Vehicle Speed Control Monitoring for Unintended Acceleration Detection
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Solution Overview
Problem
Existing acceleration hazard monitoring systems in motor vehicles are less than optimal in efficiency and prone to false failures during closed-loop speed control modes, such as one-pedal driving, due to reliance on commanded acceleration values rather than actual acceleration and failure to account for external forces.
Innovation Solution
A method and system that calculate desired acceleration by accounting for external forces and measure actual acceleration using a speed profile, with a controller determining an acceleration delta value to detect unintended acceleration events, and temporarily adjust powertrain output torque or speed to prevent false failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commanded acceleration values are used for hazard monitoring during closed-loop speed control, then the system can detect acceleration events, but false failures occur due to not accounting for external forces and regenerative braking effects
Solution Approach 1:
The system uses feedback from multiple sensors (accelerometer, speed sensor, torque sensor) to continuously monitor actual vehicle acceleration and compare it with expected acceleration during closed-loop speed control. This feedback mechanism allows the system to distinguish between intentional regenerative braking and unintended acceleration events, reducing false failures while maintaining reliable hazard detection.
Solution Approach 2:
The system changes the monitoring parameter from commanded acceleration to actual acceleration measured by sensors. By measuring actual vehicle acceleration directly and comparing it with the acceleration command, the system can detect discrepancies indicating unintended acceleration while accounting for external forces and regenerative braking effects that alter the relationship between commanded and actual acceleration.
2Reliability
If traditional acceleration-based monitoring is used during one-pedal driving, then the system can identify acceleration events, but efficiency decreases due to high false failure rates requiring system shutdowns
Solution Approach 1:
The system dynamically adjusts the monitoring strategy based on the operating mode. During closed-loop speed control modes like one-pedal driving, the system switches to a specialized monitoring algorithm that accounts for regenerative braking and external forces. This dynamic adaptation allows continuous operation without unnecessary shutdowns while maintaining accurate hazard detection capability.
Solution Approach 2:
The system performs preliminary identification of closed-loop speed control modes using speed and torque signals before applying the specialized monitoring algorithm. By detecting the operating mode in advance, the system can switch to the appropriate monitoring strategy proactively, preventing false failures before they occur and maintaining continuous operation.
3Device complexity
If commanded acceleration is compared with actual acceleration without considering external forces, then the monitoring is simple, but accuracy deteriorates due to road loads and grade effects
Solution Approach 1:
The system uses a universal monitoring framework that adapts to different operating conditions. The same basic comparison mechanism (commanded vs. actual acceleration) is used across all modes, but with mode-specific adjustments for closed-loop speed control. This multi-functional approach maintains algorithm simplicity while improving accuracy through contextual adaptation rather than requiring completely separate algorithms for each scenario.
Data Source
AI summary
A method detects unintended acceleration of a motor vehicle during a closed-loop speed control mode by determining external forces on the vehicle via a controller, and then calculating a desired acceleration using a measured vehicle speed and the external forces. The method includes determining an actual acceleration of the vehicle, including filtering a speed signal as a first actual acceleration value and/or measuring a second actual acceleration value using an inertial measurement unit (IMU). During the speed control mode, the method includes calculating an acceleration delta value as a difference between the desired acceleration and the actual acceleration, and then using the acceleration delta value to detect the unintended acceleration during the speed control mode. A powertrain system for the motor vehicle, e.g., an electric vehicle, includes the controller and one or more torque generating devices coupled to road wheels of the vehicle.