Tilting Vehicle Seat Cushion Using Shape Memory Actuation
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Solution Overview
Problem
Deep seats and stiff bolsters, while effective in reducing lateral acceleration effects, can cause discomfort during normal driving conditions due to excessive support when larger lateral forces are not experienced.
Innovation Solution
Incorporating shape memory material members, such as SMA or SMP, between the seat pan and frame to selectively tilt the seat cushion laterally in response to sensor-determined acceleration conditions, providing adjustable support only when needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deep seats and stiff bolsters are used, then lateral support during high acceleration is improved, but comfort during normal driving deteriorates
Solution Approach 1:
The seat cushion is made dynamically adjustable through shape memory material members that change the cushion's tilt angle based on detected lateral acceleration conditions. During normal driving, the cushion remains in a first configuration for comfort, while during high lateral acceleration, it tilts to a second configuration to provide lateral support, thus resolving the contradiction between comfort and support effectiveness.
2Reliability
If stiff bolsters are used, then lateral acceleration effects are reduced, but occupant comfort during normal driving deteriorates
Solution Approach 1:
The physical parameters of the seat cushion (specifically its tilt angle and configuration) are changed dynamically based on lateral acceleration conditions. The shape memory material members enable the cushion to transition between a first configuration during normal driving and a second tilted configuration during high lateral acceleration, providing counteraction only when needed while maintaining comfort otherwise.
3Ease of operation
If adjustable lateral support is added, then comfort during normal driving is improved, but device complexity increases
Solution Approach 1:
Traditional mechanical adjustment mechanisms (actuators, linkages, motors) are replaced with shape memory material members that use thermal or electrical stimulation to change the seat cushion's configuration. This substitution reduces mechanical complexity while achieving the same adjustable lateral support function, as the shape memory materials directly induce the tilting motion without requiring complex transmission mechanisms.
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
The system provides enhanced comfort by offering adjustable lateral support during high lateral acceleration conditions while minimizing discomfort during normal driving by dynamically tilting the seat cushion, thus counteracting lateral forces without the need for large actuators or complex mechanisms.
Implementation Method 1
a first shape memory material member and a second shape memory material member. The first shape memory material member can be located between the seat pan and the seat frame. The first shape memory material member can be operatively positioned such that, when activated, the first shape memory material member engages the seat pan to cause the seat pan to tilt in a first lateral direction.
Data Source
AI summary
A vehicle seat can be configured to provide support to a vehicle occupant in conditions when lateral acceleration is experienced. Shape memory material members can be operatively positioned with respect to a seat portion of the vehicle seat. The shape memory material members can be selectively activated by an activation input. When activated, the shape memory material members can engage a seat pan so as to cause the seat pan to tilt in a respective lateral direction. As a result, a seat cushion supported by the seat pan can also tilt in the respective lateral direction. The seat cushion can be tilted in a lateral direction that is opposite to the direction of the lateral acceleration. Thus, the effects of lateral acceleration felt by a seat occupant can be reduced. The shape memory material members can be selectively activated based on vehicle speed, steering angle, and/or lateral acceleration.