Questions tagged [localization]

Localization is the problem of estimating a robot's pose relative to a map of its environment.

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Autonomous Indoor Positioning System Robot based on CV approach

I have some questions regarding an IPS autonomous robot system, Configuration: Mounting a camera to the ceiling of a room Assume the room is a cube of 5mx5mx5m (LxWxH) Assume the camera is ...
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2answers
71 views

How to guide a camera through a circular tube?

Let's say I have a 6-DOF flying camera and I want to make it move through a circular tube autonomously and let's suppose that the camera and the system that makes it fly are considered to be just a ...
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1answer
149 views

Locating Omni-Directional Robot

I have an omni-directional robot, such as a X-Drive or mecanum Drive that I need to track the position of. I can put encoders on the wheels, but that is all I can do in terms of the sensors. I have no ...
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1answer
153 views

Implementation of wall and obstacle avoidance

I have a task of developing a simulation of an adaptive robot control system but I don't seem too have anyone to discuss my uncertainties with. I want to keep the simulation as simple as possible as I ...
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3answers
2k views

Can triangulation by measuring angles to 3 beacons to find location work over a large outdoor area

To determine an outdoor location I think that I need to measure the angles between at least 3 beacons and take into account the order I sweep the beacons. Is this a workable solution to get ...
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1answer
197 views

Implementing a position control for UAV through a flight controller. Plant model is unknown

We are using Naza-M-Lite for our flight controller without GPS. The localization is obtained through our RGB-D camera sensor. We are able to teleoperate and even implement PID controllers for Roll, ...
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1answer
95 views

Path comparison

Problem: the cartesian position of an end effector (no orientation) of a robot arm is recorded, say, every millisecond (the time steps can not be changed), during a motion. The robot arm is commanded ...
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2answers
316 views

Maximum likelihood estimator (ML Data Association) EKF

This question is an extension to my previous problem (Data association with ekf). My problem here is in the line 16 in the aforementioned link. 16.     $ j(i) = \underset{k}{\operatorname{...
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1answer
29 views

How to perform map matching algo using lidar scan s

I have run a code to extract features from lidar scans like poles and facades, and I created the reference map just concatenating results from each scan (i.e local map) now my question is; How can I ...
2
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1answer
113 views

What's the correct approach to merging of localization and odometry data?

We've got a mobile platform with a source of odometry and an IMU, which are merged in an EKF filter (robot_localization node), producing continuous odom->base_link transform. The robot is also ...
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1answer
74 views

Applying Rotation & Translation Matrix Obtained from Iterative Closest Point

Suppose I have M lidar contour points from t = k and N lidar contour points from t = k+1. (Some of you might question why I have differing number of contour points, and the reason is that these lidar ...
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2answers
77 views

How do you handle angle discontinuities in estimation problems?

When one is implementing a state estimator in a system that involves kinematics, will inevitably face the problem of angle discontinuities, i.e., the fact that the angles have to be wrapped between ...
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1answer
128 views

Where to include velocity in a Kalman filter

I am trying to understand some of the basics of the Kalman filter. The problem I am working on is quite complex, but I have spent some time trying to simplify the problem with an example. So, let's ...
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2answers
51 views

How to calculate the mean of an unsymmetric distribution (Particle Filter)

I'm attempting to implement a variant of Monte Carlo localization in a 2D space with obstacles. While the object is moving around the obstacles the particles flow around the obstacle like in images ...
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1answer
164 views

Follow up question to Robot path planning

So I was browsing through the localization section and found this question and the code which answered it. https://robotics.stackexchange.com/a/7932/21145 but I have a follow-up question to this. So ...
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1answer
156 views

EKF localization data association

I am working with ROS indigo and clearpath huskyA200 and wanted to implement the EKF localization with unknown correspondences with my own hokuyo lidar data for a school project. Giving the algorithm ...
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1answer
221 views

Graph Slam Landmark remove and then again add it

I try to implement Graph Slam in real dataset. My data set have some data that describe that the Robot observe same landmark over and over with a large amount of time difference. Prof. Sebastian ...
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2answers
238 views

Why use GraphSLAM?

