The intended sensorised insole system is integrated to the operator’s shoes which is able to dynamically measure weights and pressure changes when a person is lifting or lowering a heavy weight. The aim of the FSR (Force Sensing Resistor) insole system is to indirectly infer when the exoskeleton should assist the wearer and also to detect how much assistance is required.
Insole FSR system module. a) Sensor arrangement under foot, 8 force sensors divided in two modules (metatarsals on the front and heel on the back). b) Insole module with force sensors. c) Insole integrated in the shoe.
Right figure: a) Protection circuit for FSR sensors. b) Compression test machine for FSR calibration to responses (0 to 441N). Left image: Force-resistance curves from the Left foot back FSR sensors, revealing different responses to the same applied force.