---
publication_id: "OT-2026-000002953"
title: "Variable stiffness mechanism"
published_at: "2026-09-15T19:16:21.657668Z"
canonical_url: "https://opentechnical.org/p/OT-2026-000002953"
categories:
  - "robotics-automation/robot-architectures"
keywords:
  - "b25j19/0004"
  - "b25j9/0009"
  - "b25j9/0009"
  - "b25j19/00"
  - "b25j19/0004"
  - "b25j19/0004"
---

# Variable stiffness mechanism

## Abstract

A variable stiffness mechanism for robotic applications. A robotic arm segment comprising two bodies pivotably coupled together at one end and having a generally elongate form factor. A spring-loaded carriage moves longitudinally along one of the two bodies and is in contact with the other body, such that the effective rotational stiffness of the pin joint is equal to the stiffness of the carriage spring multiplied by the distance between the pin joint and the spring. The distance between the pin joint and the spring can be varied using a motor and belt drive arrangement. A stopper may be coupled to the belt drive to lock the relative motion of the two bodies.