10
votes
Accepted
How can we use the accelerometer for altitude estimation?
The barometer carried on the pixhawk has an altitude resolution of 10 cm. If that isn't enough, you could write a kalman filter that uses the accelerometer data in the prediction step and the ...
- 1,825
7
votes
Open source implementations for GPS+IMU sensor fusion?
Yes. The px4 software for the pixhawk autopilot has an extended kalman filter that uses an accelerometer, a gyroscope, gps, and mag.
A paper describing the a smaller ekf which only estimates attitude ...
- 1,825
6
votes
Accepted
How to localise a underwater robot?
Localization under water was always a problem in ocean robotics as electromagnetic signals do not propagate very well in water. I think your best localization sensor in that case would be the good old ...
- 671
5
votes
Accelerometer, gyro, and magnetometer sensor fusion in 2d
The gyrometer gives you angular velocity about each axis. You simply integrate these values to get the roll, pitch and yaw of the robot. Since this is 2D, all you care about is yaw, and you'll ...
- 866
5
votes
How to track robot position?
How to estimate a robot's position depends on how well you'd like to estimate it. If you just need a rough guess, try odometry, it works OK. For better results, you have to incorporate more sensors. ...
- 5,162
4
votes
How to localise a underwater robot?
If it's actually underwater, how about a webcam looking at the tile pattern on the floor? (Could be considered "cheating" as it will obviously fail in a natural lake, for example.)
You can find a ...
- 1,021
4
votes
How to localise a underwater robot?
One of the prime sensors for global localisation on land is GPS. This is not an option underwater because electromagnetic waves get absorbed quickly.
There are however alternatives, which provide ...
- 2,954
4
votes
How to track robot position?
I am not allowed to comment, so I have to add a reply. By position, do you mean the location in space (so X, Y coordinates), or orientation (tilt, etc)?
If position, you can use the accelerometer ...
- 169
4
votes
Accepted
Multiple position estimates fusion
What you are describing is essentially a textbook case for using a Kalman filter. First you need a prediction step. Let's assume you are predicting the pose of the robot $(x,y,\theta)$, given the ...
- 950
4
votes
Open source implementations for GPS+IMU sensor fusion?
ROS has a package called robot_localization that can be used to fuse IMU and GPS data. This package implements Extended and Unscented Kalman filter algorithms.
The package can be found here.
- 378
3
votes
Simple Sensor Fusion for pose estimation
So you have acceleration readings from your IMU (linear and angular), and you get velocity readings (linear only) from wheel encoders.
Get velocity from linear and angular accelerations with
$$
v = ...
- 14.7k
3
votes
Accepted
Transforming angular velocity?
I think your diagram is missing an angle for the laser angle with respect to the vehicle body -- I'm going to call that angle $\alpha$, see this diagram for clarity:
Since it seems you are tracking ...
- 1,357
3
votes
Accepted
Balancing a plate with an IMU offset from the center
Basically it does not matter.
But you have to be carefull if the plate is rotating fast, because the rotation of the plate around its center point, with the IMU placed out of center, will cause the ...
- 1,647
3
votes
Overcorrecting Kalman Filter
There is an error in your posted equation for the Jacobian $F_J$, so that could be the source of the problem. It should look like this:
$F_J = \begin{bmatrix}
1 & 0 & -C \sin \theta \\
C \...
- 1,357
3
votes
How to localise a underwater robot?
If you cannot use a camera the task is nearly impossible with your money limitations.
Professionals use a scanning sonar like the tritech micron and a particle based localization like [3] based on ...
3
votes
Accelerometer, gyro, and magnetometer sensor fusion in 2d
Using an IMU you can only measure: acceleration, rate of rotation, and direction of magnetic field. You cannot measure velocity, you can only integrate the acceleration to infer velocity. As you can ...
- 6,337
3
votes
Accepted
quaternion implementation
So, as I mentioned in an earlier comment, it looks like you're using a mashup of methods. You're not applying any one method correctly; instead you're mis-using part of one method, then using the ...
- 14.7k
3
votes
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 ...
- 5,162
2
votes
Controlling a system with delayed measurements
The most straightforward approach is to use a Kalman filter with a memory of recent state history. While waiting for measurements you do the standard time update. When a new measurement arrives, you ...
- 2,689
2
votes
Accepted
Measurement and physics model fusion
Kalmnan filters are typically used for sensor fusion. You create a model for what you expect the process to look like, use your sensors as inputs, and the output is the filtered estimate. I'm not ...
- 14.7k
2
votes
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 (...
- 21
2
votes
Solution for INS and GPS integration
I was in exactly the same boat with my master's thesis; wave-based imaging (sonar and radar) seemed so common that all the papers I read assumed you knew the fundamental concept and they were going to ...
- 14.7k
2
votes
Are there off the shelf solutions for GPS+INS (accelerometer,gyro,magneto) sensor fusion for getting filtered/fused location and speed output?
There are many GPS+INS fusion units available on the market. The price, weight and size of the units can vary dramatically depending on the GPS positioning accuracy and rate of drift from the INS. The ...
- 21
2
votes
Accepted
Robot positioning using IMU quaternion data?
The quaternion only contains information about the rotation of the vehicle. It will not contain information about the location of you vehicle on a 2-d plane.
One method of converting quaternions to ...
- 1,825
2
votes
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 ...
- 872
2
votes
Gyro Yaw Drift Compensation With The Aid of Magnetomer
my roll and pitch drifts are corrected with accelerometer inside IMU
You mean they're being correct by the IMU, or you're correcting the readings yourself using the accelerometer from the IMU?
i ...
- 14.7k
2
votes
Is it possible to track position using gyroscope and accelerometer without a magnetometer?
The short answer is that it's possible, but tricky.
To estimate position you integrate accelerometer readings over time to get linear velocity estimates, and then integrate the velocities to get ...
- 1,266
2
votes
Accepted
EKF sensor fusion
An EKF or any of the variants of the Kalman filter, as you said mainly works in two steps: prediction and correction. The prediction steps gives you a state estimate based on your process model and ...
- 114
2
votes
Bias correction for multiple sensor fusion through Kalman Filtering
Your state vector $x$ is correct.
When you do bias estimation(look up IMU kalman filters) you assume that the bias is constant/slowly varying. So your $F$ matrix is just the identity(5x5).
Your $H$ ...
- 1,581
2
votes
Accepted
GPS Course vs IMU Course
So this probably won't work as course over ground and heading are often 2 different things. Heading is the direction your vehicle is facing, while course over ground is the direction your vehicle is ...
- 1,581
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