Haptic Tool Guidance for Precise Surgical Manipulator Placement
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Solution Overview
Problem
Surgical systems face challenges in precisely placing a tool at a target position and orientation, especially when operating in manual mode, where user control is less precise, and in autonomous mode, where user perception of control is diminished.
Innovation Solution
A surgical system with a manipulator and control system that utilizes sensors to measure forces and torques, generates virtual constraints, and provides haptic feedback to guide the user towards a target state or orientation through a virtual simulator and constraint solver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the manipulator operates in manual mode to allow user control, then the user can engage the tool and maintain perception of control, but the precision of tool placement at target position and orientation deteriorates
Solution Approach 1:
The system implements haptic feedback by applying constraint forces through the manipulator that guide the user's manual movements toward the target state. The force feedback loop provides real-time tactile guidance, allowing the user to maintain engagement and control perception while achieving precise tool placement that would be difficult through manual control alone.
Solution Approach 2:
Virtual constraints act as an intermediary between the user's manual control inputs and the target tool position/orientation. These software-based constraints generate guiding forces that mediate the interaction, translating user intent into precise movements without requiring direct autonomous automation.
2Manufacturing precision
If the manipulator operates in autonomous mode to achieve precise tool placement, then manufacturing precision improves, but the user's perception of control deteriorates
Solution Approach 1:
The system allows the user to maintain manual engagement with the tool while the virtual constraints automatically generate the necessary guiding forces to achieve precise positioning. The user serves their own control needs by directly manipulating the tool, while the system simultaneously provides autonomous guidance through haptic feedback, eliminating the need to switch to fully autonomous mode.
3Manufacturing precision
If virtual constraints and haptic feedback are implemented to guide tool movement, then tool placement precision improves, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical guidance mechanisms with software-based virtual constraints that run in simulation. Instead of physical guides or mechanical linkages, the control system uses computational models to generate haptic feedback forces, achieving precise tool guidance through software rather than hardware complexity.
Data Source
AI summary
A manipulator supports a tool and operates in a first mode to move the tool along a tool path and a second mode to move the tool in response to user forces/torques applied to the tool. Sensor(s) measure forces/torques applied to the tool. Controller(s) generate virtual constraints based on a target state and a current state of the tool. The controller(s) calculate constraint forces to attract the tool toward the target state from the current state based on the virtual constraints. A virtual simulator simulates dynamics of the tool in a virtual simulation based on input from the sensor(s) and the constraint forces to output commanded poses. The controller(s) command the manipulator to move the tool in the second mode based on the commanded poses to thereby provide haptic feedback to the user that guides the user toward placing the tool at the target state.