A Biomimetic, Self Tuning, Fully Adaptable Smart Lower Limb Prosthetics with Energy Recovery

Lead Research Organisation: University of Leeds
Department Name: Mechanical Engineering


Every year, thousands of people lose a lower limb as a result of a range of factors such as circulatory problems, complications of diabetes or trauma.
Current lower limb prostheses can be divided into three groups: i) Purely passive mechanical and requiring a significant voluntary control effort; ii) Actively controlled in which the limb performance is measured and parameters altered to improve performance; iii) Actively driven, or powered prostheses using actuators to directly input mechanical work into the limb. The latter devices do not take into consideration the dynamic interaction between the body elements and prostheses. As a result, they require large amounts of energy and have low efficiency. Therefore they are not in harmony and synergy with the human body. Hence, there is a need for a new generation of lower limb prostheses which can mimic the human muscle by combining active and passive modes.
The new generation of prostheses should have a plug and play characteristic and the limb would self tune to the current walking situation (level, slopes and stairs) to optimise the system performance to the user. During the walking cycle, the artificial limb will switch between delivering energy to the walking motion to harvesting energy during the swing phase; prolonging battery power and reducing the burden on the batteries.
The aim of this project is to design and develop a new smart lower limb prosthesis through a research programme structured around the following activities.
1) Use of body hub sensors to measure gait dynamics in real time;
2) Use of prosthesis integrated sensors interfaced with the human limb to measure reaction loads during prosthesis use;
3) Estimation of user intent and evaluation of the potential for haptic or other forms of feedback from the prosthesis to enhance its usability;
4) Optimisation of energy use through dynamic coupling and energy generation; and
5) Improvements in limb comfort associated with extended periods of wear.
The outcome of the research will be a step change towards the use of technology in relation to the human body and mobility considering human-machine dynamic interaction. The research outcomes will address a number of healthcare challenges associated with the restoration of mobility in amputees, and paves the way for a new direction in the design and development of devices to support mobility in an aging population and applications such as the rehabilitation of stroke patients. The world's third largest manufacture of prosthetics is in the UK and this research will boost the advancement of the UK position worldwide by providing enhanced opportunities for commercialisation.

Planned Impact

This research will have a significant academic impact. New and innovative approaches to the design and control of lower limb prosthetics will enable other researchers to develop variants of the technology applicable to sectors such as upper limb prosthetics, rehabilitation and walking robots.
Maximising the impact of the research is central to the research strategy. During the project, our user group consisting of amputees, their families and care professionals will participate to ensure the quality and relevance of this work.
Academic dissemination will be achieved through publications and conferences such as ICORR and CLAWAR and presentations at annual prosthetic events.
The outcome of this work will be a fully designed and validated system ready for testing on human subjects. An evaluation of transferring the research results into other domains will be done.
However, it is recognised that the full impact will not be achieved until the system has gone through a process of clinical testing and evaluation. For this reason, by the end of year two, an application for further funding will be made for the testing and evaluation stages and to produce the device. The device will need to gain MHRA approval for a class 2 device (active device). The team has experience with this procedure through the iPAM rehabilitation robot and are aware of the timescales and lengthy documentation. Possible funding routes include:
1) A Knowledge Transfer Partnership grant (KTP) with Blatchfords;
2) NHS i4i funding - Members of the team have previously been involved in such a proposal. This second stage funding will prove the technology for use on human subjects and provide indications of the expected clinical performance. Following on from this stage either:
(i) Commercialisation of the technology would be undertaken through Blatchfords, or
(ii) Further funding would be sought for a full clinical trial.
The decision on which route to take, will be made during the second stage of the research programme, and if appropriate, applications made to ensure there are no funding gaps. The device would then be commercially released.
The potential impact of this proposal goes well beyond a single successful product. The prospective advances in predicting user intent are a radical forward step with the potential to become standard on all prosthetics, and the team will follow up advances with further technical applications to funding bodies such as EPSRC. The sensor systems used to measure body motions can be applied in other areas such as detecting differences in gait in people with, for example Alzheimer's prior to a wandering episode. Actuation systems developed in this work could be altered for use in prosthetic upper arms (we have close links with RSL steeper, a world class upper limb prosthetic company) or in ankle joints.


