# All Questions

4,460 questions
60 views

### unexpected inefficiency of a motor driver

I purchased one of these motor drivers and noticed that i was not getting as much time from my battery as i had expected. I tested the current draw when connecting my motor directly to the battery and ...
5 views

### Kinematics with Product-of-Exponentials terminology: not forward, not inverse

I'm working on a kinematic estimation algorithm, and am trying to come up with the right terminology. I'm using the Product-of-Exponentials formulation for kinematic chains (and ignoring position ...
62 views

### Controllability of a car with a single trailer

I'm studying the kinematic model of a car with a single trailer. This picture shows the system: I started from the following statements: With these constraints, I got the Pfaffian form: And then ...
6 views

### Hand-Eye calibration of a 2D barcode scanner and a robot

I have a Keyence barcode scanner that can give me the coordinates of a detected barcode in pixels. I have a 6 DOF robot whose end effector pose I know at any given time. My ultimate goal is to place a ...
32 views

### Gazebo - Unable to load SensorPlugin

I want to write a Doppler Velocity Log (DVL) SensorPlugin for gazebo, but gazebo fails to load the plugin. My DvlPlugin.cpp looks like this ...
16 views

### How to convert PointCloud2 message to a grid?

I'm using a Velodyne sensor which publishes on /velodyne_points topic, and its class type is PointCloud2. Now I want to convert ...
16 views

### Observed position update after motion of the robot

The equation (14) in this paper, $$P_{Cj}=RP_{Pj}+T+e_j$$ where $P_{Cj}$ and $P_{Pj}$ are the observed positions of feature $j$ prior to and after the current robot motion, $R$(otation) and $T$(...
6 views

### Library for GPS

Is there any difference between "tinyGPS++.h","tinyGPS.h", and "Adafruit_GPS.h"? Can I use the same code to extract the current GPS location for all these libraries?
4 views

### Using OMRON Microscan Camera for both pick & place and Barcode Scanning

Is it possible to use a single, machine vision camera, to do both pick-and-place and barcode scanning? The workflow: parts would basically be lying out on a table, while the camera would be mounted ...
27 views

### For pose estimation, what is the typical range of the rotation values that are estimated? Is it from -180 to 180 degrees?

I am currently working with the Rutgers APC 2015 data set for pose estimation, and see that the pose estimates, specifically the rotation estimates, have seemingly been rescaled to range between -1 ...
44 views

### 3D Inverse Kinematics Jacobian Construction

I am following this article: Overview of Jacobian IK From the link, an example says: O is a pose vector which represents the initial orientation of every joint And following this, it gives an ...
12 views

### Does anyone have documentation for a CoroWare Explorer?

I have inherited a CoroWare Explorer from someone who used it for their PhD research years ago. They have no documentation on the robot, and I cannot find any online. Does anyone have a user's manual ...
23 views

### How to use a map created with odometry

I'm using ROS Melodic with Gazebo 9 in an Ubuntu 18.04.2 LTS. I'm studying a robotics subject at the university and I have to create a map of a closed room with one obstacle using only odometry. The ...
320 views

### How to use a PS4 controller to control a Quadcopter

So this is going to be my first ever quadcopter build. What I want is to be able to control my quadcopter with my ps4/ps3 controller. And a little bit explanation on how its done so that I know whats ...
118 views

### Pictures coordinates to robot coordinates

I have a picture on my C# software and the corresponding object in real world on 2d plane of motorized XY axis table. What I want is when I select a pixel on my picture, the motorized table should be ...
84 views

### KF/ EKF - Modelling and tuning noise matrices and other parameters

I am developing C++ code to estimate roll and pitch of a camera using accelerometer and gyroscope. The roll, pitch and yaw are in my state space ($X_t$) and the process is modeled as: \$\bar{X_t} = X_{...
16 views

### Electronic Speed Controller

What should be the specification of ESC that I should use for a 320KV 1820W brushless DC Motor?. Is it necessary to use an 80A ESC?, Basically, How can I choose the required ESC for a motor?
70 views

### How to avoid matrix singularity in GraphSLAM

I am trying to implement GraphSLAM from Sebastian Thrun's paper, The GraphSLAM Algorithm with Applications to Large-Scale Mapping of Urban Structures. When I compute the inverse of my information ...
40 views

### High power jumping mechanism in small robots

I recently saw this video on YouTube featuring a jumping robot: 5 Fastest Robots In The World I was curious how this is accomplished mechanically? Do they wind a strong spring or use some sort of air ...
12 views

### Undo pitching effect of camera when pose (y-axis) is near 90 degrees?

I am using KITTI odometry dataset whereby the camera's axis is pointing X (east), Y (down) and Z (north). It also contain the frame to frame poses of the camera (first pose is fixed as the map frame). ...
48 views

### How does a self-driving car locate itself when the environment changes?

There's something I don't quite understand about SLAM. When a self-driving car wants to locate itself using a prior map, how does it do that when the environment keeps changing, e.g., new cars parked ...
10 views

### Create a torus in SDF

How do I create a torus geometry shape in SDF? I assume I need to do it manually using the <mesh> tag but am unsure of how to proceed. Note that I am NOT ...
10 views

### Drone Mapping Project

I'm mapping my college campus with a drone (as part of an approved science project). I want to film, measure the temperature, and take infrared video at the same time. What drones are good for ...
54 views

