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Re: [Paparazzi-devel] Mysterious AHRS drift on psi - Aspirin 1.5 Magneto

From: Loic Drumettaz
Subject: Re: [Paparazzi-devel] Mysterious AHRS drift on psi - Aspirin 1.5 Magnetometer
Date: Tue, 1 Apr 2014 08:46:02 +0200

Hi,

Mag calibration should be perfomed outside, far away from any metallic material (cars, watch, belt, ...)
The gyro bias can be measured with gyro scaled mean value when not moving.
This value should be always equal to the bias estimated by the AHRS filter. Otherwise, it means that the gyro and mag measurements don't agree.
In most case this is due to a bad mag calibration.
Regards
Loic

Le 31 mars 2014 20:46, "Bruzzlee" <address@hidden> a écrit :
Hi Heinrich and Alonso

Today I did the calibration about 30 times. (on different places)
Now I have calibration which I think I can work with.
Even the globe was not fully surrounded with measurement dots. (calibration graphic)
The phi and the bias is now almost stable.

biases:
p: -258     -3.61°/s
q: 9            0.125°/s
r: -160    -2.238°/s

Those values are all out of your range but I think it will work anyway, don't you?

Thank you for you hints
Bruzzlee

On 31.03.14 09:58, Prof. Dr.-Ing. Heinrich Warmers wrote:
Hi,
can you calculate the bias in °/s?
I have found that a bias in the range of  0.5-2°/s  is normal.
If the bias brake this border  change the sensor element.
regards
Heinrich


Bruzzlee schrieb:
Hello paparazzi community

After 8h of trying to get rid of my drift on phi you are my last hope.
Every hint is useful!

I think it has something to do with the AHRS.
Compensation of psi drift with MAG

The plot shows a fast 90° turn clockwise and back again.
In the lower plot you also can that the bias changes a lot, is that "normal"?

Lisa M 1.0 + Aspirin IMU 1.5
(I did the calibration of Accel and mag a few time with similar results)

Thx for any hint!
Bruzzlee 



<airframe name="Odonata_LisaM">
    
    <firmware name="rotorcraft">
        <target name="ap" board="lisa_m_1.0">
            <subsystem name="radio_control" type="spektrum">
                <!--define name="RADIO_CONTROL_SPEKTRUM_SIGNS" value="\{1,1,-1,1,-1,-1\}"/-->
                <define name="RADIO_MODE" value="RADIO_GEAR"/>
                <define name="RADIO_KILL_SWITCH" value="RADIO_AUX1"/>
                <configure name="USE_SECONDARY_SPEKTRUM_RECEIVER" value="0"/>
                <configure name="USE_KILL_SWITCH_FOR_MOTOR_ARMING" value="1"/>
                <!--configure name="AUTOPILOT_DISABLE_AHRS_KILL" value="0"/-->
            </subsystem>
        </target>
        
        <target name="nps" board="pc">
            <subsystem name="fdm"           type="jsbsim"/>
            <subsystem name="radio_control" type="ppm"/>
        </target>
        
        <subsystem name="motor_mixing"/>
        <subsystem name="actuators"     type="pwm">
            <define name="SERVO_HZ" value="400"/>
            <!--define name="USE_SERVOS_7AND8"/-->
        </subsystem>
        
        <subsystem name="telemetry"     type="transparent"/>
            <configure name="MODEM_BAUD" value="B9600"/>
        <subsystem name="imu"           type="aspirin_v1.5"/>
        <subsystem name="gps"           type="ublox"/>
        <subsystem name="stabilization" type="int_quat"/>
        <subsystem name="ahrs"          type="int_cmpl_quat"/>
        <subsystem name="ins"/>
        <!--define name="USE_INS_NAV_INIT"/-->
        <!--subsystem name="stabilization"   type="int_euler"/>
         <subsystem name="ahrs"          type="int_cmpl_euler"/-->
    </firmware>
    
