Questions tagged [imu]

Inertial Measurement Unit

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How to perform time-offset calibration use GTSAM in Camera-IMU system?

Assume we have camera poses data and IMU data(which include gyr and acc data) with different timestamps, now I want to estimate this value, I known that this can be done in many ways(EKF,MSCKF), but I ...
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PID controller for slowly varying system

I am making a robot that is required to move in a straight line, but it is slowly turning on the left or right, this error keeps accumulating (eventually resulting in a very large radius turn). So, ...
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Nao robot IMU data rates

I'm trying to stream data from the Nao's inertial unit in its trunk. However the update rate is quite slow ~ 1Hz. Is there any way to improve it? For reference, I issued the following command using ...
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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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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 ...
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Incorporating motion model in Graph Slam and Bundle adjustment

When doing global bundle adjustment how does one incorporate a motion model or IMU information? Does it simply impose a cost function in relation to how far away the expected location is of the robot ...
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Mapping IMU readings from body frame to navigation frame

I'm trying to combine IMU displacements with the time of flight sensor readings in order to navigate through the indoor environment with a non-linear Kalman filter variant. In the graphic below, I ...
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What is the consquence of Gimbal lock?

I'm learning about Gimbal lock and I understand the reason why that happened. But I don't understand why that is a big deal because it only affect this rotation. After this rotation finished, we have ...
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Could hall encoders that are attached to the DC motors affect each other or the IMUs?

I am a newbie and I want to build an autonomous mobile robot. I am planning to use 4 DC motors with hall-effect encoders. I will use 4 IMUs for localization at first. Next, I also have the plan to ...
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Uncontrolled drift of Visual Inertial Odometry

I'm trying to use the VINS-Fusion package to obtain odometry for a quadcopter. The primary sensor is an Intel Realsense D435i. I've calibrated the camera and IMU extrinsics using Kalibr. IMU ...
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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 ...
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Choosing the correct settings for Mahony or Madgwick AHRS filters

I'm using the Adafruit Mahony / Madgwick AHRS filters to get quaternions (Euler angles to better understand output), using a calibrated BMX160 sensor. I'm polling the sensor at 100Hz. I've read ...
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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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Why does the HG4930 IMU have better specifications than the HG1700, even though it's almost certainly worse?

I was browsing and looking at different IMUs and came upon the following Honeywell page: https://aerospace.honeywell.com/us/en/learn/products/sensors/inertial-measurement-units There they have a table ...
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Compensation of sudden impacts/shocks in adaptive AHRS sensor fusion algorithms

Background I have a 9-DOF MEMS-IMU and trying to estimate the orientation (roll, pitch and yaw) in scenarios (e.g. car crash) where sudden shocks (mainly linear) lead to high external accelerations ...
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Why doesn't yaw angle return to its 0 state after rotations?

I'm using STM32F4 mcu with MPU6050 on it. I want to get very accurate yaw angle using gyroscope with Madgwick filter. I tried lots of things: with and without gyro thresholds, with and without ...
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Sensor fusion with extended Kalman filter for roll and pitch

I'm trying to implement an extended Kalman filter to fuse accelerometer and gyroscope data to estimate roll ($\phi$) and pitch ($\theta$). I've found a lot of kalman filter questions but couldn't find ...
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GPS + IMU data and kinematics equations

I have the following data Longitudinal acceleration, $a_x^{IMU}$ Lateral acceleration, $a_y^{IMU}$ Vertical acceleration, $a_z^{IMU}$ Yaw angle, $\psi$ Yaw rate, $\dot{\psi}$ Latitude, $\rightarrow ...
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Do electromagnets affect magnetometer calibration?

I am designing a landing pad for a drone that will have electromagnets built into the pad. My drone has a pixhawk 2 with PX4. I'm worried that the electromagnets in the pad will throw off the drone's ...
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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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How to calibrate a magnetometer on a heavy robot

I am wondering how to calibrate a magnetometer on an IMU that is installed on a heavy robot. Normally, hard and soft iron calibration is done by spinning the IMU in all axis, but since it is installed ...
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How to use Quaternion from IMU to get the transformation to inertial reference frame?

Im trying to get the Linear Velocity integrating the acceleration from IMu. I know there will be accumulated error due to integration bit before the integration I have to do couple of other steps. ...
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What would be a way to estimate IMU noise covariance matrix?

Weirdly enough, my robot platform which has an official ROS package supported by a manufacturer doesn't provide any covariance matrices of its sensors. So, I'm basically trying to estimate these ...
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C++ (ROS node) for Euler Integration to estimate Velocity knowing the acceleration

Hi I have IMU reading and would like to estimate the linear Velocity knowing the linear acceleration from the IMU using the Euler method. Im aware of the accumulated error. So need a C++(python) code ...
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Sensor fusion in a metal heavy environment

I am trying to get heading information of a forklift. I've designed a small PCB for this purpose. This PCB has a 3 axis magnetometer and a 6 axis gyroscope-accelerometer (Z- axis looking towards the ...
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Linear Velocity from robot_localization Package after IMU integration and and only one sensor (IMU) as sensor input

Im using the robot_localization robot_localizationto get the linear Velocity of underwater simulated ROV with Gazebo. In order to get the correct orientation of the linear (twist) component of the ...
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How to set up parameter in hector_localization stack to fuse IMU and Barometer (Pressure sensor)?

