Error : Unhealthy estimator

[TomRvr]

Hello ! I try to fly a multi-rotor with gazebo simulation with the following configuration : OS Version : Ubuntu 16.04 ROS Kinetic Git tag : master Xbox controller

When I want to fly, all the nodes seems to be started correctly. rqt_graph

On gazebo, I can arm the drone but when I want to slowly increase the throttle, the drone is uncontrollable and the Unhealthy estimator error occur : Terminal

I might forget to configure one parameter but I can't find which one. Parameter file

{name: ACC_LPF_ALPHA, type: 9, value: 0.8999999761581421}
{name: ACC_X_BIAS, type: 9, value: -1.542290462008822e-10}
{name: ACC_X_TEMP_COMP, type: 9, value: 0}
{name: ACC_Y_BIAS, type: 9, value: -1.789761672199575e-10}
{name: ACC_Y_TEMP_COMP, type: 9, value: 0}
{name: ACC_Z_BIAS, type: 9, value: 0.006649971008300781}
{name: ACC_Z_TEMP_COMP, type: 9, value: 0}
{name: AIL_REV, type: 6, value: 0}
{name: ARM_CHANNEL, type: 6, value: 5}
{name: ARM_SPIN_MOTORS, type: 6, value: 1}
{name: ARM_THRESHOLD, type: 9, value: 0.1500000059604645}
{name: BARO_BIAS, type: 9, value: 1.005905389785767}
{name: BAUD_RATE, type: 6, value: 921600}
{name: CAL_GYRO_ARM, type: 6, value: 1}
{name: DIFF_PRESS_BIAS, type: 9, value: 0}
{name: ELEVATOR_REV, type: 6, value: 0}
{name: FAILSAFE_THR, type: 9, value: 0.300000011920929}
{name: FILTER_INIT_T, type: 6, value: 3000}
{name: FILTER_KI, type: 9, value: 0.009999999776482582}
{name: FILTER_KP, type: 9, value: 0.5}
{name: FILTER_MAT_EXP, type: 6, value: 1}
{name: FILTER_QUAD_INT, type: 6, value: 1}
{name: FILTER_USE_ACC, type: 6, value: 1}
{name: FIXED_WING, type: 6, value: 0}
{name: GROUND_LEVEL, type: 9, value: 1387}
{name: GYRO_LPF_ALPHA, type: 9, value: 0.300000011920929}
{name: GYRO_X_BIAS, type: 9, value: -1.826129802928733e-10}
{name: GYRO_Y_BIAS, type: 9, value: 1.573581126512735e-10}
{name: GYRO_Z_BIAS, type: 9, value: 1.141862218800191e-19}
{name: MAG_A11_COMP, type: 9, value: 1}
{name: MAG_A12_COMP, type: 9, value: 0}
{name: MAG_A13_COMP, type: 9, value: 0}
{name: MAG_A21_COMP, type: 9, value: 0}
{name: MAG_A22_COMP, type: 9, value: 1}
{name: MAG_A23_COMP, type: 9, value: 0}
{name: MAG_A31_COMP, type: 9, value: 0}
{name: MAG_A32_COMP, type: 9, value: 0}
{name: MAG_A33_COMP, type: 9, value: 1}
{name: MAG_X_BIAS, type: 9, value: 0}
{name: MAG_Y_BIAS, type: 9, value: 0}
{name: MAG_Z_BIAS, type: 9, value: 0}
{name: MIN_THROTTLE, type: 6, value: 1}
{name: MIXER, type: 6, value: 2}
{name: MOTOR_IDLE_THR, type: 9, value: 0.1000000014901161}
{name: MOTOR_MAX_PWM, type: 6, value: 2000}
{name: MOTOR_MIN_PWM, type: 6, value: 1000}
{name: MOTOR_PWM_UPDATE, type: 6, value: 490}
{name: OVRD_LAG_TIME, type: 6, value: 1000}
{name: PARAM_MAX_CMD, type: 9, value: 1}
{name: PID_PITCH_ANG_D, type: 9, value: 0.05000000074505806}
{name: PID_PITCH_ANG_I, type: 9, value: 0}
{name: PID_PITCH_ANG_P, type: 9, value: 0.1500000059604645}
{name: PID_PITCH_RATE_D, type: 9, value: 0}
{name: PID_PITCH_RATE_I, type: 9, value: 0}
{name: PID_PITCH_RATE_P, type: 9, value: 0.07000000029802322}
{name: PID_ROLL_ANG_D, type: 9, value: 0.05000000074505806}
{name: PID_ROLL_ANG_I, type: 9, value: 0}
{name: PID_ROLL_ANG_P, type: 9, value: 0.1500000059604645}
{name: PID_ROLL_RATE_D, type: 9, value: 0}
{name: PID_ROLL_RATE_I, type: 9, value: 0}
{name: PID_ROLL_RATE_P, type: 9, value: 0.07000000029802322}
{name: PID_TAU, type: 9, value: 0.05000000074505806}
{name: PID_YAW_RATE_D, type: 9, value: 0}
{name: PID_YAW_RATE_I, type: 9, value: 0}
{name: PID_YAW_RATE_P, type: 9, value: 0.25}
{name: RC_ATT_CTRL_CHN, type: 6, value: 4}
{name: RC_ATT_MODE, type: 6, value: 1}
{name: RC_ATT_OVRD_CHN, type: 6, value: 6}
{name: RC_F_CHN, type: 6, value: 2}
{name: RC_MAX_PITCH, type: 9, value: 0.7860000133514404}
{name: RC_MAX_PITCHRATE, type: 9, value: 3.141590118408203}
{name: RC_MAX_ROLL, type: 9, value: 0.7860000133514404}
{name: RC_MAX_ROLLRATE, type: 9, value: 3.141590118408203}
{name: RC_MAX_YAWRATE, type: 9, value: 1.506999969482422}
{name: RC_NUM_CHN, type: 6, value: 6}
{name: RC_OVRD_DEV, type: 9, value: 0.1000000014901161}
{name: RC_THR_OVRD_CHN, type: 6, value: 6}
{name: RC_TYPE, type: 6, value: 1}
{name: RC_X_CHN, type: 6, value: 0}
{name: RC_Y_CHN, type: 6, value: 1}
{name: RC_Z_CHN, type: 6, value: 3}
{name: RUDDER_REV, type: 6, value: 0}
{name: STRM_AIRSPEED, type: 6, value: 20}
{name: STRM_ATTITUDE, type: 6, value: 200}
{name: STRM_BARO, type: 6, value: 50}
{name: STRM_HRTBT, type: 6, value: 1}
{name: STRM_IMU, type: 6, value: 500}
{name: STRM_MAG, type: 6, value: 50}
{name: STRM_RC, type: 6, value: 50}
{name: STRM_SERVO, type: 6, value: 50}
{name: STRM_SONAR, type: 6, value: 40}
{name: STRM_STATUS, type: 6, value: 10}
{name: SWITCH_5_DIR, type: 6, value: 1}
{name: SWITCH_6_DIR, type: 6, value: 1}
{name: SWITCH_7_DIR, type: 6, value: 1}
{name: SWITCH_8_DIR, type: 6, value: 1}
{name: SYS_ID, type: 6, value: 1}
{name: X_EQ_TORQUE, type: 9, value: 0}
{name: Y_EQ_TORQUE, type: 9, value: 0}
{name: Z_EQ_TORQUE, type: 9, value: 0}

