All Questions

Filter by
Sorted by
Tagged with
2
votes
3answers
95 views

How to control the velocity of a mobile robot?

I have a differential drive robot whose linear velocity and angular velocity is to be controlled. The current strategy for doing that is: A high level path tracking module spits out the reference ...
1
vote
3answers
25 views

A powerful pull/rotate device that provides a certain (controllable) force?

I don't know how to call the device I'm looking for (or need to create), maybe you can help me with terminology too so I can at least search.. I want something that either rotates or pulls with a ...
1
vote
1answer
36 views

Is it to possible to measure a room exact with rplidar?

I want to measure a room using rp3+, rplidar, ROS and SLAM. It should be easy possible to create mapping of the room. But how exact it would be? Is it possible to get less than 1 cm precision over ...
0
votes
0answers
19 views

How do I know if a wheel and stepper motor fit together?

Looking for some wheels and a stepper motor to make a self balancing robot. How do i know if the stepper motor shaft can fit in the wheels? I cant find the shaft diameter when looking at some ...
1
vote
0answers
41 views

Partial CoM, the velocity Jacobian and Control

New to robotic arms here. I am currently working with a 6-DOF robotic arm shown below: I have derived the FWD Kinematics and mapped the joint angles and the resulting end-effector positions. When I ...
0
votes
1answer
43 views

Cannot get 3 DOF bicycle model to run correctly

I'm trying to simulate a vehicle using a dynamic bicycle model but I cannot seem to get it working. If I set a constant steering angle the lateral velocity grows exponentially and creates impossible ...
0
votes
1answer
55 views

Is there a straightforward 16bit microcontroller?

Background Some of my sketches or ideas require a common data buss to all perph chips. The issue This way issue still lays before me, how then, if I am going for a common data buss. how do I ...
3
votes
1answer
52 views

IK - 3dof - iterative

I want to solve for a 3dof planar arm using gradient descent to approximate end position. Now I am a little confused about the formula and was wondering if someone can help me out. This is my thought ...
1
vote
1answer
44 views

Regarding kalman filter implementation

I think I might have originally posted this in the wrong stack exchange forum, link. I think this might be the right place, I am not sure if posting again is considered "bad style", I apologize if ...
0
votes
2answers
80 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 ...
0
votes
0answers
14 views

Two Link Manipulator End Effector Position

My professor described the end effector position as $q_{e} = \begin{bmatrix} x_e \\y_e\end{bmatrix} = \begin{bmatrix} l_1 cos(\alpha_1) + l_2cos(\alpha_1 + \alpha_2) \\ l_1 sin(\alpha_1) + l_2sin(\...
0
votes
1answer
64 views

How does it get a bizarre term in triangle law of vector equation in a paper

I am reading the paper "Motion control of wheeled mobile robots" at page 5, as we have the equation (34.7), i wonder how it contains $− dc(s)\dot s$ in side. As the triangle law of vector: $\vec{OP}=...
0
votes
0answers
18 views

3D points registration with given pairs

I have pairs of matched 3D points (10~50 points) with outliers included. I would like to find the transformation that aligns the source points to the destination points. To prevent reinventing the ...
0
votes
1answer
41 views

How to plot the 3D camera trajectory from a VSLAM output

I am totally new to VSLAM algorithms and would want to plot the path followed by the moving camera. I am using the open source implementation of ORB_SLAM2 for a rgb-d camera on benchmark dataset. The ...
1
vote
0answers
11 views

Serial Communication between RaspberryPi and CC3D?

I have built a quadcopter with a CC3D FC, using LibrePilot for configuration. Everything is smooth with the tx/rx I used to command the quad with but now I would like to effectively use the RPi as a ...
1
vote
0answers
21 views

How to perform Image alignment using pyramid levels

To gain some confidence, I want to implement the camera tracking (optimization problem) discussed in Semi Dense Visual Odometry for a monocular cameraJ Engel, J Strum, D Cremers $$E(\xi) = \underset{...
0
votes
0answers
16 views

Detecting pieces of a Version 1 QR code and processing the assembled version

I am building an aerial robot that needs to be able to detect pieces of a QR code (examples below) and combine them to process the information contained in the fully assembled QR code. I don't have ...
2
votes
0answers
28 views

value of $\gamma$ in the H-infinity norm

Suppose I have the system: $\dot{x} = Ax+Bu$ $y=Cx+Du$ and the following Hamiltonian matrix: $H=\begin{pmatrix} A & \frac{1}{2}B^TB\\ -CC^T&-A \end{pmatrix}$ I want to find the value ...
4
votes
1answer
54 views

Why do we need coriolis and centrifugal forces when it comes to the dynamics of a robotic arm?

