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4 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 ...
-1
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0answers
20 views

Tracing longest 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
10 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
3 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
15 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
8 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 ...
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1answer
32 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
15 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
10 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
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1answer
73 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
16 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
12 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 ...
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0answers
28 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
14 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
18 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 ...
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1answer
18 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
26 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
57 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
27 views

Reprogram a roomba to go from A to B and back and forth. In Toronto [closed]

So currently I’ can hardy get out of my chair due to some kinda lower back injury , (seems to be gettin worse every time) happens once or twice a year. Any how I have 2 roomba s from about 10 years ...
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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
22 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 ...
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0answers
43 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
31 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
14 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
votes
1answer
25 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
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2answers
32 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
55 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
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1answer
22 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 ...
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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
28 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
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0answers
6 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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0answers
25 views

What surfaces are topologically equivalent to a sphere and a torus? [closed]

These are the examples of what I think could be equivalent. Can someone confirm this? Topologically equivalent to sphere hourglass cereal bowl flat disc Topologically equivalent to torus (other than ...
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
42 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
20 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. ...
0
votes
0answers
12 views

How to calibrate a lens with wide fov and low F number

To calibrate a wide fov lens either a calibration board should be large or bring the calibration board closer to the lens. As making a large calibration board is expensive, I usually prefer the second ...
0
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0answers
8 views

Trajectory optimization using Direct Collocation

Are there books or resources that make use of Direct Collocation for obstacle avoidance? So far I have been only been able to find out how to implement Direct Collocation and nothing related to ...
1
vote
1answer
45 views

Searching for object in an unknown environment using ROS

Using ROS, I'm trying to build a robot able to search for specific objects in an unknown environment. Right now, I'm experimenting with a mobile robot in a simple gazebo maze, using a LIDAR for ...
0
votes
0answers
30 views

Decidability of Pursuit-Evasion games and self driving cars

I was wondering if there is any theory describing the decidability of a continuous pursuit-evasion game with constraints. Scenario: Two cars approach each other on a street with two lanes. Let's say ...
0
votes
1answer
28 views

Can 2 spaces with different dimensions be topologically equivalent?

I am a bit confused with topology and am reading the next section after configuration spaces. I bumped into the question and got really confused.

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