x) || invalid(positionTarget.y)) return;
+
+	attitudeTarget.setPitch(posX_PID.update(positionTarget.x - position.x));
+	attitudeTarget.setRoll(posY_PID.update(positionTarget.y - position.y));
+}
+
+void correctVelocity(Vector& vel) {
+	velocity += (vel - velocity) * velocityWeight;
+}
+
+void controlVelocity() {
+	Vector accelerationTarget(
+		velX_PID.update(velocityTarget.x - velocity.x),
+		velY_PID.update(velocityTarget.y - velocity.y),
+		velZ_PID.update(velocityTarget.z - velocity.z)
+	);
+
+	Vector thrustVector = (accelerationTarget + Vector(0, 0, ONE_G)) * mass;
+
+	const Vector up(0, 0, 1);
+
+	attitudeTarget = Quaternion::fromBetweenVectors(up, thrustVector);
+	float maxThrust = motorThrust * 4; // 4 motors
+	thrustTarget = thrustVector.norm() / maxThrust;
+}
+
+void controlPosition() {
+	if (positionTarget.invalid()) return;
+
+	velocityTarget = Vector(
+		posX_PID.update(positionTarget.x - position.x),
+		posY_PID.update(positionTarget.y - position.y),
+		posZ_PID.update(positionTarget.z - position.z)
+	);
+
+	controlVelocity();
+}
+
+void controlPositionSimple() {
+	if (positionTarget.invalid()) return;
+
+	// straight attitude target control
+	attitudeTarget.setPitch(posX_PID.update(positionTarget.x - position.x));
+	attitudeTarget.setRoll(posY_PID.update(positionTarget.y - position.y));
+}

flix/util.h

@@ -11,8 +11,6 @@
 const float ONE_G = 9.80665;
 extern float t;
 
-#define STRINGIFY(x) __STRINGIFY(x)
-
 float mapf(float x, float in_min, float in_max, float out_min, float out_max) {
 	return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
 }
@@ -113,7 +111,7 @@ struct Value {
 class Rate {
 public:
 	float rate;
-	float last = -INFINITY;
+	float last = 0;
 	Rate(float rate) : rate(rate) {}
 
 	operator bool() {

flix/wifi.ino

@@ -17,7 +17,6 @@ const int W_DISABLED = 0, W_AP = 1, W_STA = 2, W_ESPNOW = 3;
 int wifiMode = W_AP;
 
 int wifiLongRange = 0;
-int wifiBroadcast = 0; // 0 - broadcast until connected, 1 - always broadcast
 int udpLocalPort = 14550;
 int udpRemotePort = 14550;
 IPAddress udpRemoteIP = "255.255.255.255";
@@ -65,8 +64,7 @@ void sendWiFi(const uint8_t *buf, int len) {
 
 	if (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return;
 
-	bool broadcast = wifiBroadcast || !(t - mavlinkTime < 5); // broadcast if lost connection
-	udp.beginPacket(broadcast ? IPAddress(255, 255, 255, 255) : udpRemoteIP, udpRemotePort);
+	udp.beginPacket(udpRemoteIP, udpRemotePort);
 	udp.write(buf, len);
 	udp.endPacket();
 }
@@ -91,7 +89,7 @@ void printWiFiInfo() {
 		print("MAC: %s\n", WiFi.softAPmacAddress().c_str());
 		print("Peer MAC: %s\n", MacAddress(espnow.addr()).toString().c_str());
 		print("Encrypted: %d\n", espnow.isEncrypted());
-		print("Channel: %d\n", espnow.getChannel());
+		print("Channel: %d\n", WiFi.channel());
 		print("Lost packets: %d\n", espnow.lost);
 	} else if (WiFi.getMode() == WIFI_MODE_AP) {
 		print("Mode: Access Point (AP)\n");
@@ -115,7 +113,7 @@ void printWiFiInfo() {
 	} else {
 		print("Mode: Disabled\n");
 	}
-	print("MAVLink connected: %d\n", valid(mavlinkTime));
+	print("MAVLink connected: %d\n", mavlinkConnected);
 }
 
 void configWiFi(int mode, const char *first, const char *second) {

gazebo/flix.h

@@ -21,9 +21,6 @@ extern float motors[4];
 Vector gyro, acc, imuRotation;
 Vector accBias, gyroBias, accScale(1, 1, 1);
 LowPassFilter<Vector> gyroBiasFilter(0);
-int imuModel = 1, imuBus = 0;
-int imuSckPin = 0, imuMisoPin = 0, imuMosiPin = 0, imuCsPin = -1, imuIntPin = -1;
-int imuSdaPin = 0, imuSclPin = 0;
 