So we all know (and love) the typical dynamic equation of a robotic arm: $$ M(q) \ddot{q}+C(q,\dot{q})\dot{q}+G(q)=\tau $$ Where M is the mass matrix, G is gravity and C is Coriolis and Centrifugal ...
0
votes
1answer
55 views

Value of ROS without real-time performance in robotics?

I have a general question about ROS - since it is NOT a real-time operating system(nor is Linux which it runs on), why can it be used for robotics applications which almost always have real time ...
0
votes
1answer
54 views

What is the cheapest 20mm-diameter roll-angle-sensor (+/-10deg, 60Hz update) you have come across? [closed]

What is the cheapest roll-angle-sensor (10degree accuracy, 60Hz update) you have come across for airborne mobile robots that have a 20mm diameter, shaped like a rocket? (The robot is shaped like a ...
1
vote
1answer
58 views

How do I download libraries onto the Ubiquity Robotics Raspberry Pi image

I downloaded an sd card image by Ubiquity Robotics which is an Ubuntu OS with ROS preinstalled onto my Raspberry Pi. This image creates a pifi access point for the Raspberry Pi and allows me to ssh ...
1
vote
1answer
19 views

Depth images with undetectable outlines

I'm trying to capture depth images with a RGBD camera, but all of the images have undetectable outlines around objects: Is this expected from RGBD cameras or is mine a dud? It's an Astra Pro.
0
votes
1answer
26 views

MPU-6050 as a compass not affected by magnet!

I am using an MPU-6050 as a compass connected to an Arduino Uno and using the AccZ register presumably from the accelerometer. So, first question, is the magnetometer signal processed internally with ...
0
votes
0answers
16 views

TUM RGBD SLAM dataset file format inconsistency?

I'm looking at the TUM dataset and wonder why the depth images and the file formats appear to be inconsistent. According to the file formats: The depth images are scaled by a factor of 5000, i.e.,...
0
votes
1answer
24 views

Does Vehicle Yaw angle measures same at every point on it? If not, how to translate yaw rotation to COG of the vehicle from different point?

I am using an IMU to measure the yaw rotation angle of a car. I need to translate the rotation measured to COG of the vehicle. I can ignore roll and pitch as I am driving it on a flat surface. So, ...
0
votes
0answers
29 views

Using CTRV UKF, to predict yaw and yaw_rate without measuring it

I would like to know does it makes sense to use CTRV (constant turn rate & velocity) motion model [x, y, v, yaw, yaw_rate] with Unscented Kalman filter if I have only measurements of the position ...
0
votes
1answer
13 views

Using a ROS custom message type across machines/hosts

I am unable to use a custom ROS message type on machine B that I have created on machine A. Machine A: runs roscore. has the custom message code as a ROS package. has sourced the setup.bash of the ...
1
vote
0answers
36 views

Finding transfer function from bode plot

I try to estimate a system transfer function by hand calculation from a bode plot data but I could not succeed yet and I need someone help. it will be appreciated if anyone explains or refer me to a ...
0
votes
0answers
16 views

Ardupilot (ardurover) GPS heading

I have a a Pixhawk 4 (FMUv3) board. I want to set the yaw input from GPS. Method 1 I can use a single GPS with two antenas, to feed in the GPS 1 channel. For this, i will have to - following this ...
1
vote
1answer
27 views

Sensor options for localization on linear rail

For a thesis project for ways to localize a slide on a linear rail with a length of ~1m. The slide in question is the seat of an indoor rowing machine: Concept2 Ergometer Price is definitely an issue ...
0
votes
0answers
26 views

A* alogorithm Path Planning in ROS

Can anyone help me out on how to do A* path planning in ROS. I went through a lot of resources, but most of them are using a 2d graph? I just want to know the process or workflow.
0
votes
2answers
51 views

What is the degree of freedom of the following drone?

