Head Mounted Display Symbol Orientation Alignment
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Solution Overview
Problem
Head-mounted display (HMD) systems for vehicle pilots face challenges in reducing sensory mismatch between vestibular sensations and visual perceptions, leading to issues like motion sickness and spatial disorientation, which compromise the pilot's ability to control the vehicle effectively.
Innovation Solution
The implementation of a gaze tracking and display (GTAD) system that determines the orientation and position of the HMD relative to the vehicle's cockpit, allowing for the spatial fixation of symbol rotation axes to align with the vehicle's principal axes, thereby reducing sensory mismatch by providing a stable and aligned visual representation of critical flight parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the HMD displays information in a fixed orientation relative to the display device, then the display is simple to implement, but the visual representation becomes misaligned with the vehicle's actual orientation, causing sensory mismatch and spatial disorientation
Solution Approach 1:
The patent implements dynamic symbol orientation where the display orientation is no longer fixed to the display device but dynamically adjusts to match the vehicle's principal axes. The symbol coordinate system is selectively spatially fixed to the vehicle coordinate system based on vehicle orientation data, allowing the display to adapt its orientation in real-time according to the vehicle's pitch, roll, and yaw, thereby maintaining alignment with the vehicle's actual spatial orientation.
Solution Approach 2:
The system changes the orientation parameters of the displayed symbols by transforming them from a display-device-fixed coordinate system to a vehicle-fixed coordinate system. This involves calculating rotation transformations based on vehicle orientation data (pitch, roll, yaw) and applying these transformations to the symbol positions and orientations, thereby adjusting the display parameters to match the vehicle's spatial orientation.
2Device complexity
If the HMD symbol orientation is fixed to the display device coordinate system, then the display system is simpler, but it causes sensory mismatch between vestibular sensations and visual perceptions
Solution Approach 1:
The patent transforms the static, fixed orientation display into a dynamic system that continuously adapts symbol orientation based on vehicle motion. The symbol coordinate system is selectively spatially fixed to the vehicle coordinate system, causing symbols to rotate and reposition dynamically according to the vehicle's pitch, roll, and yaw angles, thereby maintaining visual alignment with the vehicle's actual orientation and reducing sensory mismatch.
Solution Approach 2:
The system implements feedback by continuously monitoring vehicle orientation data (pitch, roll, yaw) and using this information to adjust the symbol display orientation. The processor receives vehicle orientation data, calculates the appropriate transformation, and updates the symbol positions and orientations in real-time, creating a closed-loop system that responds to vehicle motion and maintains visual-vestibular alignment.
3Ease of operation
If the HMD allows free movement during vehicle operation, then the pilot has greater freedom of view, but the displayed information becomes unstable and misaligned with external references
Solution Approach 1:
The patent implements a dynamic stabilization mechanism where the symbol orientation is continuously adjusted based on vehicle orientation data. As the vehicle moves and the HMD rotates freely, the system calculates the vehicle's pitch, roll, and yaw angles and applies transformation matrices to keep the symbols stable relative to the vehicle's principal axes, thereby maintaining display stability despite HMD movement.
Solution Approach 2:
The system addresses the stability issue by adding a computational transformation layer between the physical HMD orientation and the displayed symbol orientation. Instead of directly mapping display device coordinates to screen coordinates, the system introduces a vehicle coordinate system transformation that compensates for HMD movement, effectively adding a dimensional transformation step that stabilizes the display information.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
Embodiments concern a method for providing information to a user of a vehicle via a display device that is worn by the user. The method comprises providing a principle axes rotation coordinate system (Vxyz) that defines a vehicle orientation relative to a world coordinate system (Wxyz) of a reference world space; providing at least one display device coordinate system (Dxyz) that defines a display device orientation relative to the vehicle coordinate system; and providing a symbol coordinate system (Sxyz) that is spatially fixed with at least one first symbol to be displayed on the display device and that defines three symbol rotation axes that are orthogonal to each other; and spatially fixing at least one of the symbol rotation axes (Sα) to a vehicle principal axis of rotation descriptive of an orientation of the vehicle.