 // declarations
 void step();
@@ -96,4 +93,4 @@ void setWiFiMode(const String& mode) { print("Skip WiFi mode set\n"); };
 class IMU {
 public:
 	float getTemp() { return 0; }
-} *imu;
+} imu;

tools/espnow-proxy/espnow-proxy.ino

@@ -11,18 +11,22 @@
 #include <Preferences.h>
 #include "../../flix/util.h"
 
-const int CHANNEL = 6;
+const bool DISABLE_SWARM = true;
+const int CHANNEL = -1; // -1 means auto search
 char key[ESP_NOW_KEY_LEN + 1] = {0}; // with trailing null
 
 Preferences storage;
 
 std::vector<ESPNOWSerial *> peers;
+bool stop = false;
 
 void onNewPeer(const esp_now_recv_info_t *info, const uint8_t *data, int len, void *arg) {
 	if (len != 4 || memcmp(data, "flix", 4) != 0) return; // check if discovery message
 
+	if (stop) return;
+
 	Serial.printf("New peer: " MACSTR "\n", MAC2STR(info->src_addr));
-	ESPNOWSerial *link = new ESPNOWSerial(info->src_addr, CHANNEL, WIFI_IF_AP);
+	ESPNOWSerial *link = new ESPNOWSerial(info->src_addr, WiFi.channel(), WIFI_IF_STA);
 	link->begin();
 	link->setKey((const uint8_t *)key);
 	peers.push_back(link);
@@ -30,9 +34,8 @@ void onNewPeer(const esp_now_recv_info_t *info, const uint8_t *data, int len, vo
 
 void setup() {
 	Serial.begin(115200);
-	WiFi.mode(WIFI_AP);
+	WiFi.mode(WIFI_STA);
 	WiFi.setSleep(false);
-	WiFi.setChannel(CHANNEL);
 
 	ESP_NOW.onNewPeer(onNewPeer, NULL);
 	ESP_NOW.begin();
@@ -43,12 +46,6 @@ void setup() {
 		storage.putString("key", key);
 	}
 	strcpy(key, storage.getString("key").c_str());
-
-	// Discover the first peer
-	while (peers.empty()) {
-		Serial.printf("espnow %s %s\n", WiFi.softAPmacAddress().c_str(), key);
-		delay(500);
-	}
 }
 
 void generateRandomKey() {
@@ -61,6 +58,20 @@ void generateRandomKey() {
 void loop() {
 	uint8_t buf[5000];
 
+	static int channelIndex = 0;
+	static const int channels[] = {6, 11, 1, 2, 6, 11, 3, 4, 5, 6, 1, 11, 8, 6, 9, 10, 11, 6, 1, 12, 13}; // 6, 1 and 11 are most common
+
+	static unsigned long last = 0;
+	if (!stop && millis() - last > 500) {
+		// Change search channel
+		last = millis();
+		channelIndex = (channelIndex + 1) % (sizeof(channels) / sizeof(channels[0]));
+		int channel = CHANNEL < 0 ? channels[channelIndex] : CHANNEL;
+		Serial.printf("Run on Flix: espnow %s %s\n", WiFi.STA.macAddress().c_str(), key);
+		Serial.printf("Searching channel %d\n", channel);
+		WiFi.setChannel(channel);
+	}
+
 	// Send from Serial to ESP-NOW
 	while (Serial.available() > 0) {
 		int b = Serial.read();
@@ -81,6 +92,15 @@ void loop() {
 	// Send from ESP-NOW to Serial
 	for (ESPNOWSerial *link : peers) {
 		int len = link->read(buf, sizeof(buf));
+		if (!stop) {
+			for (int i = 0; i < len; i++) {
+				if (buf[i] == MAVLINK_STX) {
+					// Got MAVLink message, stop discovery
+					Serial.printf("Received MAVLink from " MACSTR "\n", MAC2STR(link->addr()));
+					if (DISABLE_SWARM) stop = true;
+				}
+			}
+		}
 		if (len > 0) {
 			Serial.write(buf, len);
 		}