Admittance Haptic Trocar Simulator
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Solution Overview
Problem
Laparoscopic trocar insertion poses significant safety risks due to the lack of effective training devices that accurately simulate the forces and complexities of the procedure, leading to high injury rates and mortality, particularly during initial insertion without visual feedback.
Innovation Solution
A haptic training system utilizing an admittance control mechanism and a Stewart platform to provide realistic force feedback, simulating the penetration through multiple tissue layers of the abdominal wall, offering a low-cost and portable solution for medical training.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impedance haptic simulators are used to model trocar insertion procedure, then the training simulation capability is improved, but the device becomes costly and bulky
Solution Approach 1:
The patent replaces traditional impedance-based haptic mechanisms with a novel admittance control mechanism. Instead of using complex mechanical impedance elements to simulate tissue resistance, the system uses a motorized actuator controlled by admittance control algorithms that respond to user-applied forces by adjusting position. This substitution of mechanical complexity with control system sophistication achieves realistic haptic feedback while reducing device bulk and cost.
Solution Approach 2:
The patent changes the fundamental control parameter from impedance (force-based) to admittance (position-based). By controlling the actuator's position in response to applied forces rather than controlling output force directly, the system achieves more natural and realistic haptic interaction. This parameter change enables the use of simpler mechanical components while maintaining high-fidelity tissue simulation through intelligent control algorithms.
2Force
If traditional impedance control is used in haptic devices, then force sensation can be created, but the user cannot move the device freely
Solution Approach 1:
The patent inverts the traditional control approach by using admittance control instead of impedance control. Rather than controlling force output based on position input (impedance), the system controls position output based on force input (admittance). This inversion allows the user to move the device freely by applying forces, and the system responds by adjusting its position to simulate tissue resistance, creating both force sensation and ease of operation simultaneously.
Solution Approach 2:
The patent implements dynamic control where the actuator's position is continuously adjusted in response to user-applied forces. The system transitions from a static force model to a dynamic admittance model where the relationship between applied force and resulting position is continuously updated. This dynamic approach enables natural interaction where users can move the device freely while experiencing realistic force feedback that adapts to their movements.
3Reliability
If sufficient training is provided for trocar insertion, then surgical errors can be reduced, but limited technologies exist to practice the procedure outside the operating room
Solution Approach 1:
The patent creates a realistic copy of the trocar insertion procedure through a haptic simulation device. The system replicates the force characteristics and tissue resistance of actual abdominal wall penetration using admittance control algorithms. This copying of the surgical experience in a controllable, repeatable format enables surgeons to practice extensively outside the operating room, improving skills and reducing errors without requiring actual patients or complex surgical setups.
Data Source
AI summary
Devices, systems and methods to provide an admittance haptic feedback in response to an external force input applied to an elongated member in order to simulate a trocar insertion. In certain embodiments, the admittance haptic feedback is configured to simulate penetration of and advancement through a plurality of layers of tissue of a patient, and in particular embodiments, the admittance haptic feedback is configured to simulate penetration of and advancement through a skin layer, a muscle and fat layer, and a peritoneum layer.