Suspended Vehicle Seat Safe Mode for Unoccupied Operation
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Solution Overview
Problem
Vehicle seats designed for occupied use are prone to mechanical failure when operated in unoccupied modes due to forces exceeding their design limits, particularly in driverless operations like leader-follower, autonomous driving, or remote control.
Innovation Solution
A vehicle seat assembly with a safe mode that locks the seat in a specific position, adjusts damping or spring rate, and locks/unlocks functions based on occupancy sensors and vehicle operating modes to prevent damage when unoccupied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the seat suspension system is designed for occupied use with soft damping, then comfort for the driver is improved, but mechanical failure occurs when the seat is unoccupied due to forces exceeding design limits
Solution Approach 1:
The suspension system dynamically changes its characteristics based on occupancy status. When the seat is unoccupied, the system increases damping force or spring rate to prevent excessive movement and mechanical failure. When occupied, it returns to normal soft damping for driver comfort. This is achieved through sensors detecting occupancy and control systems adjusting suspension parameters in real-time.
Solution Approach 2:
The system changes physical parameters of the suspension (damping force, spring rate) based on operating conditions. An occupancy detection system triggers parameter changes in the suspension components - increasing stiffness and damping when unoccupied to limit movement ranges, and decreasing them when occupied to provide comfort. This allows the same suspension to serve two conflicting functions.
2Ease of operation
If the seat is allowed to move freely in unoccupied mode, then ease of operation is maintained, but damage occurs to the suspension system due to uncontrolled forces
Solution Approach 1:
The system applies preliminary protective action by detecting when the seat is unoccupied and automatically increasing suspension stiffness or damping before damage can occur. This preventive measure limits the range of motion and reduces forces on suspension components during driverless operation, preventing mechanical failure before it happens.
Solution Approach 2:
An control system acts as an intermediary between the occupancy detection sensor and the suspension actuators. When unoccupancy is detected, this intermediary system adjusts suspension parameters to provide protective stiffness, mediating between the need for seat mobility and the need to prevent mechanical damage during autonomous or driverless operation.
3Reliability
If the suspension damping is increased to prevent damage when unoccupied, then reliability is improved, but driver comfort is reduced when the seat is occupied
Solution Approach 1:
The suspension system is made dynamic by continuously monitoring occupancy status and adjusting damping characteristics accordingly. High damping is applied only when needed (unoccupied mode) to prevent damage, while low damping is maintained during occupied mode for driver comfort. This temporal separation of conflicting requirements resolves the contradiction.
Solution Approach 2:
The suspension periodically transitions between two states - a protective high-damping state when unoccupied and a comfortable low-damping state when occupied. This periodic switching based on occupancy detection allows the system to alternate between reliability-focused and comfort-focused operation modes.
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
Prevents damage to the seat suspension system by minimizing wear and tear during unoccupied vehicle operations, ensuring longevity and safety.
Implementation Method 1
a spring suspension system which suspends the seat relative to the vehicle body to isolate the seat from vibrations in the vehicle body
Implementation Method 2
an active damper... The damper control module receives mass data relating to the mass of the seat from which it can determine whether the seat is occupied
Data Source
Figure 1
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Figure 3
AI summary
A vehicle seat assembly (1) including a vehicle seat (13) mounted on a spring suspension system (14), the seat assembly having a safe mode into which it can be placed when the seat is unoccupied to avoid damage to the spring suspension system due to forces generated within the suspension system of an unoccupied seat. The seat assembly (1) is operatively connectable with a control system of an associated vehicle in which it is mounted and to invoke the safe mode in dependence on the vehicle being placed in a predetermined operating mode of the vehicle which does not require a driver to be present.