Sensor-Integrated Robotic Arm Control for Nullspace Repositioning
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Solution Overview
Problem
Existing surgical robotic systems face challenges in efficiently maneuvering medical instruments within the body without causing collisions and maintaining ergonomic positioning for the surgeon, especially in minimally invasive procedures like laparoscopy and endoscopy.
Innovation Solution
The system incorporates a robotic arm with redundant degrees of freedom and a sensor-integrated control scheme that allows for movement within a nullspace, enabling precise instrument positioning and collision avoidance, while allowing the surgeon to operate from an ergonomic position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the robotic arm uses redundant degrees of freedom for positioning, then surgical precision is improved, but device complexity increases
Solution Approach 1:
The system dynamically switches between different control modes (teleoperation mode and manual manipulation mode) based on the surgical task requirements. The controller adapts the degree of freedom activation in real-time, enabling precise control when needed while simplifying operation when redundancy is not required, thus managing complexity through dynamic adaptation rather than fixed complexity
Solution Approach 2:
The system changes operational parameters by switching between control modes. In teleoperation mode, the system operates with full redundancy for maximum precision. In manual manipulation mode, the system reduces active degrees of freedom to simplify control. This parameter change approach allows the same physical system to present different levels of complexity based on task requirements
2Reliability
If the robotic arm allows movement within nullspace to avoid collisions, then safety is improved, but ease of operation decreases
Solution Approach 1:
The system continuously monitors the position and status of the robotic arm and the surgical environment. When potential collisions are detected or when the arm approaches boundaries, the feedback system automatically adjusts the nullspace movement restrictions. This feedback mechanism ensures safety while maintaining operational ease by only limiting movement when necessary
Solution Approach 2:
The controller acts as an intermediary between the surgeon's input and the robotic arm's execution. It processes commands, checks for potential collisions, and mediates the movement by allowing nullspace exploration only when safe. This intermediary function filters out harmful movements while preserving useful ones, maintaining ease of operation within safety constraints
3Ease of operation
If the robotic arm provides ergonomic positioning for the surgeon, then ease of operation is improved, but manufacturing precision may be compromised
Solution Approach 1:
The system dynamically adjusts the level of automation based on the surgical task. During tasks requiring high precision, the system operates in teleoperation mode with full precision control. During tasks requiring ergonomic positioning, the system enables manual manipulation mode with reduced constraint. This dynamic switching allows the same system to optimize for either precision or ergonomics depending on the immediate task requirements
Solution Approach 2:
The control system segments the surgical task into different phases or modes. Rather than requiring the robotic arm to simultaneously optimize for both precision and ergonomics in all operations, the system divides work into precision-critical segments and ergonomics-critical segments, allocating computational and mechanical resources accordingly to each phase
Data Source
AI summary
Certain aspects relate to admittance control modes for a robotic surgery system. The admittance control modes can be based on detecting and/or measuring forces (rotational and/or nonrotational) on a robotic arm and moving the robotic arm in response to such interactions. The forces can include direct manual interaction with the robotic arm by a clinician. The movement of the robotic arm can be within a nullspace that maintains the positions of a medical instrument.