Redundant Robot Power and Communication for Fault-Isolated Arm Control
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Solution Overview
Problem
Surgical robotic systems face challenges with heavy and cumbersome robotic arms that cannot be easily moved, leading to potential patient safety risks during faults such as communication failures, which necessitate a fault-safe redundant power and communication architecture to prevent the robotic arms from caging the patient.
Innovation Solution
The implementation of a redundant communication architecture with two communication controllers and a monitoring controller ensures that no single failure renders the robotic arms inoperable, and a redundant power architecture with separate power sources and circuit breakers isolates faults, allowing the system to continue operating safely. Additionally, the system can switch between teleoperation and local control modes to enable user-actuated movement of the arms during communication failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single communication controller is used to control the robotic arms, then the device complexity is reduced, but the reliability deteriorates because a single failure can render the arms inoperable and potentially cage the patient
Solution Approach 1:
The communication control function is segmented into multiple independent communication controllers (first and second communication controllers) that operate in parallel. Each controller can independently control the robotic arms, so that if one controller fails, the other can take over and maintain system operation, thereby improving reliability without requiring a complete system redesign
Solution Approach 2:
A monitoring controller is implemented to continuously monitor the health status of the communication controllers and predict potential failures before they occur. When a fault is detected in one controller, the monitoring controller proactively switches control to the redundant controller, cushioning against the harmful effect of complete system failure and preventing patient caging
2Reliability
If mechanical bailouts are used to physically remove the arms from the table during faults, then the reliability is improved by freeing the patient, but the ease of operation deteriorates because a user may accidentally drop the arm on the patient causing injury
Solution Approach 1:
The mechanical bailout system is replaced with an electrical/control system solution. Instead of physically removing the arms through mechanical means that require manual handling, the system uses redundant communication controllers and circuit breakers to electrically isolate faults and maintain controlled operation, substituting a safer electrical control mechanism for a potentially dangerous mechanical one
Solution Approach 2:
Circuit breakers are introduced as intermediary devices between the power sources and the robotic arms. When a fault is detected, the circuit breakers automatically open to isolate the faulty section, acting as a protective mediator that prevents uncontrolled arm movement and potential dropping, while maintaining system stability without requiring direct mechanical intervention
3Adaptability or versatility
If the robotic arms are made heavy and cumbersome with multiple actuators and motors for full degrees of freedom, then the functionality is improved, but the ease of operation deteriorates because the arms cannot be easily moved during faults
Solution Approach 1:
The control system is made dynamic by implementing automatic failover capability. When a fault is detected in one communication controller, the system dynamically switches control to the redundant controller, allowing the heavy arms to continue operating without manual intervention. This dynamic adaptation maintains ease of operation despite the arms' weight and complexity
Data Source
AI summary
An electronic circuit for a surgical robotic system includes a central power node, a first voltage bus that electrically couples a first power source to the node, a second voltage bus that electrically couples a second power source to the node, and several robotic arms, each arm is electrically coupled to the node via an output circuit breaker and is arranged to draw power from the node. Each bus is arranged to provide power from a respective power source to the node and each bus has an input circuit breaker that is arranged to limit a first output current flow from the node and into the bus. Each breaker that is arranged to limit a second output current flow from the node and into a respective arm. A breaker is arranged to open in response to a fault occurring within the respective arm, while the other breakers remain closed.