Im checking the hector_localization hector_localization stack, that provide the full 6DOF pose of a robot or platform. It uses various sensor sources, which are fused using an Extended Kalman filter. ...
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TF is broken when using robot_localization package with only IMU sensor, how to assure that the measured velocity is the one from the robot?

Im using thisrobot_lokalization robot_localization package for the linear velocity. As only sensor input in my case is IMU. I configure the parameters and set the frames as follow ...
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How to minimize the error integrating 3D angular velocity data obtained by the IMU to get linear velocity?

I have IMU sensor that gives me the raw data such as orientation, Angular and Linear acceleration. Im using ROS and doing some Gazebo UUV simulation. Furthermore, I want to get linear velocity from ...
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How to do transformation to get correct linear velocity from linear acceleration IMU data?

I have IMU sensor that gives me the raw data such as orientation, Angular and Linear acceleration. Im using ROS and doing some Gazebo UUV simulation. Furthermore, I want to get linear velocity from ...
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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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How do you convert the covariance matrix of a 3D rotation error-state to the covariance matrix of the corresponding quaternion?

I'd like to convert the covariance matrix of an error-state Kalman Filter that uses Euler angles to the corresponding covariance matrix of a quaternion state. I basically use this for standard INS-...
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Obtaining Heading vector from IMU

First time here. I'm an electronics engineer who has been tasked with this problem: Given the 4D quaternion representing a vehicle orientation, how do you get the heading vector? The vehicle ...
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Do you need to know the orientation between aircraft and IMU for IMU alignment?

I have a fixed wing aircraft and a MEMS IMU, but I am uncertain of the exact orientation between the IMU and aircraft. In the manual for the IMU, it recommends undergoing an alignment procedure prior ...
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Bug in code of Self-Balancing Bot

I am making a Self balancing bot as my project in which I am using MPU6050, Arduino Uno, motor driver l298n and DC motors. I am making this using data from accelerometer and gyroscope and combining ...
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GPS+IMU sensor fusion not based on Kalman Filters

Do you know any papers on or implementations of GPS + IMU sensor fusion for localization that are not based on an EKF (Extended Kalman Filter) or UKF (Unscented Kalman Filter)? I'm asking is because ...
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How to avoid gimbal with Quaternions

I'am working with an LSM6DSO32, so I'am starting with Kalman filter, everything works but with Euler angle I got gimbal lock I think... But if my pitch angle approach to 90° my roll angle jump and I ...
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Beginner needs help with Self-Balancing-Robot build

I'm looking for help on a 1st build self balancing robot, something that seemed pretty easy but not. I'm retired so have plenty of time but no real robot skills, electrical, mechanical yes. I have ...
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IMU gravity sensing

How are IMUs used to sense the direction of gravity? I have read a number of articles that talk about using IMU for orientation of flying robotics but I do not understand how. Could someone explain ...
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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 ...
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1 answer
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How to actually fuse sensor using Extended Kalman Filter

Background I'm working on 4-omniwheel mobile robot. It have encoder on each wheel and MPU 6050 IMU. The robot positioning suffer a great error because slip, so i try to increase the accuracy of ...
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Drone lost traj recovery

So I am using slam algorithm to localize the drone which is gps denied . The input to the slam algo is imu data and a video . Now after the first run of the slam algorithm it creates the trajectory ...
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How to calculate the ground truth of your own simple dataset for testing your SLAM Algorithm?

I have tested my SLAM algorithm on EuRoC, TUM and KITTI Datasets. But I would like to test on my own custom dataset. Moreover, I already rectify how to make my own dataset in TUM dataset format, but I ...
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Localization and Mapping in a Small Crop Field

I have a small crop field inside my house and I want to create a map of it. The goal is to create a map so that I can monitor the growth of the plants and do some post processing to analyze the ...
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How to set initial heading

I'm confused how to set up an initial heading for my mobile robot project. I've determined heading from gyro integration and also using magnetometer readings. Gyro initializes at 0 and magnetometer ...
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Does it matter how I mount an IMU board?

I am going through the board's calibration process and it is declaring success. Do I still need to pay attention to how I mount the board, that is, match the x,y,z directions printed on the board?
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When Implementing Madgwick filter for attitude estimation, the calculated Euler angles are drifting significantly. What could be the reason?

The Beta value is set according to the original report, which specifies for IMU B-0.033. and the sensor data acquisition and filter update is periodic at 200Hz. The angular velocity values from the ...
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IMU Change of reference frame

Im trying to rotate one accelerometer vector from body frame to ned frame, but i cant found what im doing wrong. For now, im using an online dataset that provides me roll, pitch and heading ...
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2 votes
1 answer
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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 ...
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IMU-Camera Senor Fusion

I am working on fusing IMU and Camera Sensor Fusion for the Drone to precisely land on the target location. With the Camera, I am tracking the April Tag which is on the ground. This gives me the x,y,z ...
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