I am doing some project on Slam. I have a data set of a moving Robot which can give me the value of forward velocity(m/s) and angular velocity(rad/s) and time(s). Now if this data are provided I can ...
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2answers
161 views

Localizing two points using self position and angle between this points

my question is about localizing points in 2D space. I know exact position (x,y,alpha) of my robot in some room. In room there are two points of unknow location. Robot can find angle between he and ...
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3answers
339 views

Find the robot pose from three beacon measurement

At every timestep my robot gets sensor measurements from a scanner that finds three beacons with known poses $B_1 = (B_{1x}, B_{1y})^T, B_2 = (B_{2x}^T, B_{2y}) , B_3 = (B_{3x}, B_{3y})^T$ these ...
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1answer
248 views

Covariance Check?

I have a localization data estimated and GPS_truth and generated [3x3] covariance matrix along with them. What i would like to do is to see if the covariance is correct or not? Can we check it by ...
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1answer
2k views

Modelling Point Clouds for Collision Detection in Gazebo

I am currently applying path planning to my robotic arm (in Gazebo) and have chosen to use an RRT. In order to detect points of collision, I was thinking of getting a Point Cloud from a Kinect ...
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1answer
498 views

How to make a directed graph?

I'm working on an robot that would be able to navigate through a maze, avoid obstacles and identify some of the objects in it. I have a monochromatic bitmap of the maze, that is supposed to be used in ...
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1answer
130 views

EKF Localization when robot is in parallel with a landmark.

I'm facing a real weird problem with EKF Localization. The filer gives me wrong error every time the robot is in parallel with a landmark. I've debugged the code many times but failed to solve the ...
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1answer
399 views

Data association with ekf?

Given part of the following algorithm in page 217 probabilistic robotics, this algorithm for EKF localization with unknown correspondences 9. for all observed features $z^{i} = [r^{i} \ \phi^{2} \ ...
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2answers
95 views

GPS+IMU sensor fusion not based on Kalman Filters

Do you know any papers on or implementations of GPS + IMU sensor fusion for localization that are not based on an EKF (Extended Kalman Filter) or UKF (Unscented Kalman Filter)? I'm asking is because ...
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2answers
84 views

LiDAR Feature Extraction

I'd like to extract "features" of an environment scanned with a 2D LiDAR. I tried to create a temporary occupancy map to extract "corners" with the Harris Corner Detector. However ...
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0answers
36 views

How does loop closure backpropagate the robots states into prior times?

I have read some about loop closure and I am somewhat confused. Suppose we implement something like EKF slam using LIDAR and suppose loop closure is aided by computer vision based features so that if ...
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57 views

Kalman Filter for 2d pose

I'm really sorry if this is a dumb question, but I don't have a clue on how to do this. I'm trying to write a kalman filter with a State vector of : {x, y, ẋ, ẏ, ẍ, ÿ } To estimate the 2 dimensional ...
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1answer
255 views

How to synchronise data for fusion in Kalman from multiple sensors with different timestamp information?

I'm using Kalman filter to track the position of a vehicle and receive position data from 2 sensors: A GPS sensor and an Ultrasonic sensor for which I want to implement sensor fusion into the Kalman. ...
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0answers
32 views

Fiducials in conjuction with AMCL

I'm having some trouble getting fiducials (using aruco_detect) to work alongside amcl. The goal here is to use normal amcl localization when a fiducial is not present, and to switch to localization ...
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72 views

EIF slam algorithm implementation as per Probabilistic Robotics

I want to implement EIF slam from Probabilistic Robotics Table 11.2. This is the algorithm for EIF slam. To construct $\Omega and \xi$ matrix I write down a Java code. Here is my code ...
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3answers
333 views

loop closure detection in visual SLAM

A robotic system is moving a getting its current location using visual odometry (incremental estimation of rotation and translation). To correct its localization, a loop closure technique may be added....
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204 views

