Position control draft

(Setting alpha = 1 efficiently disables the filter.)
Filtering does more harm than good in voltage monitoring.

.github/workflows/build.yml

@@ -27,6 +27,8 @@ jobs:
       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
       run: tools/check_c_cpp_properties.py
 

Makefile

@@ -1,10 +1,10 @@
-BOARD = esp32:esp32:d1_mini32:DebugLevel=error
+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*))
 
 export ARDUINO_NETWORK_CONNECTION_TIMEOUT := 1h
 
 build: .core .libs
-	arduino-cli compile --fqbn $(BOARD) flix
+	arduino-cli compile --fqbn $(BOARD) --build-property "build.core_debug_level=1" flix
 
 upload: build
 	arduino-cli upload --fqbn $(BOARD) -p "$(PORT)" flix

README.md

@@ -84,7 +84,7 @@ Additional articles:
 |*Boost converter (optional, for more stable power supply)*|*5V output*|<img src="docs/img/buck-boost.jpg" width=100>|1|
 |Motor|8520 3.7V brushed motor.<br>Motor with exact 3.7V voltage is needed, not ranged working voltage (3.7V — 6V).<br>Make sure the motor shaft diameter and propeller hole diameter match!|<img src="docs/img/motor.jpeg" width=100>|4|
 |Propeller|55 mm or 65 mm|<img src="docs/img/prop.jpg" width=100>|4|
-|MOSFET (transistor)|100N03A or [analog](https://t.me/opensourcequadcopter/33)|<img src="docs/img/100n03a.jpg" width=100>|4|
+|MOSFET (transistor)|UMW 100N03A or [analog](https://t.me/opensourcequadcopter/33).<br>Warning: don't use KIA 100N03A or other manufacturers, they might not work!|<img src="docs/img/100n03a.jpg" width=100>|4|
 |Pull-down resistor<br>Voltage measurement resistor|10 kΩ|<img src="docs/img/resistor10k.jpg" width=100>|6|
 |3.7V Li-Po battery|LW 952540 (or any compatible by the size).<br>Make sure the battery has enough discharge rate — 25C or more!|<img src="docs/img/battery.jpg" width=100>|1|
 |Battery connector cable|MX2.0 2P female|<img src="docs/img/mx.png" width=100>|1|

docs/usage.md

@@ -25,7 +25,7 @@ You can build and upload the firmware using either **Arduino IDE** (easier for b
    * `FlixPeriph`, the latest version.
    * `MAVLink`, version 2.0.25.
 5. Open the `flix/flix.ino` sketch from downloaded firmware sources in Arduino IDE.
-6. Connect your ESP32 board to the computer and choose correct board type in Arduino IDE (*WEMOS D1 MINI ESP32* for ESP32 Mini) and the port.
+6. Connect your ESP32 board to the computer and choose correct board type in Arduino IDE (*WEMOS D1 MINI ESP32* for ESP32 Mini, *ESP32S3 Dev Module* for ESP32-S3 Super Mini) and the port.
 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.
 
@@ -61,7 +61,7 @@ You can build and upload the firmware using either **Arduino IDE** (easier for b
    For ESP32-S3/ESP32-C3 boards, set the appropriate [FQBN](https://docs.arduino.cc/arduino-cli/FAQ/#whats-the-fqbn-string) using `BOARD` parameter:
 
    ```bash
-   make BOARD=esp32:esp32:esp32s3:DebugLevel=error,FlashSize=4M,CDCOnBoot=cdc upload
+   make BOARD=esp32:esp32:esp32s3:FlashSize=4M,CDCOnBoot=cdc upload
    ```
 
