Vehicle Acceleration Controller for Smooth Curve Entry
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Solution Overview
Problem
Existing vehicle dynamics controllers do not effectively manage the relation between lateral acceleration and deceleration during a vehicle's entry and exit from a curve, leading to abrupt changes in inertial forces and occupant discomfort.
Innovation Solution
A vehicle acceleration/deceleration controller that sets target accelerations and decelerations based on the curve's shape information, using predetermined maximum values and intermediate zero points to maintain constant resultant acceleration, thereby smoothing the transition and reducing occupant discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the vehicle dynamics controller controls acceleration and deceleration based only on lateral jerk, then the control system is simple, but the direction and magnitude of inertial force abruptly vary causing occupant discomfort
Solution Approach 1:
The patent changes the control parameters from only lateral jerk to include both lateral acceleration and longitudinal acceleration. By monitoring and controlling the magnitude of the resultant acceleration (combining lateral and longitudinal components), the system smoothly varies the direction and magnitude of inertial force acting on occupants, eliminating abrupt changes while maintaining reasonable control system complexity.
2Object-affected harmful factors
If the target deceleration is set to maintain constant resultant acceleration magnitude, then occupant comfort is improved, but the vehicle may feel as if traveling at the limit of tire performance
Solution Approach 1:
The patent applies partial action by setting the target longitudinal acceleration to a value that maintains constant resultant acceleration magnitude only during critical phases of curve traversal (entry and exit). During other phases, the system allows more flexible acceleration control. This partial application of the constant magnitude constraint improves occupant comfort during critical moments while avoiding the continuous high-stress condition that would create a sense of insecurity.
3Productivity
If the vehicle enters the curve with high deceleration, then the curve traversal is efficient, but the abrupt change in inertial force reduces occupant comfort
Solution Approach 1:
The patent implements dynamic control of longitudinal acceleration by continuously adjusting the target acceleration value based on the current lateral acceleration and the desired constant resultant acceleration magnitude. Instead of applying a fixed high deceleration, the system dynamically modulates the deceleration profile to maintain constant resultant acceleration, ensuring both efficient curve traversal and smooth inertial force transitions for occupant comfort.
Data Source
AI summary
A target acceleration/deceleration setting unit (28) of a vehicle acceleration/deceleration controller (16) sets a target acceleration or deceleration at a location at which a curve starts to be a predetermined maximum deceleration, sets a target acceleration or deceleration at a location at which the curve ends to be a predetermined maximum acceleration, sets a target acceleration or deceleration at a predetermined intermediate location between the location at which the curve starts and the location at which the curve ends to be zero, and sets a target deceleration D (Ld) at a location to which the travelling distance from the location at which the curve starts is Ld and a target acceleration A (La) at a location to which the travelling distance from the predetermined intermediate location is La to satisfy respective predetermined relations.