# All Questions

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4 views

### Need help with battery chemistries and limited space

I have a robot with a very small space, but needs a very powerful battery in order to power the motors in it. What I need to know is what kind of rechargeable (secondary) battery chemistry would be ...
6 views

### Motor driver damage and jerking behavior when load driving in same direction as motor

I'm having trouble with a gear motor being powered by a power supply, while it is being driven by the load in the same direction as the driver wants to drive it. Here is a simple diagram: The gear ...
30 views

### Likelihood field sensor model (Probabilistic Robotics, Thrun et al., p.169-174)

I am currently working on the "likelihood field" sensor model (aka "endpoint model") by Thrun et al. (book: Probabilistic Robotics, Thrun et al., p.169-174) In this context I have ...
13 views

### 2D point cloud registration success probability

I am trying to implement localisation by storing images from a camera and their accompanying point clouds from a 2D lidar during mapping. During localisation I then use image matching to suggest the ...
8 views

### How to get 2D map using Stereoscopic camer (RGB+D), IMU and GPS?

I am starting with slam using imu, stereo camera (that gives RGB + depth info) camera and gps mounted on my robot. I wish to create a 2D map for it like this: But with landmarks, so that I can stop ...
9 views

### LED of One of the digital pin has high intensity compared with others

I am trying to make digital pin high according to the analogue input read using Arduino Uno. Despite having same resistance of 330 Ohm with all LEDs, the intensity of LED connected to pin2 is ...
11 views

### LiDAR Feature Extraction

I'd like to extract "features" of an environment scanned with a 2D LiDAR. I tried to create a temporary occupancy map to extract "corners" with the Harris Corner Detector. However ...
12 views

### Attaching A1 Servo Splint to Shaft

I want to attach a servo that has an A1-sized end on it to a shaft. I'm building an RC submarine, and I want this to control the dive planes. My problem is that I only see horns for a servo of that ...
13 views

### BeagleBone Black “CAN” connection with Arduino uno [closed]

I want to gather 'can' messages from arduino uno which has 'can shield on it' and send the messages to beaglebone black, which also has can cape on it. The connection is basically connecting CAN-H to ...
26 views

### Are robotic, riderless street bikes common now?

I just saw what looked like a normal bicycle drive around the a block a few times without a rider. There was a clear plastic box with some electronics, a motor on the back wheel and something ...
20 views

### Choosing the right dc motor

I'm trying to find the optimal components list for a radio controlled lawn mover i'm trying to build. The blades will be rotated by a 140 cc engine. I choose this engine because it's already mine. ...
12 views

### rosserial_server wifi connection Raspberry pi ESP8266 [closed]

This post is related to ROS (Robot Operating System) and ESP8266, and has also been cross-posted on ROS Answers and Stackoverflow. I've ROS Melodic running on a Raspberry Pi 4 and need to send out ...
12 views

### Help finding a replacement for a broken gear

My robot lawn mower (a Robomow rx20u) was moving erratically, so I took apart the wheel assembly and found that one of the reduction gears has several broken teeth (in the picture, look at the right-...
19 views

### Camera module for Drone [closed]

I have made a Drone with an F450 frame, 1000 Kv motor, and Stm32 as the brain of the flight controller. Communication between flight controller and radio controller is done by an NRF24 module. I am ...
23 views

### Connecting to iRobot Create 2 serial port over WebUSB

I am attempting to connect to the supplied USB serial cable that came with iRobot Create 2 from Chromium 78.0.3904.108 (32-bit) on a Raspberry Pi 4. From lsusb, I ...
20 views

### Using DH representation, obtain the coordinates of E [closed]

The coordinates of E is required.
16 views

### How to implement the instant quote feature for CNC machining through web? [closed]

We are an Indian Robotics company that is starting something similar to 3dhubs.com. We are currently trying to figure out the instant quote feature for CNC machining. I am an intern and I am trying to ...
42 views

### What flight firmware stack is most common in aerial robotics research environments?

I'm considering Aero-Astro grad school and am looking into acquiring a drone hardware platform to implement GNC/ PNT/ autonomy papers like those I might see from, e.g., the Navigation and Autonomous ...
22 views

### system design books for robot software

I see in the realm of app/web dev theres quite a few books out there to detail on system design templates, best practices and concepts. For example senior software engineers are often asked to design ...
37 views

### Identify this robot?

Seen in this story, and in * many * others relating to AI and robots (determined via google image search...) What build is this and it's origin?
11 views

### Improvements over FastSLAM2.0

Are there some papers and/or works that describe improvements for the FastSLAM2.0 algorithm? I'm particularly interested in the following areas: The map is completely unknown at the beginning of the ...
17 views

### How does a Tesla or any self-driving car self-drive to a remote place and align itself to an object?

I am trying to understand the technology/procedure related to one of the trivial functions of a modern self-driving cars. Let us consider the example of Tesla's Model S (or any). The car is parked at ...
39 views

### What is the correct architecture of quadcopter control?

I want to make a quadcopter flight controller for my University project. Lately I was searching for systematic architecture of control system used by quadrotors. I have implemented one of the ...
26 views

### irobot create 2: random changes in driving speed

I am trying to make the Create2 dance a specific choreography. I´m not using the sensors, I just let it drive and turn for a specific amount of time. In general it works fine. But after working with ...
25 views

### difference between non-holonomic and linear control systems

I already asked this question in the mathoverflow forum, but no one could answer. Probably it is not a question of mathematics but robotics. I'm struggling with the definitions and differences between ...
11 views