 See other available Make commands in [Makefile](../Makefile).
@@ -76,8 +76,25 @@ See other available Make commands in [Makefile](../Makefile).
 In case if using different IMU model than MPU9250, change `imu` variable declaration in the `imu.ino`:
 
 ```cpp
-ICM20948 imu(SPI);  // For ICM-20948
-MPU6050 imu(Wire);  // For MPU-6050
+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
@@ -105,7 +122,7 @@ To access the console using serial port:
 To access the console using QGroundControl:
 
 1. Connect to the drone using QGroundControl app.
-2. Go to the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console*.
+2. Go to the QGroundControl menu ⇒ *Analyze Tools* ⇒ *MAVLink Console*.
 
 <img src="img/cli.png" width="400">
 
@@ -198,7 +215,7 @@ After this setup, you should see the battery voltage in QGroundControl top panel
 
 ## Setup remote control
 
-There are several ways to control the drone's flight: using **smartphone** (Wi-Fi), using **SBUS remote control**, or using **USB remote control** (Wi-Fi).
+There are several ways to control the drone's flight: using **smartphone** (Wi-Fi), using **SBUS remote control**, or using **USB remote control** (Wi-Fi/ESP-NOW).
 
 ### Control with a smartphone
 
@@ -243,7 +260,7 @@ If your drone doesn't have RC receiver installed, you can use USB remote control
 3. Power up the drone.
 4. Connect your computer to the appeared `flix` Wi-Fi network (password: `flixwifi`).
 5. Launch QGroundControl app. It should connect and begin showing the drone's telemetry automatically.
-6. Go the the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Joystick*. Calibrate you USB remote control there.
+6. Go to the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Joystick*. Calibrate your USB remote control there.
 7. Use the USB remote control to fly the drone!
 
 ## Flight
@@ -333,13 +350,13 @@ To setup ESP-NOW communication:
 
 1. Flash the second ESP32 board with ESP-NOW proxy sketch: [`tools/espnow-proxy/espnow-proxy.ino`](../tools/espnow-proxy/espnow-proxy.ino). Use Arduino IDE or command line: `make upload_proxy`.
 
-2. Open Serial Monitor or use `make monitor` command. The ESP32 will print its MAC address and generated encryption key, for example:
+2. Open Serial Monitor in Arduino IDE or use `make monitor` command. The ESP32 will print its MAC address and generated encryption key, for example:
 
    ```
    espnow 7a:c8:e3:eb:bf:e9 &PiuSysxP9+$L&5E
    ```
 
-   Run this line as a console command on each drone you want to bind to this proxy board. [The maximum number](https://github.com/espressif/esp-idf/blob/e95cab4be8fd293e3f3323181e7a2280874da6f7/components/esp_wifi/include/esp_now.h#L32-L33) of simultaneously connected drones is 20 (unencrypted) io 6 (encrypted).
+   Run this line as a console command on each drone you want to bind to this proxy board. [The maximum number](https://github.com/espressif/esp-idf/blob/e95cab4be8fd293e3f3323181e7a2280874da6f7/components/esp_wifi/include/esp_now.h#L32-L33) of simultaneously connected drones is 20 (unencrypted) or 6 (encrypted).
 
 3. Set the `WIFI_MODE` parameter to `3` on the drone:
 
@@ -352,11 +369,14 @@ To setup ESP-NOW communication:
    * Type: Serial.
    * Serial Port: choose the port of the proxy ESP32 board, e. g. `/dev/cu.usbserial-0001`.
    * Baud Rate: 115200.
-5. Click *Save*. QGroundControl should connect to the drone using ESP-NOW and begin showing the telemetry.
+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 it.
 
 ## Flight log
 
-After the flight, you can download the flight log for analysis wirelessly. Use the following command on your computer for that:
+After the flight, you can download the flight log wirelessly for analysis. Use the following command on your computer for that:
 
 ```bash
 make log

docs/user.md

@@ -4,6 +4,15 @@ This page contains user-built drones based on the Flix project. Publish your pro
 
 ---
 
+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.
+
+<img src="img/user/alicanerus/1.jpg" height=200> <img src="img/user/alicanerus/2.jpg" height=200> <img src="img/user/alicanerus/3.jpg" height=200>
+
+[Flight video](https://drive.google.com/file/d/1k0WeWTKnCAfaugkX7LcmNxsUuq79RL8Z/view?usp=sharing).
+
+---
+
 Author: [Неруш Михаил](https://t.me/NerushMV).<br>
 Description: custom frame made of 4 mm plywood, 8520 brushed motors, 75 mm propellers, MPU-6500. FlySky FS-i6X with ESP32-based adapter for ESP-NOW communication (using PPM output).<br>
 Sources and materials: [link](https://drive.google.com/drive/folders/1uWiDcuorLrtVs_IIR7Y13omij-7Q1nx8).

