Active Vehicle Seat Suspension Control for Vibration Isolation

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Solution Overview

Problem

Off-road vehicles face challenges in reducing driver fatigue due to excessive cabin movements, requiring effective suspension systems that manage both road vibrations and driver-induced vibrations while avoiding end stops in spring travel.

Innovation Solution

An active suspension system with a calculation device determining an optimal acceleration value for a vehicle seat, using an actuator to minimize deviations from this value by adjusting the seat's deflection and speed relative to the road, thereby maintaining low Seat Effective Amplitude Transmissibility (SEAT) values and ensuring limited deflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If active suspension systems are used to minimize acceleration acting on the driver, then driver comfort is improved, but the complexity of the suspension system increases

Engineering Contradiction:
Improveacceleration acting on driverVSAvoidsuspension system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the suspension system properties changeable during operation. The actuator actively adjusts the suspension characteristics in real-time based on measured acceleration values, transitioning from static passive suspension to dynamic active suspension. This allows the system to adapt to varying road conditions and driver needs, optimizing comfort while managing complexity through controlled adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by using measurement devices to detect acceleration values and feeding this information back to the control system. The control system processes this feedback and adjusts the actuator accordingly to minimize acceleration transmitted to the driver. This closed-loop feedback mechanism enables the system to respond dynamically to changing conditions while maintaining optimal performance.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If the seat suspension is softened to reduce vibration transmission, then driver comfort is improved, but the support for the driver during operation deteriorates

Engineering Contradiction:
Improvevibration transmissionVSAvoiddriver support during operation
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent resolves this contradiction by dynamically adjusting suspension properties rather than using a fixed soft suspension. The actuator modifies the suspension characteristics in real-time, providing softness when needed for comfort and firmness when operational support is required. This dynamic adjustment allows the system to balance comfort and operability based on actual driving conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by actively modifying the suspension system's mechanical properties through the actuator. Instead of relying on fixed structural properties, the system changes parameters such as stiffness and damping characteristics in response to measured acceleration and operational requirements. This enables the suspension to provide both vibration isolation and operational support as needed.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If larger spring travel is allowed to accommodate cabin movements, then suspension capability is improved, but the risk of reaching end stops increases

Engineering Contradiction:
Improvesuspension capabilityVSAvoidrisk of reaching end stops
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by using the measurement device to detect acceleration values before the cabin reaches extreme positions. The control system processes this advance information and activates the actuator proactively to counteract movements that would lead to end stops. This preventive approach allows the system to accommodate large cabin movements while avoiding the harmful effects of reaching travel limits.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses feedback to continuously monitor suspension travel and acceleration, allowing the control system to adjust actuator output in real-time. This feedback mechanism enables the system to maximize spring travel utilization for suspension capability while simultaneously preventing excursions that would reach end stops, thereby maintaining reliability.

Inventive Principle:
Principle #23Feedback

4Object-affected harmful factors

If active vibration isolation is applied to ensure driver protection, then driver comfort is improved, but the deflection of the driver's seat increases

Engineering Contradiction:
Improvevibration effects on driverVSAvoiddeflection of driver's seat
Core Design Contradiction:
Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The patent resolves this contradiction by dynamically changing suspension parameters through the actuator. Instead of using a fixed soft suspension that would allow large deflections, the system adjusts stiffness and damping parameters in real-time to provide vibration isolation while limiting seat deflection to acceptable levels. This parameter control enables simultaneous achievement of driver protection and deflection limitation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2067656B1Device and method for actively springing part of a vehicle
Publication Date: 2015.08.19 GRAMMER AG
  • EP2067656B1 patent drawingFigure 1
  • EP2067656B1 patent drawingFigure 2~3
  • EP2067656B1 patent drawingFigure 4~6

AI summary

The invention relates to a vehicle with a vehicle part (22), e.g. a cabin, which is movable by means of oscillation relative to a first vehicle part (21), e.g. a seat, and a first measuring device for measuring at least one acceleration measurement value of the first vehicle part (21) with respect to a roadway, wherein a calculation device for determining an optimal acceleration value of the second vehicle part (22) to be applied at the time the acceleration measurement value is available, and at least one actuator (9, 47, 60) arranged between the first and the second vehicle part (22) with control and regulation units (40, 42) for minimizing a deviation of a real acceleration value of the second vehicle part (22) from the optimal acceleration value by utilizing at least one available spring travel.