Robotics Stack Exchange
Robotics Stack Exchange

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Extended Kalman Filter with Laser Scan + Known Map

I am currently working on a project for school where I need to implement an extended Kalman Filter for a point robot with a laser scanner. The Robot can rotate with 0 degree turn radius and drive forward. All motions are piecewise linear…
en4bz
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Maintaining positive-definite property for covariance in an unscented Kalman filter update

I have an unscented Kalman filter (UKF) that tracks the state of a robot. The state vector has 12 variables. Each time I carry out a prediction step, my transfer function (naturally) acts on the entire state. However, my sensors provide measurements…
automatom
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In practical terms, how close is the accuracy of camera-based visual odometry/SLAM methods to lidar-based methods for autonomous car navigation?

Benedict Evans, a general partner at Andreessen Horowitz, claims that “almost all autonomy” projects are using lidar for SLAM, and that not all of them use HD maps. An MIT group is testing self-driving cars on public roads without HD maps. My…
T.A. Eady
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What is the best SE3 library for python?

I am currently googling on this topic but I would like to hear your opinion. What is the best self-contained SE3 library that offers interconversion between quaternion, rotation vector, transformation matrix? Those are the functions that I often use…
Chanoh Park
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How does rocker bogie keep the body almost flat?

How does rocker-bogie mechanism keep the body flat / keep the solar panel almost flat all the time? I know there is an differential system that connect both rocker bogie (left and right) together. But how does it actually work? Edited: Please…
ikel
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How to model the noise in a range sensor's return?

Range sensors (for example sonar, infrared, and lidar) are notoriously noisy. How can I characterize the noise characteristics to include these in a probabilistic localization sensor model?
Felix
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What are human-friendly terms for mobile-robot orientation and relative direction of non-robot objects?

Within robotics programming, orientation is primarily given in terms of x, y, & z coordinates, from some central location. However x, y, z coordinates aren't convenient for rapid human understanding if there are many locations from which to select…
Recursive Self Optimization
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Chaining Kalman filters

My team is building a robot to navigate autonomously in an outdoor environment. We recently got a new integrated IMU/GPS sensor which apparently does some extended Kalman filtering on-chip. It gives pitch, roll, and yaw, north, east, and down…
Robz
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Why do space probes need heating?

I know that temperature influences the characteristics of semiconductors and other materials, but we know how and can take that into account. Furthermore, lower temperatures makes electronics more efficient, sometimes even superconducting. I…
Ansis Māliņš
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How can we use the accelerometer for altitude estimation?

I am currently implementing an autonomous quadcopter which I recently got flying and which was stable, but is unable to correct itself in the presence of significant external disturbances. I assume this is because of insufficiently tuned PID gains…
user123456098
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Using genetic algorithm for tuning controllers

I've read some papers for controlling nonlinear systems (e.g. nonlinear pendulum). There are several approaches for targeting nonlinear systems. The most common ones are feedback linearizaing, backstepping, and sliding mode controllers. In my case,…
CroCo
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Calibrate a 2d scanner mounted on a rotary axis

A 2d laser scanner is mounted on a rotary axis. I wish to determine the transformation matrix from the center of the axis to the center of the scanner, using only the input from the scanner and the angle of rotation. The 2d scanner itself is…
HugoRune
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Angle Random Walk vs. Rate Noise Density (MPU6050)

I’ve made a datalog from a MPU6050 (IMU: gyroscope and accelerometer) at 500Hz sample rate. Now I want to calculate the characteristics from the gyro to evaluate the sensor. For the gyro I’ve found following values in the datasheet: Total RMS Noise…
Patrick Stegers
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Do I really need a gyro for an airplane flight stabilization system?

I'm working on a basic airplane flight stabilization system, as the precursor to a full autopilot system. I'm using a salvaged Wii Motion Plus and Nunchuk to create a 6DOF IMU. The first goal is to keep the wings level, then mix in the users…
Chris
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Building Robotic arm joint

I am very new to robotic design and I need to determine what parts I will need to assemble an arm joint. The joint will contain one timing belt pulley which a remote motor will be turning, a forearm that the pulley will be rotating and an upper-arm…
user912447
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