flix/cli.ino

@@ -6,10 +6,10 @@
 #include "pid.h"
 #include "vector.h"
 #include "util.h"
-#include "lpf.h"
+#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];
@@ -50,8 +50,8 @@ const char* motd =
 "sta <ssid> <password> - configure Wi-Fi client mode\n"
 "espnow <mac> [<key>] - configure ESP-NOW peer\n"
 "mot - show motor output\n"
+"mfr/mfl/mrr/mrl [<thrust>] - test motor (remove props)\n"
 "log [dump] - print log header [and data]\n"
-"mfr, mfl, mrr, mrl - test motor (remove props)\n"
 "log - show log info\n"
 "log header - show log header\n"
 "log reset - reset log\n"
@@ -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++) {
@@ -176,13 +178,13 @@ void doCommand(String str, bool echo = false) {
 	} else if (command == "ca") {
 		calibrateAccel();
 	} else if (command == "mfr") {
-		testMotor(MOTOR_FRONT_RIGHT);
+		testMotor(MOTOR_FRONT_RIGHT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
 	} else if (command == "mfl") {
-		testMotor(MOTOR_FRONT_LEFT);
+		testMotor(MOTOR_FRONT_LEFT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
 	} else if (command == "mrr") {
-		testMotor(MOTOR_REAR_RIGHT);
+		testMotor(MOTOR_REAR_RIGHT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
 	} else if (command == "mrl") {
-		testMotor(MOTOR_REAR_LEFT);
+		testMotor(MOTOR_REAR_LEFT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
 	} else if (command == "sys") {
 #ifdef ESP32
 		print("Chip: %s\n", ESP.getChipModel());

flix/control.ino

@@ -6,7 +6,7 @@
 #include "vector.h"
 #include "quaternion.h"
 #include "pid.h"
-#include "lpf.h"
+#include "filter.h"
 #include "util.h"
 
 #define PITCHRATE_P 0.05
@@ -34,7 +34,7 @@
 #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; // flight modes
+const int RAW = 0, ACRO = 1, STAB = 2, AUTO = 3, POS = 4;
 int mode = STAB;
 bool armed = false;
 
@@ -56,6 +56,7 @@ 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();
@@ -79,7 +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

@@ -5,7 +5,7 @@
 
 #include "quaternion.h"
 #include "vector.h"
-#include "lpf.h"
+#include "filter.h"
 #include "util.h"
 
 Vector rates; // estimated angular rates, rad/s
@@ -15,16 +15,24 @@ bool landed;
 float accWeight = 0.003;
 float levelWeight = 0.0002;
 LowPassFilter<Vector> ratesFilter(0.2); // cutoff frequency ~ 40 Hz
+NotchFilter<Vector> ratesNotch(382, 0);
+
+void setupEstimate() {
+	print("Setup estimation\n");
+	ratesNotch.reset();
+}
 
 void estimate() {
 	applyGyro();
 	applyAcc();
 	applyLevel();
+	estimatePosition();
 }
 
 void applyGyro() {
 	// filter gyro to get angular rates
 	rates = ratesFilter.update(gyro);
+	rates = ratesNotch.update(rates);
 
 	// apply rates to attitude
 	attitude = Quaternion::rotate(attitude, Quaternion::fromRotationVector(rates * dt));

flix/filter.h

@@ -0,0 +1,98 @@
+// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
+// Repository: https://github.com/okalachev/flix
+
+// Low pass and notch filters
+
+#pragma once
+
+template <typename T> // Using template to make the filter usable for scalar and vector values
+class LowPassFilter {
+public:
+	float alpha; // smoothing constant, 1 means filter disabled
+	T output;
+
+	LowPassFilter(float alpha): alpha(alpha) {};
+
+	T update(const T input) {
+		if (!init) {
+			init = true;
+			return output = input;
+		}
+		return output += alpha * (input - output);
+	}
+
+	void setCutOffFrequency(float cutOffFreq, float dt) {
+		alpha = 1 - exp(-2 * PI * cutOffFreq * dt);
+	}
+
+	void reset() {
+		init = false;
+	}
+
+private:
+	bool init = false;
+};
+
+template <typename T>
+class NotchFilter {
+public:
+	float frequency;
+	float bandwidth;
+	T output;
+
+	NotchFilter(float frequency, float bandwidth): frequency(frequency), bandwidth(bandwidth) {
+		reset();
+	};
+
+	T update(const T input) {
+		if (frequency <= 0 || bandwidth <= 0) return input;
+
+		if (!init) {
+			init = true;
+			x1 = x2 = input;
+			y1 = y2 = input;
+			return output = input;
+		}
+
+		output = b0 * input + b1 * x1 + b2 * x2 - a1 * y1 - a2 * y2;
+
+		x2 = x1;
+		x1 = input;
+		y2 = y1;
+		y1 = output;
+
+		return output;
+	}
+
+	void reset() {
+		const float dt = 0.001f;
+		float f = frequency;
+		float bw = bandwidth;
+		if (f < 0) f = 0;
+		if (bw < 1e-6f) bw = 1e-6f;
+
+		float q = f / bw;
+		if (q < 1e-3f) q = 1e-3f;
+
+		const float w0 = 2.0f * PI * f * dt;
+		const float c = cos(w0);
+		const float s = sin(w0);
+		const float alpha = s / (2.0f * q);
+
+		const float a0 = 1.0f + alpha;
+		const float invA0 = 1.0f / a0;
+
+		b0 = 1.0f * invA0;
+		b1 = -2.0f * c * invA0;
+		b2 = 1.0f * invA0;
+		a1 = -2.0f * c * invA0;
+		a2 = (1.0f - alpha) * invA0;
+
+		init = false;
+	}
+
+private:
+	float b0, b1, b2, a1, a2;
+	T x1, x2, y1, y2;
+	bool init = false;
+};

