Electrohydraulic Servo Redundancy With Automatic Failover
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Solution Overview
Problem
Hydraulic servo control systems face challenges in maintaining system uptime and reliability due to the lack of effective redundancy and online serviceability, leading to potential operational downtime and contamination buildup.
Innovation Solution
The implementation of a redundant hydraulic servo control system with primary and backup servo valves and controllers, along with automatic failover processes and online serviceability features, allows for continuous operation and independent detection of internal faults, enabling air bleeding and contaminant removal without interrupting active control operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant servo valves and controllers are implemented, then system reliability is improved, but device complexity increases
Solution Approach 1:
The system is divided into independent primary and backup servo control modules, each capable of autonomous operation. The servo controller is segmented to independently control multiple servo valves, allowing one module to take over if another fails, thus improving reliability without requiring complete system redesign
Solution Approach 2:
The system dynamically changes operational parameters by switching between primary and backup servo valves based on detected fault conditions. Health signals trigger parameter changes in control allocation, enabling the system to adapt to component failures while maintaining overall functionality
2Duration of action of stationary object
If online serviceability features are added, then system uptime is improved, but device complexity increases
Solution Approach 1:
The system performs preliminary health monitoring and fault detection continuously during normal operation. By detecting internal faults before they cause system failure, the system can initiate failover procedures in advance, maintaining uptime without requiring complex real-time intervention mechanisms
Solution Approach 2:
The servo controller automatically monitors its own health status and performs self-diagnosis through health signals. The system can autonomously detect faults, trigger failover to backup components, and manage its own redundancy without external supervision, improving uptime while minimizing the complexity of external monitoring systems
3Productivity
If automatic failover processes are implemented, then productivity is improved, but device complexity increases
Solution Approach 1:
The system employs feedback mechanisms where health signals from servo components are continuously monitored by the controller. When degradation or failure is detected, the feedback loop automatically triggers failover to backup components, ensuring continuous operation and maintaining productivity without manual intervention
Solution Approach 2:
The servo controller acts as an intermediary that manages the switching between primary and backup servo valves. It receives health signals, processes fault information, and coordinates the failover process, thereby automating productivity-critical functions while centralizing control logic in a single managing component
Data Source
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AI summary
The subject matter of this specification can be embodied in, among other things, an electrohydraulic positioning control system that includes a shuttle valve configured to direct fluid flow between a selectable one of a first fluid port and a second fluid port, and a fluid outlet configured to be fluidically connected to a fluid actuator, a first servo valve controllable to selectably permit and block flow between the first fluid port, a fluid source, and a fluid drain, a second servo valve controllable to selectably permit and block flow between the second fluid port, the fluid source, and the fluid drain, a first servo controller configured to provide a first health signal and control the first servo valve based on a second health signal, and a second servo controller configured to provide the second health signal and control the second servo valve based on the first health signal.