觸覺感測器於智慧石頭之安裝與系統整合

Abstract

關於土石流發生時，土石顆粒間滾動，接觸以及力學行為之研究非常有限。現有研究大部分透過例如離散元素法(DEM)進行數值模擬。土石流現場量測大多侷限於孔隙水壓與流速等觀察。這些限制使得我們至今還無法對土石流運行時之力學行為做一完整之敘述。本研究是一系列關於智慧石頭(Smart stone)研發之一部分。智慧石頭之主要功能是利用微機電(MEMS)技術，其低耗電，低成本，體積小之優點，量測模型土石滾動時顆粒間接觸與力學行為。本研究之目的是研發智慧石頭表面正向接觸力分佈量測之技術。作者使用十四片壓阻式觸覺感測器(Piezoresistive tactile sensor)包覆智慧石頭表面的技術來量測正向接觸力之分佈變化。本研究透過硬體電路，搭配Arduino微處理控制器以及整合Nordic nRF24L01 2.4GHz RF無線通訊模組，使智慧石頭可以5Hz之頻率做即時數據傳輸。作者研發遠端控制系統，使智慧石頭可採自動化監測。性能測試結果顯示，智慧石頭之壓阻式觸覺感測器具有良好的重複性；整體系統耗電量則相當省電。透過上述之結果，智慧石頭之研發展現了精簡、高效率、低功耗的優點。

Studies on the contact and mechanical behavior of granular particles during a debris flow have been limited.Most of the studies involved numerical simulations using discrete element method (DEM). Field measurements during a debris flow have been limited to those of pore pressure and flow velocity. Because of these limitations, we have not had a more complete understanding of the mechanical behavior of debris flow. This research is part of a project in the development of a “smart stone”. The main capability of the smart stone is to measure the contact and mechanical behavior among fast moving stones such as during a debris flow. The smart stone will be monitored with microelectromechanical system(MEMS) sensors, taking advantages their small size,low power consumption and low cost.The objective of this study is to develop the technique of measuring the distribution of normal forces on the surface of the smart stone. The author used fourteen piezoresistive tactile sensors to cover the surface of the smart stone and to measure the distribution of normal forces. The study could let the smart stone doing real-time data transfer in 5Hz. By integrating the hardware circuits that include Arduino micro-controller and Nordic nRF24L01 2.4GHz RF wireless communication module, readings collected by the tactile sensors can be transmitted as a maximum of 5 Hz frequency in real-time. The tactile sensor readings were reasonably repeatable and the system was energy efficient. Through these capabilities, the proposed smart stone should have the advantages of simplicity, efficiency and low power consumption.