flix/flix.ino

@@ -26,6 +26,7 @@ void setup() {
 	setupWiFi();
 	setupIMU();
 	setupRC();
+	setupEstimate();
 	setupLog();
 	setLED(false);
 	print("Initializing complete\n");

flix/imu.ino

@@ -6,7 +6,7 @@
 #include <SPI.h>
 #include <FlixPeriph.h>
 #include "vector.h"
-#include "lpf.h"
+#include "filter.h"
 #include "util.h"
 
 MPU9250 imu(SPI);

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

flix/lpf.h

@@ -1,34 +0,0 @@
-// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
-// Repository: https://github.com/okalachev/flix
-
-// Low pass filter implementation
-
-#pragma once
-
-template <typename T> // Using template to make the filter usable for scalar and vector values
-class LowPassFilter {
-public:
-	float alpha; // smoothing constant, 1 means filter disabled
-	T output;
-
-	LowPassFilter(float alpha): alpha(alpha) {};
-
-	T update(const T input) {
-		if (!init) {
-			init = true;
-			return output = input;
-		}
-		return output += alpha * (input - output);
-	}
-
-	void setCutOffFrequency(float cutOffFreq, float dt) {
-		alpha = 1 - exp(-2 * PI * cutOffFreq * dt);
-	}
-
-	void reset() {
-		init = false;
-	}
-
-private:
-	bool init = false;
-};

flix/mavlink.ino

@@ -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);
@@ -223,18 +230,24 @@ void handleMavlink(const void *_msg) {
 		mavlink_msg_set_attitude_target_decode(&msg, &m);
 		if (m.target_system && m.target_system != mavlinkSysId) return;
 
-		// copy attitude, rates and thrust targets
-		ratesTarget.x = m.body_roll_rate;
-		ratesTarget.y = -m.body_pitch_rate; // convert to flu
-		ratesTarget.z = -m.body_yaw_rate;
-		attitudeTarget.w = m.q[0];
-		attitudeTarget.x = m.q[1];
-		attitudeTarget.y = -m.q[2];
-		attitudeTarget.z = -m.q[3];
-		thrustTarget = m.thrust;
-		ratesExtra = Vector(0, 0, 0);
+		if (!(m.type_mask & ATTITUDE_TARGET_TYPEMASK_ATTITUDE_IGNORE)) {
+			// Attitude control
+			attitudeTarget.w = m.q[0];
+			attitudeTarget.x = m.q[1];
+			attitudeTarget.y = -m.q[2];
+			attitudeTarget.z = -m.q[3];
+			ratesExtra.x = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_ROLL_RATE_IGNORE ? 0 : m.body_roll_rate;
+			ratesExtra.y = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_PITCH_RATE_IGNORE ? 0 : -m.body_pitch_rate; // convert to flu
+			ratesExtra.z = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_YAW_RATE_IGNORE ? 0 : -m.body_yaw_rate;
+		} else {
+			// Rates control
+			attitudeTarget.invalidate();
+			ratesTarget.x = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_ROLL_RATE_IGNORE ? ratesTarget.x : m.body_roll_rate;
+			ratesTarget.y = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_PITCH_RATE_IGNORE ? ratesTarget.y : -m.body_pitch_rate;
+			ratesTarget.z = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_YAW_RATE_IGNORE ? ratesTarget.z : -m.body_yaw_rate;
+		}
 
-		if (m.type_mask & ATTITUDE_TARGET_TYPEMASK_ATTITUDE_IGNORE) attitudeTarget.invalidate();
+		thrustTarget = valid(m.thrust) ? m.thrust : thrustTarget;
 		armed = m.thrust > 0;
 	}
 

