Robotics Stack Exchange
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Kalman Filter with multiple inputs

Let's say I have one laser scanner and a radar device, which I should use to measure a distance to a wall (Fig. 1). Both devices are place on the same support, so... they should measure the same distance (+/- the tolerances of the single device). It…
Wilhelm
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PID Control: Is adding a delay before the next loop a good idea?

I am implementing PID control in c++ to make a differential drive robot turn an accurate number of degrees, but I am having many issues. Exiting control loop early due to fast loop runtime If the robot measures its error to be less than .5 degrees,…
droiddoes9
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Why Does an Exponential Make ANYTHING a Probability Distribution

I am posting this here because my background in estimation theory and optimization has been developed entirely through my experience in robotics. TLDR: What makes it so that any time you put something in an exponential you can suddenly call it a…
JJB_UT
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Worm gearbox for steering

I'm planning on making a smallish off-road rover (15-25kg net weight) with 4-wheel steering and I was wondering if it'd be a good idea to use (self-locking) worm gearboxes for steering. I've thought about using planetary gearboxes, but self-locking…
John M.
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Move ATRV robot to specific distance using ROS

Is there a node or package that can send commands to /cmd_vel to move ATRV-Jr like 2 meters forward or turn it 90 degree to right/left? I don't want to tell the robot to move with specified speed. For example when I use this command rostopic pub…
Maysam
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Motion profile and Motion control scheme, how do they interact?

I'm studying motion control and I start with the simplest case, I have to go from A to B in a straight line using a trapezoidal motion profile. I understand that in a real case, due to the fact that the controller is discrete I need a…
Ugo Mela
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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 equipped with a lidar, that we use for SLAM. Now, since…
mayor_Burns
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How to calculate Inertia tensor?

I'm trying to obtain dynamics of a 4 DOF robot. Firstly, I calculated all Transformation matrices and Jacobians. While solving Lagrangian there is a term I - Inertia tensor . I couldn't understand the formula and how it is applied to a link (Because…
RAKESH KUMAR K
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Line following robot with EV3 Colour Sensor

I am trying to build an advanced coloured lines following robot with the ability to differentiate between many different coloured lines and follow them. I am looking for the right sensor that will help my robot achieve its objective. As I was…
user3064497
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Synthesis gradient observer

I ask the advice of specialists on control systems. We have the following system. Where $u(t)$ and $y(t)$ time-varying input and output. The characteristic $y(t)=f(u(t))$ is assumed to be non-inertial. Only input and output are available for…
dtn
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Have bloodstream nanobots been approved in any countries?

A Google search on "bloodstream nanobots" yields thousands of results and just on the first page, many results of blog posts that date back to 2009. It is nearly 4 years later. I've had no luck in finding any information on actual APPROVAL of these…
RickyAYoder
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Do I need an accurate flight model for a UAV?

As I understand it, a Kalman filter uses a mathematical model of the robot to predict the robot's state at t+1. It then combines that prediction with information from sensors to get a better sense of the state. If the robot is an aeroplane, how…
Rocketmagnet
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ROS Laser Scan rotates with the robot in RVIZ

I am currently working on developing a ROS application for autonomous navigation using AMCl. I am first trying to get move_base to work before continuing with AMCL. I came across an issue that shows the LaserScan rotating in a similar fashion to the…
user26871
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Determining required torque for DC motor

How to determine the required torque while choosing a DC motor? Here is a simple scenario. Think of a 4WD or 2WD vehicle. The max load the vehicle will have is 100kg. Q1. How do I determine the required torque for the motor? Q2. Should the Rated…
timetraveller
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output velocity equation of compliance control

I am trying to implement a compliance controller for a robot arm and stumbled upon an existing code snippet where the compliance velocity of the endeffector is calculated by: $v_{out} = v_{in} + \frac{F}{K} - \frac{\dot{F}}{B} $ where $F$ is a 6D…
rrrruo
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