11
votes
What is inverse depth (in odometry) and why would I use it?
The inverse depth parameterisation represents a landmark's distance, d, from the camera exactly as it says, as proportional to 1/d within the estimation algorithm. The rational behind the approach is ...
- 111
9
votes
How do monocular visual odometry algorithms work?
Monocular vision is a difficult and very interesting, particularly in its application to the general navigation problem. I will make an attempt at answering your questions, but if you find anything ...
- 926
6
votes
Odometry vs Dead-reckoning
Dead reckoning is determining pose (position and rotation) using speed estimates from sensors. For example, you know your initial position and use sensors such as encoder, accelerometers, gyros, etc......
- 335
5
votes
How to align solidworks global origin with assembly origin while exporting in solidworks to urdf
I did a little step-by-step tutorial with images, but if my other answer regarding aligning frames didn't work well for you, or the definition of "Front Plane" or "Top Plane" is confusing in ...
- 16k
4
votes
Accepted
How to perform odometry on an arduino for a differential wheeled robot?
I would add a few lines after you check that theta is between +/- 2pi:
...
- 16k
4
votes
What is inverse depth (in odometry) and why would I use it?
Davison's paper introducing the method is easy enough to understand:
Inverse Depth Parametrization for Monocular SLAM by Javier Civera, Andrew J. Davison, and J. M. Martınez Montiel DOI: 10.1109/TRO....
- 51
4
votes
What's the difference between the term "pose estimation" and "visual odometry"?
It is also often the case that the author lacks knowledge, makes mistakes, or is adding unnecessary statements to their work. Just because it is published does not make it true.
In this case though, ...
- 4,385
4
votes
What's the difference between the term "pose estimation" and "visual odometry"?
Pose estimation means determining position and orientation.
Odometry is using a (any) sensor to determine how much distance has been traversed, so visual odometry is just clarification that the ...
- 16k
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 ...
- 5,312
3
votes
Need help regarding odometry using Encoder motor and raspberry pi
You could maybe use Matlab to plot the position of your vehicle? This is how I'm trying to do that:
I have a 'logging'-program running on the Raspberry Pi that counts each sampling time the pulses ...
- 155
3
votes
Accepted
Tf frame origin is offset from the actual base_link
It looks like most of your parts have no rotation, but some of them do, so I'm going to guess that you didn't mate your assembly to the origin planes in Solidworks.
First, on your base plate, open ...
- 16k
3
votes
Plotting location using wheel encoder data
A few things:
I took a look at your data set. Did you make sure you used the time column correctly? The first entry is "1429481388546050050" without the decimal. To make it in seconds, it should be ...
- 980
3
votes
Multi-Rate Sensor Fusion using EKF
Part 1. Use one or the other. Often odometery is used instead of kinematics or dynamics for prediction, at least in my work.
Part 2.
This is handled by the construction of the measurement equation ...
- 5,312
3
votes
Public dataset for monocular visual odometry
http://vision.in.tum.de/data/datasets/rgbd-dataset
This is a set of recordings for the Kinect and Asus Xtion pro, which are all indoors (in offices and a hangar). It comes with precise ground truth ...
- 176
3
votes
Public dataset for monocular visual odometry
This is another more recent one, based on the paper A Photometrically Calibrated Benchmark For Monocular Visual Odometry by Engel et al:
http://vision.in.tum.de/data/datasets/mono-dataset
This gives ...
3
votes
Wheel Odometry Covariance Matrix for Custom Robot
The covariance matrix of the control inputs is measured and known.
That is, following the EKF equations on this page, the covariance of the control, $Q$ is (often) a diagonal matrix, where the ...
- 5,312
3
votes
Accepted
Problem understanding a paper about visual odometry
So SVO works a bit differently then other VO systems as it uses dense image alignment. You need to understand this concept first before understanding SVO. Look up Lucas and Kanade image alignment. The ...
- 1,831
3
votes
How to do odometry for 4 mecanum wheeled robot?
In order to transform encoder signals to robot motions a kinematic model of the robot is needed. In some cases this is very simple, just including the gear ratios and a heading angle (e.g. with ...
- 6,652
2
votes
Accurate Wheeled Robot Odometry
First, you can try adding encoders - you don't need to buy anything to do this. Only remember to perform UMBmark procedure first. It will allow you to get much more reliable odometry from encoders ...
- 953
2
votes
What is inverse depth (in odometry) and why would I use it?
In addition to the reasons mentioned in other answers about the numerical conditioning of inverse depth, a major reason for this term to appear in specifically visual odometry literature is in the way ...
- 324
2
votes
How to combine odometry information with time-shifted information from IMU?
You're robot must be moving pretty fast for this delay to cause problems.
Use a circular buffer to store the odometry readings, so you'll have a record of the last 100ms of odometry readings.
Use ...
- 4,385
2
votes
Plotting location using wheel encoder data
Thanks for the update. Now it looks like $x_c$ and $y_c$ denote the origin/starting position, and $\theta$ is positive, measured CCW from the positive x-axis. Now I am even more concerned about the ...
- 16k
2
votes
Mechanical odometer with digital output
The automotive industry frequently uses Hall effect sensors to measure shaft and gear rotation. The Hall effect has some beneficial properties: it operates over a wide range of temperatures, is more ...
- 4,386
2
votes
Multi-Rate Sensor Fusion using EKF
I've performed 2D localization with just odometry and a gyroscope before, and to be honest, depending on (i) how good your encoders are; (ii) what type of environment you're in (is there a chance your ...
- 980
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 ...
- 892
2
votes
Differential GPS or Simple GPS for Robot navigation and odometry?
Do not give up on encoders. They are a great complement to GPS. I don't know what precision you want to reach, or what terrain your robot will operate in, but wherever it will be, encoders will give ...
- 953
2
votes
Accepted
Markov Localization using control as an input
Multi-dimensional models
In the 2D case, $x_t$ is a vector with two components (e.g. position in $x$, $y$), but why stop at 2D? Often, the state vector $x_t$ will have your position in two or three ...
- 440
2
votes
Full 3D Pose (Scale, Rotation and Translation) Estimation using Gyro and Acceleromter sensors fusion
The packages you've found don't estimate scale or 3d pose because that's not really feasible using just an imu. The only way to get 3d pose from an imu is to integrate acceleration (adjusting for ...
- 2,794
2
votes
Accepted
Why the IMU measurements only accumulate drift in 4DOF
Correct, it's all about the gravity vector. I would argue that it is NOT necessarily possible to get the gravity vector out of the measurement, but that's because it's possible to put the IMU in a ...
- 16k
2
votes
Encoder for odometry (Wheel vs motor)
Since it's the wheels which change the robot's pose in the environment, I'd suggest putting the encoders to the wheels. Especially if the motor and the wheel are only connected by a chain, introducing ...
- 821
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