Robotics Stack Exchange
Robotics Stack Exchange

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1500 questions
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4 answers

Why does the Pixhawk have 2 IMUs

I was looking at the Pixhawk specs and noticed that it has 2 different IMUs- Invensense and STM. Is it for redundancy or does it have any other higher purpose?
sleeping_dragon
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How to choose the state space model for 1 axis gyroscope to implemnt a good kalman filter

I am using this gyroscope in order to measure the rotation of my robot around the z axis. I want to implement a kalman filter in order to improve the values. What i came with since now is this space model: $$ θ(k+1)=θ(k)+dt*θ'(k)+w(k) $$ $$ …
ChiPlusPlus
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Has hierarchical learning been embodied in a robot before?

I've been reading about hierarchical reinforcement learning (HRL) and it's applications. A well-written literature review on the subject can be found here. However, I was wondering if research has ever been done where an HRL system has been…
Seanny123
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More powerful alternatives to Lego Mindstorm NXT 2.0?

I'm interested to build Robot from my imagination, and I was looking to purchase a robotic kit. I find the Lego Mindstorm NXT 2.0 really interesting for many reasons : You can plug whatever brick you want, and you can develop in the language you…
Cyril N.
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Are there surface texture sensors for integration in circuits?

I have a project in mind for a robot which is able to recognize surfaces, and thought about including the following sensors: a temperature sensor a colour sensor, or a complex of electronic components to determine a colour and a texture sensor, or,…
Merlin
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Is it possible to use Matlab "system" function to call ROS commands?

Is it possible to use the Matlab's system function to call ROS commands? For example, using system('rostopic pub /cmd_vel geometry.msgs.Twist {....} or system('rospack find ipc_bridge). I'm trying to send some commands to ROS without using something…
Ze Nog
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Proportional controller error doesn't approach zero

I'm reading this pdf. The dynamic equation of one arm is provided which is $$ l \ddot{\theta} + d \dot{\theta} + mgL sin(\theta) = \tau $$ where $\theta$ : joint variable. $\tau$ : joint torque $m$ : mass $L$ : distance between centre mass and…
CroCo
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Finding a light load high precision servo motor

I have a project that requires me to be able to accurately and repeatedly rotate an object 120 degrees. The object is small and lightweight (let's say several grams). The axis does not necessarily have to always spin the same direction. It simply…
JR Warren
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12V compressor and air pressure control

I am trying to make a simple robot with few functionality for someone, one of these functionality is inflating a balloon inside the robot, I know how to control a compressor using Arduino but the problem is that the requested task is bit different…
Jihed Jaouabi
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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? Ideally, my team is looking for a simple beacon…
user46877
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Yaw angle calculation for drone PID from two distance sensors

I'm building a control system with a Parrot AR 2.0 drone where I have access to thrust controls for up/down (z), left/right (y), forward/backwards (x), turn left and turn right (yaw) through a Ruby library on my computer. The goal of the system is…
Chris Butler
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How to get pure end-effector translation through Jacobian?

I have a 7 DOF arm that I am controlling with joint velocities computed from the Jacobian in the standard way. For example: $$ {\Large J} = \begin{bmatrix} J_P \\J_O \end{bmatrix} $$ $$ J^{\dagger} = J^T(JJ^T)^{-1} $$ $$ \dot{q}_{trans} =…
Ben
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Natural frequency computation (for PID gains computations)

I am currently trying to parametrize the low-level gains of a robotic arm. This arm uses a classical PID for each joint. I am trying to use a method based on computation rather than a trial-and-error/tweaking approach. The method I use considers…
arennuit
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Kalman filter Issue - GPS Odometry Fusion

I am working on estimating a robots pose using Odometry and GPS. My first problem is that all kinematic model i have seen for a differential drive robot proposes using the displacement of the left and right wheels to evaluate the robots next pose.…
Lex
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I'd like to use gesture based input for my robot. What are the pros and cons between the Xtion Live and the Kinect?

As in the title, I'd like to implement gesture recognition on my robot and I'm looking for the pros and cons between the Kinect and the Xtion - and also if there are any other sensible options available. I'm thinking of the following, but open to…
berry120
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