Exploring GPS Data for Operational Analysis of Farm Machinery.

Global Positioning System (GPS) has made a great evolution in different aspects of modern agriculturalsectors. Today, a growing number of crop producers are using GPS and other modern electronic and computer equipments to practice Site Specific Management (SSM) and precision agriculture. This technology has the potentialin agricultural mechanization by providing farmers with a sophisticated tool to measure yield on much smaller scales as well as precisely determination and automatic storing of variables such as field time, working area,machine travel distance and speed, fuel consumption and yield information. This study focuses on how to interpretand process raw GPS data for operational analysis of farm machinery. Exact determinations of field activities usingGPS data along with accurate measurements and records of yield provide an integrated tool to calculate field efficiency and field machine index which in turn increases machine productivity and labor saving. The results canalso provide graphical tools for visualizing machine operator’s performance as well as making decision on field and machine size and selection

A comprehensive comparison between wave propagation and heat distribution via analytical solutions and computer simulations

Wave propagation and heat distribution are both governed by second order linear constant coefficient partial differential equations, however their solutions yields very different properties. This study presents a comprehensive comparison between hyperbolic wave equation and parabolic heat equation. Issues such as conservation of wave profile versus averaging, transporting information, finite versus infinite speed propagation, time reversibility versus irreversibility and propagation of singularities versus instantaneous smoothing have been addressed and followed by examples and graphical evidences from computer simulations to support the arguments

A review of Greenhouse Climate Control and Automation Systems in Tropical Regions.

Design and development of automation system for a tropical greenhouse involves different phases, including studying of environmental factors and crop responses, control algorithm, instrumentation and software/hardware interface. In contrast to cold arid climates, a tropical greenhouse is not to provide a warm and humid environment for crop, but to create an ideal condition in which plants can be protected against heavy rainfalls, direct sun radiation, disease, insects and birds. High relative humidity and ambient temperature climate in a tropical greenhouse creates a complicated dynamic system that is influenced by changes of external conditions, making it a challenging environmental control task. This paper reviews and addresses issues involved in the design procedure of automation control system in tropical greenhouses

Design and Simulation of Control Systems for Field Survey Mobile Robot Platform.

The aim of this study was to design automatic and accurate control systems for wheel speed and steering of an agricultural mobile robot. Three controllers, including lead-lag compensator, Proportional-Integral-Derivative (PID) and fuzzy logic controller were designed and simulated in this study to control the angular rate of the shaft of a DC motor actuator for a field survey mobile robot that moves between plants rows to perform image acquisition task through a digital camera mounted on a two link arm attached on the robot base. The response of the actuator model for each controller were determined and compared for a sinusoidal and a step input that simulated robot speed and positioning references respectively. Performance analysis showed the effectiveness of the PID and lead-lag compensator response for the wheel steering task, while the fuzzy logic controller design had a better performance in wheel speed control. The output of this analysis was a proved satisfaction of the proposed design criteria which results enhanced mobility of the robot in terms of fast response, speed control accuracy and smooth steering at row-end turnings

Data acquisition for Monitoring Vapor Pressure deficit in a tropical lowland shelter-house plant production

The objective of this study was to monitor air Vapor Pressure Deficit (VPD) in a tropical lowland shelter-house plant production. A custom-designed real-time Data Acquisition (DAQ) system with three independent microcontroller boards and sensors for monitoring aerial parameters was developed, calibrated and tested. Sample temperature and Relative Humidity (RH) data for VPD calculations were continuously collected every 60 sec, for 6 days, inside a 40 m2 shelter-house located at the Universiti Putra Malaysia agricultural experimental field. Preliminary results showed that VPD values varied from 0.16 to 2.51 kPa, with a mean of 0.83 kPa and standard deviation (Std) of 0.6 kPa. Different regression models were used to describe the nonlinear correlation that existed between temperature and VPD data. Results showed that squared polynomial model produced the maximum coefficient of determination (R2) equal to 0.976. This model was successfully used for VPD prediction based on temperature inputs. The hypotheses that collected data follow normal distribution and have different means in the 6 days of experiment were rejected at any significant level. The result of this study can be used in decision support systems’ database for controlling tropical lowland plant production environments

Design and Analysis of Full-state Feedback Controller for a Tractor Active Suspension: Implications for Crop Yield.

Vehicle suspension systems are needed in modern tractors to improve ride comfort by insulating driver’s cabin from road disturbances. Active suspension (AS) systems have the potential to improve both ride quality and handling vibration performance upon use of feedback to control its hydraulic actuator. This gives a capability to the vehicle to continuously adjust itself and response to the varying road conditions. The main objective of this study was to use a full-state feedback approach to design and analysis of AS control system for Kubota M110X tractor to eliminate the transmitted vibrations to the driver’s cabin caused by field roughness. The inputs of the system were determined as the control force generated from the hydraulic actuator of the AS and the road disturbances caused by holes and uneven surface. A simulation model was developed to analyze the behavior of the system to disturbances with 0.25 m amplitude. Results are included to show the dynamic performance and robustness of the proposed controller in dissipating the corresponding disturbance vibrations for a comfort ride with an instant overshoot of about 12% of the inputs disturbance and a settling time (ST) of 4.36 sec

Implementation of Galerkin's method and modal analysis for unforced vibration response of a tractor suspension model

