Connecting Motion Capture Data to VOXL (No Postion Estimate)
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Hello,
We are trying to incorporate motion capture data into the VOXL2 (m0054) in order to fly in position mode. We are using ROS 1 and taking motion capture data, processing and stamping the data onboard the VOXL and publishing it to /mavros/vision_pose/pose. We are seeing data streaming on /mavros/vision_pose/pose when echoing with rostopic echo /mavros/vision_pose/pose. Also when we use px4-listener to listen to vehicle_visual_odometry on the px4 side, we are also seeing data. However, in QGC, it reports no valid local position estimate (in position mode), and EKF2 does not appear to be using the vision data at all. We're not sure what is going wrong where EKF2 is not accepting the information. We've tried following for mocap data on the PX4 documentation along with following along with this forum post.
We have a suspicion that the timestamps might be messed up between MAVROS and PX4 but are unsure. We are seeing weird values when we look at the uORB messages using px4-listener (sample attached below).
Do you have any idea what we might be doing wrong?
VOXL Suite Version: 1.4.1
Sample Vehicle Visual Odometry uORB with report saying "timestamp_sample" in the future relative to timestamp
EKF2 Status
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@Andrew-Jue How is EKF2_EV_CTRL set in PX4?
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@Eric-Katzfey It's set to 11 (Horiztonal Postion, Vertical Position, Yaw)
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@Andrew-Jue Have you made sure that no other service is running that can send odometry messages that conflict with to MAVROS ones? But, yes, you have a good point about the timestamps. PX4 on VOXL 2 runs on "DSP time", not apps proc time so there is a big delta (that moves over time) between standard Linux time and what PX4 uses. That's why we use the timesync protocol to align times between our applications (like VIO) on Linux with PX4 running on DSP.
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@Eric-Katzfey I don't think that there's anything that should be interfering with MAVROS, though I'm not familiar enough with the VOXL services to know if there's one I need to be worried about. I've attached a screen capture of "voxl-inspect-services" along with the voxl-vision-hub.conf, voxl-px4.conf, voxl-mavlink-server.conf files in case you spot anything that's amiss with them.
voxl-vision-hub.conf:
{ "config_file_version": 1, "en_localhost_mavlink_udp": true, "localhost_udp_port_number": 14551, "en_vio": false, "vio_pipe": "qvio", "secondary_vio_pipe": "ov", "vfc_vio_pipe": "ov", "en_reset_vio_if_initialized_inverted": true, "vio_warmup_s": 3, "send_odom_while_failed": true, "horizon_cal_tolerance": 0.5, "en_hitl": false, "offboard_mode": "off", "follow_tag_id": 0, "figure_eight_move_home": true, "robot_radius": 0.300000011920929, "collision_sampling_dt": 0.1, "max_lookahead_distance": 1, "backtrack_seconds": 60, "backtrack_rc_chan": 8, "backtrack_rc_thresh": 1500, "wps_move_home": true, "wps_stride": 0, "wps_timeout": 0, "wps_damp": 1, "en_tag_fixed_frame": false, "fixed_frame_filter_len": 5, "en_transform_mavlink_pos_setpoints_from_fixed_frame": false, "vfc_rate": 100, "vfc_rc_chan_min": 980, "vfc_rc_chan_max": 2020, "vfc_thrust_ch": 3, "vfc_roll_ch": 1, "vfc_pitch_ch": 2, "vfc_yaw_ch": 4, "vfc_submode_ch": 6, "vfc_alt_mode_rc_min": 0, "vfc_alt_mode_rc_max": 0, "vfc_flow_mode_rc_min": 0, "vfc_flow_mode_rc_max": 0, "vfc_hybrid_flow_mode_rc_min": 0, "vfc_hybrid_flow_mode_rc_max": 0, "vfc_position_mode_rc_min": 0, "vfc_position_mode_rc_max": 2100, "vfc_traj_mode_rc_min": 0, "vfc_traj_mode_rc_max": 0, "vfc_yaw_deadband": 30, "vfc_vxy_deadband": 50, "vfc_vz_deadband": 150, "vfc_min_thrust": 0, "vfc_max_thrust": 0.800000011920929, "vfc_tilt_max": 0.43599998950958252, "vfc_yaw_rate_max": 3, "vfc_thrust_hover": 0.5, "vfc_vz_max": 1, "vfc_kp_z": 5.2899999618530273, "vfc_kd_z": 5.9800000190734863, "vfc_vxy_max": 3, "vfc_kp_xy": 0.63999998569488525, "vfc_kd_xy": 2.559999942779541, "vfc_kp_z_vio": 5.2899999618530273, "vfc_kd_z_vio": 5.9800000190734863, "vfc_kp_xy_vio": 3.2400000095367432, "vfc_kd_xy_vio": 