Questions tagged [imu]

Inertial Measurement Unit

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40 views

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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81 views

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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23 views

How to compute linear speed on scooter without gps and wheel odometry

My project is to be able to compute my linear speed on my scooter only with my IMU. I have a IMU build with my arduino which is in my backpack. I want first to compensate the acceleration measurement ...
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2answers
36 views

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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1answer
52 views

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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53 views

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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31 views

How is IMU noise dealt with between steps?

Direct integration of IMU will result in massive error incredibly quickly. What I am wondering is, how do you use an IMU over a small time intervals to aid in pose estimation? In particular, suppose ...
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31 views

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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39 views

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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133 views

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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87 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 ...
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344 views

IMU + GPS fusion and change of reference frame

I started working with GPS + IMU fusion using Kalman Filter. For this, I'm using Python, with Madgwick filter from a library (https://github.com/morgil/madgwick_py) and Kalman filter also from an ...
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41 views

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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25 views

Mono VIO vs. Stereo-Camera to recover Depth Information

I have a question. I have found some papers, where they use a Mono-VIO to recover depth of a scene. My question is: Suppose I have a robot arm and attach a mono-VIO system to it. Then I move this arm ...
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48 views

To calculate roll,pitch and yaw

How do I calculate roll,pitch and yaw value from the position co ordinates of the drone, that is x,y and z from the gps sensor??? Using the x,y and z co ordinates I have to calculate roll,pitch and ...
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Do IMU have value in SLAM?

IMU are often used in theoretical models involving SLAM. I'm a bit confused on their practical value since error accumulation is so bad that after a couple seconds you need to completely ignore it. ...
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107 views

GNSS Dead Reckoning — Sensor Fusion Filter not necessary?

My question might be a bit off-topic but I don't know where else to ask. When I do have a GNSS Module with integrated IMU and <...
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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 ...
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180 views

Sensor fusion of GNSS and IMU using UKF

I do have a land-based robot with an IMU and a GNSS receiver. From the IMU, I get the velocity and acceleration in both $x$ and $y$ directions. From the GNSS receiver, I get the latitude and ...
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43 views

“catkin_make” prompts “+make” and “recipe for target … failed” errors

I have been working on a ground vehicle project for some time that has bunch of sensors, until now I have managed to overcome the problems I have encountered. I have used catkin_make many times and ...
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28 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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41 views

IMU Vision Fusion using EKF

I am trying to track an object indoors using an IMU (only accel and gyroscope) and a visual marker. This is similar to IMU+GPS fusion, where GPS is effectively replaced by the position that my vision ...
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107 views

Detection of linear acceleration vs rotational velocity/acceleration

I am wondering, how do you differentiate between linear acceleration and rotational velocity and acceleration for IMU? A rotational velocity or acceleration will still appear to the accelerometer as a ...
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30 views

Find IMU's movement direction in x-axis

I have an IMU device with an accelerometer sensor and I fix that on top of the linear motion rail.so it can only move to the right or left (in the x-axis) side. How can I determine the direction (...
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Angular movement of a controlled arm relative to an object via Two IMUs

I've been tasked to use two YEI 3-space sensors (IMUs) to detect the azimuth and elevation (altitude in the image below) angle of a moving arm with respect to a fixed object, with a sensor on the end ...
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113 views

Custom implementation of robot_localization package

I plan to implement a sensor fusion of IMU + Visual odometry using an EKF. I came across the excellent robot_localization package which does pretty much all that I want. However, I need to use perform ...
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Angular rate controller

I try to design an attitude controller with cascaded PD-P structure (angle-angular rate) for well-known quadrotor dynamics according to the thesis. I use an imu as expected in order to get the angle(...
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93 views

Estimation of pitch, roll, yaw angles: synthesis of an observer or IMU?