This study provides a numerical tool for modeling and analyzing of a two degree of freedom suspension system that is used in farm tractors. In order to solve the corresponding coupled system of equations, dynamic modal expansion method and matrix transformation technique were first used to formulate the problem and to obtain the natural frequencies and modes of the tractor rear axle suspension. Galerkin’s method over the entire time domain was then employed to analyze the modal equation of motion for the unforced response. It was shown through calculations that the algorithm over entire time domain could not be generalized for computer implementation. In order to develop a stand-alone algorithm implementable in any programming environment, Galerkin’s method was applied over smaller elements of time domain. The modal and vertical equations of motions describing the suspension system were then solved numerically for both with and without damping cases. The program was used successfully to solve the actual coupled equations and to plot the results. Finally, for the damped case, where stability of the system was expected, the numerical results were confirmed through Lyapunov stability theorem

Fundamental Research on Unmanned Aerial Vehicles to Support Precision Agriculture in Oil Palm Plantations

Unmanned aerial vehicles carrying multimodal sensors for precision agriculture (PA) applications face adaptation challenges to satisfy reliability, accuracy, and timeliness. Unlike ground platforms, UAV/drones are subjected to additional considerations such as payload, flight time, stabilization, autonomous missions, and external disturbances. For instance, in oil palm plantations (OPP), accruing high resolution images to generate multidimensional maps necessitates lower altitude mission flights with greater stability. This chapter addresses various UAV-based smart farming and PA solutions for OPP including health assessment and disease detection, pest monitoring, yield estimation, creation of virtual plantations, and dynamic Web-mapping. Stabilization of UAVs was discussed as one of the key factors for acquiring high quality aerial images. For this purpose, a case study was presented on stabilizing a fixed-wing Osprey drone crop surveillance that can be adapted as a remote sensing research platform. The objective was to design three controllers (including PID, LQR with full state feedback, and LQR plus observer) to improve the automatic flight mission. Dynamic equations were decoupled into lateral and longitudinal directions, where the longitudinal dynamics were modeled as a fourth order two-inputs-two-outputs system. State variables were defined as velocity, angle of attack, pitch rate, and pitch angle, all assumed to be available to the controller. A special case was considered in which only velocity and pitch rate were measurable. The control objective was to stabilize the system for a velocity step input of 10m/s. The performance of noise effects, model error, and complementary sensitivity was analyzed

Development of a Field Robot Platform for Mechanical Weed Control in Greenhouse Cultivation of Cucumber

A prototype robot that moves on a monorail along the greenhouse for weed elimination between cucumber plants was designed and developed. The robot benefits from three arrays of ultrasonic sensors for weed detection and a PIC18 F4550-E/P microcontroller board for processing. The feedback from the sensors activates a robotic arm, which moves inside the rows of the cucumber plants for cutting the weeds using rotating blades. Several experiments were carried out inside a greenhouse to find the best combination of arm motor (AM) speed, blade rotation (BR) speed, and blade design. We assigned three BR speeds of 3500, 2500, and 1500 rpm, and two AM speed of 10 and 30 rpm to three blade designs of S-shape, triangular shape, and circular shape. Results indicated that different types of blades, different BR speed, and different AM speed had significant effects (P < 0.05) on the percentage of weeds cut (PWC); however, no significant interaction effects were observed. The comparison between the interaction effect of the factors (three blade designs, three BR speeds, and two AM speeds) showed that maximum mean PWC was equal to 78.2% with standard deviation of 3.9% and was achieved with the S-shape blade when the BR speed was 3500 rpm, and the AM speed was 10 rpm. Using this setting, the maximum PWC that the robot achieved in a random experiment was 95%. The lowest mean PWC was observed with the triangular-shaped blade (mean of 50.39% and SD = 1.86), which resulted from BR speed of 1500 rpm and AM speed of 30 rpm. This study can contribute to the commercialization of a reliable and affordable robot for automated weed control in greenhouse cultivation of cucumber

VRT liquid fertilizer applicator for soil nutrient management

Graphical abstract Abstract Sensor based VRT liquid fertilizer application is a suitable way to apply the nutrients for soil management of various crops. Time and resources can be saved using this technology but due to the special characteristics of cereal and tree crops like paddy and oil palm, dedicated designs of VRT liquid fertilizer applicators are needed to fulfill the nutritional requirement of respective crops. The proposed design of VRT liquid fertilizer applicator involves soil fertility sensors, speed sensor, flow control valves, flow sensors and pressure sensor. Design considers the variable fertilizer flow compensation with change in forward speed of machine between 2.5-3.5 km/h. Also this design offers the transfer of data from electronic controller to the external computer for record and performance testing of machine by computing the lag times of flow control valves and application error of machine. Originally, the design is for tree crop; however, with a slight modification in controller's program, this will also be suitable for cereal crops like paddy. To apply the fertilizer, three DC pumps of 6.89 bar pressure and 5 L/min flow rate were used in simulation with the flow lines of 6 mm internal diameter. Flow simulation revealed that the system was able to achieve the 0.06 L/s at 13.73 m/s velocity at nozzles 1 and 2 (full cone nozzles) while nozzles 3 and 4(flat fan nozzles) were delivering the same flow rate but at a little high velocity of 13.94 m/s. A comparatively uniform distribution of fertilizer application may be achieved using flat fan nozzles