Designing and Constructing an Active Boom Balancing System using a New Technique Variable Fulcrum Method and Comparing It with a Conventional Sprayer

Abstract

Introduction According to reports on trends in the agricultural industry, demand for more precise and affordable machinery is rising and precision farming methods used by farmers are expanding. Damping vibration of the boom sprayer is one of the challenges for researchers when crossing the surface roughness. The lack of uniformity of the nozzle spray pattern and the reduction of the precision and quality is the result of an uncontrolled vibration of the boom sprayer. So far, many efforts have been made to decrease the vibration of the long sprayer boom. Using active and passive methods, researchers have achieved great success in reducing the spray boom vibration. Many of these methods are based on the use of external force as a controlling force. Expensive equipment, the use of tractor hydraulic power, and high energy costs are the main disadvantages of these methods. In the present work, a new system called "variable support" was designed and built. The boom rests on a round bar at its midpoint; as the boom tends to oscillate, a minute amount of rotation of the bar activated by a servomotor in an appropriate direction, alters the position of the resting point of the boom on the supporting bar, bringing the boom back to its initial balanced position as a result. Materials and Methods To carry out experiments, the universal tractor U650 and a mounted tractor sprayer model tms500 with 8 m boom and a 500-liter tank, was used in this research by making changes to the design of the simple tractor sprayer a new active sprayer designed and built with intelligent online balancing system that in addition to balancing the boom angle, it reduced the fluctuations that occur during work. Electronic control was used to control the position of the boom. The microcontroller programming codes were developed and uploaded in the microprocessor to execute instantaneous commands to the mounted activator due to the need for boom positional data for analyzing experiments, a data logger was also designed in conjunction with the controller circuit and the algorithm was loaded after coding with C++. To compare the new sprayer with the conventional, a field test was conducted. Tests were carried out according to manufacturer's instructions at three-speed levels of 3 (low), 5 (medium), and 8 km h-1 (high), with three bumps heights of 10, 15, and 20 cm with three replications. For the acquisition of vertical acceleration as well as axial rotation data in the conventional sprayer, a data logger with an accelerometer and gyroscope was used. The data logging rate and the accuracy of the accelerometer and gyroscope measurement were set to 50 Hz, 0.1 m s-2 and 0.1°, respectively. Results and Discussion To compare the behavior of the active and the conventional spray booms in terms of vibrations, the univariate analysis was used. The results showed that there was a significant difference between the performances of two sprayers at 5% probability level with the sig. number of 0.000. To compare the behavior of the active and the conventional spray booms in terms of axial rotation, also the Univariate analysis was used. The results showed that there was significant difference between the performances of two sprayers at 5% probability level with the sig. number of 0.000. Also, comparing the marginal mean values of the data obtained from the data logger showed that the active boom compared with the conventional boom had less axial rotation and less vertical acceleration. Conclusions Results of experiments showed that the new sprayer with variable support system, relative to the conventional sprayer in terms of controlling boom acceleration and the angular balance of the boom with a significant difference had relative superiority and can be considered as an appropriate alternative to increase the accuracy of spraying, although more research on large scale booms are necessary before coming to final conclusion.

Keywords

• active force control
• balanced long boom sprayer
• precision farming
• variable support