Nonlinear Seat Suspension for Low-Frequency Vibration Isolation
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Solution Overview
Problem
Off-road vehicle drivers are exposed to significant low-frequency whole-body vibrations (WBVs) that cause discomfort, fatigue, and increased risks of musculoskeletal disorders, with existing suspension systems failing to effectively mitigate these vibrations due to conflicting design requirements and limited ability to adapt to varying body masses and operational velocities.
Innovation Solution
A suspension system featuring a kinematic structure with paired base and upper beams, a tensioning device, and a damping system that constrains motion along orthogonal axes, providing nonlinear stiffness and damping properties to isolate vibrations effectively, with adjustable parameters for optimal performance across different conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional suspension mechanisms are used to control ride vibration, then vibration control is achieved through strong couplings between ride and roll/directional stability, but conflicting design requirements are imposed on the suspension systems and tires
Solution Approach 1:
The invention separates the vibration control function from the ride stability function by introducing a dedicated seat suspension mechanism that operates independently from the vehicle's main suspension system. This segmentation allows each system to be optimized for its specific function without conflicting design requirements
Solution Approach 2:
A seat suspension mechanism acts as an intermediary between the vehicle suspension and the driver, providing an additional layer of vibration isolation specifically tailored for the driver's comfort without affecting the overall vehicle suspension design
2Object-affected harmful factors
If existing suspension systems are designed for vibration control, then some level of protection is provided, but they fail to effectively mitigate low-frequency whole-body vibrations due to limited ability to adapt to varying body masses and operational velocities
Solution Approach 1:
The seat suspension mechanism incorporates adjustable parameters including spring stiffness, damping coefficients, and pre-compression forces that can be dynamically tuned to match different driver body masses, seating positions, and operational velocities, enabling effective mitigation across varying conditions
Solution Approach 2:
The system allows modification of key parameters such as spring constants, damper characteristics, and equilibrium position to optimize performance for different body masses and velocity ranges, transforming a fixed-design system into an adaptable one
3Object-affected harmful factors
If conventional suspension systems are used, then basic vibration isolation is provided, but they have complex designs with multiple components that increase system complexity
Solution Approach 1:
The invention combines multiple functions (vibration isolation, shock absorption, and driver support) into a single integrated seat suspension mechanism, eliminating the need for separate components and reducing overall system complexity while maintaining effective vibration isolation
Solution Approach 2:
The seat suspension mechanism serves multiple purposes simultaneously: it isolates low-frequency vibrations, absorbs shock loads, supports the driver's weight, and can be adjusted for different operating conditions, replacing what would traditionally require multiple specialized components
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 achieves ultra-low resonant frequency with superior vibration isolation performance, adaptable to various body masses and velocities, and simpler design compared to conventional systems, enhancing driver comfort and reducing the risk of musculoskeletal disorders.
Implementation Method 1
a relationship between a change in the third displacement along the first axis relative to the tension applied to the kinematic structure to constrain the second displacement of the kinematic structure in the second axis is a non-linear relationship
Implementation Method 2
a damping device configured to dampen a second movement of the kinematic structure along the second axis to dampen the third displacement of the kinematic structure along the first axis
Implementation Method 3
in response to application of a compressive force to the kinematic structure in a first direction defined by the first axis, the at least one spring extends along the second axis, thereby constraining the third displacement of the kinematic structure along the first axis
Data Source
AI summary
A suspension system with vibration isolation is described. The system can incorporate a kinematic structure comprising pairs of X-shaped supporting structures connected in parallel. The kinematic structure limits motion in the vertical direction to a single degree of freedom. Tensioning/damping of the kinematic structure orthogonally to the vertical motion limits horizontal motion of the kinematic structure with a corresponding constraint of motion of in the vertical direction. The tensioning/damping imparts passive nonlinear stiffness and nonlinear damping of the vibrational energies across the suspension system. A tuning mechanism can be incorporated enabling tension/damping adjustment to accommodate different heights and payloads. The system can provide vibration isolation at low frequencies and over a wide range of operational frequencies. The suspension system has tunable ultra-low resonant frequencies with anti-resonance characteristics. In an example application, the suspension system can be incorporated into a seat for applications experiencing whole body vibrations.