EV Charging Socket Pose Estimation Using an Oblique 2D View
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automating the precise positioning of a charging connector to an electric vehicle's socket for conductive charging is challenging due to the need for accurate alignment within a few millimeters, which existing methods using multiple cameras or 2D cameras struggle to achieve efficiently and economically, especially in large fleet settings.
Innovation Solution
A method utilizing a 2D camera with a view on the socket, where the camera and vehicle are positioned such that the line of sight is intentionally angled relative to the plug-in direction, allowing for 3D pose estimation using fiducial markers and algorithms like PnP or RANSAC, to determine the socket's position and orientation with high accuracy, enabling automatic connector alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple cameras or 3D viewing techniques are used to determine socket position and orientation, then measurement precision is improved, but device complexity increases and cost becomes prohibitive
Solution Approach 1:
The patent introduces a fiducial marker with known 3D geometry that encodes spatial information in multiple dimensions. By projecting this 3D structure onto a 2D camera plane and using the known marker dimensions, the system recovers depth and orientation information that would normally require multiple cameras, effectively adding dimensional information through the marker's geometric encoding
Solution Approach 2:
The fiducial marker acts as an intermediary object between the camera and the socket. Instead of directly measuring socket position and orientation with complex multi-camera systems, the marker serves as a中介 reference that simplifies measurement by providing easily detectable fiducial features with known geometric relationships
2Device complexity
If a single 2D camera is used to determine socket position and orientation, then device complexity is reduced, but measurement precision deteriorates due to insufficient depth information
Solution Approach 1:
The fiducial marker's known 3D geometry encodes depth and orientation information that is then projected onto the 2D camera plane. By analyzing the projection of this multi-dimensional structure and using the known marker dimensions, the system recovers accurate 3D position and orientation data from a single 2D image
Solution Approach 2:
The system changes the parameters of the measurement object by attaching a fiducial marker with specific geometric properties (known dimensions, distinctive pattern) to the socket. This transformation allows the 2D camera to accurately measure parameters (position and orientation) that would otherwise be difficult to obtain, by converting the measurement problem into one of detecting the marker's known geometric features
3Ease of operation
If the camera is positioned directly aligned with the plug-in direction, then ease of operation is improved, but measurement precision deteriorates due to insufficient angular information for pose estimation
Solution Approach 1:
The patent intentionally positions the camera at an asymmetric angle relative to the plug-in direction, rather than directly aligned. This asymmetric positioning provides the angular diversity needed for accurate pose estimation, as the oblique view allows better discrimination of the socket's orientation and depth position through the fiducial marker's projected geometry
Data Source
AI summary
Determining a position and orientation of a socket of an electric vehicle, the socket adapted for plugging in a charging connector in one unique plug-in position with one unique plug-in orientation and in one unique plug-in direction, as well as a front plane and/or a fiducial marker having an optical gravity point, includes providing a 2D camera with a view on a vehicle's charging location having a camera view comprising view lines for providing a 2D image of a focal plane perpendicular to said central view line, bringing the socket within said camera view, defining a view line going through the optical gravity point on the socket as the line of sight, viewing the socket with the camera, obtaining a 2D image, and analyzing the 2D image, wherein the vehicle and the camera are mutually positioned such that the line of sight is under an angle with the plug-in direction.