Sensing elasticity from the phase difference of the stepper motor

Area of Science:

• Biomedical Engineering
• Robotics
• Materials Science

Background:

• Surgical support manipulators require precise sensing of organ mechanical properties.
• Customization based on patient-specific grasping force is crucial for safety and efficacy.
• Existing methods for assessing tissue elasticity during surgery are limited.

Purpose of the Study:

• To develop an elasticity-sensing model for surgical manipulators using stepper motor phase differences.
• To establish a method for customizing manipulators based on patient-specific maximum grasping force.
• To validate the proposed sensing model with in vitro experiments on various materials and biological tissues.

Main Methods:

• A made-to-order surgical support manipulator prototype was developed.
• An elasticity-sensing model was established based on stepper motor phase differences correlated with material strength.
• Experiments were conducted using silicon rubber and canine in vitro organs.
• Material properties (Young's modulus E, spring constant K) were measured using the prototype and a material testing machine.

Main Results:

• The prototype demonstrated accurate measurement of Young's modulus and spring constant.
• Results from the prototype showed good agreement with a conventional material testing machine.
• The proposed elasticity-sensing model proved effective for in vitro organ testing.

Conclusions:

• The developed elasticity-sensing model is a valuable tool for assessing material properties of organs.
• The proposed model and prototype show significant potential for advancing surgical support manipulator technology.
• This research contributes to the development of safer and more effective robotic surgical systems.