Introducing new particles in particle filters for localization

Standard particle filters can produce bad localization result if the initial particle generation step produces no particle that is close to location (and bearing) of tracked object. The accuracy ...
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2answers
105 views

Aligning datasets with drift

I have a dataset that contains position information from tracking a robot in the environment. The position data comes both from a very accurate optical tracking system (Vicon or similar) and an IMU. I ...
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98 views

2D Positioning of mobile robot [closed]

I am just starting to explore an idea and I am somewhat of a novice in robotics. I am looking to position a mobile robot as accurately as possible on a concrete slab. This would be during new ...
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4answers
385 views

making a robot that knows your location

I've just made a radio frequency remote control using PIC microcontroller and I want to do something useful with it. I am thinking of a robot that gets things for you while you are at bed but here ...
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0answers
152 views

Random number generation for Particle Filter

I implemented a bootstrap Particle filter on C++ by reading few Papers and I first implemented a 1D mouse tracker which performed really well. I used normal Gaussian for weighting in this exam. I ...
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4answers
308 views

Image based 3d position estimation with one camera

There is too many 2d position estimation with one camera. Is there any 3d position estimation application or technique with one camera? If there is no application or technique why?
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1answer
256 views

Robot localization without any sensors

Is it possible to localize a robot without any sensors, odometer and servo motors? Assume robot has dc motors and no obstacles.
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1answer
262 views

Kalman filter for vision based pose estimation: 'good' measurements not improving system covariance

I am starting off with a very simple Kalman filter for vision based pose estimation (PnP algorithm). The filter is inspired by the constant velocity model in this OpenCV tutorial, but I am ignoring ...
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1answer
49 views

$p(m|x_t, u_t, x_{t-1})$ What does Thrun mean with the "map probability"?

Different question from the last one since I still struggle with the concept. In his book "Probabilistic Robotics", Thrun has the following equation: (Context here) (5.49) $p(x_t|u_t,x_{t-1},m) = \...
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1answer
106 views

In vision based localization, is it possible to make multiple vehicles cooperate to improve the estimation of each other?

I am currently working on a project that involves structure from motion using multiple cameras on multiple aerial vehicles (each vehicle has a monocular camera: think of it as a distributed stereo), ...
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1answer
1k views

Linearize a non linear system

How do I linearize the following system using taylor series expansion: $\dot x = v cos\theta \\ \dot y = v sin\theta \\ \dot \theta = u$ Here, $\theta$ is the heading direction of my robot, measured ...
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1answer
94 views

No difference between UKF and EKF for SLAM

I built EKF and UKF SLAM algorithms. The problem is that I expected to see a difference because of the more precise approximation of the system in the UKF. Here's a screenshot from the estimated path ...
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2answers
49 views

Extract laser scan from a map and known location

If we have the map of an environment (an occupancy grid for instance) and precisely know the pose of the robot within it. How can one reconstruct what the laser scan should look like at a given ...
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1answer
46 views

Uncertainty in grid based fastslam

Given I am building a grid map, and poses are represented using particles, how can I calculate the uncertainty of a pose In a grid based fastslam 2.0?
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1answer
128 views

How many landmark measurements to localize a planar robot?

How many landmark measurements are required to localize a robot (i.e. find its x,y position and orientation) moving in a 2D world using 1. only range measurements 2. range plus bearing measurements?
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2answers
309 views

Laser Scanner for localization in particle filter

I'm working on a particle filter implementation in Matlab and I found one very good in the Robotics Toolbox (available here https://github.com/petercorke/robotics-toolbox-matlab). My problem is that I ...
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1answer
1k views

Process noise and Measurement noise in Kalman filter

I am doing the robot localisation project. Now I stuck on the effect of measurement and process noise in Kalman filtering. Could you please explain what impacts they have while estimating the position ...