6
votes
Understanding Drift in Simultaneous Localization and Mapping (SLAM)
Your intuition is mostly correct. Returning to where you started and re-observing landmarks you mapped earlier is called closing the loop in the SLAM literature. As you mentioned, your uncertainty ...
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6
votes
Which is a good and cheap 3D LIDAR or other options?
There are now some sub and around ~1000USD 3D Lidars available. I wanted to provide an answer for future reference if anyone else comes looking for "cheap" Lidars.
LeddarTech M16 ~500 USD ...
4
votes
3D mapping using only a 2D Lidar
That is an already solved problem. As Squelsh mentioned CSIRO released its initial version in 2009 and their work is commercialized by GEOSLAM already.
One of a CMU student released a open source ...
- 1,527
4
votes
How does 3D Lidar work?
Lidar, sonar, and radar all work generally the same:
Emit a pulse. For radar, this means briefly energizing an antenna. For sonar, it means briefly energizing a sound transducer/speaker. For lider, ...
- 16k
4
votes
Occupancy grid maps
As the wikipedia page of Occupancy grid mapping explains, the result of the mapping process is a binary 1 or 0, occupied or not, the decision itself may be based on noisy data, which involves the ...
- 6,652
4
votes
Accepted
Calculate transform from different poses
I am just going to explain from the basics. So feel free to skip through the first part and scroll to the bottom if you want the answer.
Basics:
The 3 parameters of your pose are $x,y,\theta$.
These ...
- 1,831
4
votes
Accepted
Autonomous Mapping help!
I think there is a bit of misconception with what SLAM does, just remember that SLAM stands for; Simultaneous Localization and Mapping, what you want is to explore the map (autonomously of course) so ...
- 76
3
votes
In EKF-SLAM, why do we even need odometry when there is a more reliable sensor?Also, are all SLAM algorithms feature-based?
Just to add up on this, using odometry to estimate the robot position is much faster than using data from a laser scanner. In most situations, data from a range scanner is handled as a 2D PointCloud. ...
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3
votes
Accepted
3D mapping using only a 2D Lidar
I don't think what you're asking is possible with the state of the art sadly. You cannot, AFAIK, generate a 3D map from a hand held 2D LIDAR without any other sensors. It's a very interesting question ...
- 571
3
votes
Accepted
How does information gain based exploration differ from frontier based?
Frontier based exploration is concerned primarily with exploring the physical space in order to produce an occupancy grid (or cost map) of the terrain traversibility. The control actions follow a set ...
- 892
3
votes
Accepted
A sensor that can see glass/transparent objects and surfaces
I'm pretty sure that a very basic IR proximity sensor would do the trick. Glass is opaque to all but visible light. IR (as well as UV) will not penetrate the glass and you ought to be getting reliable ...
- 1,047
3
votes
A sensor that can see glass/transparent objects and surfaces
Unless you need very good resolution or a very tight detection pattern, I would go with an ultrasonic sensor. They can be very cheap and easily meet your detection range specs, for the very low end ...
- 1,919
3
votes
World and Map Frame for a real robot
As you've figured, static transforms are valid for fixed offsets such as sensor positions. They are the minimal solution the more complete recommended solution is to setup a robot model. There's ...
- 24.7k
3
votes
Accepted
slam_toolbox mapping is not life-long?
They are removed, but it takes some data to do so. We store a set of hit vs misses for each cell in the grid. If you went over it and laser scans saw it in lets say 10 iterations, it would take at ...
- 5,290
3
votes
ROS2 Map not received when using nav2_bringup
The nav2 map server is the one that puts the map into the /map topic, the map is published once during launch and not continuously published. If you would like to see the map again you could use the ...
- 108
2
votes
Autonomous Indoor Positioning System Robot based on CV approach
The camera should work fine as long as you can easily find the rover in the environment. An easy way to accomplish this is to place two different colored markers on the rover. By finding the markers ...
- 1,853
2
votes
Understanding and correct drift when using BreezySLAM (aka tinySLAM / CoreSLAM)
Till now this is the easiest SLAM implementation that I've found.
It works pretty well, however, there is a lot of room for improvement using the same principle used in the original code online.
"1- ...
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2
votes
Understanding and correct drift when using BreezySLAM (aka tinySLAM / CoreSLAM)
You'll find that Gmapping works a lot better. I have used core slam quite a bit with the 04lx, tweaked the code, and tuned the algorithm. It works in a lot of cases, but...
If you really want to ...
- 4,385
2
votes
Accepted
Path of the robot
One of the ways to do path tracking is by indoor mapping. In indoor mapping you can use Triangulation method. Basically, this method uses the help of Relative Received Signal Strength (RSSI) from ...
- 179
2
votes
How can I implement tremaux algo in arduino line follower to navigate and create map?
I would highly recommend using the encoders over estimating travel distance by rpm + time. Estimating motor velocity is notoriously tricky. Especially at slow speeds.
A direct measurement is ...
Ben♦
- 5,825
2
votes
Accepted
Is SLAM done only first time in a given environment
Is SLAM in general used only for first time mapping within an
environment?
Yes, SLAM is used only once to build map of the environment before navigation operation. Also, In case of significant ...
- 384
2
votes
Is SLAM done only first time in a given environment
SLAM is a recursive algorithm with no base case. I suppose you could have a termination criteria for the algorithm stating that "This Map is Sufficient", and then change your algorithm to localization....
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2
votes
Accepted
Uncertainty in grid based fastslam
This depends on how you want to quantify the uncertainty. For example, you can compute the sample covariance between all state variables i.e.,
$$ q_{jk} = \frac{1}{N-1} \sum_{i=1}^{N} (x_{ij} - \bar{...
- 335
2
votes
Occupancy grid maps
Cause of the intrinsic noise in sensory data, we have to consider a probabilistic model (mostly Gaussian) for the sensor measurements. As a matter of fact, the description and definition of the ...
- 96
2
votes
How to detect loop closures in 2D laser SLAM?
The most traditional method is to keep looking at the trajectory and see if your current location is close enough to the previously visited place. Once this happens run the ICP. If ICP converged ...
- 1,527
2
votes
Mobile Bot Maze Solving
Here's a video of a micromouse competition. The video starts with what I believe you're looking for - a mapping run.
How do you ensure you have appropriate coverage, though? It's up to you to define ...
- 16k
2
votes
Why visual SLAM is seldomly used in autonomous driving?
There are a couple of reasons.
Autonomous driving is all about perception and localization. Not the mapping. For localization, a simple map and GPS are enough. In terms of perception, the ...
- 1,527
2
votes
Accepted
ROS2 Map not received when using nav2_bringup
I have found the mistake, I have renamed my yaml and png map files and forgot to adjust the new png name in the yaml file.
Thank you very much for the help still akchobby!
- 21
1
vote
3D mapping using only a 2D Lidar
If it was fixed:
- You can place it vertically and define a rotating mechanism so it spins on itself and the 2D beam eventually maps the 3D surroundings.
If it is hand-held:
- You will have to ...
- 156
1
vote
How can I implement tremaux algo in arduino line follower to navigate and create map?
A good starting point is to solve the problem first in simulation. If the algorithm not work on a 2D map on screen it will never work on a real arduino. For inspiration github is a good ressource. ...
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