Active Suspension Posture Control for Pre-Crash Traction
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Solution Overview
Problem
Existing vehicle safety systems, particularly those with electric power steering (EPS), lack sufficient responsiveness and road feel, and accidents still occur despite advancements in sensors and control systems, necessitating rapid defensive actions to prevent or mitigate collisions.
Innovation Solution
An active suspension system with actuators capable of rapid response, sensors to detect imminent collisions or road conditions, and a controller to adjust vehicle height and wheel forces for optimal posture and traction, integrated with other vehicle systems for coordinated safety measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electric power steering (EPS) systems are used to replace hydraulic systems, then fuel economy is improved and system maintenance is simplified, but steering responsiveness and road feel are degraded
Solution Approach 1:
The EPS system pre-calculates and stores steering torque characteristics for various driving conditions (speed, steering angle, acceleration) in lookup tables. When the driver turns the steering wheel, the system quickly retrieves pre-computed torque values rather than calculating in real-time, maintaining responsiveness while using electric actuation.
Solution Approach 2:
The EPS system dynamically adjusts steering assist torque based on multiple parameters including vehicle speed, steering angle, lateral acceleration, and yaw rate. By changing the assist torque parameter in real-time according to driving conditions, the system mimics the adaptive behavior of hydraulic systems while maintaining energy efficiency.
2Speed
If computer-based control strategies are used to mimic hydraulic system characteristics, then steering responsiveness is improved, but system complexity increases
Solution Approach 1:
The control system is divided into separate functional modules: sensor input processing, lookup table retrieval, torque calculation, and motor control. Each module handles a specific aspect of the control strategy, making the overall complex system manageable and maintainable while achieving responsive steering.
Solution Approach 2:
Lookup tables serve as intermediaries between the complex control logic and the simple motor actuation. The tables pre-store the results of complex calculations, allowing the system to achieve sophisticated steering characteristics without real-time computational complexity.
3Reliability
If active suspension systems with rapid response actuators are used to adjust vehicle posture for collision avoidance, then safety is improved, but system complexity and cost increase
Solution Approach 1:
The active suspension system is integrated with the EPS system and other vehicle control systems through a centralized controller that shares sensor data and coordination logic. This merging reduces overall system complexity by eliminating redundant components and enabling coordinated control across multiple vehicle systems.
Solution Approach 2:
The active suspension actuators are designed to perform multiple functions: normal ride control, collision avoidance posture adjustment, and impact force mitigation. By making the suspension system multi-functional, the patent reduces the need for separate dedicated systems for each function, thereby managing complexity while improving safety.
Data Source
AI summary
In some embodiments, a rapid-response active suspension system controls suspension force and position for improving vehicle safety and drivability. The system may interface with various sensors that detect safety critical vehicle states and adjust the suspension of each wheel to improve safety. Pre-crash and collision sensors may notify the active suspension controller of a collision and the stance may be adjusted to improve occupant safety during an impact while maintaining active control of the wheels. Wheel forces may also be controlled to improve the effectiveness of vehicle safety systems such as ABS and ESP in order to improve traction. Also, bi-directional information may be communicated between the active suspension system and other vehicle safety systems such that each system may respond to information provided to the other.