Active ISA Pedal Interface Signal Modification
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Solution Overview
Problem
Active Intelligent Speed Adaptor (ISA) systems have not gained widespread adoption due to compatibility issues with various vehicle types, safety concerns, and the need to operate in harsh automotive environments, with previous solutions failing to ensure consistent speed reduction and reliability across different conditions.
Innovation Solution
The development of an active ISA system that modifies accelerator pedal sensor signals to limit vehicle speed, featuring a pedal interface with both digital and analog signal processing circuits, a mechanical relay for signal modification, and a safety supervisor to ensure only speed reduction, along with a calibration method to maintain precision across temperature and manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active ISA systems modify accelerator pedal signals to limit vehicle speed, then speed limit compliance is improved, but compatibility with various vehicle types deteriorates
Solution Approach 1:
The patent implements a universal signal processing interface that can handle multiple vehicle types through a single standardized architecture. The system uses a relay-based signal modification mechanism that works across different vehicle platforms, making the ISA system adaptable to various vehicle types while maintaining consistent speed limit enforcement functionality.
Solution Approach 2:
The system modifies accelerator pedal sensor signals by changing their electrical parameters (voltage levels, signal patterns) to indicate reduced pedal position. This parameter modification approach allows the ISA system to work with different vehicle types by adjusting signal characteristics rather than requiring vehicle-specific hardware modifications.
2Reliability
If active ISA systems modify accelerator pedal signals to limit vehicle speed, then accident reduction is improved, but system safety deteriorates due to potential unintended acceleration
Solution Approach 1:
The system applies preliminary anti-action by pre-configuring the signal processing to only reduce indicated pedal position, never increase it. The relay-based modification mechanism is designed to subtract from or maintain the original pedal signal, ensuring that the ECM can never receive a signal indicating greater acceleration than the driver actually requested. This prevents unintended acceleration before it can occur.
Solution Approach 2:
The patent introduces an intermediary relay-based signal processing system between the accelerator pedal sensor and the ECM. This intermediary modifies signals to indicate speed limitation while maintaining a clear, unambiguous communication channel that prevents misinterpretation, thereby eliminating the risk of unintended acceleration while still achieving accident reduction through speed limiting.
3Reliability
If active ISA systems operate in harsh automotive environments, then speed limitation functionality is improved, but measurement precision deteriorates due to temperature sensitivity and manufacturing tolerances
Solution Approach 1:
The system performs preliminary calibration during installation to establish baseline signal characteristics for the specific vehicle and environmental conditions. This pre-calibration stores reference values that compensate for manufacturing tolerances and initial temperature variations, ensuring accurate speed limitation functionality from the start of operation without requiring continuous precision adjustments.
Solution Approach 2:
The patent implements ongoing calibration using feedback from the accelerator pedal sensor signals themselves. The system continuously monitors signal characteristics and adjusts calibration parameters to compensate for temperature drift and manufacturing variations, maintaining measurement precision across harsh automotive environments while preserving reliable speed limitation functionality.
Data Source
AI summary
An intelligent speed adaptor (ISA) system includes a pedal interface configured to receive accelerator pedal sensor (APS) signals output from a pedal sensor and provide the output APS signals to an engine control module (ECM). The system is configured to modify the output APS signals by changing an indicated position of the accelerator pedal before being provided to the ECM, whereby the ISM system limits the speed of the vehicle to an allowed speed that is determined by the ISA system. Preferably, the pedal interface includes a first signal-processing circuit for modifying digital APS signals and a second signal-processing circuit for modifying analog APS signals and is configured to detect whether an APS signal is digital or analog and profile ranges of pedal movement. The system further includes a signal generator for generating reference signals for calibration; and a mechanical relay for bypassing the pedal interface.