Questions tagged [python]

Python is a widely used high-level, general-purpose, interpreted, dynamic programming language.

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2 views

Trying to convert videos to frames

my problem is that the extension of the video that I have is .avi so how can I do this with the video's extension .avi ??
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Having Issues Importing and Using RLGlue locally with Python For Reinforcement Learning

I'm going through an online course on Coursera for Reinforcement Learning that makes use of RLGlue. I want to try to run and adapt the code locally, but am having issues using RLGlue, and not sure why....
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Ardupilot - Dronekit Setting the Current Location of the Vehicle

hope you are all doing well. I am doing in a project in which I receive GPS data (Longitude, and Latitude) from an Android device via an SQL server. What I am trying to do is to send this Longitude - ...
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Relative scale problem

I am doing Monocular Visual Odometry, and I have problem with relative scale. Most of the time its value is between 0.8-1.1, but sometimes it goes crazy and it has value 3,4 and once it had value 25. ...
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6DOF kinematic robotic arm programm

I am trying to find a well documented library which I can use for my 6dof robotic arm (https://www.thingiverse.com/thing:1693444) But I cant find anything :( Does anyone have a python/c code for ...
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Eliminating drift generated from double integration of acceleration signal using Envelope Method

I'm trying to remove the drift generated upon the double integration of a noisy acceleration signal. But this question discusses only removing the drift upon single integration to generate velocity ...
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1answer
32 views

Path planning for robot car on grid

I am currently doing a project as my hobby. I am trying to simulate a robot car in a grid arena. Below is the image of the arena: The start point of the car is the bottom-right corner(dark green ...
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2answers
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How do you send multiple data bytes to Irobot Roomba via python serial

So I'm trying to send commands to my Roomba Discovery via python serial and it works fine as long as it only requires the command opcode. The commands that require additional data bytes (like specific ...
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1answer
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AttributeError: darknet_ros_3d instance has no attribute 'Xmin' [duplicate]

After publishing the messages from another package, I am using darknet_ros_3d package and writing a subscriber. For saving the messages into variables for the later use, I am following the answer ...
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60 views

How can I save messages publishing from a ROS package into a variable?

I am using darknet_ros_3d package and writing a subscriber. So far, I have followed the code given as under: ...
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1answer
89 views

How to subscribe message coming from a package of ROS into Python code of another package?

I am using darknet_ros_3d package and getting the published 3D coordinates. Now I need to subscribe these coordinates into a Python file (...
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ImportError: /opt/ros/kinetic/lib/python2.7/dist-packages/cv2.so: undefined symbol: PyCObject_Type

So I followed this guide to install opencv on Ubuntu 16.04 LTS https://www.pyimagesearch.com/2016/10/24/ubuntu-16-04-how-to-install-opencv/. When I try running a python script that imports cv2 I get ...
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ROS TURTLESIM using PYTHON

In ROS TURTLESIM, While moving the turtle in circle using the linear velocity and angular velocity , how do i track the distance so as to stop the turtle moving after one revolution ??
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4answers
467 views

Best microcontroller for develop a robot for the market

I am planning to produce and release a robot to the market and also worked with different platforms for development such as arduino,pic,micropython/python. But now I want to do this professional. I ...
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1answer
59 views

Res-Scaling method beats PID controller. How?

Scenario: I have a robotic arm that has a (1D) lidar on its end, to orient itself with respect to the slant table in front of it. The lidar returns pretty accurate distance values in mm. The motor ...
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1answer
151 views

Are there any tutorials for OMPL in Python?