### Scale drift correction in monocular ORB-SLAM2 [closed]

Trying to correct scale drift in monocular ORB-SLAM2, but leads to multiple track loss events (for instance, track lost on KITTI 03 around 5-6 times). Using the scale correction method as described by ...
8 views

### ECEF postion vs. LAT/LON/Height position with odometry

So I do have a wheeled robot and I want to fuse position data with odometry data. Someone suggested using the position encoded in ECEF rather than using the LAT/LON/Height information I get from the ...
14 views

### What could cause quaternion error to go up drastically when a gyroscope is rotated on more than one axis at a time?

Alright, I'm working on a small Arduino script that determines orientation using a a gyroscope and a quaternion. My hardware: LSM9DS1 IMU (Gyroscope, Accelerometer, Magnetometer) Teensy 4.0 My basic ...
35 views

### How to make a CNC machine from scratch?

I want to make my own CNC machine from scratch because it's cheaper to make than buy a premade one. I noticed that some machines go for tens of thousands of dollars and I cannot understand how they ...
16 views

I'm interested in quadcopter position tracking using a mix of IMU and visual navigation. I want to implement an EKF filter but what's not clear to me is how the filter would be updated using the ...
18 views

### Relation between control and reinforcement learning

Has the relation between Control and reinforcement learning been studied by the scientific community? I would like to read credible studies about each ones pros and cons when it comes to control ...
11 views

### Use of Communication Systems in Robotics

So I recently started working on a Communication System for receiving and transmitting data from a Ground Station to a Drone. I want to know if there are any other applications of Communication ...
52 views

### Sensor fusion of GNSS and IMU using UKF

I do have a land-based robot with an IMU and a GNSS receiver. From the IMU, I get the velocity and acceleration in both $x$ and $y$ directions. From the GNSS receiver, I get the latitude and ...
22 views

### “catkin_make” prompts “+make” and “recipe for target … failed” errors

I have been working on a ground vehicle project for some time that has bunch of sensors, until now I have managed to overcome the problems I have encountered. I have used catkin_make many times and ...
15 views

### How does 3DHub find instant quotes for CNC machining? [closed]

We are an Indian Robotics company that is starting something similar to 3dhubs.com. We are currently trying to figure out the instant quote feature for CNC machining. I am an intern and I am trying to ...
23 views

### Sam C21 Xplained Pro - Linux toolchain

I recently got a ATSAMC21N Xplained Pro dev board. I was planning to use avr-g++ and avrdude to do development (I’m running ...
13 views

### List of tuples as argument in ROS2 launch

I'd like to define an argument in ROS2 launch file which is a list of tuples. How should the list in default_value be formatted? ...
23 views

### How can I calibrate 3 cameras and track the object using only synchronized cameras feeds from all the cameras?

I have camera feed (in the form of RGB images) from 3 cameras with partially overlapping Field-of-view i.e. for the time stamp 0 to 100, I have total 300 frames or say synchronized 100 RGB frames for ...
19 views

### When a permutation matrix is desired for transforming camera frame to world frame?

When dealing with rectified images, why would the inverse of a simple permutation matrix $$P = {\begin{bmatrix} 0 & -1 & 0 \\ 0 & 0 & -1 \\ 1 & 0 & 0 \end{bmatrix}}^{-1}$$ ...
33 views

### Where to buy cheap motors and mechanical parts for hobby robotics applications? [closed]

My kids want to get into robotics, where Online can I buy the motors (dc,ac,stepper...) and mechanical assembly (nuts, bolts, sheet metal, springs, rods...) for a very affordable price, you know I ...
14 views

### What should be a good frequency for the EKF prediction and correction updates?

This is my first post on the forum although I read Q&A posted here constantly. I haven´t seen a similar question so here it goes: I am implementing an EKF for localization from scratch just for ...
9 views

### How does isam compare with Gmapping and Hector?

I read about incremental smoothing and mapping (iSAM) first in the paper on hector_slam (a flexible and scalable SLAM system with full 3D motion estimation by Stefan Kohlbrecher et al) and then read ...
17 views

### How to pick the right motor driver?

I have this brushed DC motor (Vex 775pro: https://motors.vex.com/vexpro-motors/775pro; motor curve data here I assume is useful but I do not exactly know how to make sense of it) My question is, how ...
15 views

### Size of smallest feature from pixel depth resolution

How do I get the size in mm of the smallest feature a depth camera can detect? Known variables are: distance from the target (for instance 1 meter), depth resolution in pixels (for instance 1280 x 720)...
34 views

### DIY Smart Devices [closed]

I am a software developer. I make apps. I have several ideas for Bluetooth-enabled smart devices using basic accessories and peripherals like cameras, speakers/headphones, lights and some external ...
24 views

### How to deal with Gaussian Errors, which don't have a mean value of 0?

I'm writing a SLAM algorithm. One of the main problems is, that the landmark measurement error is not really Gaussian distributed, which means, their error doesn't have a mean value of 0. I already ...
94 views

### How can I calibrate 3 cameras without knowing global pose of the object & camera locations? How can I find the pose of each camera wrt the first one?

I have camera feed (in the form of RGB images) from 3 cameras with partially overlapping Field-of-view i.e. for the time stamp 0 to 100, I have total 300 frames or say synchronized 100 RGB frames for ...
27 views

### Calculate the Vehicle corner points given localization

I am trying to calculate the corner points of the vehicle given the details below: Localization data from rear axle of the vehicle Length and Width of the vehicle Heading of the vehicle ENU Could ...