Sumitomo Riko Co Ltd developed a cushion that enables to detect the fatigue and drowsiness of an auto driver.
Sumitomo Riko, which deals with automotive vibration-absorbing rubbers, etc, exhibited the cushion at Automotive Engineering Exposition 2018, which took place from May 23 to 25, 2018, in Yokohama City, Kanagawa Prefecture, Japan.
The company expects that the cushion can reduce the risk of traffic accidents when combined with warning devices. It is promoting the cushion to the manufacturers of commercial vehicles and auto seats, aiming to commercialize the cushion by 2021.
The newly-developed cushion can measure the distribution and change of a pressure applied to it. Based on pressure distribution, it is possible to estimate the posture change and physique of the driver. Also, from pressure change, breathing rate, heart rate and other states of the driver can be estimated.
By analyzing data collected by the cushion, it is possible to detect the driver's states that can lead to accidents such as fatigue and drowsiness, Sumitomo Riko said.
The cushion consists of three rubber layers: a seat-shaped rubber layer sandwiched between conductive rubber layers (electrodes). When the distance between the upper and lower electrodes changes due to the movement of the driver, the capacitance between the electrodes changes. Based on the amount of the change, a pressure applied to the cushion is measured.
"It takes several seconds to process the calculation of breathing rate, heart rate and so on from the pressure," Sumitomo Riko said.
The reduction of the processing time is a future development subject, the company said.
Flexibility differentiates cushion
The electrode developed by Sumitomo Riko has a flexibility. It was realized by printing a flexible conductive rubber material called "SR (smart rubber)" on a base material made of rubber. It can keep its conductivity even when stretched by about 100%.
"Because the cushion is made by combining flexible rubber materials, the driver does not feel uncomfortable much even when driving a car while sitting on it," the company said.
By changing the size of the rubber material, it becomes possible to make a cushion larger than the seat surface. It can also be applied to the backrest.