Visiting Research Associate (Sensewheel)

Researchers at the UCL Aspire Centre for Rehabilitation Engineering and Assistive Technologies (CREATe) have developed Sensewheel, a prototype wireless instrumented wheelchair pushrim which measures the forces of propulsion in real time using Bluetooth communication. This is aimed clinically at developing a user feedback system to inform the user about their propulsion efficiency; training users to push more efficiently and therefore preserve shoulder function and minimise injury in the long term.

Force measuring load cells (slaves) connecting the pushrims to the wheels send their strain data serially to software which synchronises them and inputs the data to a LabView graphical user interface (GUI). Here the strains are converted to forces and moments and then combined mathematically to find the full force system acting at each wheel. Data are captured, processed and plotted in real time. Currently the hardware exists as printed circuit boards and as several flexible printed circuits, some of which are built into slave load cells with strain gauges attached. These slave load cells have 6 degrees of freedom (dof) and are amongst the smallest such load cells available anywhere. They will measure the 3 forces and 3 moments at each connection point.

Currently we have several slave load cells built but not tested or calibrated, and two with electrical faults. The calibration algorithms to be used are not fully tested; neither are the algorithms written in LabView to decode the outputs from the slaves, combine them and produce the overall force system acting on the wheel. This is an opportunity for an electronic, mechanical or computer science engineer to become a part of the technical team, and to help take Sensewheel into the clinical phase of the project.

The aims of this internship are to:

• Become familiar with the electronic hardware and GUI software
• Test the static and dynamic performance of the system on printed circuit boards, using fixed resistors and sinewave generator
• Complete the construction of the slave load cells
• Set up the calibration protocol, and apply forces and moments to the slave load cells, log data and interpret
• Produce the calibration matrices for the slave load cells, based on the sensitivities to force and moment, and apply to the GUI
• Check the LabView algorithms relating each slave forces and moments to the wheel based co-ordinate system
• Build a wheel of 3 slaves, apply loads and reported forces and moments.
• Compile documentation on Google drive / Dropbox

All consumables for the project are available. Each slave load cell comprises a flexible printed circuit which is wired to strain gauges by the gauging subcontractor. Completing the build requires a rechargeable lithium battery to be soldered to the flexi circuit, folding the flexi and using adhesive to attach a cap to seal the load cell.

This project ideally requires the following capabilities:

• Experience with the LabView visual programming environment;
• Basic electronic knowledge (not essential);
• An understanding of force vectors and combining them;
• Good mathematical ability in regression, vectors and matrices;
• Manual dexterity for building slave load cells, and soldering ability
• A methodological approach with good attention to detail;
• Good English verbal and written communication skills.

If you would like further information about this project, please email:

• [email protected]

This internship is available now and is expected to last for a period of approximately 6 months.It would potentially suit graduating students from an electronic/biomechanical/software engineering background. Bluetooth programming experience is not necessary.