Robotic Bone Cutting Feed Rate Control at Tissue Transitions
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Solution Overview
Problem
Existing robotic surgical systems struggle to seamlessly switch between semi-autonomous and manual modes of operation during a single procedure, particularly when transitioning between different types of bone structures like cortical and cancellous bone, and to prevent instrument collision with undesired objects at the surgical site.
Innovation Solution
A surgical system with a robotic arm and sensor that adjusts feed rates based on sensed forces/torques to navigate predefined tool paths, allowing manual or semi-autonomous operation, and prevents instrument movement beyond defined boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the robotic system operates in semi-autonomous mode with a preprogrammed path, then the instrument can move along a defined path with high accuracy, but the system cannot adapt to real-time tissue transitions between cortical and cancellous bone
Solution Approach 1:
The robotic system incorporates sensors that provide real-time feedback on tissue characteristics during instrument advancement. This feedback loop enables the control system to detect transitions between cortical and cancellous bone and dynamically adjust operational parameters, resolving the contradiction between maintaining preprogrammed path accuracy and adapting to real-time tissue variations.
Solution Approach 2:
The system transitions from a static, preprogrammed path approach to a dynamic control mode where feed rate and other parameters are continuously adjusted based on real-time sensor data. This dynamic adaptation allows the system to maintain positioning accuracy while responding to tissue transitions, combining the benefits of both preprogrammed precision and real-time adaptability.
2Productivity
If the robotic system uses a fixed feed rate for instrument advancement, then the system operation is simple, but the system cannot optimize cutting performance across different bone densities
Solution Approach 1:
The system dynamically changes the feed rate parameter based on detected bone density and tissue characteristics. By automatically adjusting this critical parameter in response to sensor feedback, the system optimizes cutting efficiency across different bone types without requiring complex manual intervention, balancing productivity improvement with acceptable system complexity.
Solution Approach 2:
The robotic system performs self-adjustment of feed rate based on its own sensor measurements of tissue properties. This self-service capability eliminates the need for constant practitioner intervention to optimize cutting parameters, improving productivity while keeping the control system complexity manageable through automated decision-making algorithms.
3Adaptability or versatility
If the practitioner manually controls the instrument position in real-time, then the system can adapt to tissue variations, but positioning accuracy decreases due to human factors like muscle strain and twitching
Solution Approach 1:
The robotic system acts as an intermediary between the practitioner's intent and the actual instrument manipulation. The robot executes precise movements while sensors detect tissue variations, combining machine precision with adaptive decision-making. This intermediary role eliminates the direct connection between human physiological limitations and positioning accuracy while maintaining real-time adaptability through sensor feedback.
4Productivity
If the robotic system operates autonomously without practitioner input, then the procedure efficiency is high, but the system cannot respond to unexpected conditions or prevent collisions with undesired objects
Solution Approach 1:
The system incorporates multiple sensor feedback mechanisms that continuously monitor the surgical environment for unexpected conditions and potential collisions. This feedback enables the autonomous system to detect and respond to safety concerns in real-time, maintaining high procedure efficiency while ensuring reliability through automated safety monitoring and practitioner alert systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise and safe instrument movement by adapting feed rates and preventing collisions, enhancing surgical precision and safety during bone manipulation.
Implementation Method 1
A sensor senses forces/torques applied to the energy applicator
Data Source
AI summary
Surgical systems and methods for manipulation of an anatomy that includes cortical and cancellous bone. A surgical manipulator has a robotic arm to move an instrument with an energy applicator. A sensor senses forces/torques applied to the energy applicator. Controller(s) obtain a tool path for the energy applicator to traverse. A segment of the tool path transitions into, or between, cortical bone and cancellous bone. The controller(s) control the manipulator to advance the energy applicator along the tool path according to a first feed rate to manipulate the cortical or cancellous bone and detect, with the sensor, a change in the forces/torques being indicative of the transition. In response to detection of this change, the controller(s) control the manipulator to advance the energy applicator along the tool path according to a second feed rate, greater/less than the first feed rate.