The public defense of Per Hellström’s doctoral thesis in Electronics

Doctoral thesis and Licentiate seminars

Datum: 2019-12-06
Tid: 13.30
Plats: room Delta, MDH Västerås.

The public defense of Per Hellström’s doctoral thesis in Electronics will take place at Mälardalen University, room Delta (Västerås Campus) at 13.30 on December 06, 2019.

Title: “Wearable Pedobarography System for Monitoring of Walk Related Parameters”.

Serial number: 301.

The faculty examiner is Docent Helena Grip, University of Umeå and the examining committee consists of Docent Petra Heideken Wågert, Mälardalen University, Professor Dag Stranneby, Örebro University and Professor Miguel Ángel Valero Duboy, Universidad Politecnica de Madrid.

Reserve; Docent Elisabeth Uhlemann, Mälardalen University.


Health care costs have increased over the last decades due to an ageing population. Therefore, research in personal health monitoring (PHM) has increased in response to this. PHM has advantages such as mobility (monitoring of health at work or at home), early detection of health problems enabling preventive health measures and a reduction of health care cost. Human motion analysis, using for example pedobarography (PBG), is an important subcategory of PHM. PBG is used to study the force fields acting between the plantar surface of the foot and a supporting surface. Gait and posture analysis, prosthetics evaluation and monitoring of recovery from injury or disease are examples of PBG applications. Portable PBG can be performed using force sensing resistors built into the insole inside the shoe.

In accordance with this, the research aim for this thesis is to design, build and evaluate a wireless wearable measurement system based on PBG for monitoring of walk related parameters. Monitoring of carried weight and walking speed were chosen as the applications for validation of the system. Motivations for choosing these applications are that there is a lack of a wearable system for monitoring of weight while walking and a possible combination with accelerometers to improve the estimation of walking speed. Both walking speed and weight are important factors for estimating energy expenditure. A portable system, that estimates weight while walking, enables monitoring of heavy working conditions.

The main research contributions include design of a PBG measurement system with a sensor implementation resulting in good sensor durability, several novel methods for weight estimation during walk and a novel method for analysing walking intensity and relating it to walking speed. The research results show that the new PBG system, in combination with the novel analysing methods, are suitable for use in wearable systems for monitoring of health related walk parameters.