Surgical Instrument Insertion Control Using Operator-Defined Virtual Bounds
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Solution Overview
Problem
The longitudinal movement of surgical instruments in robotic systems can be inadequately controlled, posing a risk of accidental puncture when targeting surfaces on organs, especially without reliable sensor data for determining safe boundaries.
Innovation Solution
A surgical robotic system with a movable arm part and a processor that uses positioning commands from a human operator to establish a virtual bound, allowing safer and more accurate control by transitioning control behavior based on these commands, without relying solely on sensor data, and allowing longitudinal movement only up to the defined virtual bound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If longitudinal movement of surgical instrument is allowed without sufficient control, then productivity is improved by enabling faster movement towards surgical target, but reliability deteriorates due to risk of accidental puncture
Solution Approach 1:
A virtual bound is introduced as an intermediary control element between the human operator and the surgical instrument. The virtual bound acts as a software-based mediator that translates operator intent into controlled movement, allowing fast movement when safe and automatic restriction when approaching dangerous zones. This resolves the contradiction by enabling high productivity through operator control while maintaining reliability through automated boundary enforcement.
Solution Approach 2:
The control system dynamically adjusts the level of automation and movement restrictions based on the surgical instrument's proximity to the virtual bound. When the instrument is far from the bound, the system allows high-speed movement for productivity. As the instrument approaches the virtual bound, the system automatically transitions to restricted control mode, reducing speed and requiring explicit operator confirmation for further movement. This dynamic adaptation resolves the contradiction between speed and safety.
2Device complexity
If virtual bound is determined based on positioning commands without sensor data, then device complexity is reduced by eliminating sensors, but measurement precision deteriorates due to lack of direct feedback
Solution Approach 1:
Instead of using physical sensors to detect the surgical target location, the system creates a virtual copy or representation of the safe operating boundary based on operator-provided positioning commands. The virtual bound is a software construct that mirrors the conceptual safe zone without requiring physical measurement devices. This approach reduces device complexity by eliminating sensors while maintaining functional equivalence through computational modeling.
Solution Approach 2:
The virtual bound serves as an intermediary representation that translates operator intent into a measurable control parameter. Rather than directly measuring physical distances with sensors, the system uses the virtual bound as a mediator that encapsulates safety criteria in a computable form. This intermediary approach simplifies the system architecture while providing sufficient precision for control purposes.
3Ease of operation
If control behavior transitions based on virtual bound, then ease of operation is improved by providing automated safety control, but device complexity increases due to additional control logic
Solution Approach 1:
The system implements continuous feedback monitoring of the surgical instrument's position relative to the virtual bound. The control software automatically compares real-time position data with the virtual bound definition and adjusts control behavior accordingly. This feedback mechanism provides automated safety control that enhances ease of operation, while the rule-based feedback logic keeps the added software complexity manageable through systematic design.
Solution Approach 2:
The control system dynamically transitions between different operational modes (unrestricted movement, restricted movement, confirmed movement) based on the instrument's proximity to the virtual bound. This dynamic control architecture automates safety decisions, improving ease of operation. The complexity is managed by implementing clear state transitions and well-defined control rules that systematically handle different operational scenarios.
Data Source
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AI summary
A surgical robotic system comprises a surgical arm (080) comprising a movable arm part (082) for mounting of a surgical instrument (119), the movable arm part having at least one degree-of-freedom to enable longitudinal movement (109) of the surgical instrument towards a surgical target (123). A human machine interface (020) is provided for receiving positioning commands (022) from a human operator for controlling the longitudinal movement of the surgical instrument, and an actuator (060) is configured and arranged for actuating the movable arm part to effect the longitudinal movement of the surgical instrument. The actuator is controlled by a processor in accordance with the positioning commands and a virtual bound (132-135). The virtual bound establishes a transition in the control of the longitudinal movement of the surgical instrument in a direction towards the surgical target. The virtual bound is determined, during use of the surgical robotic system, based on the positioning commands.