Vehicle Suspension Control Under Actuator Output Limits
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Solution Overview
Problem
Existing vehicle behavior control systems using three actuators can cause discomfort due to the actuators reaching their output limits, leading to reduced comfort and ineffective active vehicle behavior control.
Innovation Solution
A vehicle behavior control device that includes a controller to perform a required control force reduction process when the output of an actuator exceeds its capability, reducing all required control forces for the actuators to prevent the actuators from reaching their output limits, thereby maintaining comfort and effective vehicle behavior control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the required control force is increased to improve vehicle behavior control performance, then the vehicle behavior control effectiveness is improved, but the actuator output limit is reached causing discomfort
Solution Approach 1:
The control force reduction ratio is dynamically adjusted based on the saturation state of actuators. When an actuator reaches its output limit, the system automatically reduces the control forces for all actuators by a calculated ratio, allowing the system to adapt its control strategy in real-time to avoid discomfort while maintaining effectiveness
Solution Approach 2:
The system monitors the output state of each actuator and uses this feedback to determine when control force reduction is necessary. The saturation state of actuators is continuously checked, and the control forces are adjusted based on this feedback to prevent reaching output limits that cause discomfort
2Object-affected harmful factors
If the actuator output range is increased to avoid reaching output limits, then comfort is improved, but the device complexity and cost increase
Solution Approach 1:
Instead of increasing the physical output range of actuators, the system changes the control parameter by reducing the control forces through a calculated reduction ratio. This software-based parameter adjustment avoids the need for more powerful (and complex/expensive) actuators while still preventing output limit saturation
Solution Approach 2:
The patent replaces a mechanical solution (increasing actuator output capability) with a control strategy solution (reducing control forces through calculation). This substitution avoids the complexity and cost of upgrading physical actuator hardware while achieving the same comfort improvement
Data Source
AI summary
A vehicle behavior control device includes: an ith suspension mounted on an ith wheel of a vehicle (where i=1 to 3); a fourth suspension mounted on a fourth wheel; and a controller. The ith suspension includes an ith actuator. The controller converts a required value of a behavior parameter to an ith required control force for the ith actuator. When a kth required control force (k is any of 1 to 3) is greater than a kth output range according to an output capability of a kth actuator, the controller performs a required control force reduction process of reducing all of first to third required control forces, and controls the ith actuator based on the ith required control force after the required control force reduction process.