Stepper Motor Stabilization for Vehicle HUD Image Stability
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Solution Overview
Problem
Conventional head-up display devices for vehicles experience instability in the display position of virtual images due to mismatched electric and mechanical stabilization points in stepper motors, leading to discomfort and unreliability for passengers as the display position adjusts after stabilization.
Innovation Solution
A head-up display device with a stepper motor having multiple electric and mechanical stabilization points, where the control system continues to apply a drive signal until the electric stabilization point is reached, and then allows inertia-driven rotation to the mechanical stabilization point, minimizing phase difference and maintaining image stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive signal is continued to be applied until the electric stabilization point is reached, then the stepper motor is electrically stabilized by holding torque, but the electric stabilization point and mechanical stabilization point are different in phase due to manufacturing tolerance, causing the stepper motor to temporarily stop and then start rotation toward the mechanical stabilization point, which makes the display position of the virtual image move again after being stopped once
Solution Approach 1:
The control system continues to apply the drive signal beyond the electric stabilization point to ensure the rotor reaches the mechanical stabilization point where the detent torque provides reliable mechanical stabilization. This preliminary continuation of the driving action compensates for the phase difference caused by manufacturing tolerances and prevents subsequent unwanted rotation.
Solution Approach 2:
The control system monitors the rotation state of the stepper motor and adjusts the drive signal duration based on the actual position reaching. By detecting when the rotor has reached the mechanical stabilization point, the system can terminate the drive signal at the appropriate moment, ensuring the virtual image display position remains stable without unwanted movement.
2Productivity
If the drive signal is stopped immediately after the electric stabilization point is attained, then the stepper motor should be stabilized, but due to the phase difference between electric and mechanical stabilization points, the stepper motor temporarily stops and then starts rotation, causing discomfort and unreliability for passengers
Solution Approach 1:
The control system anticipates the phase difference between electric and mechanical stabilization points by continuing to apply the drive signal for a predetermined period after the electric stabilization point is detected. This ensures the rotor has sufficient time to reach the mechanical stabilization point before the drive signal is terminated, preventing subsequent unwanted rotation while maintaining fast response.
Solution Approach 2:
The control system provides a cushioning period where the drive signal is maintained beyond the electric stabilization point to prevent the harmful effect of temporary stopping and subsequent rotation. This cushioning action ensures smooth and stable positioning of the virtual image, eliminating discomfort for passengers.
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
This configuration enhances the reliability of the virtual image display by reducing the deviation of the display position after adjustment, ensuring a stable and consistent viewing experience for vehicle information.
Implementation Method 1
The stepper motor has plural electric stabilization points, at which a motor operation is electrically stabilized by a holding torque generated when powered
Implementation Method 2
plural mechanical stabilization points, at which the motor operation is stabilized by a detent torque generated when not powered
Implementation Method 3
The optical system includes a reflection mirror, which is provided rotatably to reflect the light-emitted image and project a reflected image toward a projection target so that a virtual image of the light-emitted image is displayed
Data Source
AI summary
A HUD device includes a stepper motor, which rotates a reflection mirror for adjusting a display position of a virtual image. The stepper motor has an electric stabilization point and a mechanical stabilization point. A control system controls a drive signal for the stepper motor in response to an adjustment instruction. Pole teeth of a specified phase, which provides a greater magnetic attraction force with the rotor when not powered than by pole teeth of other phase, is set as stabilization pole teeth. The control system continues to apply the drive signal until the target stabilization point is attained even after the adjustment instruction is stopped. The target stabilization point is set to the electric stabilization point, at which the holding torque is provided by the stabilization pole teeth of the specified phase.