Vehicle Hill Ascent Angle Estimation Without Brake Detector
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle control systems fail to accurately determine the slope of the road surface when the brake detector fails, leading to erroneous hill descent control, as they cannot differentiate between deceleration caused by braking and natural slope changes, resulting in inadequate transmission control.
Innovation Solution
A control device that uses vehicle speed, rotation speed, acceleration operation amount, and transmission gear ratio to estimate the slope and control the automatic transmission, incorporating a deceleration determiner and hill ascent angle estimator to prevent unintended acceleration and ensure proper gear shifting based on driver intent, even without a functional brake detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brake detector is used to determine driver braking intention, then the control system can respond to brake operations, but when the brake detector fails, the system cannot accurately determine whether the driver intends to decelerate, leading to erroneous slope determination
Solution Approach 1:
The patent introduces an intermediary estimation mechanism that uses available sensor data (vehicle speed, rotation speed, acceleration operation amount) to infer brake detector status and slope conditions when the brake detector fails. This intermediary system acts as a mediator between the failed detector and the control system, allowing the ECU to make informed decisions about hill descent control despite the detector failure
Solution Approach 2:
The system implements feedback by continuously monitoring vehicle speed, rotation speed, and acceleration operation amount to detect abnormal patterns that indicate brake detector failure. When the estimated slope and vehicle behavior deviate from expected patterns during deceleration, the system adjusts its control strategy accordingly, using feedback from multiple sensors to compensate for the failed brake detector
2Device complexity
If the ECU determines slope based on vehicle speed and rotation speed alone, then the system remains simple, but it cannot accurately differentiate between deceleration caused by braking and natural slope changes
Solution Approach 1:
The patent makes the existing sensors (vehicle speed detector, rotation speed detector, acceleration operation amount detector) multi-functional by using them not only for their primary purposes but also for estimating slope and detecting brake detector failures. This universal usage of existing components allows the system to achieve enhanced functionality without adding complex new hardware
3Measurement precision
If angle sensor or inclination sensor is added to accurately detect slope, then slope detection precision is improved, but the cost and device complexity increase significantly
Solution Approach 1:
The patent creates a virtual copy of slope detection functionality by algorithmically estimating slope from existing sensor data instead of using physical angle sensors or inclination sensors. This virtual copying approach replicates the information that specialized sensors would provide, but through computational methods using already-available data from vehicle speed, rotation speed, and acceleration operation amount detectors
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A control device 10 for a vehicle has a hill ascent angle update determiner 74, a slope estimator 76, a deceleration determiner 78, and a hill ascent angle estimator 80. The deceleration determiner 78 determines that a vehicle 12 is in a deceleration state when the throttle opening is equal to or lower than a threshold TH. The hill ascent angle update determiner 74 prohibits update processing of an estimated hill ascent angle θ in the increase direction by the hill ascent angle estimator 80 if the slope estimator 76 estimates that a road surface 92 has an upward slope and the deceleration determiner 78 determines that the vehicle 12 is in the deceleration state. This prevents erroneous operation of an ECU if a brake detector has failed, and enables control of an automatic transmission in conformity with the intention of a driver.