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H. F. Maqbool (2018) A Real-Time Gait Event Detection for Lower Limb Prosthesis Control and Evaluation in Transactions on Neural Systems & Rehabilitation Engineering

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Husman MA (2016) A wearable skin stretch haptic feedback device: Towards improving balance control in lower limb amputees. in Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

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Hussain T (2019) Computational model for the recognition of lower limb movement using wearable gyroscope sensor in International Journal of Sensor Networks

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Kian Sek Tee (2015) A visual guide for lower limb prothetic alignment in ARPN Journal of Engineering and Applied Sciences

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Lui ZW (2015) Virtual prototyping of a semi-active transfemoral prosthetic leg. in Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine

Description New methods have been developed to predict user intent during activities of daily living.
Exploitation Route A series of publications are already available in the public domain as the outcomes of this research.
Sectors Education,Healthcare,Manufacturing, including Industrial Biotechology

Description We have already had a number of stakeholder events with focus on lower limb prosthetics. In these events we had prosthetic end users, clinicians, neurologist, industry and academics. Further collaboration with Leeds Teaching Hospitals was one of the outcomes of the event. It is envisaged that the outcome of this research will have impact on products of the largest manufacture in the UK (our collaborator) for lower limb prostheses. (A recent publicity document has been produced by the EPSRC press team to highlight some of the impacts, see Key Findings please) The findings have also served towards further research and subsequent funding proposals for continuation of research.
Sector Healthcare
Impact Types Societal

Description Industrial Collaboration (with Blatchford the largest lower limb prostheses manufacturer in the UK) 
Organisation Blatchford Clinical Services
Country United Kingdom 
Sector Private 
PI Contribution Product research and development
Collaborator Contribution Industrial advice, Components, Lab and facility access
Impact Research collaboration is on going.
Start Year 2013
Description Stake holders collaboration 
Organisation Leeds Teaching Hospitals NHS Trust
Country United Kingdom 
Sector Public 
PI Contribution A number of meetings were organised with Seacroft Hospital staff in the prosthetic and orthotic department. This was followed by a number of events in the University of Leeds. In 2013 a stake holders group was established: Research and Innovation in Assistive Technologies Engineering And Manufacture (R&I ATEAM). Two relevant events are listed below: 2013 - Assistive Technologies, Lower limb prosthetics, half-day workshop 2014 - Assistive Technologies, Benefits to Movement, half-day workshop 2015 - Assistive Technologies, Lower limb prosthetics, half-day workshop
Collaborator Contribution From the first event we established the requirements for future prosthetic devices in consultation with the stakeholders group: Some of the concluding remarks of this event in respect of need are quoted here: "adaptability in the foot standing and balance is more difficult than walking; adaptability and sensory feedback in the foot shell; ankle movement is very important; current knees are less adaptable to variable speeds; walking on uneven ground is difficult; turning towards amputated side quite difficult; socket is extremely important; smart socket to relax or firm up according to activity; heat sensitivity; more flexibility at joints particularly ankle joint; shock absorbing mechanism; smart limb alignment; interaction with user feedback is definitely needed (amputees currently use visual feedback, they need to look at the foot); contact feedback: heal, toe, rough ground, driving; do not know where the foot is; comfort of socket fit; adaptable socket for different activities/time of the day; aesthetics are also important; energy expenditure is currently too high; affordable prostheses; a fully integrated limb is needed as part of the body (forgotten limb); powered ankle and knee are essential for some activities; adaptability: prosthetic leg should adapt to the patient not the patient to the prosthesis; reliable and easy to maintain; to be robust for different environments; learning, training and rehabilitation issues". In addition, the School of Mechanical Engineering sponsored one of the amputees who was interested to carry out research in this area. He started an MRes from Octorber 2013. These activities proved to be very beneficial for the amputees and for the project as the system design was being carried out in close collaboration with the stakeholders including the end users.
Impact Direct input from the stakeholders including the end users into the system design and the way project was being conducted. Additional inputs from those who are not directly named in the project but had interest in the project and attended the events. This collaboration which involves relevant staff from the University and from the Teaching Hospitals are multidisciplinary and very beneficial for all the stakeholders.
Start Year 2013
Description Assistive Technologies Event (Lower limb prosthetics 1) 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact In this event, stake holders were present.
A number of presentations were given by the lower limb amputees, Leeds City Council, and the academics in the University of Leeds.
Current issues with lower limb prosthetic devices were discussed directly with the end users to provide input to the design of Smart BioLeg, the next generation of prosthetic systems.

The end users (amputees) were very positive about the event and its impact on future research and development to improve their quality of life.
Year(s) Of Engagement Activity 2014
Description Stake holders event (Lower limb prosthetics 2) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Other audiences
Results and Impact The event included two parts.
The outcome of the research on Smart BioLeg was presented to the stakeholders in the first part.
In he second part the participant in small groups were asked to focus on certain questions regarding current problems in lower limb prosthetic devices and also the expectations from future devices from the point of view of the stakeholders.
Each group included at least an end user, a clinician/prosthetist, industrial member, and a research.
The outcome of the meeting was circulated to all the participant via email.
The results of the discussions were taken into consideration for the design and implementation of the Smart BioLeg system.
Year(s) Of Engagement Activity 2015
Description Stakeholder engagement (Mobility) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Other audiences
Results and Impact A half day workshop was organised in which there were two parts.
In part one of the event, the staff in the University gave presentations relevant to the current project.
In the second part, small groups were formed. In each group there was a facilitator, end users, practitioners and other stakeholders. Discussion were conducted around certain topics with aim to feedback to the project direction.
Year(s) Of Engagement Activity 2015