Surgical Tool Guidance via Planar Articulation and Real-Time Localization
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Solution Overview
Problem
Surgical robotic devices with less than five motorized degrees of freedom are unable to fully guide the trajectory of a surgical tool, such as a rotary cutting tool, to align with a planned trajectory defined by a target axis, limiting their effectiveness in surgical interventions.
Innovation Solution
A system comprising a robotic device with at least three motorized degrees of freedom, an end effector, a planar articulation, a localization device, and a control unit that constrains the operative axis of the surgical tool within a single plane or perpendicular to it, allowing alignment with the target axis using real-time position and orientation data, and user interface feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a surgical robotic device has less than five motorized degrees of freedom, then device complexity is reduced, but the ability to fully guide the trajectory of the surgical tool is lost
Solution Approach 1:
The system divides the trajectory guidance task into two independent parts: (1) the robotic device handles positioning within a plane using three degrees of freedom, and (2) the planar articulation handles orientation alignment. This segmentation allows the device to achieve full trajectory guidance capability without requiring five motorized degrees of freedom, thus resolving the contradiction between device complexity and adaptability.
Solution Approach 2:
The planar articulation acts as an intermediary mechanical component between the robotic device and the surgical tool. It receives the positioning from the robotic device and provides the additional orientation freedom needed for full trajectory alignment. This intermediary element enables the system to achieve five degrees of freedom functionality using only three motorized degrees of freedom plus a passive mechanical articulation.
2Ease of manufacture
If a surgical robotic device has fewer than five motorized degrees of freedom, then ease of manufacture is improved, but manufacturing precision of the trajectory alignment is compromised
Solution Approach 1:
By segmenting the guidance function between the robotic device (positioning) and the planar articulation (orientation), the system achieves precise trajectory alignment without requiring complex five-DOF robotic architecture. This modular approach simplifies manufacturing while maintaining precision, as each component can be manufactured independently with standard tolerances.
Solution Approach 2:
The localization device provides real-time feedback on the surgical tool's position and orientation relative to the target trajectory. This feedback enables the control unit to adjust the planar articulation and robotic device positioning to achieve precise alignment, compensating for the reduced number of motorized degrees of freedom and maintaining manufacturing precision.
3Device complexity
If a planar articulation constrains movement to a single plane, then device complexity is reduced, but the ease of operation is limited
Solution Approach 1:
The localization device continuously monitors the surgical tool's position and orientation, providing real-time feedback to the user interface. This feedback system compensates for the planar constraint by informing the user of their deviation from the target trajectory, enabling them to adjust their movements accordingly. The control unit actively compensates for the constraint, maintaining ease of operation despite the reduced degrees of freedom.
Solution Approach 2:
The system replaces the need for additional mechanical degrees of freedom with a control-based solution. Instead of providing five motorized degrees of freedom, the system uses three motorized degrees plus a planar articulation constraint, compensated by real-time control adjustments and user feedback. This substitution maintains operational ease while reducing mechanical complexity.
Data Source
AI summary
The present disclosure relates to a system for guiding a surgical tool (1) comprising an operative axis with respect to an anatomical structure according to a planned trajectory defined by a target axis (T), comprising: —a robotic device (100) comprising: o an end effector (10) comprising the surgical tool or configured to be coupled to the surgical tool; o an actuation unit (11) comprising at least three motorized degrees of freedom; o a planar articulation (12) coupling the end effector (10) to the actuation unit (11), the planar articulation being configured to constrain movement of the operative axis (R) of the surgical tool inside a single plane; —a localization device (200) configured to determine in real time a position and orientation of the operative axis (R) with respect to a coordinate system of the anatomical structure; —a user interface (300); —a control unit (400) coupled to the localization device (200), the actuation unit (11) and the user interface (300); wherein the control unit (400) is configured to: —based on the planned trajectory and on localization data from the localization device, determine a position and orientation of the operative axis (R) relative to a plane containing the target axis (T); —control the actuation unit to constrain the operative axis (R) inside the plane containing the target axis (T) while a user moves the end effector (10) closer to the target axis (T); —generate by the user interface (300) at least one signal related to the position and orientation of the operative axis (R) relative to the target axis (T).