Active Comfort System*

Seat comfort is an elusive factor that can be hard to define as we each have our own subjective sitting experience.

A seat may be designed as a fixed profile that provides support in the right places, but the resulting comfort factor is low because there is no give or compliance. This approach can work for quick, short journeys on an underground train or bus. For extended journeys though, the comfort factor becomes ever more important and can make all the difference to our journey experience. The sitting process often involves re-adjusting our posture to ease contact pressure. Using PoseNet AI-trained software we have observed how this behaviour can indicate signs of discomfort.

The design and human factors team at DCA have combined their collective experience to take a new look at seat comfort. The result is the “Active Comfort System”, based on our insights into the way seats are designed and used.

The “Active Comfort System” allows individual control of the feel of a seat cushion - changing it from hard to soft in infinite steps. This unique design uses an adjustable tension layer at the centre of a seat cushion or squab. By giving control of the fabric tension to the user, the cushion trim may be changed to suit their personal preference.

The design parameters used centre around three variables. Compliance (physical displacement of the seat cushion/squab) pressure distribution (surface stress gradients) and compression rate (cushion/squab feel).

The “Active Comfort System” controls each of these parameters via the variable tension layer. The tensioning system may be manually actuated or powered with a small, geared motor. Using the interaction of the tension layer with a dual cushion set-up, created using a combination of springs, foam or non-woven materials, each person can set the firmness and compliance to suit their preference and adjust it throughout a journey.