    
    <firmware name="lisa_test_progs">
        <target name="test_led"			board="lisa_m_1.0">
            <configure name="SYS_TIME_LED" value="none"/>
        </target>
        <target name="test_uart"			board="lisa_m_1.0"/>
        <target name="test_imu_aspirin"		board="lisa_m_1.0"/>
        <target name="test_rc_spektrum"		board="lisa_m_1.0"/>
        <target name="test_baro"			board="lisa_m_1.0"/>
    </firmware>
    
    
    <servos driver="Pwm">
        <servo name="FRONT" no="0" min="1000" neutral="1100" max="1900"/>
        <servo name="BACK"  no="1" min="1000" neutral="1100" max="1900"/>
        <servo name="RIGHT" no="2" min="1000" neutral="1100" max="1900"/>
        <servo name="LEFT"  no="3" min="1000" neutral="1100" max="1900"/>
    </servos>
    
    <commands>
        <axis name="ROLL"   failsafe_value="0"/>
        <axis name="PITCH"  failsafe_value="0"/>
        <axis name="YAW"    failsafe_value="0"/>
        <axis name="THRUST" failsafe_value="0"/>
    </commands>
    
    <command_laws>
        <call fun="motor_mixing_run(autopilot_motors_on,FALSE,values)"/>
        <set servo="FRONT" value="motor_mixing.commands[SERVO_FRONT]"/>
        <set servo="BACK"  value="motor_mixing.commands[SERVO_BACK]"/>
        <set servo="RIGHT" value="motor_mixing.commands[SERVO_RIGHT]"/>
        <set servo="LEFT"  value="motor_mixing.commands[SERVO_LEFT]"/>
    </command_laws>
    
    <section name="MIXING" prefix="MOTOR_MIXING_">
        <define name="STOP_MOTOR" value="0"/>
        <define name="TRIM_ROLL" value="0"/>
        <define name="TRIM_PITCH" value="0"/>
        <define name="TRIM_YAW" value="0"/>
        <define name="NB_MOTOR" value="4"/>
        <define name="SCALE" value="256"/>
        <!--define name="ROLL_COEF"   value="{    0, -256,    0,  256 }"/>
        <define name="PITCH_COEF"  value="{  256,    0, -256,    0 }"/>
        <define name="YAW_COEF"    value="{ -256,  256, -256,  256 }"/>
        <define name="THRUST_COEF" value="{  256,  256,  256,  256 }"/-->
        <define name="ROLL_COEF"   value="{  0  ,    0,  -256, 256 }"/>
        <define name="PITCH_COEF"  value="{  256, -256,    0,    0 }"/>
        <define name="YAW_COEF"    value="{  256,  256, -256, -256 }"/>
        <define name="THRUST_COEF" value="{  256,  256,  256,  256 }"/>
    </section>
    
    <section name="IMU" prefix="IMU_">
        <!--define name="GYRO_P_NEUTRAL" value="-60"/>
        <define name="GYRO_Q_NEUTRAL" value="1"/>
        <define name="GYRO_R_NEUTRAL" value="-40"/-->
        <!--define name="GYRO_P_SENS" value="4.359" integer="16"/>
        <define name="GYRO_Q_SENS" value="4.359" integer="16"/>
        <define name="GYRO_R_SENS" value="4.359" integer="16"/-->
        <!--define name="GYRO_P_SENS" value="4.967" integer="16"/>
        <define name="GYRO_Q_SENS" value="4.967" integer="16"/>
        <define name="GYRO_R_SENS" value="8.967" integer="16"/>
        <define name="GYRO_PQ_SENS" value="0.0" integer="16"/>
        <define name="GYRO_PR_SENS" value="0.0" integer="16"/>
        <define name="GYRO_QR_SENS" value="0.0" integer="16"/-->
        
        <define name="ACCEL_X_NEUTRAL" value="2"/>
        <define name="ACCEL_Y_NEUTRAL" value="-2"/>
        <define name="ACCEL_Z_NEUTRAL" value="-18"/>
        <define name="ACCEL_X_SENS" value="38.364291532" integer="16"/>
        <define name="ACCEL_Y_SENS" value="37.412848171" integer="16"/>
        <define name="ACCEL_Z_SENS" value="39.5532801506" integer="16"/>

