Session: 07-05-01: Biomedical Devices, Sensors, and Actuators

Paper Number: 198732

A Geometry-Aware Robotic Dosimetry Platform for Autonomous Cold Plasma Wound Therapy with Multimodal Closed-Loop Sensing 

Cold atmospheric plasma (CAP) therapy has shown considerable efficacy in treating chronic wounds by generating reactive oxygen and nitrogen species (RONS), which promote the antimicrobial activity, tissue regeneration, and cellular proliferation for wound therapy. Nevertheless, there is a lack of clinical adoption because manual probe delivery does not allow the maintenance of a consistent and controlled standoff distance, scanning velocity, or surface coverage, especially in irregular or complex wound geometries. This operator-dependent variability creates non-uniform plasma delivery and unpredictable thermal exposure, and thereby inconsistent treatment outcomes. Existing commercial plasma systems address none of these limitations while traditional treatments such as surgical debridement, moisture-balancing dressings, and topical antibiotics remain costly and inaccessible. 

This work presents an upgraded geometry-aware six-degree-of-freedom (6-DoF) robotic platform integrating a multimodal sensor head with a closed-loop dosimetry framework for autonomous plasma wound treatment. Building upon a prior iteration that was focused on mechanical design and basic motion control, this system introduces a quantitative sensing array of sensors for real-time safety compliance checks. An end-to-end software pipeline was developed from wound surface reconstruction to plasma delivery. The platform establishes a pathway towards accessible and intelligent research-grade plasma dosimetry.

The redesigned platform features closed-loop actuators (up to 15 Nm) and support a 1.5 kg end-effector payload with 3D-printed PETG structural links and EMI-resistant cabling and a custom PCB to integrate motor drivers, magnetic encoder feedback channels, power regulation and hardware safety logic including emergency stop into one board. Key components on the board include six TMC5160 Pro motor drivers and a Teensy 4.1 microcontroller for low-level motion control. The sensor head integrates four modalities crucial for safe plasma dosimetry: a Intel RealSense D415 stereo depth and lidar camera for real-time 3D point-cloud mapping of the wound surface; a MLX90640 32x24 thermal array for temperature monitoring and tissue safety (cutoff ≤40°C), an Ocean Optics HR4C4660 emission spectrometer (195.70-1134.2 nm) for in-situ RONS verification; and an IR reflective sensor for wound perfusion metrics. A custom software framework integrates depth data into wound boundary coordinates and generates G-code raster paths for uniform plasma dosimetry over both planar and curved wound surface geometries. Additionally, the software routes any and all motion commands through the safety arbiter to enforce safe operation parameters. The DBD plasma torch serves as the end effector of the robot and operates at 10 kV AC @ 20-50 kHz with helium carrier gas.

Mechanical accuracy validation demonstrates a sub-millimeter positional accuracy (mean error: 0.027 mm, max: 0.069 mm) over a 50 mm work space achieving a 100% pass rate under a 0.5 kg payload. Optical emission spectroscopy during the plasma operation confirms the characteristic multi-peak RONS spectra between 300-500 nm were consistent with RONS emission bands for N₂ and OH^- respectively, validating biologically relevant plasma chemistry for it’s wound healing benefits. End-to-end testing on a 3D-printed silicone wound phantom demonstrated successful autonomous raster scanning from point-cloud measurements to G-code execution with continuous thermal monitoring confirming surface temperatures remain under the safety threshold. 

This results establish a reproducible and quantitively validated robotic platform for CAP wound dosimetry. Future work will target adaptive plasma parameter control through real-time spectroscopy feedback and pre-clinical bacterial sterilization on ex-vivo tissue models.

Presenting Author: Aayushya Patel IntelliScience Institute

Presenting Author Biography: My current research interests lie in instrumentation and control, robotics, image processing, and it's application in plasma medicine. I would like to pursue my academic and research career in this field.

Authors:

Aayushya Patel IntelliScience Institute
Sohail Zaidi San Jose State University