Surgical Robot Force Estimation With Visual Feedback Control
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Solution Overview
Problem
Existing surgical robots lack the ability to accurately determine and control the force applied by their output joints, especially when operating within a body cavity, which can lead to inefficiencies and potential harm to the patient.
Innovation Solution
A computer-implemented method and system for a cable-driven surgical robot that uses a motor to apply force to a cable connected to the output joint, identifies kinematic parameters through sensors or simulation, and determines the output force by performing a dynamical simulation, allowing for real-time adjustments and generating audiovisual feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force estimation and visual feedback systems are added to surgical robots, then surgical precision and safety are improved, but device complexity increases
Solution Approach 1:
The patent implements visual feedback by displaying virtual objects that dynamically change based on determined output forces. The system provides real-time force estimation feedback to the surgeon through visual representations, allowing the surgeon to perceive and control the force being applied during surgical procedures. This feedback mechanism improves measurement precision by making force information visible and actionable.
Solution Approach 2:
The patent introduces a computational intermediary layer that processes motor forces and kinematic parameters to estimate output forces. Instead of directly measuring forces at the output joint, the system uses sensors to measure motor forces and system parameters, then computationally estimates the output force through a model of the robotic system. This intermediary approach avoids the complexity of direct force sensing at the end effector.
2Reliability
If real-time force control is implemented, then surgical safety is improved, but computing resources and time are increased
Solution Approach 1:
The patent performs preliminary identification of kinematic parameters and system model characterization before actual surgical operations. By pre-characterizing the robotic system's dynamics and parameters, the system reduces the computational burden during real-time operation. The preliminary actions include identifying motor parameters, cable parameters, and joint parameters that are then used in force estimation without requiring complex real-time calculations.
Solution Approach 2:
The system uses the robotic system's own operational data (motor forces, joint positions, cable tensions) to estimate output forces without requiring external force sensors at the end effector. The system serves itself by using its built-in sensors and actuators to generate force estimation information, eliminating the need for additional expensive and complex sensing hardware that would increase system complexity and cost.
3Measurement precision
If comprehensive parameter identification is performed, then force determination accuracy is improved, but measurement and sensing requirements increase
Solution Approach 1:
The patent extracts and identifies individual kinematic parameters separately (motor parameters, cable parameters, joint parameters) rather than requiring a comprehensive simultaneous measurement system. By taking out the parameter identification process into separate identification steps, the system reduces the complexity of any single sensing requirement. Each parameter can be identified using simple, dedicated measurements rather than requiring a complex array of sensors operating simultaneously.
Data Source
AI summary
Described herein are methods and systems for determining force in a robotic surgical system. In some embodiments, a force applied by a robotic component (e.g. a robotic arm, a segment of a robotic arm, or a joint of a robotic arm) is determined. Also described herein are methods and systems for providing visual (e.g., direction and magnitude) feedback to a user without the need for direct haptic feedback. Such visual feedback may be presented to the user in conjunction with haptic feedback.