Predictive Vehicle Motion Control on Rutted Road Surfaces
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Solution Overview
Problem
Existing vehicle control systems are inadequate in ensuring travel stability on road surfaces with irregularities such as ruts, as simply selecting a target course and controlling the steering angle is insufficient to handle the effects of these irregularities.
Innovation Solution
A vehicle control system that acquires road condition characteristics using external information, generates vehicle behavior control variables and trajectory tracking control variables based on estimated state variables, and outputs control commands for the suspension, steering, and braking devices to maintain stability by controlling the vehicle's longitudinal, transverse, and vertical axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple target course selection and steering angle control is used, then the control system is simple, but travel stability on irregular road surfaces deteriorates
Solution Approach 1:
The patent combines multiple control functions (suspension control, steering control, braking/driving force control) into a unified control system that processes road condition information and coordinates all three systems simultaneously. This integration allows the system to maintain travel stability on irregular road surfaces by coordinating responses across all vehicle systems rather than treating them separately.
Solution Approach 2:
The patent acquires road condition information in advance using external recognition units (cameras, LIDAR, etc.) and uses this information to predict upcoming irregularities. The control system then proactively adjusts suspension, steering, and braking/driving forces before the vehicle encounters the irregularity, preventing stability issues rather than reacting to them after they occur.
2Reliability
If multiple control commands for suspension, steering, and braking are generated based on road conditions, then travel stability improves, but device complexity increases
Solution Approach 1:
The control system is designed as a universal multi-functional unit that handles road condition acquisition, analysis, and coordination of three different control systems (suspension, steering, braking/driving). This unified approach consolidates what would otherwise be separate control functions into a single system that manages all aspects of vehicle stability control.
Solution Approach 2:
The control system processes different aspects of vehicle control separately (suspension control variables, steering control variables, braking/driving force control variables) while coordinating them through a unified framework. This segmentation allows each control function to be optimized independently while maintaining overall system integration and stability.
3Reliability
If the vehicle decelerates and adjusts height to track target trajectory on irregular surfaces, then travel stability improves, but speed and productivity decrease
Solution Approach 1:
The control system continuously monitors road conditions and periodically adjusts vehicle parameters (speed, height, steering angle) in response to detected irregularities. Rather than maintaining constant deceleration, the system applies speed adjustments only when and where road irregularities are detected, allowing the vehicle to maintain higher speeds on smooth road sections while still ensuring stability when needed.
Data Source
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AI summary
The vehicle control device of the present invention acquires characteristics of a road condition in front of a traveling vehicle based on external information; acquires vehicle behavior control variables for controlling the behavior of the vehicle based on estimated state variables of the vehicle that are obtained based on the characteristics, and control variables concerning speed of the vehicle based on the external information; acquires trajectory tracking control variables for causing the vehicle to track the target trajectory based on the target trajectory on which the vehicle travels that are obtained based on the characteristics and the estimated state variables; and outputs the control commands for controlling the suspension device, steering device, and braking and driving device based on the vehicle behavior control variables and the trajectory tracking control variables. This improves travel stability of the vehicle on a road surface on which an irregularity such as ruts exists.