        <!--define name="ACCEL_XY_SENS" value="0.0" integer="16"/>
        <define name="ACCEL_XZ_SENS" value="0.0" integer="16"/>
        <define name="ACCEL_YZ_SENS" value="0.0" integer="16"/-->
        
        <define name="MAG_X_NEUTRAL" value="-101"/>
        <define name="MAG_Y_NEUTRAL" value="32"/>
        <define name="MAG_Z_NEUTRAL" value="-42"/>
        <define name="MAG_X_SENS" value="4.04547589416" integer="16"/>
        <define name="MAG_Y_SENS" value="4.57546806101" integer="16"/>
        <define name="MAG_Z_SENS" value="4.01214304094" integer="16"/>

        <!--define name="MAG_XY_SENS" value="0.0" integer="16"/>
        <define name="MAG_XZ_SENS" value="0.0" integer="16"/>
        <define name="MAG_YZ_SENS" value="0.0" integer="16"/-->
        
        <define name="BODY_TO_IMU_PHI"   value="0." unit="deg"/>
        <define name="BODY_TO_IMU_THETA" value="0." unit="deg"/>
        <define name="BODY_TO_IMU_PSI"   value="90." unit="deg"/>
    </section>
    
    <section name="AUTOPILOT">
        <define name="MODE_MANUAL" value="AP_MODE_ATTITUDE_DIRECT"/>
        <define name="MODE_AUTO1"  value="AP_MODE_ATTITUDE_Z_HOLD"/>
        <define name="MODE_AUTO2"  value="AP_MODE_HOVER_Z_HOLD"/>
    </section>
    
    <section name="BAT">
        <define name="CATASTROPHIC_BAT_LEVEL" value="9.3" unit="V"/>
    </section>
    
    
    <section name="STABILIZATION_RATE" prefix="STABILIZATION_RATE_">
        <!-- setpoints -->
        <define name="SP_MAX_P" value="10000"/>
        <define name="SP_MAX_Q" value="10000"/>
        <define name="SP_MAX_R" value="10000"/>
        <define name="DEADBAND_P" value="20"/>
        <define name="DEADBAND_Q" value="20"/>
        <define name="DEADBAND_R" value="200"/>
        <define name="REF_TAU" value="4"/>
        
        <!-- feedback -->
        <define name="GAIN_P" value="400"/>
        <define name="GAIN_Q" value="400"/>
        <define name="GAIN_R" value="350"/>
        
        <define name="IGAIN_P" value="75"/>
        <define name="IGAIN_Q" value="75"/>
        <define name="IGAIN_R" value="50"/>
        
        <!-- feedforward -->
        <define name="DDGAIN_P" value="300"/>
        <define name="DDGAIN_Q" value="300"/>
        <define name="DDGAIN_R" value="300"/>
    </section>
    
    <section name="STABILIZATION_ATTITUDE" prefix="STABILIZATION_ATTITUDE_">
        <!-- setpoints -->
        <define name="SP_MAX_PHI"     value="45." unit="deg"/>
        <define name="SP_MAX_THETA"   value="45." unit="deg"/>
        <define name="SP_MAX_PSI"     value="45." unit="deg"/>
        <define name="SP_MAX_R"       value="90." unit="deg/s"/>
        <define name="SP_MAX_P"       value="90." unit="deg/s"/>
        <define name="DEADBAND_E"     value="0"/>
        <define name="DEADBAND_A"     value="250"/>
        <define name="DEADBAND_R"     value="250"/>
        
        <!-- reference -->
        <define name="REF_OMEGA_P"  value="800" unit="deg/s"/>
        <define name="REF_ZETA_P"   value="0.85"/>
        <define name="REF_MAX_P"    value="400." unit="deg/s"/>
        <define name="REF_MAX_PDOT" value="RadOfDeg(8000.)"/>
        
