# All Questions

4,566 questions
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### Can neural network probability directly be used as inverse sensor model?

For my robot i'm using semantic segmentation neural network that assigns to every pixel probability of being "road" (not occupied). By using homography matrix i'm re-projecting image to top-down view. ...
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### AD01 Blue Prism Developer Certification

Has any of you used the dumps questions of AD01 Blue Prism Certification offered by Vumingo platform? I've been using them to prepare my certification and I am pretty sure than some of them are wrong....
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### ROS meta-package ros-melodic-desktop-full doesn't include mav packages

Why doesn't the installation of the meta-package ros-melodic-desktop-full on Ubuntu 18.04 Melodic include the packages ...
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### PID to control discharging current of battery

i want to maintain battery cell voltage at specific setpoint for that i am varying discharging current by monitoring cell voltage. for that i m using https://github.com/br3ttb/Arduino-PID-Library for ...
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### UR5 Visual servoing(image based, eye in hand)

I am implementing IBVS on a UR5 using ROS. The algorithm works very well in linear X, Y and Z and omega Y. When I try to add a fifth axis(omega X or Omega Z), the robot jerks heavily and goes into ...
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### How do I set the weights of an Unscented Kalman Filter?

In most of the papers I have read, calculation of weights is done by the following formula: Where L is the dimensionality of my state and lambda is calculated by: And the usual values for alpha, ...
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After doing my final year project on Robotic Hand Simulation. I have found out this three link equation. As it was not available on internet so I have made it on matlab. My question is "Is the ...
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### Helium Balloon Altitude and Velocity Control System

I am designing a helium balloon which implements a control system that can expand and contract the balloon using a motor, thereby increasing or decreasing buoyancy and, subsequently, acceleration. I ...
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### Choosing the correct data logger [on hold]

I would like to choose a data logger which can log temperature and length measurements. I also want to transmit this via bluetooth or similar, to eventual format of excel. any advice would be ...
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### Servo malfunction

Summary I am making an automatic door for my chickens including a servo motor. In the process I actually shorted my 5V from my Arduino. The servo is powered by external batteries and only gets its ...
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### Robot Hand to Eye calibration without joint encoder

I have two degrees of freedom robot with a camera mounted on the tool center point where the system is modeled as $^wT_c = {^wT_z}(\theta_1){^zT_m}(\theta_2) {^mT_c}(\textbf{r})$, \$\textbf{r} \in ...
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### Which controller (PI or PD) is generally more robust to noisy sensor measurements and why?

Assuming no filter is used to measure error (or rate of change in error) with respect to a desired state, would a PI controller more/less/about equally robust to signal input noise compared to a PD ...
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### EKF SLAM : Missing older landmarks in new observation

I am a beginner to SLAM and robotics in general and I have been trying to implement SLAM on my GoPiGo3 robot car kit using primarily Chapter 10 from Probabilistic Robotics by Sebastian Thrun as ...
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### How can I pass I/O through to the host system in Fanuc's ROBOGUIDE

In Fanuc's ROBOGUIDE software, one can "simulate" digital I/O when in the program through the use of the virtual Teach Pendant. This, however, is much too slow for me to do in real time, as the ...
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### Gazebo Compatibility with Red Hat Enterprise Linux Distribution

Does anyone know if it is possible to install and run Gazebo on a machine using the Red Hat Enterprise Linux Distribution? The company I am working at doesn't allow users to run Ubuntu typically so ...
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### Resolved Motion Rate Control, Rotational Part

I'm controlling 6 DOF robot arm based on image processing. Robot arm will grab the object. Below what my system looks I can control the translational part of robot very well. But i cant control the ...
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### Why are brushless servos more common than steppers in Cobots?

Essentially every cobot I've worked with uses BLDCs instead of stepper motors in the joints. When searching for answers as to why I see a lot of posts that suggest one or the other, but nothing ...
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### Action client waiting forever for server to start

I'm in the process of writing an action cpp file and the client side seems to be stuck waiting for the server to start and I'm not quite sure why. Here's the code: ...
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### PID control loop and feedback acquisition synchronization

In many real-time PID control loop application I have seen that the control loop is triggered exactly as the ADC interrupts arrives in order to achieve maximum synchronization between feedback ...
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### How to publish odometry from 3 wheeled omnidirectional robot?

I'm new to ROS and robotics and I'm trying to implement the ROS navigation stack in a 3 wheeled omnidirectional robot. I already made the map using RTABMap but now I'm stuck in the 'Publishing ...
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### Matlab Code for Lynx Robot

In this section, you will need to write a function lynx_fk which returns the positions of 10 points along the robot arm as defined later, given the joint angles of the robot. For this question, ...
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### Selection Of coupling and determining size of motor to rotate heavy disc [migrated]

Following image is something I want to design. The uniform stainless steel round plate of diameter 1000mm and thickness 10mm is rotated by a stepper motor. But after every turn, a pressure of 3000 kg/...
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### Rotation Matrices Using DH Parameters

I need to find rotation matrices between the frames of references of the vertices of the cube, and the DH parameters. For the rotation between the first to second frame of reference, I got alpha as pi/...
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### calibrating larg scale manipulator

I'm facing the problem of model calibration for a larg-scale manipulator (e.g. example image) with a half-spherical workspace of around 40m diameter. The typical approach would be computer vision, ...
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### object pixel (u,v) to camera (x,y) error---pick position for robotic arm?

