# Sensorless Impedance Control of Micro Finger Using Coprime Factorization

## TL;DR

This paper introduces a sensorless control method for a small soft robot finger using mathematical techniques to estimate and control force.

## Contribution

A novel impedance control method for micro fingers using coprime factorization and observer-based force estimation without sensors.

## Key findings

- Impedance control of micro finger tip force is achieved without physical sensors.
- The proposed control system is validated through experimental testing.
- Coprime factorization and Youla–Kucera parameterization enable effective observer design.

## Abstract

Soft robots are attracting attention as next-generation robots because they enable flexible movement. The micro finger is a soft robot that can bend and is small and can grasp objects of various shapes, so it is expected to be applied to surgical robots. However, because it is small, sensors cannot be attached, making it difficult to measure force. This paper proposes impedance control of the tip of a micro finger by estimating the tip force with an observer. The control system is designed using coprime factorization and Youla–Kucera parameterization by operator theory. The effectiveness of the proposed method is confirmed through experiments.