This might be a stupid question to ask here .i am confused whether the dof of this drone is 3 or 4?
1
vote
2answers
44 views

Block algebra and normal algebra inconsistent

I've been playing around with some block maths, mostly trying to remember how it actually works, and I've come to a simple example that should be reduced, however when doing the normal maths, compared ...
0
votes
1answer
35 views

How to get transformation between a camera and a CNC plotter?

I have a question about robot and camera calibration. I have experience to calibrate btw 6DOF robot arm and hand-eye camera. But this time I should use a machine like CNC plotter. This machine can ...
0
votes
2answers
40 views

SLAM and navigation

I have a question about SLAM. Is it common for SLAM to be used for mere map generation? For instance, have a map generated using ORB-SLAM and then freeze the map for future path planning where future ...
0
votes
1answer
73 views

What are wheel ticks and wheel impulses?

I'm tracking the position of a vehicle along a certain trajectory using the Kalman filter and we have odometry data provided to us which gives the x-position of the vehicle, y-position of the vehicle ...
0
votes
2answers
54 views

Convert Vehicle coordinates to World coordinates for positioning

I'm tracking the position of a vehicle along a certain trajectory using the Kalman filter and the idea is to check for improvements in position estimation through fusion of data from multiple sensors (...
0
votes
1answer
55 views

How timer interrupt is handled in the presence of other interrupt services?

When timer interrupt is received, if there is already some ISR being executed, doesn't it delay (elongate) the time interval measured? If yes, how is it handled? For the sake of precise time ...
0
votes
2answers
48 views

Why would I use three state variables for a second order system? [state space modeling]

I'm currently being asked to write a state space model of a falling object (equation attached). I had taken a linear systems course five years ago in which I did a lot of conversion between high ...
2
votes
1answer
26 views

Constant Offset matrix

I've been reading about controlling systems via momentum wheels. Such as in Satellites, or fancy inverse pendulums. In a particular paper, the writer tries to explain away an offset and settling of ...
3
votes
2answers
46 views

Calculating Error of Arm Manipulator

How can we calculate the error position of arm manipulator? Let's say we have a Transformation Matrix: $$\begin{bmatrix} R_{00} & R_{01} & R_{02} & x\\ R_{10} & R_{11} & R_{12} &...
4
votes
1answer
101 views

question about spatial velocity in the book <modern robotics>

I think the equation(3.73) should be: $\dot p-w_s$x$p=\dot p-\dot p=0$ have no idea how it can be wrong and don't know the difference between infinitely large body and a body just include the fix-...
2
votes
0answers
10 views

Can't set ID to Dynamixel MX-64

I have 2 WidowX robots which I already successfully address ID's for all the MX-28 and AX-12A servos using ROS code in the Arbotix controller with the Dynamanager 1.3 on a Mac but I can't detect any ...
0
votes
1answer
41 views

How does sensor fusion help in robot localization

Good day... Sorry for bigner quesion, but really I need some friendly explanation rather than long reference I have 9 dof mpu9250 imu and gps. I found some source that calculate euler angle in ardunio ...
0
votes
0answers
22 views

Line Following Acute and Right angles and Proportional steering help

I am trying to figure out the logic for a line follower with the path shown in the attached image. I am having trouble with <= 90 degree angle turns. So far, I have been using the logic where if ...
0
votes
3answers
33 views

Is there a specific way or module I can use to stream video data from a camera hooked to an Arduino Uno board?

I'm currently thinking about the feasibility of creating a robot which streams live video footage and other data such as temperature, humidity, etc. to a smartphone. Is it possible to do this on an ...
1
vote
1answer
32 views

IR sensor spacing in sensor array relative to line width

I'm trying to build a line follower bot that follows a 3cm wide black line. I have a line sensor array with 6 analog sensors spaced 1cm apart. This means that in an ideal situation, i.e bot going ...
0
votes
0answers
29 views

Robot moves sideways in RVIZ ROS

I'm using robot_localization to fuse odom, imu and gps data on a husky robot. After fusion, the robot now moves forward in gazebo but sideways in rviz. I found this question. But the suggested ...
1
vote
0answers
15 views

What is the baseline of a RGBD camera?

I'm looking at some ORB SLAM2 settings where there's a parameter for "IR projector baseline times fx". Could someone here explain what exactly is the baseline of an IR projector? Is it the distance ...

15 30 50 per page