ESSENCE: Embedding Softness into Structure Enabling Distributed Tactile Sensing of High-order Curved Surfaces

Lead Research Organisation: King's College London
Department Name: Informatics


Tactile perception is essential for robotic systems to perform tasks efficiently involving physical interactions with the environments such as carrying out assembly tasks or manipulating objects in manufacturing, in particular in uncontrolled environments. Research has shown that the efficiency of human manipulation is largely based on the sophisticated tactile afferents distributed across the human skin. If the tactile sensory system of human skin is neurologically damaged, a person significantly loses the efficiency for manipulation. Human tactile perception is still far beyond that of tactile sensing technology hitherto. To narrow the gap, extensive research has been carried out to develop robot skin with distributed tactile sensing elements (tactels). The existing tactile array sensing methods commonly utilize piezoresistive or capacitive materials, strain gauges, conductive elastomer or liquid and fiber-optics. While tactile sensing technologies have dramatically advanced in regards to spatial resolution, sensitivity, sensor flexibility and stretch-ablity, one major unsolved problem is to provide distributed tactile sensing capability to complex structural surfaces, which are normally described use high-order polynomial geometric equations, such as quadratic ellipsoidal surfaces, especially with small radii.The existing flexible and stretchable tactile array sensors are fabricated in the form of a film, thus difficult to be attached to those high-order polynomial surfaces. Since those surfaces are commonly used in various engineering designs, this problem significantly reduces the applicability of existing tactile array sensing methods.

This project proposes a novel method to solve this bottleneck by utilizing 3D printing technique to embed distributed sub-millimeter soft material channels within that structure. Forces applied to the structure surface will induce micro deformations of the soft material channels. Thus those soft material channels act as tactile afferent fibres within human tissue providing distributed tactile information on the structure. Through the project, we aim to develop the general principles of using the proposed method for accurate and robust tactile sensing.

Compared to existing tactile array sensors, the proposed method provides the capability of placing the tactels on a structure with arbitrary surfaces according to bespoke designs; it requires simple fabrication processes and is easy to be applied to miniaturized structures; the proposed method is also cost effective for providing large number tactile sensing elements.

The immediate project success will be assessed based on the achieved tactile sensing performance compared to the current state of the art commercial tactile array sensors, as well as the reliability and adaptiveness of the proposed method demonstrated in our exemplary application with SHADOW. The long-term success of the project will be measured by the takeup of the proposed sensing principles that we shall develop by both the academic communities and industries.

Planned Impact

The project will directly benefit sectors of the UK economy including robotics and autonomous systems industries, healthcare technology industries, and manufacturing industries. The technology advancements that shall be brought by this project are applicable for improving the health and safety in both manufacturing settings and healthcare services. In addition, experience gained by the Research Associate working on this multidisciplinary project creates a skill set useful in many scenarios.

1. The robotics and autonomous systems industries will be primary beneficiaries of this project. Robotics is of national importance for the UK. It is considered to be one of the eight great technologies for the future. The technical challenge, fabrication complexity paired with the associated cost for equipping a robot body with distributed tactile sensors have significantly hindered the takeup of tactile sensing technology by robot manufacturers. This project will provide robot manufacturers a customizable and cost effective solution for enabling distributed tactile sensing on an arbitrary structure. Thus the proposed research and the transfer of research findings to the industrial collaborator have the potential for significant contribution to the UK's competitiveness in those industries. In addition, the healthcare technology sector requiring tactile sensing technologies, such as manufacturers for medical and prosthetics devices will also be a beneficiary of this project owing to the adaptiveness, biocompatibility of the proposed tactile sensing method.

2. This project will benefit the UK's manufacturing sector. The manufacturing sector increasingly demands robotic and automation systems that can assist human workers to increase productivity especially in low-volume/high-variation manufacturing settings. Providing a robotic system with distributed tactile sensing capability will be essential for the interaction with environment and human workers, ensuring the health and safety as well as the task efficiency. Similarly equipping tactile sensing capability to instruments used in medical treatments will increase the awareness of clinicians in the interaction between the instruments and human body, benefiting patient safety and treatment efficiency.

