Surgical Endoscope Control via Curved Tip Trajectory
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Solution Overview
Problem
Controlling the movement of a surgical endoscope with angled optics is complex, as any motion causes the view to tilt, making it difficult to precisely move in or out of the surgical field without altering the direction of the view.
Innovation Solution
A method involving a control system that calculates a curved path, such as a circle passing through a pivot point and a nominal view point, to maintain the view within the field of the endoscope tip during movement, allowing for precise positioning and zooming in or out.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the endoscope tip is moved to change depth in the surgical field, then the positioning precision is improved, but the view direction tilts and the nominal view point moves out of the field of view
Solution Approach 1:
The patent applies spherical geometry by moving the endoscope tip along a circular arc path that passes through the pivot point and the nominal view point. This curved motion path ensures that the nominal view point remains within the field of view while achieving depth adjustment, resolving the contradiction between positioning precision and view stability
Solution Approach 2:
The patent transforms the one-dimensional linear depth adjustment problem into a two-dimensional circular arc motion problem. By adding the angular dimension and moving along a circular path rather than a straight line, the system maintains view stability while achieving precise depth positioning
2Ease of operation
If a straight endoscope is used, then the control is simple, but the viewing angle is limited to zero degrees relative to the longitudinal axis
Solution Approach 1:
The patent introduces dynamic control for angled endoscopes by calculating time-varying joint motions that adapt to the angled configuration. The control system dynamically adjusts the robot arm movements based on the endoscope angle, maintaining ease of operation while enabling versatile angled viewing capabilities
Solution Approach 2:
The patent changes the control parameters by incorporating the endoscope angle α into the motion calculation. The control system uses different parameters (including the angle α and nominal view point distance n) to calculate the circular arc path, allowing the same system to handle both straight and angled endoscopes effectively
3Device complexity
If the endoscope tip is moved along a straight line to change depth, then the motion path is simple, but the nominal view point moves out of the field of view
Solution Approach 1:
The patent replaces the simple straight-line motion path with a circular arc path that geometrically guarantees the nominal view point remains within the field of view. This curved path construction using spherical geometry resolves the contradiction by accepting increased path complexity to ensure reliable view point retention
Data Source
AI summary
A method of controlling movement of the tip of a surgical endoscope from a first position (E) to an intermediate position (E′), the field of view from the tip of the endoscope being at an angle (α) relative to a longitudinal shaft of the endoscope, the method comprising: receiving a command to move from the first position in a first direction; identifying a nominal view point (N) from the tip of the endoscope in the first position; calculating a tip movement path from the first position based on the received command, the identified nominal view point and the angle (α); determining the intermediate position; and moving the tip to the intermediate position, the intermediate position being such that the nominal view point remains within the field of view from the tip.