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# Questions tagged [imu]

Inertial Measurement Unit

106 questions with no upvoted or accepted answers
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381 views

### Inferring joint orientation on multi-joint arm

Not a robotics question in the strictest sense, I guess, but related closely enough, I hope: I have an arm-like articulated two(-plus-one)-joint appliance that I want to use as a 3D input device. It ...
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32 views

### How to calibrate IMU for large scale deployments possibly using deep neural network

We were testing our visual SLAM algorithm on robots. We were getting poor performance. Then we calculated wite noise and random walk parameters (using kalibr) for the IMU and used it in our algorithm ...
• 151
533 views

### How to fuse IMU with encoders in EKF

Background I have a car-like mobile robot (4 wheels, where the forward ones are steering wheels) and I want to estimate its pose and velocity assuming 2D planar motion. I'm trying to solve this ...
375 views

### How is the GPS fused with IMU in a kalman filter?

I've been trying to understand how a Kalman filter used in navigation without much success, my questions are: The gps outputs latitude, longitude and velocity. While the IMU outputs acceleration and ...
• 131
399 views

### Frequency Limitation in robot_localization's EKF Node

I'm using version 2.7.4 of the robot_localization package for ROS Noetic. I'm currently utilizing two nodes of the package: EKF Local Node: Fuses data from an IMU (100Hz) and wheel encoders (4Hz). ...
55 views

### transform IMU reference to robot reference

I have an IMU rigidly attached to the end effector of a robotic arm. The goal is to compare the orientation of the IMU to the orientation of the robot arm. The 9-axis IMU data is used in a sensor ...
324 views

### Particle Filter for IMU tilt angle and bias estimation from Kalman Filter models

I understand the functioning of Particle Filters from the book Probabilistic Robotics and the robotics course provided by Cyrill Stachniss. I want to implement, from scratch, a particle filter to ...
617 views

### How to estimate yaw angle from magnetometer and gyroscope?

I'm using the MPU9250, it measures acceleration, magnetometer, gyro, etc. Complementary filter tutorial for this is here, however this tutorial does not have a magnetometer and I do, thus I thought I ...
223 views

### How to handle sensor data for a sensor-fusion algorithm

I am implementing the explicit complementary filter(see below) with a 9DOF MEMS sensors (accelerometer, magnetometer and gyroscope) for attitude estimation. Currently, the gyro and accel update rates ...
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### How to properly calibrate a magnetometer in IMU for precise yaw?

EDIT: Moved to ElectricalEngineering StackExchange Community I'm using Sparkfun Razor IMU 9DOF sensor which incorporates accelerometer, gyroscope, and magnetometer, for giving the Euler's angles (yaw,...
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1 vote
20 views

### Obtaining UAV flight trajectory from accelerometer and gyro data

I have an accelerometer and gyro scope data logged from several drone flights. I want to obtain flight trajectories from this data. I am considerably new to robotics. But from what I read, I ...
• 121
1 vote
30 views

### Observability of Gravity in SLAM

A number of SLAM systems only optimize over 4 variables(location and yaw) as they argue gravity is observable which constrains roll and pitch. I don't understand this argument since in theory you ...
• 359
1 vote
103 views

### High frequency robot-localization output when fusing GNSS + IMU

I'm in the process of tuning a robot-localization package parameters in my sensor-fusion ROS2 package. I have a dataset from various sensors mounted on a vehicle (IMU, GNSS, Lidar, Rgb Cameras, Radar, ...
1 vote
413 views

### How does IMU pre-integration work and how is it different from EKF?

My understanding is that IMU pre-integration is to get away from having to re-integrate the the IMU between key-frame intervals when doing bundle adjustment. The formulations I ave seen involve a ...
• 359
1 vote
53 views

### Compensate tractor's (vehicle's) tilts in the GNSS-IMU based system

I have the following setup: a tractor with a dual band antenna (from ublox) installed on the vehicle's symmetry axis on the roof (h=3m), approx. 1m ahead of the center of the rear axis (which I ...
• 11
1 vote
682 views

