Vehicle Torque Limiting for Low-Speed Collision Avoidance
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Solution Overview
Problem
Conventional vehicle collision avoidance and reduction systems face challenges in accurately detecting object distance and relative speed at low vehicle speeds, leading to potential discomfort for drivers and increased collision risks due to inadequate torque control.
Innovation Solution
A vehicle control apparatus that includes a vehicle speed sensor, object distance/relative speed detector, and electronic control unit, which calculates the time to reach an object and adjusts torque output and braking to prevent collisions by limiting torque when the driver mistakenly accelerates at low speeds and initiating forced braking when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If forced braking is performed at extreme small traveling speeds, then collision avoidance is improved, but detection accuracy of object distance and relative speed becomes insufficient
Solution Approach 1:
The system performs preliminary torque limitation when the driver mistakenly operates the acceleration pedal at low speeds, before forced braking becomes necessary. This preliminary torque restriction prevents the vehicle from accelerating to speeds where detection inaccuracies would cause problematic forced braking, while still providing collision avoidance protection.
2Object-affected harmful factors
If torque output is limited to prevent strong collision, then collision impact is reduced, but vehicle may reach object before forced braking can be initiated
Solution Approach 1:
The system dynamically adjusts the torque limitation level based on real-time conditions including object distance, relative speed, and vehicle speed. When the object is far and relative speed is high, torque is limited more aggressively to prevent reaching the object. When conditions are less critical, torque limitation is relaxed to maintain normal vehicle performance, thus resolving the contradiction between collision impact reduction and collision avoidance reliability.
3Object-affected harmful factors
If torque limitation is applied at low speeds, then strong collision is prevented, but driver comfort deteriorates due to unexpected braking
Solution Approach 1:
The system continuously monitors multiple parameters including acceleration pedal operation amount, vehicle speed, object distance, and relative speed to determine whether torque limitation should be applied. This feedback mechanism ensures torque limitation is only activated when a mistaken acceleration pedal operation is detected, preventing unnecessary torque restriction that would cause driver discomfort, while still providing protection when truly needed.
Data Source
AI summary
The disclosure relates to a vehicle control apparatus. The apparatus executes a torque limit control for limiting an output torque of a vehicle to a torque equal to or smaller than a first torque when a torque limit condition is satisfied and a forced braking control for forcibly braking the vehicle when a forced braking condition is satisfied. The apparatus determines whether or not it is estimated that a stop condition that if the output torque is a predetermined torque larger, the forced braking condition is satisfied, is satisfied. The apparatus executes the torque limit control such that the output torque is limited to a torque equal to or smaller than a second torque equal to or larger than the predetermined torque when the torque limit condition and the stop condition are satisfied.