All Questions

4,441 questions
2 views

How to use depth map in A* path planning?

I've currently built a quadrotor with standard PID controllers for attitude, angular rates, and position control. I now want to implement obstacle avoidance and path planning using A*. I have a stereo ...
4 views

Help Interpreting Raspberry Pi GPIO's allocated to Robot starter kit called AlphaBot2

I am a complete newbie to robotics, so please excuse me if this is a simple question. I bought this robot starter kit and need help understanding which features are associated to which GPIO pins: ...
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Robot Arm with vacuum gripper

For my thesis beginning in 3 months, I am lookking for a robot arm with a vacuum gripper. I want to build an automated test station as a prototype. I am really new to robotics and wanted to ask if ...
5 views

Can the collision sensor data from a commodity drone be combined with images to build a 3d site model?

I'm exploring the use of drones to survey a site for build on a site with existing buildings. Having done a bit of research on various image stitching solutions, but it strikes me that they don't ...
15 views

Project suggestions

Thank you for any input in advance! Also I am not totally sure this is the right place for this question. If not then I apologize but couldn't think of a better place to post it. I am working on a ...
7 views

Make a map using ONLY odometry

I need to do the following exercise in my robotics' subject: make a map using odometry. I'm going to use ROS but I have no idea about how to do it. I need to build the map using ONLY odometry. I will ...
9 views

Design of the baseplate of mobile robot

I need to construct a Mobile robots preferably circular type of diameter 30 cm, it will be carrying a payload of 5kg. What will be optimal thickness the baseplate considering the material as aluminium?...
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How communication work between Motoman robot controller and OpenCV?

Can anyone guide me how can I give object POSE to robot controller for Pick and Place operation? How can I transfer coordinates through OPENCV OR PCL library to controller? or am I thinking in wrong ...
18 views

motor controlled lazy susan

I'm trying to figure out an easy lazy susan setup. This is for video production, I want to be able to put an object on the platter and get a smooth consistent turn in order to shoot the object ...
24 views

Can a neural network emulate a physics engine?

Before a motion controller for a robot can be created, a step before is needed, called “system identification”. The aim is to create a prediction model which can say, what will happen if a certain ...
17 views

bluetooth that could track mobile phone location

newbie here. after my research, i couldnt find anything that could found what i wanted to search for my project(following robot for indoor location). without gps, bluetooth only, could i get the exact ...
32 views

What is a Velocity Smoother?

I'm learning ROS and I have found an expression that I don't understand. I'm reading the book "Mastering ROS for Robotics Programming - Second Edition", and on a controller to move a robot using ...
29 views

Choosing a position sensor (encoder) and obtaining velocity from it

How do I know how many counts per revolution I need for an encoder for my application? I need to be able to accurately capture a 1000 Hz signal on an input side running from 1-133 rev/sec (60-8000 ...
34 views

How to quantify motion?

I am working on a calibration algorithm where the motion is related to the observability of the parameters that I am calibrating. Let's say we have a 6 dof trajectory and wants to quantify its motion ...
38 views

How to handle sensor data for a sensor-fusion algorithm

I am implementing the explicit complementary filter(see below) with a 9DOF MEMS sensors (accelerometer, magnetometer and gyroscope) for attitude estimation. Currently, the gyro and accel update rates ...
41 views

Are underactuated robots easier to program?

The first examples for passive dynamics were introduced by Ted McGeer in the early 1990s. The main principle of so called underactuated robotics is, that not all joints in the system can be controlled ...
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i have read a spec. about gear motor and it shows that Stall: 9-13 Nm torque 25A max Per my understanding Stall torque is the maximum torque that can be applied to the shaft and cause the ...
23 views

How to perform active search in point feature based monoSLAM?

I am modifying an implementation of SLAM with single camera, MonoSLAM [1]. Instead of image patches, I want to use features points (ORB) to track landmarks. MonoSLAM uses a EKF framework. So for ...
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Combining P and D gains properly

I'm trying to perfectly tune my quadcopter and I'm at the point where P gain feels about right as it tracks my stick movements perfectly, yet it wobbles after a sharp stick input. If then I raise my D ...
23 views

How can i connect arducopter to raspberry?

This is my school project. I would like arducopter connect to raspberry but I do not know how to do it. Please help me!
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Loop time for self balancing robot

I have been working on a self balancing robot and there are quite a few parameters and one of them is loop execution time (t_loop henceforth). To my understanding, the smaller t_loop, the better it is ...
25 views

Is system identification and a physics engine the same?

In the control theory the term “system identification” is used quite often. A typical sentence in a robotics oriented paper is that the author is trying to “build a model of a plant with matlab”. The ...
15 views

Inexpensive & minimally viable systems for testing SLAM algorithms?

