Vehicle Shift Signal Abnormality Control for Failsafe Driving
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle control systems fail to permit startup and running in failsafe mode when an abnormality occurs in the shift position sensor, particularly when it cannot determine the shift range as the D or R range, leading to inability to recover driving force even if the shift range is correctly identified as the drive range.
Innovation Solution
A control device with an abnormality determination unit and a running control unit that assesses shift signals to permit vehicle startup and recover driving force when the shift signal is abnormal, provided the brake is pressed, the vehicle is stopped, and the accelerator pedal operation is minimal, allowing the shift range to be set to the drive range indicated by the shift signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle control system permits startup only when the shift range is normally determined as N range, then safety is improved, but the vehicle cannot run in failsafe mode even when shift range is correctly identified as D or R range
Solution Approach 1:
The control system dynamically adjusts the startup permission criteria based on the abnormality state. When abnormality is detected, the system transitions from requiring normal N-range determination to accepting D or R range determinations combined with brake pedal detection, enabling failsafe mode operation while maintaining safety through multiple verification conditions.
Solution Approach 2:
The system changes the operational parameters for startup permission when abnormality is detected. Instead of requiring normal N-range determination, the system accepts alternative conditions including D or R range determination plus brake pedal detection, effectively changing the parameter set for safe operation under abnormal conditions.
2Productivity
If the control system allows startup in failsafe mode when shift signal is abnormal, then vehicle operability is improved, but risk of unintended movement increases
Solution Approach 1:
The control system applies preliminary anti-action by detecting brake pedal operation as a prerequisite condition before permitting startup in failsafe mode. This pre-condition ensures that the vehicle remains stationary during startup sequence, preventing unintended movement while allowing operability recovery.
Solution Approach 2:
The system uses feedback from the brake pedal detection to control startup permission. The brake pedal state serves as a feedback signal that must indicate active braking before the system permits startup, creating a closed-loop safety mechanism that prevents unintended movement while enabling failsafe operation.
3Reliability
If multiple conditions are required for startup in failsafe mode, then safety is improved, but system complexity increases
Solution Approach 1:
The control system merges multiple detection functions into a unified abnormality determination process. The ECU combines shift signal abnormality detection with brake pedal detection and startup permission control into an integrated control logic, reducing overall system complexity while maintaining multiple safety checks.
Solution Approach 2:
The brake pedal detection serves multiple functions: it acts as a safety check for failsafe mode startup, a condition for permitting startup, and a means to prevent unintended movement. This multi-functionality reduces the need for separate dedicated safety mechanisms, simplifying the overall control logic.
Data Source
AI summary
An ECU determines whether or not there is an abnormality (shift pattern abnormality) in a combination of shift signals provided from a shift position sensor. After occurrence of the shift pattern abnormality is determined, ECU determines whether or not a first condition that a shift pattern has changed into a normal pattern of a drive range, a second condition that a brake is ON and a vehicle is in a stop state is satisfied, and a third condition that an accelerator is OFF are satisfied. When occurrence of the shift pattern abnormality is determined, ECU stops generation of driving force of the vehicle and prohibits switching to the drive range. When ECU determines that the above-mentioned first to third conditions are satisfied after occurrence of the shift pattern abnormality is determined, ECU switches the shift range to the drive range indicated by the shift pattern.