Vehicle Deceleration Control Guard Processing for Oscillation Suppression
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Solution Overview
Problem
Existing deceleration control systems for motor vehicles experience instability, or 'hunting,' when the vehicle is turning due to oscillations in yaw rate and lateral acceleration, which are influenced by road conditions and steering, leading to unsatisfactory control response and speed management.
Innovation Solution
A deceleration control apparatus with turning state acquisition circuitry, control value acquisition circuitry, and guard processing circuitry that detects oscillations in yaw rate and lateral acceleration, setting guard values to stabilize the speed limit and acceleration demand, preventing instability by ensuring the speed limit only decreases and not increases, thereby stabilizing deceleration control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If deceleration control is executed based on successively obtained values of turning state quantity and control quantity, then control response speed is improved, but instability (hunting) occurs due to oscillation of these values when running on curved sections
Solution Approach 1:
The guard processing circuitry detects oscillation commencement in advance and establishes guard values before the oscillation fully develops. This preliminary detection and guard value establishment prevents the oscillation from causing instability while maintaining rapid control response, as the system switches to using guard values only when oscillation is detected rather than always using them
Solution Approach 2:
The guard values act as an intermediary between the oscillating turning state quantity/control quantity and the deceleration control execution. When oscillation is detected, the guard values mediate by providing stable reference values that prevent hunting, while allowing the system to still respond quickly to legitimate changes in vehicle state
2Stability of the object's composition
If guard processing is executed to set guard values and prevent speed limit variation in the increase direction, then instability is suppressed, but device complexity increases
Solution Approach 1:
The system dynamically adjusts its behavior based on detected conditions. The guard processing is activated only when oscillation is detected during curved section running, and the guard values are established dynamically based on current vehicle state. This dynamic approach provides stability when needed while keeping the system simple during normal operation
Solution Approach 2:
The system changes the parameter used for control based on detected conditions. When oscillation is detected, the system switches from using successively obtained control quantity values to using guard values that are established based on the guard processing of turning state quantity. This parameter change approach suppresses instability without requiring a completely different control system
Data Source
AI summary
When a vehicle runs along a curved path, successive values of a speed limit are calculated based on the yaw rate of the vehicle, and values of acceleration demand are calculated and applied to control the actual vehicle speed based on the speed limit. If commencement of oscillation of the yaw rate and acceleration demand is detected, due to running along the curved path, guard processing is applied to the values of speed limit used to calculate the acceleration demand or is applied to the acceleration demand, such as to prevent the acceleration demand from varying in a direction that would increase the speed limit. Instability of deceleration control due to the oscillation is thereby substantially suppressed.