### Discontinuities in IMU data in pitch only

I am having a problem with pitch measurements with Bosch BNO055 IMU. The device is rotated on a relatively stable rotating spindle and does a revolution on a circle around 10cm radius. It is upright ...
21 views

### Sensor complement in Drone

I saw a question posted by @Rocketmagnet (Why do I need a Kalman filter?) about the need for a Kalman filter. In that question, he says he's designing an UAV and lists the following sensors he will ...
219 views

### MPU6050: Changing Gyro Output Range Throws off Positional Reading

I am using the MPU6050 in conjunction with an Arduino and Jeff Rowberg's i2cdev library, and my project requires that the gyro rate outputs be more precise than the default setting, which is 1/16.4 of ...
110 views

### Accuracy of 3D scanners in featureless environments

I am trying to 3D reconstruct a room that has been freshly constructed but the walls have not yet been either plastered or painted/wallpapered. So far I have tried using mapping techniques(like rtab ...
13 views

### Robot rolls and rotates with different parameters

I am currently trying to build a robot with ackermann steering. As an example I found https://github.com/trainman419/ackermann_vehicle-1 for this robot. It works pretty well with the set parameters ...
21 views

### Where can I buy irobot-create?

im looking to buy irobot-creat, i can't find it on amazon or any other place. Im on Chile, would be any shipping options? Thanks!
3 views

### How can i connect to AWS Robomaker simulation job using ros_bridge?

We have a web app which we are using to show details of robot on including video, position and feeds like lidar feed. We are using http://wiki.ros.org/rosbridge_suite Rosbridge for this successfully ...
25 views

I'm trying to build an Autonomous parcel delivering rover using GPS.So after giving destination coordinates, I don't know how to make the robot understand to which direction it should move. Basically, ...
288 views

### iCreate 2 with Arduino (Just getting going)

I am new to the iRobot Create 2 but I do know a thing or two about the Arduino (don't assume too much though). However, in this case, I am beyond stumped over what I am sure is something simple but is ...
347 views

### Lego Mindstorms EV3 gyro sensor offset fix

I am currently working on a project for a Lego Mindstorms EV3 autopilot using Matlab/Simulink. Basically, I am using a closed loop control system with a PID controller for the control of the control ...
95 views

### Weird behaviour with a Create2 connected via XBEE

This is not really a problem but something strange is going on. When Create2 is connected to a PC via the USB original connector lead, when you start-up the computer the Create2 is activated by the ...
5 views

### Calculating acceleration relative to ground using an accelerometer in a drone

I use a gyroscope and an accelerometer to measure the rotation of my drone and now I would like to measure it's acceleration along the Z (Vertical) axis. Problem is I need this relative to the ground ...
44 views

### Graph slam augmentation of Identity Matrix

I am trying to implement GraphSlam. I go through this paper http://robots.stanford.edu/papers/thrun.graphslam.pdf. I have some doubt about the algorithm. I attached a picture with this question My ...
116 views

### Driving the iRobot Create 2 straight

I am attempting to make the iRobot Create 2 drive in a straight line using the opcode 137 with the parameters specified in the OI documentation. "Straight = 32768 or 32767 = 0x8000 or 0x7FFF" I have ...
796 views

### Stabilizing a Drone

I have my IMU and I can get attitude (pitch, roll, yaw) as well as gyro (x, y, z) As far as I can tell, ...
278 views

### Baxter and Robotics System Toolbox

I am trying to setup a two way communication with the Baxter Robot using the Robotics System Toolbox from MATLAB. However, I am unable to move the arms or record a trajectory using the rosactionclient ...
65 views

### Sensor fusion with gyroscope and motor rotations

I am building a robot (2 powered wheels and one ball bearing). The problem is that I can't seem to make it drive straight. I literally find it impossible, I have been trying for weeks. I have two ...
3k views

### What are the advantages of optimal control as opposed to control theory?

For a robot, say path planning in particular, what are the pros and cons of choosing classical control theory or optimal control (LQR for example) ?
80 views

### Add image onto box in URDF file

I'm trying to display an image on top of a box in a .urdf file. How could I achieve this?
264 views

### DH parameters to solve forward kinematics problem

When solving the kinematics problem for a robot using DH parameters, if there are some passive joints between the actuator and the end effector, do I have to define the axis and transformations of ...
103 views

### How to implement reference control signal for robot heading?

Some time I found that some robot controller uses a critically damped reference control signal such as in Autonomous Surface Vehicle (ASV) heading controller. My question is how do we implement this ...
43 views

### How to create a stable 48V 10A power supply?

I'm shopping for batteries and it's easy to find a 48V lithium ion battery that has like 30A max continuous discharge rating. However, I know that the battery supply has a variable voltage from 54V - ...
29 views

### How can a motor be run at higher voltage for longer?

A 12V windshield wiper motor to run at 24V for more speed but near-equal driving force. Testing with a variable DC supply between 21.6V & 26.4V showed the current maxes at 3.72 - 3.90A, as ...
16 views

### What is an axial and polar vector?

In Robot Kinematics and Dynamics by Herman Bruyninckx, it states: Axial vectors have an inner orientation, i.e., the direction of the vector indicates the positive orientation. For example, a unit ...
36 views

### How do I calculate the direction robot is facing, pose from velocity and yaw rate?

I have a simple car robot with four wheels moving relatively slowly (5~10 mph). The robot has a velocity magnitude and yaw rate sensor and the sensor samples about every 0.1 seconds. I want to map the ...