Stepper Motor Reflector Hysteresis Compensation in HUD
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Solution Overview
Problem
Conventional vehicular head-up display devices experience misalignment and prolonged startup times due to hysteresis effects when the ignition is turned on, causing delays in displaying images on the windshield.
Innovation Solution
A vehicular head-up display device with a stepper motor connected to a reflector, where the motor is controlled to rotate by a specific angle corresponding to hysteresis when the ignition is turned off, and then returns to the requested position when turned on, eliminating misalignment and reducing processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor is supplied with extra steps to rotate the concave mirror beyond the final rotation stop position to prevent misalignment, then the alignment reliability is improved, but the process time and startup delay increase
Solution Approach 1:
The invention applies preliminary action by rotating the concave mirror beyond the final rotation stop position before normal operation begins. This preliminary rotation in the same direction as the final adjustment eliminates the need for backward rotation and extra steps during startup, thereby preventing misalignment while reducing startup delay.
2Reliability
If the concave mirror is rotated backward to return to the final rotation stop position, then misalignment is prevented, but the process time increases
Solution Approach 1:
The invention applies inversion by changing the rotation strategy from backward rotation to forward rotation beyond the stop position. Instead of rotating backward to correct position, the mirror rotates forward beyond the stop position and then proceeds directly to the final position, eliminating the time-consuming backward rotation process while maintaining position accuracy.
3Manufacturing precision
If a special mechanism is used to reduce looseness in mechanical movable portion or gear backlash, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The invention applies parameter changes by modifying the rotation control parameters (number of steps and rotation direction) rather than changing the mechanical structure. This software-based parameter adjustment eliminates the need for special mechanical mechanisms to reduce looseness or backlash, thereby maintaining manufacturing precision while avoiding increased device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents misalignment and quickly displays images on the windshield by addressing hysteresis effects, allowing for faster startup and improved driver experience.
Implementation Method 1
a reflector that reflects the display light, which is emitted from the display, to a windshield to display a virtual image of the display information in a driver's forward visual field
Implementation Method 2
a rotation direction spring that applies a force to a rotary shaft of the stepper motor in one rotation direction of the rotary shaft
Implementation Method 3
a rotation direction spring that applies a force to a rotary shaft of the stepper motor in one rotation direction of the rotary shaft
Implementation Method 4
an axis direction spring that applies a force to the rotary shaft in an axial direction of the rotary shaft
Data Source
AI summary
A vehicular head-up display device is provided. The vehicular head-up display device includes: a reflector for reflecting display light, which is emitted from a display, to a windshield to display a virtual image; a stepper motor for rotating the reflector and a controller for controlling the stepper motor to control a rotation position of the reflector. When a driver changes a request position of the virtual image to a new position in a direction toward a reset position and the ignition switch is turned off, the controller rotates the stepper motor to change the position of the virtual image to the reset position and thereafter instructs the stepper motor to rotate by a specified angle corresponds to a hysteresis generated at a time of a change in the rotation direction of the reflector between a forward rotation direction and backward rotation direction.