        <define name="REF_OMEGA_Q"  value="800" unit="deg/s"/>
        <define name="REF_ZETA_Q"   value="0.85"/>
        <define name="REF_MAX_Q"    value="400." unit="deg/s"/>
        <define name="REF_MAX_QDOT" value="RadOfDeg(8000.)"/>
        
        <define name="REF_OMEGA_R"  value="500" unit="deg/s"/>
        <define name="REF_ZETA_R"   value="0.85"/>
        <define name="REF_MAX_R"    value="180." unit="deg/s"/>
        <define name="REF_MAX_RDOT" value="RadOfDeg(1800.)"/>
        
        <!-- feedback -->
        <define name="PHI_PGAIN"  value="750"/>
        <define name="PHI_DGAIN"  value="500"/>
        <define name="PHI_IGAIN"  value="100"/>
        
        <define name="THETA_PGAIN"  value="750"/>
        <define name="THETA_DGAIN"  value="500"/>
        <define name="THETA_IGAIN"  value="100"/>
        
        <define name="PSI_PGAIN"  value="1500"/>
        <define name="PSI_DGAIN"  value="1000"/>
        <define name="PSI_IGAIN"  value="10"/>
        
        <!-- feedforward -->
        <define name="PHI_DDGAIN"   value=" 150"/>
        <define name="THETA_DDGAIN" value=" 150"/>
        <define name="PSI_DDGAIN"   value=" 300"/>
    </section>
    
    <section name="INS" prefix="INS_">
    </section>
    
    <section name="GUIDANCE_V" prefix="GUIDANCE_V_">
        <define name="MIN_ERR_Z"   value="POS_BFP_OF_REAL(-10.)"/>
        <define name="MAX_ERR_Z"   value="POS_BFP_OF_REAL( 10.)"/>
        <define name="MIN_ERR_ZD"  value="SPEED_BFP_OF_REAL(-10.)"/>
        <define name="MAX_ERR_ZD"  value="SPEED_BFP_OF_REAL( 10.)"/>
        <define name="MAX_SUM_ERR" value="2000000"/>
        <define name="HOVER_KP"    value="400"/>
        <define name="HOVER_KD"    value="350"/>
        <define name="HOVER_KI"    value="144"/>
        <define name="GUIDANCE_V_NOMINAL_HOVER_THROTTLE" value ="0.9"/>
    </section>
    
    <section name="AHRS" prefix="AHRS_">
        <define name="H_X" value=" 0.03075352"/>
        <define name="H_Y" value=" 0.99765715"/>
        <define name="H_Z" value=" 0.06111"/>
        <!--define name="H_X" value=" 0.460452"/>
        <define name="H_Y" value=" 0.0031046"/>
        <define name="H_Z" value=" 0.8876792"/-->
    </section>
    
    <section name="GUIDANCE_H" prefix="GUIDANCE_H_">
        <define name="PGAIN" value="50"/>
        <define name="DGAIN" value="50"/>
        <define name="IGAIN" value="0"/>
    </section>
    
    <section name="MISC">
        <define name="FACE_REINJ_1"  value="1024"/>
    </section>
    
    <section name="SIMULATOR" prefix="NPS_">
        <define name="ACTUATOR_NAMES"  value="{&quot;front_motor&quot;, &quot;back_motor&quot;, &quot;right_motor&quot;, &quot;left_motor&quot;}"/>
        <define name="JSBSIM_INIT" value="&quot;reset00&quot;"/>
        <define name="SENSORS_PARAMS" value="&quot;nps_sensors_params_booz2_a1.h&quot;"/>
        <!-- mode switch on joystick channel 5 (axis numbering starting at zero) -->
        <define name="JS_AXIS_MODE" value="4"/>
    </section>
    
    <!--modules main_freq="512">
        <!--load name="vehicle_interface_overo_link.xml"/->
        <load name="gps_ubx_ucenter.xml"/>
    </modules-->
    
    
</airframe>
  

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