Questions tagged [localization]
Localization is the problem of estimating a robot's pose relative to a map of its environment.
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Particle filters: How to do resampling?
I understand the basic principle of a particle filter and tried to implement one. However, I got hung up on the resampling part.
Theoretically speaking, it is quite simple: From the old (and ...
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Absolute positioning without GPS
Using an IMU a robot can estimate its current position relative to its starting position, but this incurs error over time. GPS is especially useful for providing position information not biased by ...
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How To Determine Heading Without Compass
Lets say I drop a robot into a featureless environment and any magnetic field based sensors (magnetometer/compass) are not allowed.
What methods are there of determining where north is?
Tracking the ...
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What are good methods for tuning the process noise on Kalman filters?
Most often tuning the Kalman filter noise matrices is done by trial and error or domain knowledge. Are there more principled ways for tuning all the Kalman filter parameters?
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Quadcopter Localization Beacon
I want to use an RF beacon to localize my quadcopter for autolanding, when GPS is not precise enough, for example, when my driveway is only 10 feet wide, and the GPS is only showing 20-30 ft. accuracy ...
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Extended Kalman Filter using odometry motion model
In the prediction step of EKF localization, linearization must be performed and (as mentioned in Probabilistic Robotics [THRUN,BURGARD,FOX] page 206) the Jacobian matrix when using velocity motion ...
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EKF-SLAM Update step, Kalman Gain becomes singular
I'm using an EKF for SLAM and I'm having some problem with the update step. I'm getting a warning that K is singular, rcond evaluates to ...
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What's the most accurate way to obtain a locational fix using GPS?
Obviously GPS is the most obvious and accessible technology for obtaining a locational "fix" for a robot at any particular time. However, while it's great sometimes, in other locations and situations ...
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Why should I still use EKF instead of UKF?
The Unscented Kalman Filter is a variant of the Extended Kalman Filter which uses a different linearization relying on transforming a set of "Sigma Points" instead of first-order Taylor series ...
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Ambiguous definition of Error-State (Indirect) Kalman Filter
I am confused by what precisely the term "Indirect Kalman Filter" or "Error-State Kalman Filter" means.
The most plausible definition I found is in Maybeck's book [1]:
As the name indicates, in ...
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With a 6-axis robot, given end-effector position and range of orientations, how to find optimal joint values
Given a six-axis articulated robot arm holding a tool at its end-effector, if I have a desired tool position and tool orientation, there will be exactly 1 solution to the inverse kinematics equation ...
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How to make an "invisible line following robot"?
I would like to build a robot which follows a virtual path (Not a visible path like a 'black line on a white surface', etc).
I'm just enthusiastic by seeing some sci-fi videos which show robots carry ...
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What are human-friendly terms for mobile-robot orientation and relative direction of non-robot objects?
Within robotics programming, orientation is primarily given in terms of x, y, & z coordinates, from some central location. However x, y, z coordinates aren't convenient for rapid human ...
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Localizing a swarm of robots
I have a 300cm x 300cm room with a 25cm high ceiling (yes twenty five centimeters). It contains 50 small wheeled robots (about 20cm x 20cm). A central computer will orchestrate the movements of the ...
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What algorithm can I use for constructing a map of an explored area using a number of ultrasound sensors?
Ultrasound sensors are incredibly cheap these days which makes them a popular choice for many hobbyist robotic applications, and I'd like to use a bunch of them (say 10) around a robot with an ...
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How to model unpredictable noise in Kalman Filter?
Background:
I am implementing a simple Kalman Filter that estimates the heading direction of a robot. The robot is equipped with a compass and a gyroscope.
My Understanding:
I am thinking about ...
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Understanding and implementing belief space planning
I am currently working on state estimation/navigation for a system with multiple robots. As of now, what I have is each robot localizing itself with a Kalman filter, given vision based measurements. ...
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In EKF-SLAM, why do we even need odometry when there is a more reliable sensor?Also, are all SLAM algorithms feature-based?
In the book of SLAM for dummies, why do we even need the odometry when the robot would use the data retrieved from the laser scanner which is more accurate than odometry? Why not just rerly on the ...
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Whats the logic to implement a particle filter for a robot with range sensor?
I am trying to implement a particle filter for a robot in Java. This robot is having a range sensor. The world has 6 obstacles - 3 in the top and 3 in bottom. I am calculating the distance of the ...
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Accelerometer, gyro, and magnetometer sensor fusion in 2d
I have not yet built this so this is basically a theoretical question. I am still wrestling with some C code to manage i2c ...
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Visual Odometry options? [closed]
What are the pros/cons of the different visual odometry options?
Stereo Camera
Optical Flow
SLAM
other?
Criteria:
how well it performs vs other odometry options/sensors (lidar, radar)
sensor ...
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Multiple position estimates fusion
I have a system in which I have two separate subsystems for estimating robot positions.
First subsystem is composed of 3 cameras which are used for detecting markers the robot is carrying and which ...
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innovation step ekf localization?
Let's say we have a bunch of observations $z^{i}$ from sensor and we have a map in which we can get the predicted measurements $\hat{z}^{i}$ for landmarks. In EKF localization in correction step, ...
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Monte-Carlo Localization
I'm implementing Monte-Carlo localization for my robot that is given a map of the enviroment and its starting location and orientation. Mine approach is as follows:
Uniformly create 500 particles ...
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What kind of performance can I expect when using an Extended Kalman Filter for calibration and localization?
