# Questions tagged [imu]

Inertial Measurement Unit

98 questions with no upvoted or accepted answers
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### 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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### 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 ...
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### 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 ...
361 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 ...
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### 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 ...
315 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 ...
605 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 ...
222 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
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### 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 ...
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1 vote
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### 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
384 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 ...
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1 vote
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### 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 ...
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1 vote
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### 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" ...
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1 vote
445 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
122 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
281 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://...
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1 vote
589 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 ...
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1 vote
80 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 ...
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1 vote
71 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
66 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 ...
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1 vote
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### 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
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### 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
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### 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
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### 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 ...
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1 vote
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### 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: ...
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1 vote
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### 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
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### 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
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### 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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### 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 ...
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### 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 ...
41 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'...
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### 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 ...
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### 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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### 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 ...
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### robot_localization performance with two IMU+GPS combinations

I use the same config file to compare the performance of two different IMU+GPS fusion for the same experiments. The performance of one pair of the IMU+GPS sensor fusion performs great when ...
60 views

### EKF not providing good position estimation

I am working on a robotics project and I am using the package robot_localization in ROS2. I am trying to fuse the wheel odometry and IMU data, but I am struggling a lot to make it work. I've read a ...
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### Can you recommend imu sensor?

I am making a self-driving car. I use ros2 humble. I need imu sensor and driver. Can you recommend imu sensor and driver?
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### Aligning Point Cloud with IMU Heading in Sensor Fusion Setup

I'm currently working on a sensor fusion setup involving an IMU that provides absolute orientation with respect to True North and an Ouster Lidar generating PointCloud2 data. The IMU publishes to the ...
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### How odometry data generated from IMU and motor encoders

I am working on an autonomous robot that needs nav_msgs/Odometry to work with ros navigation stack nav_msgs/Odometry ...
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### I am publishing Yaw. I am getting continuous rotation along Z axis

I am reading and publishing Yaw from mpu6050.but i am seeing continuous rotation along Z axis. I am using Rviz to visualize MPU data. although when I actually rotate the sensor I get rotation. below ...
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### I need IMU file

I am developing a self-driving car using the ros2 humble. I don't have IMU sensor now. https://github.com/CCNYRoboticsLab/imu_tools But I want to see if the codes on this site work properly on my ...
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### How to integrate IMU9250 with RPLidar A1M8 using ROS 2 Humble

I am trying to integrate IMU9250 with RPLidar A1M8 using ROS 2 Humble. Therefore, I have taken the following steps: Installed Ros2 humble on Raspberry Pi 4 Installed RPLidar A1M8 Launched the RPLidar ...
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### Why multiply noise and random walk values by some constant value

I was exploring calculation of IMU intrinsics (random walk and noise values) for IMU using kalibr tool using this video. At timestamp 25:48, Patrick says, "typically we dont use values generated ...
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