Dual-Method Functional Safety Control for Seamless Mode Transitions
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Solution Overview
Problem
Implementing functional safety requirements in complex electromechanical systems, such as indirect brake devices and automatic steering systems, is challenging due to increased complexity and cost, especially when using sensor data and algorithms, and conventional methods often result in degraded system behavior during transitions between control modes.
Innovation Solution
A method and device that utilize two control methods, a first method meeting strict safety requirements and a second more complex method, allowing for simultaneous or sequential operation within tolerance ranges to maintain functional safety while reducing complexity and cost, with the first method ensuring safety and the second enhancing system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If complex control methods with sensor data and algorithms are used, then system performance is improved, but device complexity and development costs increase
Solution Approach 1:
The control system is segmented into two independent control methods operating in parallel: a first control method that ensures functional safety and a second control method that optimizes system performance. Each control method processes control signals independently, and their outputs are combined through a combination unit, allowing the system to benefit from both safety and performance without requiring a single complex control architecture.
2Reliability
If redundant control methods and monitoring units are implemented, then functional safety is improved, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple control methods and a monitoring unit into a unified control device. The first and second control methods are integrated within the same device, along with a combination unit that merges their output signals. This consolidation achieves functional safety through redundancy while avoiding the complexity of separate distributed monitoring systems.
3Adaptability or versatility
If transitions between control modes are made, then system adaptability is improved, but system stability deteriorates due to degraded behavior during transitions
Solution Approach 1:
The combination unit continuously merges control signals from both the first and second control methods without interruption during mode transitions. This continuous signal generation ensures that the controlled system experiences no gaps or degradation in control authority during transitions, maintaining system stability while allowing flexible switching between control modes based on operational conditions.
Data Source
AI summary
A system, a device, and a method for controlling the system with functional safety requirements. The method includes determining a control for the system according to a first control method, which satisfies first requirements for the functional safety of the system; determining a control for the system according to a second control method; determining a difference between the control for the system according to the first control method and the control for the system according to the second control method; and outputting a signal for controlling the system according to the first requirements for the functional safety of the system on the basis of the determined difference.