External Rotation 3D Lidar for SLAM Localization Accuracy

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Solution Overview

Problem

Existing hybrid solid-state lidars with small fields of view suffer from limited sensing capabilities, large localization errors, and low mapping efficiency when applied to robots, posing challenges for SLAM algorithms.

Innovation Solution

An external rotation 3D lidar device and a SLAM method that combines error-state iterated Kalman filtering with pose graph optimization, enabling 360-degree environment sensing and correcting cumulative errors through loop-closure optimization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a hybrid solid-state lidar with small field of view is used, then long-distance detection capability is improved, but sensing capability and localization effect deteriorate

Engineering Contradiction:
Improvedetection distanceVSAvoidsensing capability
Core Design Contradiction:
Length of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent introduces a rotating mechanism that adds temporal dimension to the scanning process. The lidar performs multiple scanning cycles at different angular positions, transforming a static small FoV system into a dynamic 360-degree coverage system through multi-dimensional scanning patterns.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system transitions from a static lidar mounting to a dynamic rotating structure. The rotation angle and scanning patterns are adjustable, allowing the system to adapt to different environmental conditions and robot motion states, thereby improving both sensing coverage and localization accuracy.

Inventive Principle:
Principle #15Dynamics

2Length of stationary object

If a hybrid solid-state lidar with small field of view is used, then long-distance detection capability is improved, but mapping efficiency deteriorates

Engineering Contradiction:
Improvedetection distanceVSAvoidmapping efficiency
Core Design Contradiction:
Length of stationary objectVSProductivity

Solution Approach 1:

The system performs preliminary scanning at multiple angular positions before completing the full mapping process. By pre-collecting data from different angles and using predictive algorithms to estimate robot pose, the system prepares information in advance that accelerates the overall mapping efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from previously scanned data to guide subsequent scanning operations. The pose estimation results from earlier scanning cycles inform the planning of future scans, allowing the system to optimize its scanning pattern and reduce redundant measurements, thereby improving mapping efficiency.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If feature extraction based on scanning characteristics is used, then point cloud processing is improved, but localization effect in unstructured environments deteriorates

Engineering Contradiction:
Improvepoint cloud processing qualityVSAvoidlocalization effect
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts processing parameters based on the detected environment type. In unstructured environments, it switches from feature-based processing to direct point cloud registration methods, changing the algorithmic parameters to match the environmental characteristics and maintain localization accuracy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The localization algorithm transitions from a static feature extraction approach to a dynamic method that adapts its processing strategy based on real-time environmental assessment. The system can switch between different processing modes (feature-based vs. direct registration) depending on the structure and complexity of the environment.

Inventive Principle:
Principle #15Dynamics

4Measurement precision

If tightly-coupled lidar inertial odometry is used, then pose accuracy is improved, but device complexity and implementation difficulty increase

Engineering Contradiction:
Improvepose accuracyVSAvoidimplementation difficulty
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a slip ring as an intermediary component that enables the rotation mechanism to function. The slip ring provides continuous electrical connection while allowing rotational movement, simplifying the overall system architecture compared to alternative solutions like wireless power transmission or complex rotary joints.

Inventive Principle:
Principle #24Intermediary (Mediator)

5Adaptability or versatility

If external rotation mechanism is added to achieve 360-degree sensing, then sensing capability is improved, but device complexity increases

Engineering Contradiction:
Improvesensing capabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The rotating mechanism serves multiple functions simultaneously: it provides 360-degree sensing coverage, enables the lidar to track moving targets, and allows the system to adapt to different scanning patterns. This multi-functionality justifies the added complexity by delivering multiple performance benefits from a single structural addition.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250147185A1External rotation 3D lidar device and simultaneous localization and mapping (SLAM) method thereof
Publication Date: 2025.05.08 BEIJING INST OF TECH
  • US20250147185A1 patent drawing
  • US20250147185A1 patent drawing
  • US20250147185A1 patent drawing

AI summary

An external rotation 3D lidar device and a simultaneous localization and mapping (SLAM) method comprises a 3D hybrid solid-state lidar device that is driven to rotate by an external motor. The device significantly improves the horizontal field of view of the lidar and can be mounted on a ground robot to comprehensively improve its 360-degree environment sensing capabilities. Error-state Kalman filtering and pose graph optimization are combined and the overall framework is divided into two parts: front-end odometry and back-end loop-closure optimization. Therefore, high-frequency odometry that meets the requirements of the robot can be output in real time and cumulative errors can be eliminated through the back-end loop-closure optimization.