Currently I have a tricycle style robot that uses an extended kalman filter in order to track 6 state variables. The inputs to the system are a steer encoder, a distance encoder, and a rotating laser ...
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How to localise a underwater robot?
I am building an autonomous underwater robot. It will be used in swimming pools. It should be capable of running in any normal sized pool, not just the pool in which I test. So I cannot rely on a ...
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Can you seed a Kalman filter with a particle filter?
Is there a way of initializing a Kalman filter using a population of particles that belong to the same "cluster"? How can you determine a good estimate for the mean value (compute weighted average ?) ...
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Kalman filter GPS + IMU fusion get accurate velocity with low cost sensors
I'm new to all this robotics stuff. Especially to Kalman filter.
My initial goal is to have velocity as accurate as possible
Here is my case:
I have a phone which is mounted, for example in the ...
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Robot docking for self-recharging
I want to build a simple obstacle avoider robot, but this time I want it to be self-recharging so I am building a dock for this purpose, so I want it to be able to locate the dock and go for it when ...
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What is a good approach for outlier rejection during real time data filtering?
I'm trying to finish up a localization pipeline, and the last module I need is a filtering framework for my pose estimates. While a Kalman filter is probably the most popular option, I'm using cameras ...
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Kalman Filter GPS + IMU
I know this probably has been asked a thousand times but I'm trying to integrate a GPS + Imu (which has a gyro, acc, and magnetometer) with an Extended kalman filter to get a better localization in my ...
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Motion Model for Holonomic Robot
We are working with an holonomic robot equipped with three (120 degree shifted) omnidirectional wheels. The relative movement is estimated by dead reckoning using wheel encoders. To improve this ...
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Build a ROS robot with SLAM without laser
I've build a simple wheeled robot based on two continuous servos, controlled by Raspberry Pi running ROS-groovy, with a smart phone mounted on top to provide additional sensors. I'd like to situate ...
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LIDAR Points as Landmarks
I am currently trying to implement a GraphSLAM/SAM algorithm for LIDAR. From papers I've read, you generate a directed graph from expected LIDAR measurements to landmarks similar to the image below (...
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Likelihood field sensor model (Probabilistic Robotics, Thrun et al., p.169-174)
I am currently working on the "likelihood field" sensor model (aka "endpoint model") by Thrun et al. (book: Probabilistic Robotics, Thrun et al., p.169-174)
In this context I have ...
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Determining position from a 2D map and LIDAR
We need to determine the 2D position of my robot. To do so, we have a LIDAR at a known high, with an horizontal plane, which gives us the distance to the nearest point for each angular degree (so 360 ...
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laser scanner distance
I'm looking at laser scanners and I see a huge range of detection distances. The furthest I've see are 30m if you exclude the very expensive ones that claim up to 150m. My question is what is the ...
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Do simple, non-sonic, omni-directional rangefinding beacons exist?
I am on a robotics team that plans to compete in a competition where one of the rules is that no sort of sonic sensor is allowed to be used. I guess that limits it to some sort of EM frequency right?
...
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Understanding Drift in Simultaneous Localization and Mapping (SLAM)
I am trying to understand the effect of drift in Simultaneous Localization and Mapping (SLAM). My understanding is that drift occurs because the robot tracks its position relative to a set of ...
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Different Particle Filter min and max particle numbers give almost the same result
I'm using amcl package in ROS to localize a mobile robot. I've changed min_particles and max_particles several times then ...
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Particle filter implementation in ROS
I'm looking for particle filter implementation in ROS to use in mobile robot localization, but it seems the only available package is amcl (Adaptive Monte Carlo), I'm not sure is it possible to use it ...
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SLAM for Autonomous car
I am working on SLAM for autonomous car like vehicles with 2D lasers and IMU (deriving odometry).
I would like to know how efficient is using the existing SLAM algorithms (for example: gmapping in ...
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What frame of reference is used during Visual Servoing?
I'm new to the whole visual servoing area.
I'm now reading the tutorial Visual Servo Control
Part I: Basic Approaches" and I don't understand something fundamental - what information is available to ...
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Which is a good and cheap 3D LIDAR or other options? [closed]
Our team is planning to go for European Rover Challenge (ERC) 2018 for which we are designing an Autonomous rover. In order to implement SLAM, we need a way of mapping (with a range of atleast 2-4 ...
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Algebraic and geometric in inverse kinematic
I'm just wondering that is there any case that when algebraic way can't solve the problem while the geometric can ? Cause I'm working on a 2DOF robotics arm This one, I know the length of L1 and L2, ...
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Plotting location using wheel encoder data
Context: I am working with the SFU Mountain Dataset [http://autonomylab.org/sfu-mountain-dataset/]
The UGV image - via the SFU Mountain Dataset website:
I have used the following state update ...
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What is the difference between Positioning and Localization Systems
I would like to know what are the differences between Positioning and Localization Systems. In most review papers they are used interchangeably. Are they the same?
For example:
GPS(Global Positioning ...
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Is SLAM done only first time in a given environment
I am training Turtlebot 2 to move around the office. I come from robotics hardware background but relatively new to computer vision and robotic mapping.
Here are my two fundamental questions related ...
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Addressing the sample impoverishment in particle filter
I have implemented a particle filter algorithm for the state estimation of a mobile robot.
There are several external range sensors(transmitters) in the environment which gives information on the ...
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How can my robot find its position in any given map without GPS, including when the initial point is not given?
Consider this map
The Contest arena shown in figure 1 consists of two sub arenas, both the sides are identical to each other and their scientists and safe zone locations are similar.
Each sub arena ...