Redundant Actuator Channel Switching Using Motor Speed Cross-Checks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing actuator architectures, such as triplex and CON/MON, are costly and complex due to the need for multiple fully functional channels and slow control processes, respectively, which are disadvantageous in safety-critical applications like aviation and autonomous driving.
Innovation Solution
An actuator with redundant channels that utilizes a motor information unit to generate additional speed information, allowing a selection unit to decide which channel is functioning correctly based on speed and motor information values, eliminating the need for a higher-level control computer and reducing the requirement for a fully functional third channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a triplex architecture with three fully functional channels is used to increase reliability, then system reliability is improved, but device complexity and cost significantly increase
Solution Approach 1:
The invention segments the control architecture into two distinct parts: a first channel with a first functional unit for control tasks, and a second channel with a second functional unit for monitoring tasks. This segmentation allows each channel to be optimized for its specific function, reducing overall complexity while maintaining reliability through functional redundancy.
Solution Approach 2:
The second channel is designed to serve dual purposes: it monitors the first channel's control tasks and can also execute control tasks itself when needed. This multi-functionality reduces the need for completely separate redundant systems, thereby reducing device complexity and cost while maintaining reliability.
2Reliability
If a CON/MON architecture with a central control computer is used to monitor control tasks, then system reliability is improved, but the control process speed decreases due to communication delays
Solution Approach 1:
The invention segments the monitoring function from the central control computer and places it directly in the second channel's functional unit. This segmentation allows monitoring to occur locally and independently, eliminating communication delays with the central computer and maintaining fast control process speed while ensuring reliable monitoring.
Solution Approach 2:
The second channel performs self-monitoring of the first channel's control tasks without requiring external intervention from a central control computer. This self-service approach enables real-time monitoring and rapid response to faults, maintaining both reliability and control speed.
3Stability of the object's composition
If a central control computer with lower clock frequency is used to make control decisions, then system stability is improved, but the intervention time increases resulting in late response to faults
Solution Approach 1:
The invention segments the fault detection and decision-making functions into distributed functional units in the first and second channels, rather than concentrating them in a central control computer. This segmentation enables parallel processing and local decision-making, reducing intervention time while maintaining system stability through coordinated operation of the channels.
Solution Approach 2:
The second channel continuously monitors and prepares to take over control tasks in advance, before any fault occurs. This preliminary action ensures that when a fault is detected in the first channel, the second channel can immediately assume control without waiting for a central control computer's decision, thereby reducing loss of time while maintaining stability.
4Reliability
If three fully functional redundant channels are implemented to ensure safety, then system reliability is improved, but cost significantly increases
Solution Approach 1:
The second channel is designed to serve dual purposes: it monitors the first channel's control tasks and can also execute control tasks itself when needed. This multi-functionality reduces the need for completely separate redundant systems, thereby reducing quantity of components and cost while maintaining reliability through functional redundancy.
Solution Approach 2:
The invention segments the control architecture into specialized functional units with different responsibilities. The first functional unit handles control tasks while the second functional unit handles monitoring and can also perform control. This segmentation allows for more efficient resource utilization and reduced component requirements, lowering cost while maintaining safety-critical reliability.
Data Source
Figure 1
AI summary
The invention relates to an actuator with redundant channels, comprising a motor for actuating the actuator, a sensor, in particular a speed sensor, for detecting and transmitting a speed signal from the motor, a first channel comprising a first functional unit connected to the sensor for operating the actuator, a second channel redundant to the first channel comprising a second functional unit connected to the sensor for operating the actuator, and a selection unit for selecting whether the first channel or the second channel takes control of the actuator, wherein the first channel provides a first speed information value based on the speed signal and the second channel provides a second speed information value based on the speed signal to the selection unit.The actuator is characterized by a motor information unit for providing a motor information value, in particular a third speed information value of the motor, to the selection unit, wherein the selection unit is designed to make a decision, based on the motor information value as well as the first and second speed information values, as to whether the first channel or the second channel receives control over the actuator.