I see this error is on the forum ( https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwif7oCfw8_fAhUB0RoKHaVSDokQFjAAegQIABAB&url=https%3A%2F%2Fdiscuss.rosflight.org%2Fdiscussion%2F11%2Funhealthy-estimator&usg=AOvVaw0LRiXSyyI0ZVY3OH5SQmpW ) but the forum seems to be down for the moment and I can't access to the topic.

I search for some help to indicate me the things to checks to find a solution. Thanks !

[superjax]

I'm so sorry this took me so long to respond. Somehow this issue fell to the bottom of my inbox and I just noticed it this morning!

This error is thrown here estimator.c L#217

What's going on is that the estimator is looking at the magnitude of acceleration (line 165) and if the magnitude of acceleration is within 10% of the nominal gravity vector, then the accelerometer measurement is fused, otherwise it is ignored. The UNHEALTHY_ESTIMATOR error is thrown if more than 500ms have elapsed since the last time acceleration magnitude was close enough to gravity that we could fuse the accelerometer measurement and indicates that the estimator may be drifting, because we've been going off of gyros-only for a while.

This happens a lot more often in simulation than in hardware. I'm actually not 100% sure why that is the case, probably because the noise in hardware is often a bit larger than in sim, but it's not really anything to worry about. If your accelerometers are calibrated then that's really the best you can do.

We should probably extend the timeout to something like 10 seconds, rather than 500 ms and that would solve the annoying error. When I look at your log, it looks like the estimator is "recovering" (i.e. getting some valid acceleration measurements) within about .2 seconds, so everything seems to be working properly.

[TomRvr]

Thank you for your very clear answer. Now I understand why this error happened.

Congrats for your work on this project.

[superjax]

No Problem! Thanks!