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;
@@ -51,9 +51,9 @@ bool motorsActive() {
 	return motors[0] != 0 || motors[1] != 0 || motors[2] != 0 || motors[3] != 0;
 }
 
-void testMotor(int n) {
+void testMotor(int n, float thrust) {
 	print("Testing motor %d\n", n);
-	motors[n] = 0.2;
+	motors[n] = thrust;
 	delay(50); // ESP32 may need to wait until the end of the current cycle to change duty https://github.com/espressif/arduino-esp32/issues/5306
 	sendMotors();
 	pause(3);

flix/parameters.ino

@@ -5,14 +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, udpLocalPort, udpRemotePort, espnowChannel;
-extern float rcLossTimeout, descendTime;
+extern float rcLossTimeout, descendTime, disarmTilt;
 extern float voltageScale;
 extern LowPassFilter<float> voltageFilter;
+extern PID posX_PID, posY_PID;
 
 Preferences storage;
 
@@ -59,6 +61,12 @@ 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_ROT_ROLL", &imuRotation.x},
 	{"IMU_ROT_PITCH", &imuRotation.y},
@@ -74,6 +82,8 @@ Parameter parameters[] = {
 	{"EST_ACC_WEIGHT", &accWeight},
 	{"EST_LVL_WEIGHT", &levelWeight},
 	{"EST_RATES_LPF_A", &ratesFilter.alpha},
+	{"EST_RATES_NF_F", &ratesNotch.frequency, setupEstimate},
+	{"EST_RATES_NF_BW", &ratesNotch.bandwidth, setupEstimate},
 	// motors
 	{"MOT_PIN_FL", &motorPins[MOTOR_FRONT_LEFT], setupMotors},
 	{"MOT_PIN_FR", &motorPins[MOTOR_FRONT_RIGHT], setupMotors},
@@ -144,6 +154,7 @@ Parameter parameters[] = {
 	// safety
 	{"SF_RC_LOSS_TIME", &rcLossTimeout},
 	{"SF_DESCEND_TIME", &descendTime},
+	{"SF_DISARM_TILT", &disarmTilt}
 };
 
 void setupParameters() {

flix/pid.h

@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "lpf.h"
+#include "filter.h"
 
 class PID {
 public:

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/power.ino

@@ -5,11 +5,11 @@
 
 #include <soc/soc.h>
 #include <soc/rtc_cntl_reg.h>
-#include "lpf.h"
+#include "filter.h"
 #include "util.h"
 
 float voltage = NAN;
-LowPassFilter<float> voltageFilter(0.2);
+LowPassFilter<float> voltageFilter(1);
 int voltagePin = -1;
 float voltageScale = 2;
 

flix/safety.ino

@@ -8,10 +8,12 @@ extern float controlRoll, controlPitch, controlThrottle, controlYaw;
 
 float rcLossTimeout = 1;
 float descendTime = 10;
+float disarmTilt = radians(120);
 
 void failsafe() {
 	rcLossFailsafe();
 	autoFailsafe();
+	tiltFailsafe();
 }
 
 // RC loss failsafe
@@ -36,7 +38,7 @@ void descend() {
 // Allow pilot to interrupt automatic flight
 void autoFailsafe() {
 	static float roll, pitch, yaw, throttle;
-	if (roll != controlRoll || pitch != controlPitch || yaw != controlYaw || abs(throttle - controlThrottle) > 0.05) {
+	if (abs(roll - controlRoll) > 0.05 || abs(pitch - controlPitch) > 0.05 || abs(yaw - controlYaw) > 0.05 || abs(throttle - controlThrottle) > 0.05) {
 		// controls changed and mode switch is not configured
 		if (mode == AUTO && invalid(controlMode)) mode = STAB; // regain control by the pilot
 	}
@@ -45,3 +47,15 @@ void autoFailsafe() {
 	yaw = controlYaw;
 	throttle = controlThrottle;
 }
+
+// Disarm if tilted too much
+void tiltFailsafe() {
+	if (!armed) return;
+	if (mode != STAB) return;
+
+	Vector up = Quaternion::rotateVector(Vector(0, 0, 1), attitude);
+	float tilt = acos(up.z);
+	if (disarmTilt && tilt > disarmTilt) {
+		armed = false;
+	}
+}

flix/wifi.ino

@@ -58,7 +58,7 @@ void sendWiFi(const uint8_t *buf, int len) {
 		espnow.write(buf, len);
 
 		static Rate discovery(2);
-		if (discovery) espnowBroadcast.write((const uint8_t *)"flix", 4); // broadcast message to help finding this device
+		if (espnow.isEncrypted() && discovery) espnowBroadcast.write((const uint8_t *)"flix", 4); // broadcast message to help finding this device
 		return;
 	}
 
