HMI Assisted Visual Servoing for Autonomous Trailer Hitch Alignment
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Solution Overview
Problem
Accurately aligning a tow hitch ball with a trailer drawbar is challenging due to the need for operator skill and experience, and existing visual assistance systems require manual control of the vehicle, making the process difficult and imprecise.
Innovation Solution
A human-machine interface (HMI) assisted visual servoing process that uses rearview camera images displayed on a touch screen to register the tow hitch ball and target location, allowing the vehicle to autonomously move and align the hitch ball with the drawbar, using template matching and Kalman-Bucy filtering to predict and track the target location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual alignment method is used by operator, then alignment can be achieved, but alignment precision is low and requires high operator skill
Solution Approach 1:
The patent replaces the manual mechanical alignment process with an automated visual feedback system. A camera captures images of the hitch ball and drawbar, processing algorithms analyze their positions, and the system automatically guides the vehicle to achieve precise alignment, eliminating the need for operator skill and experience in manual positioning.
Solution Approach 2:
The system implements a closed-loop feedback mechanism where the camera continuously monitors the relative positions of the hitch ball and drawbar, the processing algorithm calculates alignment errors, and the system provides real-time guidance feedback to the operator or automatically adjusts the vehicle position to eliminate the error and achieve precise alignment.
2Measurement precision
If visual assistance system is used with manual control, then alignment guidance is provided, but alignment precision is limited by manual control capability
Solution Approach 1:
The patent replaces manual control of vehicle movement with automated control. The system processes camera images to determine precise positions of the hitch ball and drawbar, calculates the required vehicle movement, and automatically controls the vehicle's steering and propulsion systems to achieve accurate alignment, eliminating the precision limitations of manual control.
Solution Approach 2:
The system enables the vehicle to autonomously perform the alignment task by itself. The onboard camera, processing algorithm, and vehicle control systems work together to automatically position the vehicle and achieve precise alignment between the hitch ball and drawbar without requiring external manual intervention for positioning.
3Measurement precision
If camera parameters are not recalibrated, then system simplicity is maintained, but alignment accuracy deteriorates due to load changes
Solution Approach 1:
The system implements continuous feedback through the camera system that monitors the actual positions of the hitch ball and drawbar. This feedback loop allows the system to detect and compensate for camera parameter drift caused by load changes, maintaining alignment accuracy without requiring periodic manual recalibration of the camera system.
Solution Approach 2:
The system performs self-calibration by using the visual feedback from the camera to automatically adjust for parameter changes. The processing algorithm continuously refines the relationship between camera image coordinates and real-world positions based on observed alignment errors, enabling the system to maintain accuracy despite changes in vehicle load or camera position.
Data Source
AI summary
A method for autonomously aligning a tow hitch ball on a towing vehicle and a trailer drawbar on a trailer through a human-machine interface (HMI) assisted visual servoing process. The method includes providing rearview images from a rearview camera. The method includes touching the tow ball on a display to register a location of the tow ball in the image and touching the drawbar on the display to register a location of a target where the tow ball will be properly aligned with the drawbar. The method provides a template pattern around the target on the image and autonomously moves the vehicle so that the tow ball moves towards the target. The method predicts a new location of the target as the vehicle moves and identifies the target in new images as the vehicle moves by comparing the previous template pattern with an image patch around the predicted location.