Seat Rotation Position Sensor Using Helical Ramp and LVDT
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Solution Overview
Problem
Existing vehicle seating systems do not effectively allow for the rotation of seats between forward-facing and rearward-facing positions in autonomous vehicles, limiting occupant comfort and safety during vehicle operation.
Innovation Solution
A vehicle seating system incorporating a rotatable seat mechanism with a linear variable differential transformer (LVDT) and solenoid, allowing the seat to rotate 360 degrees, with a helical ramp and plunger system to determine and lock the rotational position, and a computer system to control the solenoid for precise seat positioning and occupant restraint system operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rotatable seat mechanism is implemented in autonomous vehicles, then occupant comfort and safety are improved, but device complexity increases due to the need for sensors, solenoids, and control systems
Solution Approach 1:
The patent replaces complex mechanical position detection mechanisms with a magnetic field-based LVDT sensor system. The plunger with magnet interacts with the helical ramp to convert rotational position into linear displacement, which is then detected by the LVDT, eliminating the need for complex mechanical encoders or multiple sensors.
Solution Approach 2:
The patent introduces a plunger as an intermediary component that translates the rotational movement of the seat into linear displacement. This plunger acts as a mediator between the rotational motion and the LVDT sensor, simplifying the measurement process and reducing system complexity.
2Measurement precision
If the plunger is moved away from the helical ramp during seat rotation, then measurement accuracy is maintained, but additional control mechanisms are required
Solution Approach 1:
The patent implements a dynamic plunger control system that adjusts the plunger position based on seat rotation state. During rotation, the plunger is retracted to avoid interference; during positioning, it extends to contact the helical ramp for accurate measurement. This dynamic adjustment optimizes both measurement accuracy and system simplicity.
Solution Approach 2:
The plunger operates in periodic cycles: extending to measure position when the seat is stationary, and retracting when rotation is detected or about to occur. This periodic engagement and disengagement pattern ensures accurate measurements are taken only when appropriate, while minimizing interference during rotation phases.
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
Enables comfortable and safe rotation of seats between forward and rearward positions, enhancing occupant experience and safety by accurately determining and adjusting the seat orientation for various vehicle operations, including occupant restraint system activation.
Implementation Method 1
a linear variable differential transformer (LVDT) including a housing fixed relative to the other of the base and the seat and a plunger moveably supported by the housing
Implementation Method 2
The vehicle may include a solenoid operatively coupled to the plunger of the linear variable differential transformer
Data Source
AI summary
A vehicle includes a base and a seat rotatable relative to the base. The vehicle includes a helical ramp fixed relative to one of the base and the seat. The vehicle includes a linear variable differential transformer (LVDT) including a housing fixed relative to the other of the base and the seat and a plunger moveably supported by the housing. The plunger contacts the helical ramp.