# Tag Info

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### what is the algorithm to get position (Linear displacement and linear velocity ) using IMU (Like MPU6050)?

I thought for sure that there would have been a duplicate question somewhere on the site that answers this question, but I can't find one, so here's a quick description of the method. Put your IMU ...
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### Explanation of Quadcopter Dynamics, Components and Control

A couple things, the first is that the controller does not really care what the "real" values are. Everything is relative, if the controller sees that it is sinking it will increase the thrust until ...
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### What information an IMU gives to a drone?

You already know the answer - because as you say it contains an accelerometer and a rate gyro. An accelerometer measures linear acceleration, a rate gyro measures angular velocity. These are the only ...
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### Stabilizing a Drone

Gyro is needed to stabilize angular acceleration. Knowing only your attitude, drone doesn't know how fast on which axis is rotating, knows only where is gravity ...
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### Kalman Filter GPS + IMU

This is a complete re-working of the answer I had originally provided. If you're curious, you can check the edit history and see what was posted earlier. In comments to this question, OP stated that ...
• 15.9k
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### Detection of linear acceleration vs rotational velocity/acceleration

The IMU itself cannot distinguish between "true" linear acceleration and "fictitious" (Coriolis) linear acceleration induced by rotation of the IMU coordinate frame with respect to ...
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### How to avoid gimbal with Quaternions

Quaternions are a more efficient way of storing the orientation matrix of a frame. I use the vector-scalar convention for quaternions (3+1 = 4 quantities) and have defined the following utility ...
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### Practicality of using magnetometer inside AUV

Mags are used in almost all UAVs. It will be useful and it will be a unique source of information. Adding a some shielding between the mag and your computers and power lines will greatly reduced the ...
• 1,853
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### What is the consquence of Gimbal lock?

I made a clip for you (https://i.sstatic.net/Z0q5Y.jpg) using Unity, which internally represents rotations as quaternions, but uses Euler angles for display and positioning. You can see that, at zero ...
• 15.9k
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### Why do we need to know the translation between Camera and IMU?

You answered yourself. Your underlying model of point moving through space usually assumes the center of gravity to match the camera frame. If your inertial sensor have a translational offset from ...
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### Localising a robot placed at an unknown position in a known environment

The problem is that you can't apply path planning until you know where the robot is in the global coordinate frame. There are many localization techniques, and each has its pros/cons; I have used ...
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### Self balancing robot control system strategies

I can recommend an alternative which has worked for me quite well. I derived the dynamical model of a inverted pendulum, then linearised it around the stable operating point. With this simplified ...
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### Shield IMU from magnetic interferences

Nope. Magnetometers measure the magnetic field. The field it's measuring is going to be the sum of fields from a variety of sources. The field you're interested in is the earth's. But it is not ...
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### Need help regarding development of Extended Kalman Filter for sensor-data fusion of odometry and IMU data

Adding to the above, my favorite way to debug a misbehaving filter is to isolate each step. Make sure your prediction step works before correcting it. Your bot should drive straight right with 0,0,0 ...
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### Compensation for IMU mounting misalignment

You need the transformation from the car to the IMU. You can get this by recording the IMU published attitude with the car in known orientations. You should be able to construct the IMU to car ...
• 1,853
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### I fused a GPS and IMU and I am wondering if my results make sense

Do you have a simulation? I would recommend that you simulate the data first to debug and tune your KF. The simulation should model the true IMU outputs (Grove has some details on that) and true ...
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### angular velocity output of IMU

1) An inertial frame is one in which a free particle travels in a straight line at constant speed, or is at rest. Practically speaking, you usually check if a frame is inertial or not by ...
• 341

### Navigation - GPS + IMU; how to make it more accurate?

You should use a Kalman Filter. Here are two nice tutorials that explain how Kalman Filter algorithm works and the working principle of IMU/GPS sensors. short: https://www.navlab.net/Publications/...
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### Yaw from IMU acceleration

If you assume the IMU lies on a fixed incline plane with pitch $\theta$, and you define yaw $\psi$ as the rotation between the IMU and the downhill direction, then the answer is \psi = \text{atan2}(-...
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### Some Kalman filter implementation queries

Answers are inline Qn 1. Does kalman filter require constant time step? Correct it does not. The reason you may find in literature that it requires a constant time step has to do with with lack ...
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### Extended Kalman filtering for IMU and Encoder

EKF sensor fusion is achieved simply by feeding data streams from different sensors to the filter. So all you need to do is setup your implementation to accept both encoder and IMU data. This is ...
• 1,363
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### Do IMU have value in SLAM?

IMU's are extremely useful in SLAM. Here is just a basic list of some of the benefits/uses. Provides an initial guess on pose for optimization methods. Helps filter out outliers for computer vision ...
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### Do IMU have value in SLAM?

The IMU should be used for what it does best : measure accelerations and angular velocities. As you guessed, the IMU integration is poor (not usable for navigation purpose) and the attitude estimation ...
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### To calculate roll,pitch and yaw

The position coordinates x, y, z are inadequate information to compute the roll pitch and yaw. x, y, and z are the position of the vehicle in space. roll, pitch, and yaw are the attitude or ...
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### Does it matter how I mount an IMU board?

Not necessarily, so long you're aware how the IMU's mounting orientation may affect readings. I don't know what IMU model you're using or how, but assuming it integrates a gyroscope and accelerometer, ...
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### C++ (ROS node) for Euler Integration to estimate Velocity knowing the acceleration

I find it easiest to make a class for stuff like this, where you have data you want to use between callbacks, or your want to publish a message inside of another callback. For example, your class ...
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### How to deal with asynchronous samples in a kalman filter framework multi-sensor fusion?

The correct way of integrating multi-rate observations in a Kalman framework when the measurements are unavailable is to let the system evolve resorting merely to the prediction steps. Therefore, set ...
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### Open source implementations for GPS+IMU sensor fusion?

A followup on holmeski's reply. It seems those pages have been taken down. I found the old webpages on the 'Way Back Machine'. Pixhawk Attitude Estimator (EKF) Pixhawk ekf_att_pos_estimator (...
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### Need help regarding development of Extended Kalman Filter for sensor-data fusion of odometry and IMU data

You should first validate your filter is working before second-guessing your modelling choices. But I agree both those filters look OK (although I did not double check all the maths) and both of your ...
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