I've been studying SLAM on my own for some time, I can sift through texts over texts and try my best understanding them. However, without actually implementing them myself, I think I still don't fully ...
52 views

underactuated robot problem

Lets say the robot has 4Dof and the operator gives (x,y,z,roll,pitch,yaw ) as control input( rank(J) < dim(task) ). Now the robot is overwhelmed and will probably show some jerky movement. But can ...
8 views

Connecting a Roboclaw 2x15a to an Arduino

I'm new to robotics but have a background in programming. I recently purchased an Arduino Uno starter pack as well as a Roboclaw 2x15a motor controller with 118 RPM motors from ServoCity. I haven't ...
4 views

L298N briefly works, then shorts when controlling Nema 17

I'm trying to control a Nema 17 stepper motor with a L298N H-Bridge. My wiring is as below (except I'm using a ESP8266 not a YUN, and I have a mains 12V supply rather than batteries). This is ...
41 views

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 ...
18 views

What is a good way to measure the perpendicular distance (from a mobile robot eg) to a laser beam?

What is a good way to measure the distance (from a mobile robot eg) to a laser beam? The purpose of course is for the mobile to track the laser beam. The mobile may go temporarily off the beam by ...
9 views
+50

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/...
9 views

Problem with UKF weights when calculating predicted state

I'm having troubles implementing a UKF during the calculation of $\overline{\mu_t}$, specifically in this step: $$\overline{\mu_t} = \sum_{i=0}^{2n}w_m^{[i]}\chi_t^{*[i]}$$ My problem I'm facing is ...
19 views

I need to read a lot of analog signals without any analog pins

I have an nvidia xavier with gpio running linux. It should work very similarly to raspberry pis. I need to connect a bunch of pressure sensors, thermistor, potentiometers, and vibration sensors to my ...
20 views

Accuracy of hall sensor encoders on Raspberry Pi

I have 2 motors (JGA25-370) with hall-sensor encodes. They emit about 90-100 interrupts every 100ms, so 1000 a second. Which means I have an interrupt happening every 1ms. The motors are driven by ...
33 views

What is a good way to measure the perpendicular distance to a laser beam? [duplicate]

What is a good way to measure the perpendicular distance (from a mobile robot eg) to a laser beam?
17 views

Combining data from 9DOF IMU

My team and I are building an AUV and are planning to replace the existing 6DOF MPU-6050 sensor with a 9DOF Adafruit BNO055 sensor. However, we're unable to figure out how to combine the data from the ...
30 views

Which sensors can be used to feel breeze blowing by the robot?

Am faced with a situation where my robot needs to feel breeze blowing by over its artificial skin. While there exist many types of tactile sensors, nothing seems to fit the bill. I might abandon the ...
29 views

How many encoders should I have?

I'm planning a robot vehicle and plan to get one or more motors that have encoders built in. How many encoders do I need I really need in order to gather solidly accurate information about speed ...
24 views

How to calculate observation matrix Jacobians in EFK based mono slam? What are projection Jacobians?

I have been trying to understand an implementation of monoSLAM 1. But my question is generic to EKF based single camera SLAM. My Jacobian calculation leads to complex and lengthy expressions while ...
42 views

Why can't motors be as elegant as human muscles? Why do we have to use electromagnetism to create movement?

Pretty much as the title says. Why isn't it possible to build motors as microscopically and simply as they're built in humans? Why can't we recreate electronic nerves and muscles?
23 views

FastSlam2.0: ICP Scan Matching vs Odometry? What is the typical time step?

When working with a FastSlam2.0 algorithm, ICP Scan Matching is supposed to give more accurate measurements than odometry. The problem is, that given some noisy measurements from the laser scanner, ...
13 views

message_filters doesn't call the callback function

I'm trying to use the message_filters in order to subscribe to two topics. Here's my code ...
13 views

How can I detect change of color of path for a lego ev3 robot? [on hold]

I cant detect the inversion of color in the path my robot follows. the path color goes from black to white and the robot should be able to detect it. thats the code for color inversion detection
24 views

Depth Sensor and Depth Camera [duplicate]

What is the difference between a depth sensor and a depth camera ? I think that the depth sensor is the hardware tool equipped with a special software which can detect the depth in 3-dimensional ...
36 views

How can I preserve a high framerate while using at least 1280x720 resolution on 2 USB cameras on the same computer?

To expand on this, I have a down-facing camera using the whycon ROS node on Ubuntu 16.04 Kinetic on a quad-core computer with 640x480@60fps MJPG video. I'm also using the ...
17 views

What are the components required to mount a servo inside an ActoboticsTM facing outwards a channel?

Being new into the ActoboticsTM set, it's not always clear to me what the parts are supposed to do. I'm currently in need of placing a servo inside a channel facing outwards, as depicted on the ...
28 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 ...
31 views

Quaternion error in one degree of freedom

I would like to control a system which orientation I measure with as quaternion based EKF in one degree of freedom. Obviously the simplest thing would be to convert the quaternion estimate to euler ...
9 views

Compile webots for Python 3.6 for Windows

I would appreciate if someone could assist me in compiling webots source for Python 3.6 to allow me and others to use TensorFlow with it. I already tried but apparently there is something not ...
22 views

ABB Object Oriented RAPID language

How do I create something like a class and have instances of it in ABB RAPID language?
33 views

Microcontrollers and Python

So I am fairly new to robotics however I do have some background with the python coding language. Recently I set myself the task of learning some basics for robotics just to increase my knowledge base....
40 views

outdoor autonomous robot [closed]

i had search over google and found out more or less some sensor that i could use like sonar, gyroscope, accelerometer,magnetometer and gps and 2d lidar (which is less expensive, around \$300) i have ...

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