Active Shock Absorber Control for Damping and Oscillation Stability
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Solution Overview
Problem
Existing active shock absorbers lack an efficient method to optimize damping response while maintaining driving comfort and stability, particularly in varying road conditions.
Innovation Solution
A control method for active shock absorbers using an electronic control unit to determine a target force based on vertical acceleration and speed of translation between elements, employing open-loop transfer functions to enhance damping and stability without triggering undesired oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If active shock absorbers make autonomous movements to maximize dynamic performance or improve driving comfort, then driving comfort and dynamic performance are improved, but the damping response optimization becomes complex and difficult to control
Solution Approach 1:
The patent applies parameter changes by modifying the damping coefficient as a function of velocity. The control method changes the damping parameter dynamically based on the relative velocity between suspension elements, allowing the shock absorber to adapt its characteristics to different operating conditions. This resolves the contradiction by providing a systematic way to optimize damping response without excessive complexity.
Solution Approach 2:
The patent implements dynamics by making the damping coefficient variable rather than fixed. The active shock absorber dynamically adjusts its damping characteristics based on real-time velocity measurements, enabling the system to respond optimally to varying road conditions and suspension movements. This dynamic adaptation improves both comfort and control while maintaining manageable system complexity.
2Reliability
If complex control calculations are used to optimize damping response, then damping optimization improves, but processing time and memory requirements increase
Solution Approach 1:
The patent employs a simplified control approach that uses basic velocity measurements and straightforward transfer functions rather than complex computational models. This approach prioritizes real-time responsiveness over highly accurate but computationally intensive calculations, effectively using simpler, faster-to-compute methods that satisfy the optimization requirement without excessive processing demands.
Solution Approach 2:
The patent applies partial action by implementing a control method that uses only the essential measurements (velocity) and calculations needed for effective damping optimization. Rather than employing full-state feedback or complex multi-parameter optimization, the system uses a streamlined approach that achieves sufficient damping performance with minimal computational overhead, thereby reducing processing time and memory requirements.
3Productivity
If active shock absorbers react to road surface stresses, then dynamic performance is maximized, but the system becomes sensitive to road conditions and may trigger undesired oscillations
Solution Approach 1:
The patent applies preliminary anti-action by using velocity-based damping control that anticipates and counteracts potential oscillations before they develop. The control method incorporates damping contributions that are proportional to velocity, which naturally counteracts oscillatory tendencies by providing restorative force in the direction opposite to motion. This prevents undesired oscillations while maintaining dynamic performance.
Solution Approach 2:
The patent implements feedback control by continuously measuring the relative velocity between suspension elements and adjusting the damping force accordingly. The velocity measurement provides real-time feedback about the suspension's state, and the control system uses this information to modulate the damping coefficient, thereby stabilizing the system while responding to road conditions. This feedback mechanism prevents oscillations by automatically adjusting damping to counteract destabilizing movements.
Data Source
AI summary
A method to control an active shock absorber of a road vehicle. The active shock absorber is part of a suspension connecting a frame of the road vehicle to a hub of a wheel and has: a first element, which defines an end of the active shock absorber, a second element, which defines another end of the active shock absorber and is mounted so as to slide relative to the first element; and an actuator, which is configured to generate a force, which is applied between the two elements. The control method comprises the steps of: determining a vertical acceleration of the hub; determining a speed of translation between the two elements of the active shock absorber; determining a target force for the actuator of the active shock absorber based on the vertical acceleration of the hub and based on the speed of translation between the two elements of the active shock absorber; and controlling the actuator (10) of the active shock absorber so as to pursue the target force.