3.9600000381469727, "vfc_w_filt_xy_vio": 10, "vfc_vel_ff_factor_vio": 0.899999976158142, "vfc_xy_acc_limit_vio": 2.5, "vfc_max_z_delta": 3, "vfc_att_transition_time": 0.5, "vfc_stick_move_threshold": 30, "vfc_flow_transition_time": 1, "vfc_q_min": 10, "vfc_points_min": 7, "vfc_en_submode_announcement": 1, "vfc_disable_fallback": false, "vfc_traj_csv": "/data/voxl-vision-hub/traj.csv", "en_voa": true, "voa_upper_bound_m": -0.15000000596046448, "voa_lower_bound_m": 0.15000000596046448, "voa_voa_memory_s": 1, "voa_max_pc_per_fusion": 100, "voa_pie_max_dist_m": 20, "voa_pie_min_dist_m": 0.25, "voa_pie_under_trim_m": 1, "voa_pie_threshold": 3, "voa_send_rate_hz": 20, "voa_pie_slices": 36, "voa_pie_bin_depth_m": 0.15000000596046448, "voa_inputs": [{ "enabled": true, "type": "point_cloud", "input_pipe": "dfs_point_cloud", "frame": "stereo_l", "max_depth": 8, "min_depth": 0.300000011920929, "cell_size": 0.079999998211860657, "threshold": 4, "x_fov_deg": 68, "y_fov_deg": 56, "conf_cutoff": 0 }, { "enabled": true, "type": "point_cloud", "input_pipe": "stereo_front_pc", "frame": "stereo_front_l", "max_depth": 8, "min_depth": 0.300000011920929, "cell_size": 0.079999998211860657, "threshold": 4, "x_fov_deg": 68, "y_fov_deg": 56, "conf_cutoff": 0 }, { "enabled": true, "type": "point_cloud", "input_pipe": "stereo_rear_pc", "frame": "stereo_rear_l", "max_depth": 8, "min_depth": 0.300000011920929, "cell_size": 0.079999998211860657, "threshold": 4, "x_fov_deg": 68, "y_fov_deg": 56, "conf_cutoff": 0 }, { "enabled": true, "type": "tof", "input_pipe": "tof", "frame": "tof", "max_depth": 6, "min_depth": 0.15000000596046448, "cell_size": 0.079999998211860657, "threshold": 3, "x_fov_deg": 106.5, "y_fov_deg": 85.0999984741211, "conf_cutoff": 125 }, { "enabled": true, "type": "rangefinder", "input_pipe": "rangefinders", "frame": "body", "max_depth": 8, "min_depth": 0.300000011920929, "cell_size": 0.079999998211860657, "threshold": 4, "x_fov_deg": 68, "y_fov_deg": 56, "conf_cutoff": 0 }] }voxl-px4.conf
AIRFRAME=MULTICOPTER GPS=NONE RC=M0065_SBUS ESC=VOXL2_IO_PWM_ESC POWER_MANAGER=VOXLPM AIRSPEED_SENSOR=NONE DISTANCE_SENSOR=NONE OSD=DISABLE DAEMON_MODE=ENABLE SENSOR_CAL=ACTUAL ARTIFACT_MODE=DISABLE EXTRA_STEPS=()voxl-mavlink-server.conf
{ "primary_static_gcs_ip": "192.168.8.10", "secondary_static_gcs_ip": "192.168.8.11", "onboard_port_to_autopilot": 14556, "onboard_port_from_autopilot": 14557, "gcs_port_to_autopilot": 14558, "gcs_port_from_autopilot": 14559, "en_external_uart_ap": false, "autopilot_uart_bus": 1, "autopilot_uart_baudrate": 921600, "autopilot_mission_delay_start": -1, "autopilot_mission_delay_sound": false, "autopilot_mission_notif_dur": 0.1, "en_external_ap_timesync": 1, "en_external_ap_heartbeat": 1, "udp_mtu": 0, "gcs_timeout_s": 4.5 } -
@Andrew-Jue I think there are a couple of issues. One is the timestamp issue. You can see here that px4 tries to align the timestamps with timesync information: https://github.com/modalai/px4-firmware/blob/2bbaa6875fedff9c9bc8282a35c4cbb5612046ea/src/modules/mavlink/mavlink_receiver.cpp#L1251. The next issue is that ekf2 doesn't deal with the mocap odometry directly, it relies on the local position estimator module to process that and that module is not included in our build.
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@Eric-Katzfey So I see that the firmware is supposed to apply the estimated offset to the timestamp to make sure that the timestamps align. Is there a way to change or correct the timesync system if it isn't correct (as seems to be the case here)? Or at least check the timesync status?
And regarding the mocap position estimate, is the local position estimator module you are referring to this LPE estimator referred to in the PX4 documentation or is it a different module specifically for EKF2? I'm just trying to get an understanding of what is going on, especially since it seems like in the documentation from PX4, there's a choice to either use the LPE or EKF2 with slightly different parameters and workflows for each.
Regardless, what method would you recommend for getting mocap position data sent to PX4? Is there a service in VOXL that we could try to route the position data through from ROS that would work better?
