Soil compaction is a common problem facing conservation fields that restricts crop root growth and causes yield decrease. Subsoil techniques have been developed to break up the compaction layer. However, subsoil implement requires large draft power that hampered the development of subsoil techniques for most of developing countries due to lack of large scale tractors. Aiming to optimize the penetration resistance of the subsoiler and create a good working environment for the operators, a staggered vibrating subsoiler was developed. A new staggered vibrating mechanism was designed to generate the staggered vibration of the shanks meanwhile the V-shape shanks arrangement was adopted to keep relative balance for the subsoiler. In order to obtain optimum working parameters of the vibration frequency and forward speed, the trajectory of shanks was simulated by using the MATLAB software. The forward speed of 2-3 km/h with vibration frequency of 12 Hz was recommended to acquire an effective decrease in draft force. Field performance of this subsoiler was evaluated in terms of the draft force, power requirement and tractor wheel slippage. By comparing the two operation modes, staggered vibrating (SV) and rigid (NV) of shanks, the decrease ratios of draft force for SV were determined by 16.97%, 12.12% and 9.02% at forward speeds of 2.2 km/h, 2.6 km/h and 3.1 km/h, respectively. This is better than the research for the 1SZ-460 vibratory subsoiler that was decreased by 9.09% in draft force. The power requirement for SV was not significantly greater than that for NV. The obviously decreased wheel slippage was observed for SV by decrease of 12.47%, 17.96% and 21.79% at forward speeds of 2.2 km/h, 2.6 km/h and 3.1 km/h, respectively. In conclusion, the staggered vibrating subsoiler presents preferable working performance and is recommended to be applied in subsoil tillage process for developing countries. Keywords: vibrating subsoiler, staggered vibrating mechanism, V-shape arrangement, field experiment DOI: 10.25165/j.ijabe.20191201.4297 Citation: Wang Y X, Osman A N, Zhang D X, Yang L, Cui T, Zhong X J. Optimized design and field experiment of a staggered vibrating subsoiler for conservation tillage. Int J Agric & Biol Eng, 2019; 12(1): 59–65.

The mechanized sowing operation of corn breeding can improve test accuracy and efficiency and speed up the test process. In view of the problems of low flexibility, high price, and poor sowing quality of the current seeder in corn breeding experiments, the critical components of a hand-pushing corn plot precision planter were optimized. Through the analysis of the relative motion between corn seed and the hole seed-metering wheel, the hole diameter range and hole depth range of the hole seed-metering wheel were determined as 13~19 mm and 6~12 mm, respectively. The chamber structure was optimized to improve the seed filling performance under the condition of a small number of seeds. The angle range between the connecting plate and the horizontal line (ACP) and the angle range between the back plate and the horizontal line (ABP) were 35~55° and 40~70°, respectively. EDEM was used to simulate the seeding circumstances of hole seed-metering wheel with different holes sizes. The optimal combination of hole diameter and depth under different seeds’ sizes and the appropriate angle combination of ACP and ABP were obtained through the orthogonal test. The results of the simulation experiment showed that the optimal hole diameter–depth combinations of the small, medium, and large corn seeds were 13–8, 15–10, and 17–8 mm, respectively. The angle ACP and the angle ABP were, respectively, 45°and 70°. The soil bin test was carried out to further verify the actual seeding effect and the influence of the rotating speed of hole seed-metering wheel on seeding. The results showed that when the rotating speed of hole seed-metering wheel was less than 16.0 r/min, the qualified seeding rates and the double seeds rates of the small, medium, and large corn seeds were higher than 90% and 85%, respectively. The missing seeding rates were 0%. The variation coefficients of plant spacing were less than 5%, indicating good stability of plant spacing, which met the design requirements. The study results can provide a theoretical reference for the optimization design of maize breeding equipment in a plot.

The accuracy and real-time performance of the speed measurement method were important factors influencing the accuracy of the seeding spacing monitoring. In this study, three different speed measurement methods (including GNSS (Global Navigation Satellite System) receiver speed measurement, radar speed measurement, and encoder measurement rotation speed) were used to compare and analyze the monitoring results of seeding spacing. The same monitoring system was used to calculate the seeding spacing under three different speed measurement methods. The encoder directly measured the rotation speed of the seeding disc instead of the traditional method of measuring the rotation speed of the driving wheel. The monitoring results of uniform-speed and variable-speed seeding field tests showed that the three speed measurement methods have extremely high correlations, with a correlation coefficient R > 0.95. There was small difference among the three speed measurement methods, and they all met the needs of field seeding operations. After comprehensively considering the use cost and installation complexity, it was recommended to use GNSS receiver speed measurement to monitor the speed of the seeding operation and the real-time seeding spacing.

Remote monitoring system for maize seeding parameters based on Android and wireless communication

To avoid issues such as the greenhouse working robot’s inability to perform normal tasks or reduced working accuracy due to the influence of uneven ground, this study designed a set of greenhouse self-balancing mobile robots. The self-balancing mobile robot system designed in this study uses a quadruped mobile robot as a carrier, equipped with a three-degrees-of-freedom wheel-leg structure and is complemented with a posture control algorithm. The algorithm calculates the adjustment of each leg based on the vehicle’s tilt angle and wheel-ground pressure, achieving control over the robot’s posture angle, the center of gravity height, wheel-ground contact force, and other functions. To address the issue of over-constrained (weak legs) posture adjustment during mobile robot fieldwork, a flexible joint sensor based on the PR structure has been designed and developed. After field testing, it was verified that the greenhouse self-balancing mobile robot proposed in this study can adapt well to field environments, such as climbing hills, overcoming obstacles, crossing furrows, and so on. The response speed of the flexible joint sensor can meet the requirements of self-balancing while effectively solving the problem of weak legs.