Note:For application researches, we are doing with the cooperation of the department of prosthetics and orthotics and the department of assistive technology in the same research institute of the rehabilitation center.
Purpose
We are developing a thin and small sheet type shear force sensor that can be inserted inside the prosthesis socket and the seat of the wheelchair.
Achievement so far
The sensor
device itself is newly developed in the laboratory and operates based on
its own principle and structure using liquid electrolyte (Fig. 1). So far, we have
developed a sensor with 0.7 mm thickness (the smallest diameter of the head is 6.5 mm). We
have also developed a portable measuring system to drive the sensor and
capture data on the PC (Fig. 2). Furthermore,
with its own compensation method, it has succeeded in suppressing
temperature fluctuation without incorporating a temperature sensor, and
it is almost not affected by pressure. Since
it is possible to extend the flat cable from the sensor head to the
connector for a long distance, it is easy to incorporate the sensor on the
inside surface of the prosthetic foot.
Sensors
and measurement devices have already been distributed to multiple
collaborators, and applied research results are emerging.
Figure 1. Operating principle of shear force sensor.
Figure 2. Photographs of shear force sensor (right) and measurement system.
Original papers
- S. Toyama, Y. Tanaka, S. Shirogane, T. Nakamura, T. Umino, R. Uehara, T. Okamoto, H. Igarashi, Development of Wearable Sheet-Type Shear Force Sensor and Measurement System that is Insusceptible to Temperature and Pressure, Sensors, 17(8), 1752 (2017).
- S. Toyama, Y. Tanaka, Y. Ishikawa, K. Hara, Simple Fabrication Method to Produce Flexible Electrode Capable of Soldering, Sensors and Materials, 28, 279-288 (2016).
- S. Toyama, S. Utsumi, T. Nakamura, T. Noguchi, Y. Yoshida, A Novel Thin Shear-Stress Sensor Using Electrolyte as a Conductive Element, Sensor Letters, 11, 442 (2013).