I want to learn and understand the Open Motion Planning Library (OMPL) through Python as I don't have much experience with C++. Almost all tutorials are written in C++ and there are some demos in ...
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1answer
84 views

2D Visual-Inertial Extended Kalman Filter

I am trying to implement an Extended Kalman filtering for combining IMU data and visual odometry in a simple 2D case where I have a robot that that can only accelerate in its local forward direction ...
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ModuleNotFoundError: No module named 'second.core.non_max_suppression.nms'

I am using Anaconda base environment for second.pytorch of ubuntu 16.04 after executing the following: nvidia-docker run -it --rm -v /media/yy/960evo/datasets/:/root/data -v $HOME/pretrained_models:/...
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1answer
85 views

ROS2 and TypeError when publishing custom message to Topic

I have defined a custom message: uint8[] data The custom message is imported in my Node class with no problems: ...
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2answers
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OpenCV4.2 and Ubuntu16.04 with python2.7?

Summary: I'm using new vision of opencv, opencv 4.2 with ubuntu 16.04 and python 2.7 After built cv_bridge, the output is: ...
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Simulating sensor readings based on an existing Alan Variance Analysis

My goal is to model an accelerometer and a gyroscope based on real hardware. I understand deterministic errors like bias and scaling but the different types of non-deterministic errors are difficult. ...
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1answer
111 views

How to find visual odometry by video from cellphone camera mounted on robot?

I am writing codes in python for visual odometry from single camera. I used cell phone camera for testing. I took video of 35 sec with camera moving. I used code below to read first image ...
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94 views

Applying initial guessing to LiDAR point cloud for ICP processing in Graph SLAM

I am currently in the process of implementing Graph SLAM using ICP and g2o in python 2.7 The data I have are pose data (4 x 4 transformation matrix) and lidar data ( in the format of [x y z 1] with ...
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3answers
376 views

Path planning algorithm better than RRT* and Artificial Potential Field

Hello robotics stack exchange community, hope my message finds you well during these challenging times. I need an opinion regarding path planning algorithms. Goal I am looking for a path planning ...
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1answer
169 views

How do I convert centre-returning joystick values to dual hobby-motor direction?

Currently my setup is: 2x hobby TT motors connected to a Pi Zero with a motor HAT Python script running on the Pi which runs a Blynk python client and controls motors via the gpiozero library Blynk ...
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Use Realsense camera to get the camera image

I have to use LIDAR in my project. I was searching for some LIDARs with a camera and came across the Intel RealSense d400 series. I know it has a camera but please suggest a way to use that camera ...
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3answers
792 views

Are Rospy subscriber callbacks executed sequentially for a single topic?

Suppose a ROS node receives new batch of data on a topic while the previous batch is still being processed by callback. Will ROS wait for its completion or will it spin a new thread and run both at ...
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1answer
41 views

Dynamixels (AX-12A) no longer detected after id change

I have 8 dynamixels that are connected together. Everything worked fine until I changed all their ids to 200,201,202, ... To change their ids, I used this python library. Now, none of my motors are ...
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1answer
72 views

Make robot drive as far from obstacles as possible

I am trying to make robot drive around the room, avoiding obstacles with pathfinding. The problem is I get few waypoints from pathfinding algorithm for robot to drive to (green dots), but it drive a ...
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43 views

G-code to cartesian co-ordinate converter

Hope you all are doing well. So I built a 5 bar linkage mechanism using arduino and python.It uses 2 servos, an arduino mega, a 12v power supply,a dc-dc step down converter to power everything. The ...
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2answers
853 views

/odom topics not matching ERROR

I have an existing ROS workspace which was built in C++. I am trying to implement a node built by The Construct in python which reads distance travelled from the ...
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1answer
222 views

How to synchronise data for fusion in Kalman from multiple sensors with different timestamp information?

