Enabling technologies for soft robots

The performance and versatility of soft robots is underpinned by the fundamental technologies that power them. Technologies that are actuated by electric voltage are easily integrated with electronics and electrical power sources making them suitable for application in robotics. In this regard, we have been involved in creating robots based on dielectric elastomer artificial muscles, developing novel stretchable self-healing electroluminescent materials and applying them to sensing applications in soft robots, and electroactive origami to power mobile robots made using paper. Ongoing work includes electrodhesion actuators that help robots anchor during locomotion.

Selected references:

Tan, Yu Jun, Hareesh Godaba, Ge Chen, Siew Ting Melissa Tan, Guanxiang Wan, Guojingxian Li, Pui Mun Lee, Yongqing Cai, Si Li, Robert F. Shepherd, John S. Ho, and Benjamin C. K. Tee. 2020. “A transparent, self-healing and high-κ dielectric for low-field-emission stretchable optoelectronics.” Nature Materials (2019) [link]

Li Jisen, Hareesh Godaba, Zhi Qian Zhang, Choon Chiang Foo, and Jian Zhu. 2018. “A soft active origami robot.” Extreme Mechanics Letters 24 : 30-37. [link]

Bioinspired soft robots

Natural living organisms display a very wide range of naturally evolved technologies that enable different species to move, locomote, forage, adapt, and survive. Taking inspiration of either form or function from nature can enable us to develop new technologies and robots to solve challenges. Bioinspiration is a theme that runs through many of our projects and previous works we have been involved in are the first dielectric elastomer underwater robot inspired by jellyfish and omnidirectional eyeball actuators inspired by the extraocular muscles in the eyeball and plant inspired growing robots. A broad goal of our work is to develop soft robots that are as smart, functional and versatile as many organisms we encounter in our daily lives.

Selected references:

Hareesh Godaba, Jisen Li, Yuzhe Wang, and Jian Zhu. 2016. “A Soft Jellyfish Robot Driven by a Dielectric Elastomer Actuator.” IEEE Robotics and Automation Letters 1(2): 624–31. [link]

Li Lu, Hareesh Godaba, Hongliang Ren, and Jian Zhu. 2018. “Bioinspired Soft Actuators for Eyeball Motions in Humanoid Robots”. IEEE/ASME Transactions on Mechatronics 24, no. 1: 100-108. [link]

Soft robots for extreme environments

Field based applications pose many challenges to robots requiring us to develop new functionalities that make the robots more versatile in these environments. Manipulation and grasping in environments such as nuclear power plants, subsea or off-shore structures is challenging due to the high access constraints, tight spaces and requirements for safety of the robot and the interacting structures. Soft robots with high maneuverability as well as compliance offer solutions to these challenges. In this regard, we have been involved in the development and modelling of plant-inspired growing manipulators, flexible gripper capable of changing their stiffness, flexible sensors to sensorize soft structures. An ongoing project for field-based application involves a morphable soft robot capable of all-terrain locomotion.

Selected publications:

Hareesh Godaba, Aqeel Sajad, Navin Patel, Kaspar Althoefer, and Ketao Zhang, "A Two-Fingered Robot Gripper with Variable Stiffness Flexure Hinges Based on Shape Morphing". 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Las Vegas, NV, USA, 2020, pp. 8716-8721. [link] [presentation]

Hareesh Godaba, Ivan Vitanov, Faisal ALJaber, Ahmad Ataka, and Kaspar Althoefer. A bending sensor insensitive to pressure: soft proprioception based on abraded optical fibres. In 2020 3rd IEEE International Conference on Soft Robotics (RoboSoft), pp. 104-109. IEEE, 2020. [link] [presentation]

Ahmad Ataka, Taqi Abrar, Fabrizio Putzu, Hareesh Godaba, and Kaspar Althoefer. 2020. “Model-based pose control of inflatable eversion robot with variable stiffness.” IEEE Robotics and Automation Letters 5.2 (2020): 3398-3405. [link] [pdf]

Hareesh Godaba, Fabrizio Putzu, Taqi Abrar, Jelizaveta Konstantinova, and Kaspar Althoefer. “Payload Capabilities and Operational Limits of Eversion Robots”. Towards Autonomous Robotic Systems. TAROS 2019. Lecture Notes in Computer Science; 3rd - 5th July 2019. [link] [pdf]

Mechanics of soft active materials

Many natural biological structures are composed of soft materials and the ability to simulate stimuli responsive behaviours (such as muscular actuation, sensory transduction in the skin and gyrification in the brain) in soft active materials provides us an excellent tool to both understand and replicate nature. Investigating the mechanics of soft active materials and soft structures, understanding how to trigger different instabilities, and developing methods to harness these instabilities for practical applications is an area of interest.

Selected publications:

Hareesh Godaba, Zhi-Qian Zhang, Ujjaval Gupta, Choon Chiang Foo, and Jian Zhu. 2019. “Instabilities in dielectric elastomers: buckling, wrinkling and crumpling”. Soft Matter 15, 7137-7144. [link]

Hareesh Godaba, Zhi-Qian Zhang, Ujjaval Gupta, Choon Chiang Foo, and Jian Zhu. 2017. “Dynamic Pattern of Wrinkles in a Dielectric Elastomer.” Soft Matter 13(16):2942–51. [link]

Hareesh Godaba, Choon Chiang Foo, Zhi Qian Zhang, Boo Cheong Khoo, and Jian Zhu. 2014. “Giant Voltage-Induced Deformation of a Dielectric Elastomer under a Constant Pressure.” Applied Physics Letters 112901: 8–12. [link] [video]

Zhe Li, Yingxi Wang, Choon Chiang Foo, Hareesh Godaba, Jian Zhu, Choon Hwai Yap. 2017. “Large-volume fluid pumping by harnessing the reversible snap through of dielectric elastomer”. Journal of Applied Physics 122, no. 8 : 084503. [link]

Research Videos

NUS feature on thestretchable, self-healing electroluminescent device for application to next generation displays and soft robots

I presented my work on low-cost bending sensor based on off-the-shelf fibre optic cables in IEEE Robosoft 2020 that was held online.

Reuters feature on soft electroactive origami robot