@@ -89,7 +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");

gazebo/Arduino.h

@@ -20,6 +20,10 @@
 #define radians(deg) ((deg)*DEG_TO_RAD)
 #define degrees(rad) ((rad)*RAD_TO_DEG)
 
+#define MALLOC_CAP_SPIRAM (1<<10)
+#define MALLOC_CAP_8BIT (1<<2)
+#define ESP_NOW_MAX_DATA_LEN_V2 1470
+
 #define constrain(amt,low,high) ((amt)<(low)?(low):((amt)>(high)?(high):(amt)))
 template<typename T> T max(T a, T b) { return a > b ? a : b; }
 template<typename T> T min(T a, T b) { return a < b ? a : b; }
@@ -157,6 +161,7 @@ class EspClass {
 public:
 	void restart() { Serial.println("Ignore reboot in simulation"); }
 	uint32_t getFreeHeap() { return 300 * 1024; } // assume 300 KB free heap
+	uint32_t getFreePsram() { return 8 * 1024 * 1024; } // assume 8 MB free PSRAM
 } ESP;
 
 unsigned long __delayTime = 0;
@@ -166,11 +171,16 @@ void delay(uint32_t ms) {
 	__delayTime += ms * 1000;
 }
 
+void *heap_caps_calloc(size_t n, size_t size, uint32_t caps) {
+	return calloc(n, size);
+}
+
 bool ledcAttach(uint8_t pin, uint32_t freq, uint8_t resolution) { return true; }
 bool ledcWrite(uint8_t pin, uint32_t duty) { return true; }
 uint32_t ledcChangeFrequency(uint8_t pin, uint32_t freq, uint8_t resolution) { return freq; }
 int8_t digitalPinToAnalogChannel(uint8_t pin) { return -1; }
 uint32_t analogReadMilliVolts(uint8_t pin) { return 0; }
+float temperatureRead() { return 0; }
 
 unsigned long __micros;
 unsigned long __resetTime = 0;

gazebo/flix.h

@@ -9,7 +9,7 @@
 #include "quaternion.h"
 #include "Arduino.h"
 #include "wifi.h"
-#include "lpf.h"
+#include "filter.h"
 
 extern float t, dt;
 extern float controlRoll, controlPitch, controlYaw, controlThrottle, controlMode;
@@ -38,7 +38,7 @@ const char* getModeName();
 void sendMotors();
 int getDutyCycle(float value);
 bool motorsActive();
-void testMotor(int n);
+void testMotor(int, float);
 void print(const char* format, ...);
 void pause(float duration);
 void doCommand(String str, bool echo);
@@ -72,6 +72,7 @@ void failsafe();
 void rcLossFailsafe();
 void descend();
 void autoFailsafe();
+void tiltFailsafe();
 int parametersCount();
 const char *getParameterName(int index);
 float getParameter(int index);
@@ -82,10 +83,14 @@ void resetParameters();
 
 // mocks
 void setLED(bool on) {};
-void calibrateGyro() { print("Skip gyro calibrating\n"); };
 void calibrateAccel() { print("Skip accel calibrating\n"); };
 void printIMUCalibration() { print("cal: N/A\n"); };
 void printIMUInfo() {};
 void printWiFiInfo() {};
 void configWiFi(bool, const char*, const char*) { print("Skip WiFi config\n"); };
 void setWiFiMode(const String& mode) { print("Skip WiFi mode set\n"); };
+
+class IMU {
+public:
+	float getTemp() { return 0; }
+} imu;

gazebo/simulator.cpp

@@ -23,7 +23,7 @@
 #include "estimate.ino"
 #include "safety.ino"
 #include "log.ino"
-#include "lpf.h"
+#include "filter.h"
 #include "mavlink.ino"
 #include "motors.ino"
 #include "parameters.ino"
@@ -56,6 +56,7 @@ public:
 		Serial.begin(0);
 		setupParameters();
 		setupLog();
+		rcRxPin = 1; // set rc pin to enable rc reading
 		gzmsg << "Flix plugin loaded" << endl;
 	}
 
@@ -88,7 +89,7 @@ public:
 
 		applyMotorForces();
 		publishTopics();
-		logData();
+		loopLog();
 		syncParameters();
 	}
 

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);
 		}