A Soft Multi-Axis High Force Range Magnetic Tactile Sensor for Force Feedback in Robotic Surgical Systems

Area of Science:

• Robotics
• Biomedical Engineering
• Materials Science

Background:

• Robotic surgical systems require precise force feedback for enhanced dexterity and safety.
• Existing tactile sensors often face limitations in multi-axis force decoupling, force range, and cost-effectiveness.

Purpose of the Study:

• To develop and characterize a low-cost, multi-axis soft magnetic tactile sensor capable of measuring normal, shear, and angular forces with high accuracy.
• To achieve full decoupling of force responses and a wide force range suitable for robotic surgical applications.

Main Methods:

• Fabrication using rapid prototyping with Neodymium magnets embedded in an elastomer over Hall sensors.
• Finite Element Method (FEM) simulations to optimize magnet-Hall sensor spacing for maximum displacement range.
• Experimental characterization of the sensor's response to normal, shear, and angular forces.

Main Results:

• The sensor demonstrated sensitivities of 16 mV/N (normal), 30 mV/N (shear), and 81 mV/N (angular) with minimal mechanical crosstalk.
• Achieved force ranges of 0-20 N (normal), 0-3.5 N (shear), and 0-1.5 N (angular).
• Exhibited linear behavior and a low hysteresis error of 8.3%.

Conclusions:

• The developed soft magnetic tactile sensor is suitable for tactile sensing and biomedical applications, particularly in robotic surgery, due to its multi-axis capability, high force range, and low cost.
• The study highlights the potential of elastomer material properties to further tune sensor performance.