There is a pressing need of new chemical application sprayer for small scale farms in Indian agricultural pesticides spraying. A new air-assisted electrostatic nozzle has been designed and developed for small scale farms with a specific focus on Indian agricultural and rural developing economies. An air-assisted electrostatic nozzle is a combination of an air-assisted nozzle and induction based electrostatic charging system. Spray droplets are electrified to more than 10mC/kg charge-to-mass ratio by charging voltage less than 2.5kV at liquid flow of 150ml/min and electric power consumption less than 75mW. Higher charge-to-mass ratio ensured the high range spraying distance to overcome the charge neutralization by recombination of naturally occurring ions present in the environment and charged liquid droplets. The results of applied induction electrification process were characterized by a charge-to-mass ratio and the results are in good agreement with the theoretical considerations. There has been 2–3 fold increase of liquid deposition with better uniformity on the obscured as well as front target. This nozzle is light weight, highly efficient, reduces pesticide use and human health risks, and eco-friendly.

A system for spraying liquid pesticides to crops and orchards combines an induction based electrostatic nozzle and externally air-assisted manually controlled mechanical device. In this paper, an innovative concept has been executed for variable coverage high range spraying through an external air-assistance system, which supplies compressed air to assist the finely divided charged liquid droplets by farming a virtual covering around the fine mist of liquid spray. External air-assistive device consists of movable support for air supplies whose variation of cone angle is from parallel spray center line (0°) to maximum spray cone angle (25°). This provides a means to transport electrostatically charged fine mist of liquid droplets to intended target with variable spray coverage angle of target, applicable in high wind and transient conditions with enhanced performance without degradation of charge-to-mass ratio. The results of applied induction electrification process were characterized by a charge-to-mass ratio as a function of applied voltage, target distance, and wind current. It has been shown that the wind current has an insignificant (p value=0.021615) and significant (p value=0.000325) effects on the performance of the electrostatic nozzle at 99% confidence level with and without external air-assistive mechanical device respectively. The experimental results are in good agreements with proposed concept.

The development of reliable means of charging for finely divided particulate matter is among the major portion of the research activities in electrostatic spraying. This paper presents the role of electrode material and engineering aspects in spray charging with emphasis on theoretical considerations of selection of electrode material and its dimensional shape and size. It reveals the charge-to-mass ratio dependency on variables such as electrode material, shape and geometrical specifications, which is in good agreement with the theoretical considerations. For the particular designed electrostatic nozzle, it is found that optimum electrode position is in the range of 2.0–3.0 mm from the nozzle tip. The copper electroplated with nickel as a charging electrode material can be plausible alternative for spray charging as excellent charge-to-mass ratio 2.8 mC/kg is attained for improved efficacy and efficiency of the electrostatic spraying processes. Possible limitations requiring further research includes the design for maximum charge injection rate, which is thought to be limited by corona breakdown, again a trade-off in air media between charging electrode and liquid sheet.

Electrostatic induction charging has proven itself as one of the best methods adopted in agricultural pesticides spraying. Pesticide droplets get charged while passing through a charging electrode which is connected to a high voltage along with the grounded liquid jet. Negatively charged droplets follow the electric lines of forces and get attracted towards the target which is at ground potential. In this paper, a compact size DC to DC converter is designed and developed to generate high voltage. The circuit consists of two sections, a DC to AC converter and an AC to DC converter, which can also be termed as an inverter and Cockcroft Walton multiplier. The converter utilized a 9.0 volt DC rechargeable battery to give a high voltage output. The converter has been used for spray charging in air-assisted electrostatic nozzle system placed inside the nozzle holder. The results were in good agreement with the theoretical concepts and practices. The designed power supply system showed the output stability at higher frequency range which has optimum ripple and voltage drop when applied with load.

A major portion of the autonomous mobile robotics research has been in the development of reliable means for navigation and control of autonomous systems in a complex, irregular, unstructured and dynamic environment for farm duties such as seeding, pruning, pesticide spraying, reaping etc. Several practices have been established by numerous researchers in the motion planning of mobile robots. This paper presents an ultrasonic multi-sensor fusion based technique for navigation and control of the autonomous mobile robotic system for collision avoidance, target detection and canopy mapping. The autonomous system is a combination of real time monitoring and navigation, detection of the target and canopy mapping which delivers controlled dose of pesticide in a targeted manner according to the information gathered from the sensory attributes of precision farming data set through online and real time monitoring of the objects. Real time monitoring and navigation control, complex algorithm, data acquisition and storage, calculation and processing are designed with motors and sensors interfaced with microcontroller. Test results showed that the ultrasonic sensor fusion technique was capable of performing satisfactory guidance in dynamic environment and desired paths. The sensor fusion navigation was capable of compensating large error and resulting in satisfactory agricultural vehicle guidance.