Rico贾若童的博客

Robotics - [3D SLAM - 5] Loosely and Tightly Coupled Lidar Inertial Odometry

FastLIO

Loosely vs Tightly Coupled LIO In loosely coupled LIO, the IMU and GPS are first fed into error state kalman filter which outputs a global pose estimate T_G. T_G is fed into a lidar odometer (such...

Posted by Rico's Nerd Cluster on March 11, 2025

Robotics - [3D SLAM - 4] Iterative Extended Kalman Filter

Prediction: xk = xk_1 + F_k (x_k-1 - x_k) Observation: h(x_k) = h(x_k-1) + H_x (xk-xk-1) innovation = z - h(x_k) My understanding is in innovation, we do it iteratively. x = get_kf_pose kf.updat...

Posted by Rico's Nerd Cluster on March 8, 2025

Robotics - [3D SLAM - 3] Lidar Odometry

Direct Lidar Odometry, NDT, Incremental NDT, Indirect Lidar Odometry, LOAM

Direct Lidar Odometry When given two scans, a direct NDT method means no features are extracted. The two scans would directly go through NDT for finding their relative poses. The workflow is as fo...

Posted by Rico's Nerd Cluster on March 4, 2025

Robotics - [3D SLAM - 2] Scan Matching Hands-On Notes

Preact-Mojave, Lidar-Only Front-End

Preact-Mojave Build & Workflow The ROS2 driver for Preact-Mojave can be found here. When testing it, I ran into below questions: Why make provision & make ros2? make provisi...

Posted by Rico's Nerd Cluster on March 3, 2025

Robotics - [3D SLAM - 1] Scan Matching

3D Point-Point ICP, 3D Point-Plane ICP, NDT

Point-Point ICP If we write out our state vector as [theta, translation], the pseudo code for point-point ICP is: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 pt_pt_icp(pose_estimate, source_scan, target_...

Posted by Rico's Nerd Cluster on March 1, 2025

Robotics - [Bugs - 2] SLAM Related Small Bugs

Passing Ptr By Value

⚠️ Beware of Passing Smart Pointers by Value Passing a smart pointer (e.g. std::shared_ptr or boost::shared_ptr) by value is fine when you’re only modifying the object it points to. But if you int...

Posted by Rico's Nerd Cluster on February 1, 2025

Robotics - [Bugs - 1] SLAM Related "Epic Bugs"

G2O Optimization Vertex Updates, Compiler-Specific Bugs, Yaml-cpp

Below is a list of bugs that took me multiple hours, if not days, to troubleshoot and analyze. These are the “epic bugs” that are worth remembering for my career. Epic Bug 1: G2O Optimization Didn...

Posted by Rico's Nerd Cluster on February 1, 2025

Robotics - A Survey On Oil Pipe Inspection Robotics (Revising)

Sonar Imaging

Non-Destructive Testing Methods American Society for Testing and Materials (ASTM) and American Society of Mechanical Engineers (ASME) develops standards for pipe inspections Ultrasonic Testing...

Posted by Rico's Nerd Cluster on December 20, 2024

Robotics - ROS2 Logging

Logging Level Tweaking

Logging Level Tweaking Programmatic API (in-process) In C++, any rclcpp::Logger can have its level tweaked at runtime: 1 2 3 #include <rclcpp/logger.hpp> auto my_logger = rclc...

Posted by Rico's Nerd Cluster on December 12, 2024

Robotics - ROS2 TF2

Transform Listener

TF2 and Sim Time When working with ROS2 and tf2, you may encounter the following warning when visualizing data in RViz or processing buffers: 1 Warning: TF_OLD_DATA ignoring data from the past fo...

Posted by Rico's Nerd Cluster on December 5, 2024

Rico's Nerd Cluster