3. Lastly, the Research Associate working on the project will gain practical experience in computer-aided design, 3D printing, finite element modelling, mechatronics system design, as well as the opportunity of working with the industrial partner for robotic system integration. This skill set can be applied in a wide range of engineering sectors, and is becoming an increasingly valuable as both academic communities and industries in the field of robotics are growing rapidly.
Description The aim of this research is to embed soft material channels into a 3D printed structure, and use the soft material channel like a tactile nerve to measure the touch information. The challenge at the beginning was that use of soft material tends to reduce the sensing sensitivity. During this project, the research team has discovered a new way to treat the embedded soft material channels to significantly increase the tactile sensing sensitivity. The new finding was that the geometry of the soft material channel and the stiffness distribution can significant affect the tactile sensing sensitivity. By optimizing this parameters, the tactile sensing sensitivity can increase more than 10 times. Furthermore, the research team developed and validated a mathematical model for the proposed sensing principle and gained new theoretical knowledge on the working principle and thus is now able to optimize the design parameter to achieve highly sensitive tactile sensing
Exploitation Route The new finding will make the proposed tactile sensing technology become applicable in tasks requires measuring small forces such as in delicate medical procedures
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Electronics,Healthcare,Manufacturing, including Industrial Biotechology

Description The tactile sensing technology generated from this grant has been used to create a robotic tactile gripper. Partnering with Ericsson and the 5G lab at King's College London, this tactile gripper was demonstrated through a demo at the Mobile World Congress 2017 (the largest industrial telecommunication conference) at Barcelona, 01 March 2017. The demo showed the concept of future robotic surgery to be carried out with 5G network, remotely providing a surgeon the detailed sense of touch for finding cancerous tissue during minimally invasive surgery. This demonstration was very successful and well received. A innovative design of a tactile surgical gripper has been resulted from this research and a patent application is under preparation. In addition in July 2017, the PI in collaboration with the urology department at Guy's Hospital received a bright idea fund from Guy's St Thomas NHS Trust to further translate this technology into a medical device. Furthermore, PI received EPSRC Impact Acceleration award from KCL to further explore the use and translation of the developed soft tactile sensing technology for the GI endoscope.
First Year Of Impact 2018
Sector Healthcare
Impact Types Cultural,Societal,Economic

Description Bright Idea Fund
Amount £74,000 (GBP)
Organisation Guy's and St Thomas' NHS Foundation Trust 
Sector Public
Country United Kingdom
Start 01/2018 
End 02/2019
Description EPSRC Impact Acceleration Account
Amount £52,727 (GBP)
Funding ID EP/R511559/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 09/2017 
End 09/2018
Description Ericsson 
Organisation Ericsson
Country Sweden 
Sector Private 
PI Contribution The new tactile sensor developed within the ESSENCE project is promising to provide new touch sensing capability for the products of Shadow Robot. Since the new tactile sensing method allow miniaturized tactile gripper to be created for surgical tasks, this new development provide a ideal showcase for the concept of tactile internet for medical applications, being prompted by Ericsson. A prototype of the tactile gripper developed using ESSENCE technology will be demonstrated by Ericsson at the Mobile World Congress 2017. At the Mobile World Congress 2019 in Barcelona, King's College London, Tianjin University, China Mobile, and Ericsson jointly demonstrated technology for providing remote surgical treatment across regions as a part of development in LoCoMoTE project funded by EPSRC Since last year, we have been conducting tests on the use of our breakthrough technology for natural orifice surgical tools with integrated haptic sensing. Thanks to the low latency, large bandwidth, slicing and edge computing of 5G, the first successful lab-based remote surgery trials were completed in December 2018.
Collaborator Contribution Partners financial support for prototyping developments
Impact A prototype of the tactile gripper developed using ESSENCE technology will be demonstrated by Ericsson at the Mobile World Congress 2017. This collaboration is multi-disciplinary, since it combine the expertise from robotics and telecommunication as well as inputs from the clinicians for sensor functionality requirements
Start Year 2016
Description Shadow Robot Company 
Organisation Shadow Robot Company
Country United Kingdom 
Sector Private 
PI Contribution The new tactile sensor developed within the ESSENCE project is promising to provide new touch sensing capability for the products of Shadow Robot.
Collaborator Contribution Shadow provide user cases and design specifications for the sensor design
Impact In progress
Start Year 2016
Description IROS 2017 Workshop: Soft Morphological Design for Haptic Sensation, Interaction and Display 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact about 100 researchers in robotics attended this workshop. This event sparked further discussion and awareness of the importance of making use of material softness for haptic sensing and interaction and created further opportunities for researchers from different field to work together
Year(s) Of Engagement Activity 2017