Portfolio of projects

Michael HillmanPhD, CEng

FIMechE, MIPEM

Rolls Royce (Bristol) Aero Engines

Undergraduate Apprenticeship

Technology Engineer in the Installation Aerodynamics Department

Bath Institute of Medical Engineering

‘Working alongside those with healthcare problems and disabilities to develop and apply technology to improve the quality of life for all.’

Rehabilitation Robotics

Problem: Many people with severe physical disabilities can benefit from a “robot” to give them the ability to handle and manipulate everyday items.

The engineering challenge is how to integrate the technical device into the person’s environment

Solutions were developed through User survey Models / sketches / mock ups Trials of prototype system with potential end

users. My contribution: Project management of team

of industrial designer, mechanical engineer, electronics engineer, occupational therapistDesign contribution System design Mechanical design Software

Outcome – 3 working prototype systems Workstation based Mobile Wheelchair mounted

3D Ultrasound Breast Imaging

Problem: Ultrasound scanning is regularly used for identification of breast tumours, but only gives a simple 2D image. A tumour is approximately spherical so it is easy to lose much of the 3 dimensional information in a simple 2D scan.

Challenge: To design a scanner to collect and analyse a 3D dataset for better imaging and quantification of breast tumours. Working as part of a multidisciplinary team including medical physicists and a radiologist.

My contribution: Heading the engineering aspects of the project, and all the mechanical design work. Involved in the user trials with patients coming through the breast clinic.

Outcome: Working prototype system, but with much usability development still needed. A patent was granted, but lack of commercial drive from the team to push the exploitation of this patent.

Breast Elastography

Problem: How to identify potentially cancerous tissue without carrying out a biopsy

Background: Ultrasound elastography is an exciting technique in which the elastic properties of tissue may be quantified non invasively. A focussed ultrasound beam disturbs the tissue and an ultrasound imaging beam measures the amount of movement, so giving the elastic stiffness of the tissue

Working as part of a multidisciplinary team consisting of physicists and numerical analysis engineers from Bath and the Institute of Cancer Research.

My contribution: Lead for BIME’s engineering contribution. Design of electromechanical scanning tank for

sample testing. Design of ultrasound forcing transducer

Outcome from project: Working test rig handed over to team at the Institute of Cancer Research

Cardiac Phantom

Background: Software on nuclear medicine “cameras” calculates the ejection fraction of the heart (ratio of blood volume pumped to residual volume)

Problem: There is a need to produce a repeatable heart simulator (phantom) for quality control. Most phantoms are simple static simulators – this needs to be dynamic

Development process: Initial build of device didn’t work due to negative pressures causing ingress of air into the fluid actuation systems.

Solved by Analysis of pressure drop through the system Replacing valves and connectors with alternative

components giving a lower pressure drop Replacing simple sliding seal piston with rolling

diaphragms. Outcome. Prototype device built and working

effectively. It requires more development to make it a reliable system.

Sip Cup Problem: People with dysphagia (for example

because of motor neurone disease) require a restricted volume of fluid for safe swallowing

Concept development: Several complicated solutions were identified involving a combination of valves, and tubes before the concept principles were put together to give a simple and effective solution

Solution: A two part cup delivers a limited volume each time the cup is brought to the lips. Effectively the person is drinking a set volume from the bottom of the cup each time

Prototyping and testing The first prototype used a vacuum formed inner cup within a standard mug. This wasn’t effective as the person drinking had to stretch their neck back to obtain a drink – solved by using an angled cup.

Further prototypes used a combination of vacuum forms, vacuum castings and standard plastic caps. (At the time 3D printing technologies were not readily available)

Outcome: The design has been developed for injection moulding.

Fold Flat Commode Chair

Project: To design a wheeled commode chair which will fold flat for use when travelling.

Protoypes First prototype – investigated general

configuration. Final prototype – in use with volunteer clients.

Problems solved. Two problems were overcome by a combined single solution, that is an armrest brace which gave adequate strength and also acted as a catch to lock the seat back in its upright position. Several concepts were investigated for the footrests

Shown to several manufacturers but considered to be too expensive as an end product

Lessons learnt: Careful use of 3D CAD allowed the development

of a folding mechanism where the parts didn’t interfere with each other.

Even though a small detail, the position of the footrest was vital to the seating position of the user

Inspiration

Footrest concepts

Brittle Bone Potty Seat

Problem: Children with brittle bone disease need to be handled very carefully, for example when toileting. The potty seat needs to have several adjustable support surfaces to allow the parent to safely handle the child.

Background: Early work was carried out by several earlier engineers with a product design background. I was give the task of designing for small batch manufacture.

Manufacturing concepts used (some new to BIME)

Extensive use of laser cut aluminium parts. One bent component takes the place of several individual components satisfying differing functional requirements as well as locating the other components to facilitate welding.

Main cushions moulded from polyurethane “Off the shelf parts” Obviously items such as

castors, but also the potty is a “Wilco” dog bowl!

Omni Wheelchair Problem: Wheelchairs are difficult

to manoeuvre in a confined space – would this be helped by some form of omni-directionality?

Background: Many omni-directional mechanisms are both complex and expensive. BIME identified a simple robust approach

My contribution: To integrate the omni-directional function into a wheelchair base. Suspension: I identified the need for

suspension to keep all four wheels in contact with the ground. This comprises a rear subframe holding all the power components and at the front, a pivoting beam with a torsional rubber spring

User control was investigate using a virtual reality simulation.

User feedback: The design was reviewed by a wheelchair users focus group

Lessons learnt: Requirements for outdoor use

conflict with requirements for indoors manoeuvrability

Manoeuvrability is a compromise between Size of chair, Directional modes and an intuitive control system.

Cervical head brace

Problem: After accidents those with suspected neck injuries are put in a cervical collar. Existing collars are uncomfortable and do not provide fully effective immobilisation

Challenge: To develop a better head brace Starting from earlier research work in Bath at

RNHRD Hospital & BIME Working collaboratively with the Helen Hamlyn

Centre for Design. IP for project is to be protected, so images are

chosen to only give a partial view of the design process.

Measurement & Testing Developed test methods for degree of

immobilisation and interface pressures. Immobilisation measured using XSens

accelerometer sensors & CODA active IR markers.

Interface pressure measured using Tekscan pressure sensors

Led application to MHRA for Clinical Investigation

Main tests involved extraction of volunteers from a wrecked car.

Outcome: Work still in progress. Contacting potential manufactures for potential commercialisation.

Referral “one-offs”

Referral service: BIME provides a service to the Royal United

Hospital to produce one-off solutions primarily for the Children’s Centre and Medical Physics Department

Challenge: Requires efficient solutions within a limited

budget Often working to tight timescales to meet

patient’s needs.

Projects illustrated: (top left, clockwise) Steps for child with restricted growth to reach

sink. Modified elbow crutch for patient with carpal

tunnel syndrome – angled handle relieves pressure on the wrist.

Steps to enable child with restricted growth to climb off stair lift

Trolley to carry oxygen therapy equipment for child at school.