All Questions

0
votes
2answers
26 views

Motor encoders randomly start counting backward, then go back to normal

I am making an Arduino-controlled differential drive robot, and I am having the following problems: the encoders built into the motors are being used for measuring the rotary displacement, and while ...
-1
votes
2answers
24 views

need help to get inverse kinematics

I have a 3 degree of freedom arm robot and by using D-H representation method get the forward kinematics but I can't derive the inverse kinematics can someone help me please ?
0
votes
0answers
23 views

Overcoming or managing deadband in vehicle steering controller [duplicate]

I found out there is a deadband in my steering controller after several runs. And the transfer function for it in the \$s\$-domain is $$ H(s)=\frac{270\cdot e^{-0.03s}}{0.015\cdot s + 1} $$ To ...
1
vote
0answers
35 views

Camera pose to world coordinate transformation

I have managed to receive camera_pose for ORB-SLAM by following their code. If I run $ echo /world /camera_pose I receive something like this: ...
1
vote
1answer
68 views

Likelihood Field Matching

I have LIDAR data of an environment in my hand and I want to apply likelihood field matching to this data. I found a source. But I don't understand what the variables of the algorithm mean and how it ...
2
votes
3answers
99 views

Finding Mass/Inertia Matrix of a robot

Hi I am trying to model my humanoid robot. The general EoM is $M(q)\ddot{q}+C(q,\dot{q})+G(q)=U$ I know $M(q)$ is Inertia matrix which depends on joint positions $\textbf{q}$. However, I am having ...
1
vote
1answer
61 views

Fusing absolute robot localization from markers

I have a system which is composed of a rig of 8 cameras which are used for detecting markers in the environment and which outputs 8 estimates of the absolute robot's position and orientation. Now, I ...
2
votes
0answers
27 views

Overcoming or managing deadband in vehicle steering controller

I found out there is a deadband in my steering controller after several runs. The transfer function for it in the $s$-domain is $$H(s)=\frac{270\cdot e^{-0.03s}}{0.015\cdot s + 1}$$ To overcome this ...
0
votes
2answers
69 views

What are the prerequisites for entering into robotics?

I'm doing my Engineering in Electronics, what subjects which I need to specialize in order get into robotics and also suggest additional things I have to study
3
votes
5answers
81 views

Is it correct to think of forward kinematics as merely a 'check' for the inverse kinematics?

When the only inputs to your robot are the next x,y,z coordinates of the next point on and on, I can simply just calculate IK to find the angles and make my actuators move to these angles. Whats the ...
0
votes
1answer
39 views

How can I attach an arm to a double-flat drive stepper motor?

This is my first robotics experience, outside of one class 10 years ago. I've been Googling this question for about an hour but I can't find an answer! I'm using a ROHS Step Motor 28BYJ-48 (with an ...
0
votes
1answer
37 views

Are examples for jerking robotarms available?

I'm trying to find some youtube videos which are showing robot arms with some malfunction in it. The problem is, that the keyword is unclear. Should i search for “unstable”, “tremble”, “jerking” or “...
0
votes
1answer
20 views

How to change endian for multi-byte I/O outputs?

When using the Yaskawa Smart Pendant SDK API (Java client), it is possible to set multi-byte I/O values via: ...
0
votes
1answer
50 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 ...
1
vote
1answer
33 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: ...
0
votes
0answers
9 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 ...
-1
votes
1answer
22 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 ...
1
vote
0answers
16 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?...
0
votes
1answer
37 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 ...
1
vote
1answer
39 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 ...
1
vote
2answers
29 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 ...
1
vote
1answer
47 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 ...
0
votes
0answers
30 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 ...
0
votes
0answers
46 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 ...
2
votes
0answers
72 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 ...
1
vote
1answer
52 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 ...
0
votes
1answer
30 views

Please help me with stall property of gear motor

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 ...
1
vote
1answer
30 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 ...
-1
votes
1answer
28 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!
0
votes
1answer
42 views

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 ...
1
vote
1answer
35 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 ...
0
votes
0answers
17 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 ...
0
votes
2answers
60 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 ...
1
vote
0answers
6 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 ...
0
votes
1answer
47 views

Head movement using gyroscope

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 ...
2
votes
2answers
56 views

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/...
1
vote
0answers
12 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 ...
0
votes
0answers
21 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 ...
0
votes
1answer
23 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 ...
0
votes
0answers
20 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 ...
0
votes
1answer
32 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 ...
1
vote
1answer
32 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 ...
1
vote
0answers
36 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 ...
-2
votes
1answer
48 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?
1
vote
1answer
41 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, ...
0
votes
0answers
20 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 ...
2
votes
1answer
57 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 ...
0
votes
1answer
116 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 ...
0
votes
1answer
45 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 ...
0
votes
0answers
17 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 ...

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