BioDreamMachine Exploring Nature's Solutions

In contrast to the flexibility of animal motion by even the most primitive organisms, most robots are design for specific environments with a focus on efficiency and optimization of specific tasks.  Takuya Umedachi of Hiroshima University has developed a robot that demonstrates versatile and adaptive motion based on a decentralized system using local sensory feedback, modeled on the slime mold, a primitive organism without any central nervous system but can switch from random movement to directed motion in the presence of an attractor.

Research into slime molds led to a three-node oscillator model that simulated the various modes of motions seen in slime molds and also the ability to switch between these different modes.  Umedachi turned this mathematical model into a physical robot constructed of real-time tunable springs (similar function to the actin and myosin proteins in muscles), friction control units that enable griping and sliding, and a fluid-filled balloon that enables interaction between the various elements.  Control is provided by coupled oscillators with local sensory feedback.  Video clips on the webpage show surprisingly life-like motion without any central control mechanisms.  The amoeboid robot can easily move around and between obstacles. 

Details of the work have been published in the paper Fluid-Filled Soft-Bodied Amoeboid Robot Inspired by Plasmodium of True Slime Mold (subscription or purchase required). 

Authors: Umedachi, Takuya¹; Idei, Ryo²; Nakagaki, Toshiyuki³; Kobayashi, Ryo⁴; Ishiguro, Akio⁵

Source: Advanced Robotics, Volume 26, Number 7, 2012 , pp. 693-707(15)

Abstract: This paper presents a fluid-filled soft-bodied amoeboid robot inspired by the plasmodium of the true slime mold. The significant features of this robot are 2-fold. (i) The robot has a fluid circuit (i.e., cylinders and nylon tubes filled with fluid), and a truly soft and deformable body stemming from real-time tunable springs — the former seals protoplasm to induce global physical interaction between the body parts and the latter is used for elastic actuators. (ii) A fully decentralized control using coupled oscillators with a completely local sensory feedback mechanism is realized by exploiting the global physical interaction between the body parts stemming from the fluid circuit. The experimental results show that this robot exhibits adaptive locomotion without relying on any hierarchical structure. The results obtained are expected to shed new light on the design scheme for autonomous decentralized control systems.