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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 ...
Andreas Klintberg's user avatar
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 ...
Chanoh Park's user avatar
  • 1,577
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, ...
Chuck's user avatar
  • 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 ...
50k4's user avatar
  • 6,682
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 ...
edwinem's user avatar
  • 1,891
4 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 ...
Steve Macenski's user avatar
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 ...
Harley Lara's user avatar
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. ...
bergercookie's user avatar
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 ...
Malcolm's user avatar
  • 571
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 ...
Octopus's user avatar
  • 1,057
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 ...
Mark Omo's user avatar
  • 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 ...
Tully's user avatar
  • 25.1k
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 ...
akchobby's user avatar
  • 118
3 votes

[slam_toolbox]: Failed to compute odom pose

I can see the standard frame in slam_toolbox param file is base_footprint. See yaml-file. I can't see it in your tf.
Nobel's user avatar
  • 56
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- ...
AL-ROBOT's user avatar
  • 319
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 ...
hauptmech's user avatar
  • 4,445
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 ...
ron123456's user avatar
  • 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's user avatar
  • 5,865
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 ...
nayab's user avatar
  • 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....
koverman47's user avatar
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{...
Ralff's user avatar
  • 345
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 ...
hosh0425's user avatar
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 ...
Chanoh Park's user avatar
  • 1,577
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 ...
Chuck's user avatar
  • 16k
2 votes

Include information on the environment in map-aware particle filter

Answer Create a new "probability grid" for each sensing modality and combine them after you have estimated the position of the robot in each of the many different grids. In short, you have a ...
Josh Vander Hook's user avatar
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 ...
Chanoh Park's user avatar
  • 1,577
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!
DJ1NN's user avatar
  • 21
2 votes

SLAM_TOOLBOX , topic /map is empty

Should I be sending data to the /map topic in some way, or should the SLAM Toolbox process the odometry and lidar data and publish to /map itself? No, SLAM publishes the ...
Steve Macenski's user avatar
2 votes
Accepted

SLAM_TOOLBOX , topic /map is empty

I’ve solved the issue, and the map is now building correctly! The mistake was that I initially constructed the TF tree incorrectly. In my case, the ‘robot’ was the lidar itself, so I had two static ...
Ivan Mokiets's user avatar
1 vote

Do I need a camera along with LIDAR for SLAM?

Please see this link which will give you good idea about differences between LIDAR and Depth Cameras (Kinect is one example). http://lidarradar.com/info/differences-between-the-lidar-systems-and-...
Muthanna Alwahash's user avatar

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