### robot_localization not fusing imu data

According to the documentation in : http://docs.ros.org/en/noetic/api/robot_localization/html/state_estimation_nodes.html I was able to transform the imu data header fram from "imu_link" ...
• 11
1 vote
476 views

### How do you rotate positions from ENU-frame to body frame?

If positions are in the local frame of ENU (or ECEF - either works), how do you rotate that to the body frame of the device? Logically, I thought that I could use the pitch, roll, and yaw angles of ...
1 vote
126 views

### IMU Senosr fusion algorithm of gyro and accelerometer during acceleration of vehicle

Hello so we have a car with 10 IMUs mounted at different locations of the car and the idea is the measure the centripetal force at each location of the car and compare it to each other. We also need ...
1 vote
297 views

### What exactly is meant by the "Bias instability over temperature range" specification on IMUs?

I'm trying to become educated on IMU specifications, and my understanding is that when comparing IMUs, the Gyros make the big difference. I am looking at the InertialLabs IMU-Nav-100: https://...
• 11
1 vote
608 views

### Why does AHRS system with Madgwick filter has so big drift?

I have an MPU9250 on my PCB and I use an AHRS system with a Madgwick filter to get yaw angle. I want to get very accurate and non-drifting yaw angle, but, for unknown reasons, I can't. I calibrated ...
• 158
1 vote
82 views

### Digital compass precision in urban environment

I'm working on an application to compute the absolute heading (yaw) using the following hardware: WIT-Motion HWT905 IMU https://www.wit-motion.com/digital-inclinometer/witmotion-hwt905-ttl.html. It ...
• 111
1 vote
74 views

### How do you derive the soft iron matrix for magnetometer calibration?

Can someone send reliable sources for how this is derived? I understand the diagonal values are for scale, but how do you determine all 6 values needed for this matrix? I would also like to normalize ...
1 vote
67 views

### What could cause quaternion error to go up drastically when a gyroscope is rotated on more than one axis at a time?

Alright, I'm working on a small Arduino script that determines orientation using a a gyroscope and a quaternion. My hardware: LSM9DS1 IMU (Gyroscope, Accelerometer, Magnetometer) Teensy 4.0 My basic ...
1 vote
92 views

### Barometer altitude calculation

I want to calculate altitude using a barometer which is mounted in the proximity of a number of components which get quite hot and raise the localised temperature. The barometric pressure equation is ...
• 69
1 vote
215 views

### Can someone help me understanding reference frames in OxTS data in KITTI Vision Benchmark dataset?

If anyone has worked with KITTI dataset, can you explain the reference frame used in roll pitch yaw values? I downloaded the raw data from this link: http://www.cvlibs.net/datasets/kitti/raw_data.php ...
1 vote
60 views

### Intel Realsense Cameras for Object Avoidance and SLAM to go to destination

My goal is to make a UAV which can search an area while avoiding obstacles. I figured I would navigate using the SLAM and Intel Realsense D435i (a stereoscopic camera with an IMU built in), but all of ...
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1 vote
1k views

### Yaw, Pitch, Roll rate concepts and how to calculate them with an IMU

I need help understanding the difference from Y/P/R rate and the data that I can get from a gyroscope. I am using the raw readings of my IMU (MPU9250) and the Madwick Filter to calculate a quaternion ...
1 vote
52 views

### Yaw from quaternion with non zero pitch

If IMU is gravity aligned, pitch is zero and yaw is unobservable. If IMU is not gravity aligned, pitch is non zero and yaw is observable. Question: given an input quaternion with non null pitch, how ...
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1 vote
75 views

### Kalman filter to fuse ultrasonic altitude sensor and accelerometer

I'm a little confused on how to set up the Kalman filter matrices to fuse an ultrasonic altitude sensor and accelerometer from IMU. I am trying to implement this for a quadcopter. And what I'm ...
• 71
1 vote
132 views

### Writing IMU accelerometer data into as twist messages into cmd_vel

I am reading accelerometer data from the wiimote /wiimote/state topic. A sample of the data I'm working with is as follows: ...
• 155
1 vote
350 views

### Is it my PID that is unstable or my physical system? (Quadcopter)

I've been working on this Arduino-MPU6050 quadcopter for a while now, and it looks like it's close to being finished. I have programmed it in rate mode, so the PID's control the rotational velocity. ...
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1 vote
138 views

