All Questions

4,446 questions
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 ...
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 ?
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 ...
35 views

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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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?
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, ...
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 ...
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 ...
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 ...