The objective of this study is to clarify the differences of tractive performances generated by the sandy loam-grouser system and the clay soil-grouser system. The tractive performances of the grouser/track shoes are widely researched by previous researchers. However, it is essential to illustrate the influences of the soil properties on the tractive performances of the grouser shoe. Sandy loam and clay soil were used as the test soils for investigating soil parameters in this study. Moisture contents of soil were from 7.5% to 27%, dry basis. Parameters of sandy loam were obtained through direct shear tests, penetration tests, bulk density, and moisture content measurements in laboratory. The grouser shoe was made of steel. Based on the prediction result of tractive performances, the clay soil will always be performed better than the sandy loam no matter which dimension was chosen for single grouser shoe. Based on the experimental results, the grouser height of the track should be 5 cm in order to provide enough traction force, if a tracked vehicle is operated on the environment of either clay soil or sandy loam.

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Aiming at the low mechanization of paddy field weeding and lack of dedicated agricultural machinery for paddy field weeding in China, a self-propelled system of paddy field weeding machine was designed. The overall structure and working principle of self-propelled system were illustrated and analyzed. The interaction mechanism of wheel-soil during weeding was analyzed. The wheel-soil interaction model was established, then, wheel traction and surface flatness were selected as the evaluation indexes for discrete element simulation experiment. The steering performance, stability, and over ridge ability of self-propelled system were analyzed, and field experiment was carried out. The simulation experiment results show that the wheel traction is approximately 600 N and the surface flatness is less than 30 mm. The field experiment results show that the minimum turning radius of the prototype is 2,050 mm in paddy, overturning limit angle of the prototype is 36º, and maximum height over the ridge is 400 mm. The speed range of the weeding machine on the road and weeding operation was 0~16.20 km/h and the 0~5.40 km/h respectively. The weeder can meet the speed demands of weeding operation. The study results can provide reference for research and development of paddy field operation machinery.

The development of high-speed camera systems and image processing techniques has promoted the use of vision-based methods as a practical alternative for the analysis of non-contact structural dynamic responses. In this study, a deviation extraction method is introduced to obtain deviation signals from structural idealized edge profiles. Given that the deviation temporal variations can reflect the structural vibration characteristics, a method based on singular-value decomposition (SVD) is proposed to extract valuable vibration signals from the matrix composed of deviations from all video frames. However, this method exhibits limitations when handling low-level motions that reflect high-frequency vibration components. Hence, a video acceleration magnification algorithm is employed to enhance low-level deviation variations before the extraction. The enhancement of low-level deviation variations is validated by a light-weight cantilever beam experiment and a noise barrier field test. From the extracted waveforms and their spectrums from the original and magnified videos, subtle deviations of the selected straight-line edge profiles are magnified in the reconstructed videos, and low-level high-frequency vibration signals are successfully enhanced in the final extraction results. Vibration characteristics of the test beam and the noise barrier are then analyzed using signals obtained by the proposed method.

The wind turbine blade is the core component of the wind turbine. However, wind turbine blades will suffer fatigue and internal crack defects, which seriously affect the safety service performance in harsh environments. The current detection mode is mainly traditional manual detection and shutdown maintenance, with high risk and low efficiency. Therefore, this research proposed a method to conduct a non-stop online inspection of the wind turbine blade’s internal defects using ultrasonic inspection mounted unmanned aerial vehicle. As the vital component of this inspection system, the optimized design of the negative pressure adsorption car was carried out. The structural characteristics of the negative pressure adsorption car were determined experimentally, followed by multivariate analysis and an integrated development and performance test study of the test system. Based on the test results, the detection rate of this test system for internal wind power blade faults is 100%. This research offers novel concepts of and theoretical insights into the intelligent and security identification of internal flaws in wind turbine blades.