### Using an AR.Drone's IMU to perform PDR

My task is simple: I want to move my drone manually around a room (IMPORTANT: I DO NOT WANT TO FLY IT) and I want to see its position update on a map using IMU data. I've attempted something in ROS ...
1 vote
217 views

### Accelerometer, gyro, and magnetometer sensor fusion for material resource survey

As a hardware engineer, I have studied quite a lot on sensor spec such as Accel, Gyro and Magnetometer including custom made fluxgate. I have studied matrix and quadarion (complex number) and so on. I ...
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1 vote
1k views

I recently decided to build a quadricopter from scratch using Arduino and now I'm faced with an orientation estimation problem. I bought a cheap 10DOF sensor with 3 axis magnetometer, 3 axis ...
1 vote
578 views

### Fusion of GNSS position data and prefused 9-dof AHRS data

Bosch, FreeScale, InvenSense, ST and maybe others are releasing 9-dof AHRS platforms containing their own fusion software and outputting filtered/sane/fused data (attitude as quaternion and linear ...
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### Sensor Synchronization, IMU and Bundle Adjustment

Sensor synchronization is a general issue with SLAM systems, the ideal is having an IMU hardware synchronized with cameras. There are a couple other possible variations though. One variation is ...
• 359
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### Integrating t265 into an existing urdf

I am developing a SLAM system using a 2D Lidar and some other sensors. I am using slam_toolbox to create the map->odom_frame tf, but I have a lot of doubts and issues about it. I am using a t265 ...
16 views

### Integrating acceleration data to obtain the trajectory - where did I do mistake?

I am trying to implement the code to obtain UAV flight trajectory by double integrating its acceleration data. To start with I prepared a dummy flight trajectory and double differentiated it to get ...
• 121
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### Unconnected tf trees to obtain IMU frame movements relative global frame in rviz (Realsense D435i)

I am trying to obtain the position and movements of the IMU within a Realsense D435i camera from a .bag file. I am using the command ...
15 views

I have a simple question about the usage of the filters included in imu_tools. So far I have succeeded sending my IMU data to rviz from a bag of a D435i RealSense ...
11 views

### IMU odometry in rviz starting from a bag file (No TF data)

I'm working on a project where I need to read IMU data from a .bag file of a RealSense D435i and obtain its spatial position through filters like those in imu_tools to visualize it in Rviz (together ...
53 views

### Implementing IMU on Hector SLAM

I am working on a project where I need to create a map of buoys on a surface vehicle and return to the starting position after finishing the parkour. The problem is, using Hector SLAM only, both the ...
16 views

### Extended Kalman filter + IMU sensor

I'm trying to implement an extended Kalman filter to the accelerometer and gyroscope. However, the result is not good. It seems to have some errors in my codes. I check the equation and code again but ...
39 views

### IMU and Magnetometer Conventions in ROS: Sanity check

I am trying to use a system that integrates one IMU and one Magnetometer for an outdoors vehicle, but I am struggling to fully understand some of the conventions used by ROS. I would like for this to ...
62 views

### Odometry with robot_localization using GPS and Imu, not encoders

I'm working with a mobile robot with GPS and IMU and I need to get the odometry without encoders so I'm trying to tune the robot_localization pkg for Ros2 Humble using dual ekf and navsat_transform. I'...
19 views

### Is it possible to set ZED 2i IMU ENU Frame

I am trying to implement the ZED 2i IMU data into the robot_localization Extended Kalman Filter. The robot_localization package requires the IMU sensor to be in the ENU frame (0 when facing east, and ...
106 views

### IMU adafruit BNO055 driver for ros2

I hope you're all having a great day! I'm here with a couple of questions regarding IMUs and their drivers: For those familiar with the Adafruit BNO055 IMU connected to an Arduino Uno, which specific ...
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38 views

### Unscented Kalman Filter Implementation for Robot Localization using wheel odometry and IMU

I'm trying to implement an unscented Kalman filter algorithm for differential robot localization. The sensors I'm using are wheel encoders and 9-DOF IMU. I've implemented the part of the filter for ...