Development of a Bolt Type Force Sensor using Strain Gauges for Sport Climbing

This paper proposes a novel bolt type force sensor that measures forces applied to an object fixed by the sensor. This sensor consists of a iron bolt and four strain gauges and can be made inexpensively compared to a 6-axis force sensor. Due to the feature of the bolt type sensor, it can measure the force applied to the object without dedicated holds, extra jigs, gaps between holds and walls. Therefore, the sensor can be applied to existing climbing holds without changes of difficulty of climbing problems. In this paper, the structure of the sensor is introduced and its calibration method is discussed. Finally, a force measurement experiments are conducted, and it was confirmed that the sensor is able to achieve highly accurate force estimation in practical situations.