Vehicle Head-Up Display Stepper Motor Stabilization
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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 moves after adjustment.
Innovation Solution
A head-up display device with a control system that continues to apply a drive signal to the stepper motor until it reaches the electric stabilization point and then immediately stops, allowing the motor to rotate by inertia to the mechanical stabilization point, ensuring continuous adjustment of the virtual image position without repositioning at the electric stabilization point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive signal is continued to be applied until the electric stabilization point is attained, then the stepper motor is electrically stabilized by holding torque, but the display position moves again after stopping because the electric stabilization point and mechanical stabilization point are different in phase
Solution Approach 1:
The control system applies the drive signal in advance beyond the detection stabilization point to ensure the stepper motor reaches the mechanical stabilization point. This preliminary action compensates for the phase difference between electric and mechanical stabilization points, preventing display position movement after the adjustment instruction is stopped.
Solution Approach 2:
The control system detects the stabilization point based on the state of the stepper motor and adjusts the drive signal application accordingly. By monitoring motor current or voltage changes that indicate stabilization, the system can determine when to continue applying power to ensure smooth positioning without causing display position shifts.
2Reliability
If the drive signal is stopped immediately after the electric stabilization point is attained, then the stepper motor stops quickly, but it steps out of phase in response to external force or vibration
Solution Approach 1:
The control system continues to apply the drive signal for a predetermined period after detecting the stabilization point. This preliminary action ensures the stepper motor has sufficient time to reach the mechanical stabilization point and become stable against external forces or vibrations, preventing phase stepping while minimizing additional stabilization time.
3Reliability
If the drive signal is continued to be applied for a while after the electric stabilization point, then the stepper motor is stabilized against vibration, but the display position moves again due to phase difference between electric and mechanical stabilization points
Solution Approach 1:
The control system monitors the state of the stepper motor to detect the stabilization point and uses this feedback to control the drive signal. By detecting changes in motor current or voltage that indicate the motor has reached stabilization, the system can precisely control when to continue applying power, ensuring the motor reaches the mechanical stabilization point without overshooting and causing display position movement.
Solution Approach 2:
The control system applies the drive signal in advance of the exact stabilization point to compensate for the phase difference between electric and mechanical stabilization. This preliminary action ensures that when the drive signal is stopped, the motor has already reached the mechanical stabilization point, maintaining both vibration resistance and positioning accuracy.
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 approach enhances the reliability of the virtual image display by preventing unwanted movement of the display position, providing a stable and consistent viewing experience for vehicle information.
Implementation Method 1
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
Implementation Method 2
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 3
The stepper motor has plural mechanical stabilization points, at which the motor operation is stabilized by a detent torque generated when not powered
Implementation Method 4
immediately stop applying the drive signal when the electric stabilization point is attained so that the stepper motor performs inertia rotation toward the mechanical stabilization point after the powered rotation
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 to change by a step angle at every predetermined period Ts in response to an adjustment instruction inputted from an adjustment switch. The control system continues to apply the drive signal until the electric stabilization point is attained even after the adjustment instruction is stopped to operate the stepper motor in a powered rotation mode. The stepper motor then operates in an inertia rotation mode toward the mechanical stabilization point is attained.