An electric linear actuator-based lysimeter soil retriever design: Performance optimization and performance loss measurement

A lysimeter-soil retriever (LSR) is a device that facilitates the efficient and non-disruptive retrieval of soil from lysimeters, streamlining the sampling of intact soil layers. This tool proves particularly advantageous when sampling a substantial quantity of lysimeters, as it simplifies and accelerates the process. Existing LSR designs are complex and better suited for large monolithic field lysimeters. However, these designs are unnecessary for retrieving soil from mini or small lysimeters. Therefore, a simple LSR was fabricated using a linear actuator to retrieve soil from mini or small lysimeters. This paper focuses on the optimization of voltage applied to a linear actuator to control the incremental stopping of soil blocks at heights of 5 and 10 cm. Additionally, performance loss measurements were conducted after soil retrieval from 80 lysimeters. To optimize speed, voltages ranging from 24 to 19 V were applied, and the linear actuator speed and soil block heights were measured. The maximum force and time required to complete a full stroke were also measured before and after the retrieval of 80 lysimeters to assess performance loss. The results showed a linear decrease in linear actuator speed with increasing voltage. Additionally, there was a significant (P<0.05) increase in soil block heights as the voltage increased. The desired soil block heights were achieved at 19 V, corresponding to an actuator speed of 11.6 mm/s. Therefore, 19 V was determined to be the optimum voltage for this study. Furthermore, after the retrieval of 80 lysimeters, there were no significant changes in the maximum force and time required for a full stroke, which were recorded as 43 s and 530 N, respectively. These findings demonstrate that the linear actuator is a suitable alternative to a hydraulic piston as a force applicator in the LSR design.