Vehicle Seat Virtual Pivot Actuation
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Solution Overview
Problem
Passengers in vehicles with stiff suspensions, such as farm tractors and sports cars, experience discomfort due to vehicle rotations about roll and pitch axes, leading to unwanted side-to-side and fore/aft motion, which existing seat systems fail to adequately mitigate.
Innovation Solution
An active suspension system with a virtual pivot point mechanism that isolates the seat from vehicle roll and pitch vibrations, using sensors and actuators to adjust the seat's position relative to the vehicle, allowing users to customize the pivot point height to reduce head acceleration and enhance comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stiff suspension is used in a vehicle, then structural strength and stability are improved, but passenger comfort deteriorates due to increased sensitivity to vehicle roll and pitch motions
Solution Approach 1:
The vehicle suspension system is segmented into multiple independent degrees of freedom, allowing different parts of the vehicle to move independently. The seat assembly is separated from the vehicle floor and given independent motion capabilities in roll and pitch directions, enabling it to compensate for vehicle motions without compromising overall structural strength.
Solution Approach 2:
The seat assembly is transformed from a static, fixed position to a dynamic, actively controllable position. Sensors detect vehicle roll and pitch motions, and actuators dynamically adjust the seat's orientation in real-time to counteract these motions, maintaining passenger comfort while the vehicle maintains its stiff suspension structure.
2Device complexity
If a passive suspension system is used, then device complexity is reduced, but ability to compensate for vehicle roll and pitch motions deteriorates
Solution Approach 1:
A feedback control system is implemented where sensors continuously monitor vehicle roll and pitch angles, and this information is fed to a controller that adjusts actuator commands accordingly. This closed-loop feedback enables the active suspension to adaptively compensate for varying road conditions and vehicle motions while maintaining manageable system complexity through standardized control algorithms.
Solution Approach 2:
Traditional purely mechanical passive suspension elements are replaced with an active control system combining sensors, electronic controllers, and actuators. This substitution allows for programmable, adaptable motion compensation that can be adjusted through software without changing physical components, reducing overall system complexity while enhancing adaptability.
3Device complexity
If the virtual pivot point height is fixed, then device complexity is reduced, but adaptability to different user preferences and activities deteriorates
Solution Approach 1:
The virtual pivot point height is made dynamically adjustable rather than fixed. A user control mechanism allows real-time modification of the pivot point height position, enabling the system to adapt to different user preferences, body types, and activities such as reading or using a laptop, while the underlying control architecture remains relatively simple and reusable.
Data Source
AI summary
A seat system for a vehicle includes a seat having a seat bottom on which a person can sit. An intermediate support structure is secured to the seat and the vehicle which allows the seat to rotate relative to the vehicle. An actuator can interact with the seat to cause the seat to rotate relative to the vehicle. The combined motion of the vehicle relative to the earth and the seat relative to the vehicle results in motion of the seat moving about a virtual pivot point. A user control is provided for adjustment of the location of the virtual pivot point.