11 votes

If I must fly my drone in bad weather, how can I maintain control of it in strong winds?

In controls this is known as disturbance rejection. In order to sustain your motion in the presence of high winds you need the controller to be as responsive as possible, and an accelerometer would ...
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  • 4,326
10 votes
Accepted

Holonomics Movement vs Holonomics Constraint

You can look at degrees of freedom as if they were the number of variables that you need to use to describe your system. So, for a robot moving in a 2D plane, its state would be represented by: $$ s=\...
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  • 214
7 votes

Implementing a boustrophedon algorithm in a given room with obstacles

I implemented something like this in College: https://github.com/Auburn-Automow/au_automow_common/tree/master/automow_planning Basically we just passed the vertices of the boustrophedon path as ...
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  • 298
6 votes

Ambiguous definition of Error-State (Indirect) Kalman Filter

Hi and welcome to the wide, ambiguous, sometimes confusing world of research. But seriously, looking at 20 years of papers will sometimes produce these confusions. Let's look at what's going on. In ...
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6 votes

SLAM: Why use two cameras (stereo) if SLAM can be done using single camera (monocular)?

The most important point is the scale. If you do monocular SLAM, your map will only be accurate up to scale so that you e.g. cannot compute the length of the travelled path in meters. The scale ...
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  • 1,335
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 ...
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  • 14.7k
5 votes
Accepted

What flight firmware stack is most common in aerial robotics research environments?

It is usually a combination of 2 different pieces software. Generally a higher level software which implements most of your autonomy, advanced navigation algorithms, and a lower level software which ...
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  • 1,571
4 votes

How to make a robot move using Arduino other than timing to predefined locations?

Cartesians Robot use sensors. All robot need sensors. Sometime they are external (camera looking at the robot), sometime they are on the robot (IMU). Basically what you're asking is : How can an ...
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  • 561
4 votes
Accepted

Weird magnetometer values

Apparently a magnetometer is useless in indoor environments like man made buildings. I cite from this paper Multi-Magnetometer Based Perturbation Mitigation for Indoor Orientation Estimation ...
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  • 671
4 votes
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Robot path planning

You have to know your initial heading, let's call it $\theta_0$. So you start at some position, $p_{start}$, and you're trying to get to some end position, $p_{end}$. Assume starting position and ...
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  • 14.7k
4 votes

Path following with precise positioning system (RTK)

Precise vehicle location is not a very useful piece of data in autonomous driving so I would not expect to see many products focusing on it. Path planning and following for cars is a solved problem. ...
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  • 4,235
4 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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  • 950
4 votes

How can we solve the problem of robot size in sensor based motion planning?

If you are able to sense obstacles with a sensor pattern that is circular (eg laser scanner, contact sensors on a circular body, etc), and you can rotate the robot pose without translation, then you ...
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  • 4,235
4 votes
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Autonomous boat obstacle avoidance

Have you considered forward-looking active sonar ? Perhaps using off-the-shelf fishfinder hardware? My understanding is that active sonar sensitive enough to detect (relatively soft) fish a hundred ...
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  • 4,385
3 votes

Create 2: Wheel interface board replacement

Here are a few ideas: Buy 0.050" spacing prototyping board. For example, here are some possible boards that could work on Digi-Key. Use a PCB prototyping service and fabricate the board you're ...
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  • 952
3 votes
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Find Centre Of Circle, when robot can "see" a partial arc

First you need to understand the math, then you need to know how to program it. So let's begin with the math. This is high school material, so I go through it quickly. The math Any two points you ...
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  • 3,210
3 votes

What are some low cost alternatives for lidar?

This representative sample of what's out there may give you some idea of what's out there at various price points: Unfortunately, you're talking several thousand dollars for an outdoor unit with 10's ...
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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 ...
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  • 14.7k
3 votes
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Testbed for testing navigation algorithms

You could use player/stage or gazebo
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  • 1,335
3 votes
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What is the intuitive explanation of using Jacobian of observation model while calculating Kalman gain in EKF SLAM?

Let's try breaking it down. Projection of uncertainty $H\Sigma H^T$ is projecting the state uncertainty into measurement space. How do we know that? $\Sigma$ denotes the the covariance of our ...
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3 votes
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Mobile robot navigation without static map

I think you're confused on a few points. Mapping is when you try to build a map, given a known location. Localizing is when you try to locate yourself, given a known map. SLAM is simultaneous ...
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  • 14.7k
3 votes
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I have to implement my own SLAM algorithm

Take some of the robotics courses of burgard wolfram. You can easily find his video lectures on his homepage. You don't need to watch all of the videos. Just watch and try to understand optimization ...
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  • 1,375
3 votes

How come LIDAR is not commonly used for indoor navigation?

I think LiDAR is common for indoor navigation. Definitely, LiDAR is the easiest and accurate solution for indoor navigation or SLAM. Many commercial robot vacuums are already in use of LiDAR for ...
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  • 1,375
3 votes
Accepted

Do self-driving robots use object-level SLAM?

How do self-driving bots usually deal with transient objects, e.g., parked cars on the side of roads when they can come and go? No. In most of the open-source slams, dynamic objects are ignored which ...
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  • 1,375
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 ...
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  • 1,146
2 votes

Is a Genetic alogorithm suitable for mobile robot path planning?

The short answer is no -- genetic algorithms are not good for path planning. The longer answer is that while a genetic algorithm is very likely capable of solving a path planning problem, it's a very ...
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  • 10.8k
2 votes

how to plot a line between two centroids in matlab

Have you tried the line() function, which plots a straight line on a figure? You do something like ...
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  • 191
2 votes

Relative Navigation Systems

I would look at the System "PIKSI" from Swift Navigation It uses one fixed GPS modul and one which is carried on your Robot. Your accuracy is about 5 centimeters, which is pretty good for a GPS based ...
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  • 1,647
2 votes

What are some low cost alternatives for lidar?

Your cheapest option will probably be to use a ultrasonic sensor on a stepper, by advancing the server one step and reading the distance. The only downside to this will be the resolution you can get, ...
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2 votes

What are some low cost alternatives for lidar?

I don't have enough reputation to comment, but I'll add my 2cents in an answer. Basically you're limited to lidar mapping if you want any decent fidelity. Stereoscopic imaging via OpenCV in one ...
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