I have a camera attached to my robot end-effector. my object is placed on flat surface. I am getting object center coordinates using OpenCV in pixel coordinates (u,v). as I know, camera is facing ...
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### Not able to communicate with Roomba with serial port

I have an IRobot Roomba model number 565 and I am trying to control it with a Wemos D1 mini with Roomba's OI. I connected the TX and RX pins from my FTDI adapter to the Roombas RX and TX and I can ...
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### Tuning PID controlling car's steering angle

We built a car model with Ackerman steering type for line following task. The distance between rear and front wheels' axes was about 42 cm. Then we tuned PID controller (really just PD: Kp = 0.9, Ki = ...
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### Information Gain Theory - Conditional Entropy

In the book "Probabilistic Robotics" in chapter 17.2.1 they describe the theoretical concept of information gain regarding to robotic exploration. I'll provide you with an excerpt: In context of ...
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### Number of inverse kinematics closed form solutions for ABB IRB 140

I've read that 6 dof manipulators give eight closed form solutions, according to a paper. What is the number of iK solutions for the ABB IRB 140? (last three axes intersect but there is a offset ...
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### Home position of robot created using modified DH Parameters doesn't match the real robot

I have created a 6-DOF robot using RigidBodyTree() method and modified D-H parameters using robotics toolbox in MATLAB. The modified DH parameters for the robot are as follows: I have followed the ...
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### how to implement autonomous navigation using lidar and hector?

I want to make an autonomous mobile robot, which can localise itself and navigate to the goal in an unknown environment. As sensor, i just have a RPLidar to get laser scan, that's it. I used Hector ...
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### A Delivery Drone

I'm building a delivery drone as my final year project. A drone that can deliver a package to offices around my small town autonomously, for my final year project. I would like to know how this drone ...
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### Robot mechanism parts names

I'm working on my first "robotic" project that involves a square platform that should drop one of the four sides at a time. ...
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### Parallel Inverse Kinematics for Multithreaded Architecture (or GPU)

Here, you can find a nice academic paper about this topic. What I am looking for it is a real implementation of it or, instead, any other implementation of IK algorithm that can run in a many-core or ...
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### Planning minimum snap trajectories

I am working on motion planning algorithm for quadrotor. As I have learned in Coursera Aerial robotics course, trajectories for quadrotors should minimize snap which is equivalent to interpolating ...
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### Is Fuzzy logic applicable for robotics research

I found some papers that use fuzzy logic to solve robotics algorithmic problems. But I have recently been told by a few roboticists that fuzzy logic should not be used in robotics because it has ...
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### Are these parts compatible to build a quadrone?

I want to build a quaddrone from scratch, without using ready made controllers. I've read a lot about drones, how they fly and what essential parts they should have. So I decided to make my own ...
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### What is the typical intro example for control systems for a spherical joint?

I have been studying Acrobot and Cart-Pole. Both of these systems I can both work out the equations of motion and linear manipulator equations for how to maintain the poles vertically. The problem ...
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### What does it actually mean by Task Planning?

According to the research paper Parallel process decomposition of a dynamic manipulation task: robotic sewing (D. Gershon, DOI: 10.1109/70.56654): Abstract - ... The task planner approach, as ...
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### Buying DC motors with fitting gears

I want to try a little project with an arduino controlled crossbow turret. Therefore I need some motors to move the turret and gears. Since this is my first try on such a project I am very unsure on ...
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### how to solve action client not connected?

does anyone knows how to solve error "action client not connected" this is error text: ...
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### Roomba 651 makes sound

Our roomba 651 makes always the error sound. But battery is ver good. We are not able to find the solution. If any one has the solution to it.
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### Determine moments of inertia of a tool experimentally

I've mounted a broom as an effector of the Kuka IIWA. I've configured a tool in the Kuka Sunrise Workbench software with approximative mass and center of gravity. However, when control is started with ...
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### How to get RPY(Roll, Pitch, Yaw) from directional cosines from a single vector?

I'm trying to find the pose of an 3D vector in terms of RPY. Let's say the two end points of the vector is P0(x0, y0, z0) and P1(x1, y1, z1). So the centered vector I get is V(Vx, Vy, Vz) = P1 - P0 = (...
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### Is it possible to calculate a homography matrix for any 2 views?

I've been experimenting with opencv to estimate the homography matrix between 2 images captured with my computer's webcam. I have noticed that when the 2 views are not very far apart (that's when I ...