A Novel Robotic Surveying Technique for Free-Falling Penetrometers

Severe floods and sea level rise (SLR) are increasingly urgent effects of global climate change. Wetlands are natural buffers that prevent inundation and destruction from floods. Anthropogenic destruction of wetlands is reducing their effectiveness as flood buffers. Rapid and timely assessment methods are needed for the effective restoration of the wetlands. This thesis presents a novel method for performing free falling penetrometer (FFP) tests for soft wetland soils. The method involves the aerial deployment of a custom FFP using a consumer quadcopter. The method was tested in three soils to examine the effect of drop height on the FFP deceleration profile and penetration depth. Further tests were conducted to determine the force required to extract the FFP after a successful drop. The effects of speed and angle on extraction force was analyzed. Field tests were simulated by conducting limited indoor surveys with the FFP and a consumer drone. The custom FFP was successful in distinguishing wetland soils in drop experiments. The relationships between drop height, penetration depth and deceleration profile were characterized. Data from extraction tests revealed a linear relationship between extraction force and speed; and an inverse relationship between extraction force and angle. By utilizing techniques to minimize the extraction force, a consumer drone was successful in deploying and retrieving the custom FFP. Further field tests are needed to validate the robustness of the novel method. If proven reliable, this method will be useful in reducing the financial and labor costs associated with wetlands surveys.