Robotics Stack Exchange
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1500 questions
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5 answers

What does "6 degrees of freedom" mean?

I am looking at this page that describes various characteristics of gyroscopes and accelerometers. Close to the end (where they speak about IMUs), the names of the items have something like this: 9 degrees of freedom 6 degrees of freedom Can…
Salvador Dali
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SLAM : Why is marginalization the same as schur's complement?

Consider the system $$ \tag 1 H\delta x=-g $$ where $H$ and $g$ are the Hessian and gradient of some cost function $f$ of the form $f(x)=e(x)^Te(x)$. The function $e(x)=z-\hat{z}(x)$ is an error function, $z$ is an observation (measurement) and …
Ash
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Measuring speed of movement in Webots

I have been experimenting with different fitness functions for my Webots robot simulation (in short: I'm using genetic algorithm to evolve interesting behaviour). The idea I have now is to reward/punish Aibo based on its speed of movement. The…
Anna Pawlicka
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2 answers

ROS on Raspberry Pi Model 2: UbuntuARM vs ROSBerryPi

Before I ask my question, I'd better confirm that I've read the most prominent post about running ROS on Raspberry Pi devices. That post contains some valuable information, but it's a bit dated, and ROS support for ARM devices is much better these…
tommytwoeyes
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calculating position based on accelerometer data

Please help me with the following task. I have MPU 9150 from which I get acceleration/gyro and magnetometer data. What I'm currently interested in is to get the orientation and position of the robot. I can get the position using quaternions. Its…
maximus
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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 ?) and the covariance matrix ? Each particle is…
zSt
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7
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Sensors for differential drive

I have the following chassis along with an Arduino and a motor shield. I'm in the process of developing a tracking mechanism for use with differential drive. Normally, a photo reflector can be placed adjacent to the wheel that will reflect when…
Marko
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7
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6 answers

Electronic circuit for heating nylon fishing line muscle

I'm trying to make artificial muscles using nylon fishing lines (see http://io9.com/scientists-just-created-some-of-the-most-powerful-muscl-1526957560 and http://writerofminds.blogspot.com.ar/2014/03/homemade-artificial-muscles-from.html) So far,…
jotadepicas
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Is there a tool for building and analysing robots (kinematics, control) visually?

I am reading research papers about robotics and many of them follow the same pattern: some construction is established kinematical formulas are read from the mechanical structure the state space is analysed (e.g. how far the robot can reach, what…
TomR
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Why are bipedal robots difficult?

Not sure if this has been asked, but there are lots of simulations of bipedal locomotion algorithms online, some of the evolutionary algorithms converge to very good solutions. So it seems to me that the algorithm part of bipedal locomotion is…
seilgu
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How to convert between classic and modified DH parameters?

I currently have a description of my 22 joint robot in "classic" DH parameters. However, I would like the "modified" parameters. Is this conversion as simple as shifting the $a$ and $alpha$ columns of the parameter table by one row? As you can…
Ben
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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 particular design or feature. It has to know it's…
daltonfury42
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2 answers

Question for those who have experience using stereo cameras/module (e.g. ZED, DUO M, Bumblebee, etc.)

This is a question for those of you who have experience using stereo cameras/modules like the ZED, DUO M, Bumblebee cameras, etc. (not TOF cameras). I can't find any sample disparity outputs out there on the internet, and I can't find any…
renzbagaporo
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Using an Arduino to control an ON / OFF connection between two pins

I've got this driver: http://www.pololu.com/catalog/product/1182 ... a A4988 stepper motor driver carrier I'm attempting to control a connection between the RESET and SLEEP pins with logic ( code ) running on my Arduino. The motor runs perfectly…
carl crott
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Is ROS hard real time safe?

I know that is a question that has been asked too many times, but still its not clear to me. I read online that it isn't but some people say that they control their robots under ROS in applications with hard real time constraints. So, because I need…
jason
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