I'm using Kalman filter to track the position of a vehicle and receive position data from 2 sensors: A GPS sensor and an Ultrasonic sensor for which I want to implement sensor fusion into the Kalman. ...
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How to make x variable change each time and read its value from txt file

I am working on my undergraduate project and this is my first time in using use python to control parrot bebop 2 drone and use BCI or BMI technology. I have x variable (int) and I want to read its ...
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1answer
219 views

Plot a map using wheel encoder and IMU data

I want to plot a map( with matplotlib or any other library ) using a wheel encoder and IMU data. Eg:- For every 10cm robot moves it should draw line (in a graph) and draw angles depending on the data ...
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How to implement stop sign XML cascade? [closed]

After training my RC car, I use the following command: python drive.py --model trainmodel.h5 This gives me IP where I can go and see if the testing was successful ...
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Inverse Kinematics of Puma 566 giving low angle results with DH convention

I am new at the robotics area, and i need to deliver an activity until this week in my college based to solve the inverse kinematics problem from an article that doesn't have any code done, and after, ...
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2answers
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I want to actuate a motor based on a wav file, but it has too many samples per second

I am trying to actuate a simple DC motor based on a wav file. At the moment I am using the "cat vs dogs sounds" from Kaggle. One of the wav files in this DB looks like this: These audio files are ...
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1answer
522 views

ROS packages for *pre-planned* path navigation rather than path generation? (Turtlebot3/ROS)

I am working on a project in which users will create paths fully constrained in terms of position (using a separate piece of software), and a robot will periodically follow those paths. We are using a ...
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1answer
37 views

What should i do to rebuild robot salto from Berkeley uni as a mechanical engineering undergrad?

What are the main components of robot salto? What are the necessary skills and knowledges to reproduce it? Also as you can see, i am a mecheng and i want to reproduce this robot as finishing project ...
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56 views

Pausing at positing in GRBL while holding motor current

I'm trying to get grbl to move the carriage of my 2D scanner to a specific position, pause there for a certain amount of time (until the sensor does its thing), and then proceed to the next position ...
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1answer
916 views

Python PID tuning - Parrot Bebop 2 - Target follower - ROS

I'm developing a PID controller for making the drone follow a detected object. I used as reference these topics: Ttracking-objects-from-camera-pid-controlling-parrot-ar-drone Tracking-objects-...
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Mission Planner: How to create a custom Waypoint Command

I am trying to set up a waypoint in Mission Planner that causes the drone to hover, take sensor data from a custom sensor, then either land or continue hovering based off of what the sensor data says. ...
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1answer
1k views

ROS how to use published data in a python script (darknet_ros)

I'm writing a python script to run with darknet_ros and bebop_autonomy package in order to take the bounding boxes of the detected objects and depending on the position of the detected objects send ...
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71 views

Real-time python reinforcement learning library

I'm looking for a reinforcement learning library that can be used for real-time robot control. What I first had in mind was ROS to describe the robot, Mujoco to simulate physics, and OpenAI gym to ...
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211 views

Python, Universal Robots, Ethernet problem

This is in regards to a UR 10 running 3.5.3.10825. For the script urx_get_robot.py ...
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2answers
178 views

ROS Theoretical Question - How does work properly a node

I'm new at ROS and I'm trying to figure out how does the node works with a pyton/C++ code. I have two codes for the same situation: Use a Xbox Controller to move the turtle in turtlesim FIRST - ...
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2answers
2k views

Uploading a trained ANN to an ESP32 board

I am working on a project that requires training a neural network with humidity and temperature values. After spending a while googling on how to run a neural network on ESP32 (Wemos LOLIN D32 Pro), I ...
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1answer
75 views

Head movement using gyroscope

I have a headset that provides 3 axis gyroscope readings. I wish to find out movement of head for e.g. if a person is nodding left to right etc. But the headset give me values in angular velocity for ...
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2answers
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iRobot Create 2 Wake over Serial on Rpi

So this thread is similiar to this one: IRobot Create 2: Powering Up after Sleep All except I am trying to do this on an RPi. I have followed these intstruction: https://www.irobotweb.com/-/media/...
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1answer
2k views

Convert local coordinates of a moving IMU to global coordinates

I am trying to compare the performance of an IMU in motion against an optical tracking system. The IMU has an accelerometer and a gyroscope and gives output in the local IMU coordinate frames. The ...