Vehicle Acceleration Control for Smooth and Accurate Target Stops
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Solution Overview
Problem
Vehicle control devices with control hysteresis in drive and braking devices lead to rapid changes in target acceleration, causing vehicles to vibrate and potentially fail to stop at target positions when larger driving or braking forces are required.
Innovation Solution
A vehicle control device with a change amount limiter that sets the current target acceleration to prevent its magnitude from exceeding a threshold change amount, and adjusts this threshold based on emergency conditions such as disturbances and remaining distance to the target stop position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a change amount limiter is used to prevent rapid changes in target acceleration, then vehicle vibration is reduced, but the drive device and braking device cannot apply the required driving or braking force when emergency conditions occur
Solution Approach 1:
The threshold change amount is dynamically adjusted based on the vehicle's operational state. When the vehicle is traveling at a high speed or a large braking force is required, the threshold change amount is set to a larger value to allow rapid deceleration. When the vehicle is traveling at a low speed or a small braking force is required, the threshold change amount is set to a smaller value to reduce vehicle vibration. This dynamic adjustment resolves the contradiction by adapting the acceleration change limitation to the current operational context.
Solution Approach 2:
The patent changes the parameter of threshold change amount based on the vehicle's speed and required braking force. By modifying this parameter according to operational conditions, the system allows large acceleration changes when necessary for safety (high speed, large braking required) while limiting acceleration changes when not necessary (low speed, small braking required), thus resolving the contradiction between vibration reduction and stopping accuracy.
2Reliability
If the target acceleration is increased to counteract disturbance, then the vehicle can reach the target stop position, but the actual acceleration cannot coincide with the target acceleration due to control hysteresis
Solution Approach 1:
The system performs preliminary assessment of the vehicle's operational state (speed, required braking force) before applying acceleration changes. By evaluating whether the vehicle is in a state requiring large braking force or high speed operation, the system prepares appropriate threshold change amounts in advance, allowing rapid response when emergency conditions are detected without suffering from control hysteresis delays.
Solution Approach 2:
The threshold change amount is dynamically adjusted based on real-time vehicle state. When disturbance detection indicates high speed or large braking requirement, the threshold is increased to allow rapid target acceleration changes, enabling the system to overcome control hysteresis and respond quickly to disturbances while maintaining stopping accuracy.
Data Source
AI summary
The vehicle control device: controls the drive device and the braking device such that an actual acceleration representing an actual acceleration of the vehicle coincides with a target acceleration for driving the vehicle so that the vehicle stops at a preset target stop position; acquires the target acceleration every time a predetermined time elapses, and sets the target acceleration to a value such that the magnitude of the change amount does not exceed the threshold change amount when the magnitude of the change amount representing the difference between the target acceleration and the previous target acceleration exceeds the threshold change amount; and sets the threshold change amount to a larger value than when the emergency condition is not satisfied in a case where a predetermined emergency condition is satisfied in a case where a driving force or a braking force larger than in a normal state is required.