Simplify lpf filter code

Begin with zero instead of the initializing value, as the latter doesn't make much sense in practice, but complicates the code much.

docs/troubleshooting.md

@@ -16,7 +16,7 @@ Do the following:
 * **Check if there are some startup errors**. Connect the ESP32 to the computer and check the Serial Monitor output. Use the Reset button to make sure you see the whole ESP32 output.
 * **Check the baudrate is correct**. If you see garbage characters in the Serial Monitor, make sure the baudrate is set to 115200.
 * **Make sure correct IMU model is chosen**. If using ICM-20948/MPU-6050 board, change `MPU9250` to `ICM20948`/`MPU6050` in the `imu.ino` file.
-* **Check if the CLI is working**. Perform `help` command in Serial Monitor. You should see the list of available commands. You can also access the CLI using QGroundControl (*Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console*).
+* **Check if the console is working**. Perform `help` command in Serial Monitor. You should see the list of available commands. You can also access the console using QGroundControl (*Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console*).
 * **Configure QGroundControl correctly before connecting to the drone** if you use it to control the drone. Go to the settings and enable *Virtual Joystick*. *Auto-Center Throttle* setting **should be disabled**.
 * **If QGroundControl doesn't connect**, you might need to disable the firewall and/or VPN on your computer.
 * **Check the IMU is working**. Perform `imu` command and check its output:

flix/cli.ino

@@ -6,6 +6,7 @@
 #include "pid.h"
 #include "vector.h"
 #include "util.h"
+#include "lpf.h"
 
 extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
 extern const int RAW, ACRO, STAB, AUTO;
@@ -14,6 +15,7 @@ extern uint16_t channels[16];
 extern float controlTime;
 extern int mode;
 extern bool armed;
+extern LowPassFilter<Vector> gyroBiasFilter;
 
 const char* motd =
 "\nWelcome to\n"
@@ -178,6 +180,7 @@ void doCommand(String str, bool echo = false) {
 #endif
 	} else if (command == "reset") {
 		attitude = Quaternion();
+		gyroBiasFilter.reset();
 	} else if (command == "reboot") {
 		ESP.restart();
 	} else {

flix/flix.ino

@@ -7,7 +7,6 @@
 #include "quaternion.h"
 #include "util.h"
 
-
 extern float t, dt;
 extern float controlRoll, controlPitch, controlYaw, controlThrottle, controlMode;
 extern Vector gyro, acc;

flix/imu.ino

@@ -19,6 +19,8 @@ Vector acc; // accelerometer output, m/s/s
 Vector accBias;
 Vector accScale(1, 1, 1);
 
+LowPassFilter<Vector> gyroBiasFilter(0.001);
+
 void setupIMU() {
 	print("Setup IMU\n");
 	imu.begin();
@@ -50,8 +52,6 @@ void readIMU() {
 void calibrateGyroOnce() {
 	static Delay landedDelay(2);
 	if (!landedDelay.update(landed)) return; // calibrate only if definitely stationary
-
-	static LowPassFilter<Vector> gyroBiasFilter(0.001);
 	gyroBias = gyroBiasFilter.update(gyro);
 }
 

flix/lpf.h

@@ -14,15 +14,6 @@ public:
 	LowPassFilter(float alpha): alpha(alpha) {};
 
 	T update(const T input) {
-		if (alpha == 1) { // filter disabled
-			return input;
-		}
-
-		if (!initialized) {
-			output = input;
-			initialized = true;
-		}
-
 		return output += alpha * (input - output);
 	}
 
@@ -31,9 +22,6 @@ public:
 	}
 
 	void reset() {
-		initialized = false;
+		output = T(); // set to zero
 	}
-
-private:
-	bool initialized = false;
 };

flix/mavlink.ino

@@ -142,7 +142,7 @@ void handleMavlink(const void *_msg) {
 		// send ack
 		mavlink_message_t msg;
 		mavlink_msg_param_value_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
-			m.param_id, m.param_value, MAV_PARAM_TYPE_REAL32, parametersCount(), 0); // index is unknown
+			m.param_id, getParameter(name), MAV_PARAM_TYPE_REAL32, parametersCount(), 0); // index is unknown
 		sendMessage(&msg);
 	}
 

flix/parameters.ino

@@ -59,6 +59,7 @@ Parameter parameters[] = {
 	{"IMU_ACC_SCALE_X", &accScale.x},
 	{"IMU_ACC_SCALE_Y", &accScale.y},
 	{"IMU_ACC_SCALE_Z", &accScale.z},
+	{"IMU_GYRO_BIAS_A", &gyroBiasFilter.alpha},
 	// estimate
 	{"EST_ACC_WEIGHT", &accWeight},
 	{"EST_RATES_LPF_A", &ratesFilter.alpha},

tools/grab_log.py

@@ -13,7 +13,7 @@ lines = []
 
 print('Downloading log...')
 count = 0
-dev.write('log\n'.encode())
+dev.write('log dump\n'.encode())
 while True:
     line = dev.readline()
     if not line: