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8 views

How do you model a physical robot (diff drive) in python?

I am using PyGame to simulate the motion of a differential drive robot. So far, I have used the standard diff drive kinematics, multiplying by delta time, and I have the motion working as expected. ...
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1answer
7 views

How to do transformation to get correct linear velocity from linear acceleration IMU data?

I have IMU sensor that gives me the raw data such as orientation, Angular and Linear acceleration. Im using ROS and doing some Gazebo UUV simulation. Furthermore, I want to get linear velocity from ...
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0answers
5 views

Algorithm for Hand-eye Calibration with static camera brings wrong parameters

I tried a hand-eye-calibration with a static camera and the following alogorithm in Matlab. https://de.mathworks.com/matlabcentral/fileexchange/48696-camera-to-robotic-arm-calibration The algorithm is ...
1
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0answers
15 views

Solution to Inverse Kinematics of a 6 DOF Articulated robot with a wrist joint

I'm working on getting a solution to the inverse kinematics of a 6DOF Articulated robot with a wrist joint. I derived the robot's forward kinematics firstly, using these angles $$θ_1 = 60.102$$ $$θ_2 =...
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0answers
6 views

Why is there a sign change in the dynamic equation and how to derive kinetic equation

I would like to find out the following (I am trying to develop a dynamic model for a 4 wheel mecanum wheel) 1: Why is there a sign change and how to derive the kinetic equation for the wheels? How to ...
0
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1answer
23 views

Locating nearest device position

I have the following use case: Given a set of points in a space, I would like to use a smartphone to detect and locate the closest point (Possibly accurate to the at least a meter range) I am not ...
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0answers
13 views

What is the best microcontroller/SBC + stepper motor controller/driver combo to build a hexapod robot?

I would like to use a set of high power stepper motor controllers and drivers (e.g. Trinamic). Communication protocol of choice is SPI and motion precision is important. What microcontroller or SBC ...
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0answers
18 views

Looking for a smaller servo than SG90

I'm building a little humanoid robot and I need a motor to open/close a simple 3D printed claw used to mimic an hand, the problem is that the SG90 servo is too big to fit inside the arm. Is there a ...
-3
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0answers
44 views

Tracing longest new words in all languages using Machine learning algorithms, AI technologies

https://www.google.com/search?q=longest+word+in+all+languages&sxsrf=AOaemvKcePJS8wsKGqzL_U6e1NC7gQvzAg%3A1631976735337&source=hp&ei=H_1FYe7REZDn-QaKqY6ACQ&oq=longest+word+in+all+la&...
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1answer
16 views

How do I identify the different wires on RPLidar?

I bought an RPLidar A1M8-R6 from the following site: https://www.dfrobot.com/product-1125.html?tracking=585c2ddea9c83 I am trying to connect RPLidar to Arduino so I could get information on the ...
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0answers
4 views

Threading on Microsoft AirSim with Python Throws Type Error

Hope everyone is doing well. I have just started use AirSim for some computer vision simulations. Right now I am trying to implement threading for navigation purposes with Python. As a starting point,...
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0answers
23 views

How to measure an optical encoder resolution and gear ratio?

I've bought a DC geared motor with an optical encoder. The vendor didn't provide specification. I can read MITSUMI M25N-2R-14 2241 and 25GA-370-12V-330RPM on the motor. There are some pages on the ...
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0answers
9 views

What are cases where bug1 algorithm would be bug2?

I have been reading Principles of Robot Motion Theory, Algorithms and Implementations by Choset et al and I can't seem to understand how bug1 would beat bug2. It is harder for me to see given that ...
-2
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1answer
40 views

cpp:585:1: warning: no return statement in function returning non-void [-Wreturn-type]

I am using this Repo when building the projects I am getting this error Ros - noetic ...
0
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1answer
18 views

Doubt regarding the likelihood field in measurement model

I don't quite understand what xztk and yztk mean? Are they meant to represent the position of the kth laserscan reading? If yes, could someone please help me figure ...
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0answers
11 views

Digital compass precision in urban environment

I'm working on an application to compute the absolute heading (yaw) using the following hardware: WIT-Motion HWT905 IMU https://www.wit-motion.com/digital-inclinometer/witmotion-hwt905-ttl.html. It ...
1
vote
1answer
86 views

3D Rigid Body Pose Optimization in flat euclidean space

I am confused about what is the best way to optimize the 3D pose of an object and the best way to parametrize the translation and rotation for optimization in flat euclidean space. Assume I have a ...
1
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0answers
18 views

Obtain a State Space System given Denavit-Hartenberg parameters and a Rigid Body Tree model in MATLAB

I'm confused regarding the representatoin of a 6 D.O.F. robot arm with multiple links. I have the denavit-Hartenberg parameters and have used these to create a Rigid Body Tree model in MATLAB. The ...
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0answers
13 views

HECTOR SLAM, odometry in a low cost differential drive robot

I'm a noob in robotics trying to evaluate requirements for a low cost differential drive indoor robot. Would highly appreciate comments on the following questions. Given the inaccuracies in the wheel ...
0
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0answers
31 views

IK Jacobian is always a singular matrix

I am trying to solve an inverse kinematics equation for 6DOF system, 3 rotation and 3 prismatic joints. I am trying to solve using perturbation method, by adjusting each joint and calculating the ...
1
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0answers
15 views

Pure Pursuit controller slow response for long look ahead

The pure pursuit calculates the steering angle based on that equation: $$\delta = \tan^{-1}\left(\frac{2L\cdot \sin(\alpha)}{ld}\right)$$ Where $L$ is the wheelbase, $\alpha$ is the target angle, and $...
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0answers
21 views

Required motor torque for a small boat

What: We are building a small boat made of a special paper foam soaked in glue and epoxy. It is aproximinatley 40 cm long and 15 cm wide. Very light. We aim to transport a single can of beer at the ...
0
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1answer
19 views

Can a Madgwick IMU filter be used to determinate the tilt angle with respect to the horizontal plane

I am using a 3-axis accelerometer and a 3-axis gyroscope to estimate the tilte angle between the X axis of the IMU sensor and the ground (horizontal plane). My robot is stationary at power up, so I ...
0
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1answer
30 views

what is difference between twist and classcial velocity

In ch 8.2.1 Classical Formulation in the book Modern Robotics by Frank C. Park I know some remarks about this formula.The origin of coordinate system is coincidence with the mass center of the rigid ...
0
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1answer
25 views

Determine road curvature radius using non GPS sensors

I’m trying to solve for the “curvature” of a road, and wondering if this can be done with a standard mobile phone. If I have a mobile phone fixed onto my vehicles windscreen, using only standard ...
1
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1answer
61 views

perplexity about ch8.2.1 the linear dynamics, in the book <modern robotics>

From previous chapters, I think I have understand the twist, it is about the angular velocity and the linear velocity, the difference is that linear velocity is not one fixed point in the body but is ...
0
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0answers
10 views

Motion planning algorithms with applications in drug design

I am reading the introduction (chapter 1) of Principles of Robot Motion Theory, Algorithms, and Implementations by Choset et al. and they mention drug design uses motion planning. The text below is ...
0
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1answer
25 views

Motion planning algorithms with applications beyond robotics in animation

I am reading the introduction (chapter 1) of Principles of Robot Motion Theory, Algorithms, and Implementations by Choset et al. and they mention that some of the work in robotics has been applied to ...
1
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0answers
23 views

simple ROS script terminating without displaying errors

I am using ROS melodic on ubuntu 18.04, turtlebot 2. I tried to create a simple ROS program, that tries to make the bot follow a specified path. My gazebo world looks like this: The task is to try to ...
0
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0answers
45 views

How to drive a motor by Python

I need to drive any small motor (with small delay) by Python without low level programming. What hardware and software I need? Does "Robot Mesh Studio" fit for this? I want to make a robotic ...
0
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0answers
34 views

Joint space trajectory script unclear

I have a script provided by The MathWorks Inc. that makes a robot end-effector follow both a task space and a joint space trajectory through several waypoints. These trajectories are then plotted in ...
1
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0answers
15 views

DH table which link refers to which joint

I'm assigning frames to my kinematic model but I'm having a hard time understanding which frame each link refers to. I labeled each of my joints with Train/Tilt/Pan/Roll and I want to match those up ...
1
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1answer
38 views

process has died , exit code -11

I installed this framework and followed the instructions, but when I run it, I get the following error: ros melodic ubuntu 18.04 ...
0
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1answer
26 views

Implementing PID on a line following bot using turtlebot

I am using ROS melodic,turtlebot 2 on Ubuntu 18.04. The idea is to create an environment consisting of lines as a path (slightly curved), and to program the turtlebot to follow the lines. Basically, a ...
0
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0answers
7 views

Focus calibration to infinity

Well, it sounds easy problem but can we do it without pointing the camera to a faraway place? How does the manufacturer do this during mass production? Is there any focusing machine?
3
votes
2answers
33 views

How does Lidar penetrate jungle canopy for archeological surveys?