Dear Robotics Specialists, I want to contact you for advice. I am developing a control system for complex parallel mechanisms like what I presented in this thread. Formulas for calculating the ...
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74 views

Measurements of IMU (accelerometer and gyroscope) are drifted or with too much error

I placed my drone on a table (i.e, at rest) and save (using a ROS topic) the IMU readings: As you can see, there's a lot of drift or error. I would expect the $x$ and $y$ acceleration to be 0 (I know ...
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Is it possible to track position using gyroscope and accelerometer without a magnetometer?

I'm looking for help on a project where I will be placing sensor data in 3D space using augmented reality. Most solutions I have found for finding position with an IMU involve the magnetometer, but ...
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73 views

I2C Arduino Connection

I am working on a wheel mobile robot with multiple sensors which are IMU, two encoders, four ultrasonic sensors, and using two Arduino: Uno and Mega. The IMU, encoders, and ultrasonic sensors are ...
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360 views

Extended Kalman filtering for IMU and Encoder

I am trying to fuse IMU and encoder using extended Kalman sensor fusion technique. how do I fuse IMU pitch, roll with the orientation data I obtained from the encoder. Also, how do I use my position x ...
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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 ...
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79 views

How can i fusion gyroscope and accelerometer when accelerometer has only roll,pitch val?

I'm currently studying IMU Sensor with 6dof(gyro and accelerometer). My goal is to get Orientation of robot, and i found out that only 6dof imu sensor wouldn't be possible to get a correct Orientation ...
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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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161 views

How to Correct for Gyroscopic Drift?

I know similar questions have been asked before, but I have researched for hours now and have not been able to find a viable solution. I have a Raspberry Pi 4 and the Adafruit LSM9DS1 IMU, which has ...
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63 views

Some Kalman filter implementation queries

Just to clear some doubts: Qn 1. Does kalman filter require constant time step? From my own study, it does not seem necessary to have a constant time step. You just need to take into account time ...
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415 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 ...
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28 views

MPU6050 Gyro rotaion always around Y axis

I am using an MPU6050 IMU. I did a small experiment having Z-axis pointing upwards. 1. Rotate 90deg around Z-axis (yaw) and back to the original position 2. Rotate 90deg around X-axis (roll) and back ...
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396 views

Yaw from IMU acceleration

When IMU is gravity aligned, yaw is not observable from linear acceleration data. However, when IMU has non null pitch, the sensor is not gravity aligned anymore and the gravity acceleration gets ...
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Gyroscope signal when mounted on a deflated tire

Before I do the experiment, I am a bit confused about the expected signals provided by a 3-axis gyroscope (angular velocities vs. time) mounted on the edge of a (slightly) deflated car tire when the ...
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1answer
66 views

How does one estimate motion from sparse encoders and IMU-Gyro data?

I have a robot which has (for simplicity) only one degree of freedom; it rotates about the z-axis (think like a crane), and has no slip. The shaft encoder delivers data in 0.1° increments, so when ...
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21 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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26 views

Optical flow inputs

I'm reading how the optical flow of my quadcopter works. The output of the optical flow that interests me is the linear (horizontal) velocity: $v_x$ and $v_y$. Here (page 10) it says that it fuses the ...
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1answer
133 views

Complementary filter for gyroscope and accelerometer

I am trying to understand how the complementary filter works. I did some research and i found this: I am confused about the noise and drift before any filter is applied. I have 2 questions: In the ...
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69 views

Does Vehicle Yaw angle measures same at every point on it? If not, how to translate yaw rotation to COG of the vehicle from different point?

I am using an IMU to measure the yaw rotation angle of a car. I need to translate the rotation measured to COG of the vehicle. I can ignore roll and pitch as I am driving it on a flat surface. So, ...
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150 views

How does sensor fusion help in robot localization

Good day... Sorry for bigner quesion, but really I need some friendly explanation rather than long reference I have 9 dof mpu9250 imu and gps. I found some source that calculate euler angle in ardunio ...
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1answer
84 views

IMU based joint angle measurement

Let us assume we have a two 2-DoF robot. Both axes rotate around x. And the goal is to measure the joint angle values with the roll value from IMUs attached on each link. However, the problem is that ...