Vehicle Driving Force Control with Road Surface Detection Prohibition
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Solution Overview
Problem
Existing vehicle systems face difficulties in accurately determining low-friction-coefficient road surfaces, leading to erroneous determinations and potential damage or reduced drivability due to abnormal rear-wheel speed sensor readings.
Innovation Solution
A driving force controlling apparatus that includes a rear-wheel speed sensor, a low-friction-coefficient road surface determining device, and a determination prohibition mechanism, which prohibits determination of a low-friction-coefficient road surface based on abnormal rear-wheel speed sensor readings, elapsed time, and gear position changes, ensuring accurate control and preventing unnecessary driving force adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If rear-wheel speed sensors are used to determine low-friction-coefficient road surfaces, then road surface detection capability is improved, but measurement precision deteriorates when sensors are abnormal
Solution Approach 1:
The determination prohibition device prohibits the low-friction-coefficient road surface determining device from operating under predetermined conditions (abnormal rear-wheel speed, recent shift range change, or high gear position) before erroneous determination can occur. This preventive action eliminates the risk of using unreliable sensor data for road surface assessment.
Solution Approach 2:
The determination prohibition device acts as an intermediary between the rear-wheel speed sensor and the low-friction-coefficient road surface determining device. It monitors sensor status and system conditions, blocking the determination process when conditions indicate potential measurement errors, thereby ensuring only reliable data influences road surface classification.
2Ease of operation
If driving force control is performed based on erroneous road surface determination, then drivability control is improved, but transmission reliability deteriorates due to excessive torque
Solution Approach 1:
The determination prohibition device applies preliminary anti-action by preventing erroneous road surface determinations before they can trigger inappropriate driving force control. By prohibiting determination under abnormal conditions, the system avoids the harmful sequence of erroneous low-friction detection → excessive torque limitation → transmission damage.
Solution Approach 2:
The system incorporates feedback through the determination prohibition device that monitors rear-wheel speed sensor status, shift range changes, and gear position. This feedback mechanism continuously assesses whether conditions are suitable for accurate road surface determination and adjusts the determination process accordingly, preventing harmful control actions.
Data Source
AI summary
A driving force controlling apparatus includes a driving force controller configured to determine a state of a road surface. A driving force controller is configured to control a driving force of a vehicle based on the road surface state. A rear-wheel speed sensor is configured to detect a rear-wheel speed. A low-friction-coefficient road surface determining device is configured to determine whether the road surface is a low-friction-coefficient road surface using the rear-wheel speed on a predetermined condition. A determination prohibition device is configured to prohibit the low-friction-coefficient road surface determining device from determining whether the road surface is a low-friction-coefficient road surface, if (a) the rear-wheel speed sensor is abnormal, or if (b) a predetermined time has elapsed from when a shift range is changed from a reverse range to a drive range and/or (c) a gear position has become greater than or equal to a predetermined gear position.