Surgical Robotic Arm Admittance Control for Precise Manual Positioning
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Solution Overview
Problem
Current surgical robotic systems face challenges in intuitively controlling robotic arms during alignment and positioning, particularly in medical procedures like bronchoscopy, where precise force application is required but not effectively managed by existing technologies.
Innovation Solution
The system employs admittance control mode, where user-applied forces are measured and used to control robotic arm movement, allowing for intuitive positioning and alignment by compensating for gravity and noise in torque sensors, with a deadband function to filter unintended movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual repositioning of robotic arm is used during alignment, then positioning flexibility is improved, but control precision and responsiveness deteriorate
Solution Approach 1:
The patent replaces manual mechanical repositioning with an automated admittance control system that uses torque sensors to detect user-applied forces and automatically adjusts robotic arm position. This substitution maintains the intuitiveness of manual operation while achieving precise, lag-free control through force-based feedback mechanisms.
Solution Approach 2:
The system implements real-time feedback by continuously monitoring torque sensor data from user-applied forces and immediately adjusting robotic arm position in response. This closed-loop feedback mechanism ensures that control precision matches user intent while maintaining the flexibility of manual operation.
2Speed
If torque sensor data is used directly for control, then responsiveness is improved, but noise and unintended movements worsen
Solution Approach 1:
The patent applies preliminary processing to torque sensor data by implementing deadband filtering and gravitational compensation before using the data for control. This preprocessing removes noise and unintended movements while preserving genuine user intent, ensuring both responsiveness and reliability in the control system.
3Measurement precision
If gravity compensation is applied, then positioning accuracy is improved, but system complexity worsens
Solution Approach 1:
The system achieves gravity compensation through self-service by using the robotic arm's own torque sensors to detect and counteract gravitational forces. The control system automatically calculates and applies compensatory torques based on the arm's configuration, eliminating the need for external gravity compensation mechanisms while maintaining positioning accuracy.
Data Source
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AI summary
Certain aspects relate to systems and techniques for surgical robotic arm admittance control. In one aspect, there is provided a system including a robotic arm and a processor. The processor may be configured to determine a force at a reference point on the robotic arm based on an output of a torque sensor and receive an indication of a direction of movement of the reference point. The processor may also determine that a component of the force is in the same direction as the direction of movement of the reference point, generate at least one parameter indicative of a target resistance to movement of the robotic arm, and control the motor, based on the at least one parameter, to move the robotic arm in accordance with the target resistance.