Sensor suit to alert you when your posture is bad

Interview with D.C.Sc. Felix Wenk, Member of Staff at the Cyber-Physical Systems Research Department at the German Research Center for Artificial Intelligence (Deutsches Forschungsinstitut für Künstliche Intelligenz (DFKI))

SIRKA: this acronym stands for a sensor suit for individual feedback of physical activity. In a joint project, the DFKI is developing a suit designed to prevent problems with poor posture. Inertial sensors are integrated into a work overall. Physiotherapists are also meant to benefit from the results.


Photo: Felix Wenk

Dipl.-Inf. Felix Wenk; © DFKI GmbH/ Annemarie Hirth

In this interview, spoke with D. C. Sc. Felix Wenk of the DFKI, about the function of the sensor suit, who benefits from using one and how data protection can be ensured for its users.

Mr. Wenk, you are contributing to the SIRKA project, which develops a sensor suit to prevent problems resulting from bad posture. How does this suit work?

Felix Wenk: Our project partner MEYER WERFT discovered that employees develop bad posture during work over an extended period of time. The suit is designed to measure the suit wearer’s posture while the employee is welding a ship together for example. The goal is to find out the reason behind these injuries. Several inertial sensors are incorporated into the work clothes. These sensors are also located in all smartphones and measure the rotational speed and acceleration. We use the inertial sensors in the suit to determine the position of the parts of the body; for instance, the position of the thigh and lower leg. This provides an overall picture of the wearer’s posture.

The sensors determine up and down direction based on the gravitational forces exerted on the body. They also measure the speed of rotation during the movements of the wearer. Currently, we are working on determining the north-south alignment of the individual body parts. So far, you can’t identify front and back yet. We developed two different versions to do this. In the first version, we attach a compass to every body part. The other version is more intricate; the structure and the body part motions are individually measured. Unlike the first method, the advantage here is that you don’t need a magnetic field. Magnetic field interference especially occurs in the shipbuilding industry.
Photo: Man wears a boiler suit

15 inertial sensors are incorporated into the work clothes. They use the inertial sensors in the suit to determine the position of the parts of the body. The positions of the sensor are marked in the picture; © MEYER WERFT GmbH

Do the sensors disturb employees when they wear them?

Wenk: The 15 sensors that are in the suit each measure an area of approximately two square centimeters and are less than one millimeter thick. In the suit, they are located in small hook-and-loop pockets that are covered with fabric. The suit wearer does not notice them and, therefore, does not perceive them as annoying. The attached computer that analyzes the posture data is slightly smaller than a pack of cigarettes and is only noticed in a limited way. Its design will also become smaller in the future.

You mentioned you work together with the shipbuilding company MEYER WERFT. Which other occupational groups could also utilize this suit as a preventive measure?

Wenk: Only those professions that involve physical labor and where you want to discover how employees move are taken into consideration. The automotive industry has already taken several measures in this area. Employees working assembly lines are observed with cameras to detect potentially poor posture. The work area in shipbuilding companies is too extensive to furnish it with cameras everywhere. An application in construction companies would also be conceivable. Employees frequently lift boxes the wrong way, with their backs. To protect the joints, people should always draw from the knees when they lift heavy objects. You could develop a vibration alert that alerts the suit wearer of bad body posture.

Photo: Part of a boiler suit with logo from the company MEYER WERFT

The sensors are located in small hook-and-loop pockets that are covered with fabric. The suit wearer does not notice them; © MEYER WERFT GmbH/ Annemarie Hirth

In the operating room, surgeons sometimes need to assume a certain body position for several hours at a time. Do you think the sensor suit could also provide health support for surgeons?

Wenk: You could integrate the sensor into surgical scrub suits. However, the suit responds better to movements than being stationary. Surgeons barely move their bodies during surgery. For now, the primary application of this suit is career fields where different postures are being assumed. When it comes to being in the same posture over an extended period of time, like sitting at an office desk for hours, it would make sense to monitor whether the posture changes during this time to warn the wearer accordingly.

Physicians and physiotherapists should be able to improve patient treatment based on the measurement results. How is this made possible?

Wenk: Physiotherapists are already collaborating in our project. They help us in detecting which postures are harmful. If the sensor suit is being used, the collected data is stored on an SD card. The wearer can remove the card from the suit at the end of the work day and use it to consult with the company physician or physiotherapist. The physician can review the results and stats with the help of data analysis software that is being developed by another project partner. The software indicates for instance how long the employee remained in a kneeling position. The goal is to identify potentially physically harmful positions. The results are subsequently used to create an individual alert function.

Can data protection for the wearer be guaranteed?

Wenk: At the beginning of the project, the idea was to transmit data not by cable but by using radio waves. We refrained from doing this because of practical, but also primarily due to data protection concerns. That’s also why the data is stored on the SD card, so third parties have no access to it. After removing the SD card from the suit, the data only remains on the card, so that the next wearer of the suit has no access to the results of the previous wearer.

Photo: Lorraine Dindas

© B. Frommann

The interview was conducted by Lorraine Dindas and translated from German by Elena O'Meara.