I've read articles like these https://www.nationalgeographic.com/history/article/maya-laser-lidar-guatemala-pacunam and wanted to understand what's going on here. My understanding is the lidar would ...
1
vote
1answer
56 views

4 Axis Gimbal Nodal Robot DH Parameters

I'm working on a robot gimbal where there are 4 revolute joints (4th axis for gimbal lock, reducing inertia etc). The robot is nodal such that all axes have the same nodal point and rotating any axes ...
0
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0answers
9 views

lens calibration with a circles grid

When we project a 3D circle onto image, its real center and the center of the ellipse fitted to the projected circle is different. To accurately estimate the true center from the projected image, a ...
0
votes
1answer
23 views

Air Resistance Drag Force Calculation For Quadcopter

Hello there. Hope you are all doing well. I have created a dynamic quadcopter model on Simulink and designed a controller for it. So far, everything is going well. However, since I am going to be ...
0
votes
1answer
22 views

UKF for a serie of observations with covariance

I have some doubts about how to implement a UKF-like algorithm when I only have motion observations and no control inputs. Assume I have a robot with state $s_t = (x_t, y_t, \theta_t)$ and the ...
0
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0answers
35 views

can anyone explain detailly this video(title: sensorless active complaince)

https://www.youtube.com/watch?v=g8Je93soOZE i am interseted in how they achieve compilance and detect collision in servo without the use of sensors. so any one please explain briefly
2
votes
1answer
29 views

Confusion over configuration space, workspace and task space

I have been watching Kevin Lynch's videos on Coursera in this series on the basics of robotics. From that I gathered these are the definitions. configuration space is the space of all configurations ...
4
votes
1answer
16 views

Why are serial manipulators almost always made of single dof joints?

I am currently taking my first robotics class and I found it curious that all serial manipulators have single dof joints. Why not use joints with more dof and reduce the number of components? Will ...
2
votes
0answers
8 views

DC motor modelling with Bond Graph

I am trying to construct an equation that describes the output torque as a function of lambda and omega I have obtained the following bond graph but I am unsure of how to proceed.
0
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1answer
18 views

If a point in a sphere can be given by longitude and latitude, why isn't a torus (also representing 2 dimensions) its configuration space?

In Modern Robotics by Kevin Lynch et al, there is mention of the difference between topology and sample representation as shown by the figure below. I am curious as to why the topology of a point is a ...
1
vote
1answer
45 views

Multiple Rotations via Matrix Multiplication

so I am having an issue understanding why you right multiply for current frame rotation vs left multiply for fixed frame. Let us say you want to: Rotate about x, then Rotate about current y, then ...
0
votes
1answer
21 views

How do you end up with 1 degree of freedom with one big link connecting 3 other links?

I was reading Modern Robotics by Kevin Lynch et al. and this robot was presented. They had introduced Grubler's formula which assumes independent joint which gives $dof = 0$ but this is not the case ...
0
votes
0answers
14 views

Any advantage in placing IR sensors on a curved line for line following?

The line following IR sensor arrays that are available in the market usually comes with IR sensors placed along a straight line. If I am to make an IR sensor array for line following from scratch, is ...
0
votes
0answers
28 views

C program to find the rotation matrix (orientation) of a 6DOF robot from its end effector position and link parameters

I'm writing a C program to find the inverse kinematics of a 6DOF robot. I've been able to write it successfully based on the general concept of Inverse Kinematics using DH parameters (i.e. finding the ...
1
vote
1answer
32 views

Is there a device for detecting what room you are in of a building?

I have found some inspiration for creating an smartphone application. But one of the main segments of the app requires it to know where the smartphone is located. It doesn't have to be that precies. ...

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