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Papers by Rasika Abeyrathna

Research paper thumbnail of Development of a 3D Printed New Metering Mechanism for a Multi-Crop Seed Broadcasting System Using an Autonomous Small-Scale Vehicle

Inventions

Developing countries in Asia widely use manual seed broadcasting methods due to a lack of appropr... more Developing countries in Asia widely use manual seed broadcasting methods due to a lack of appropriate seeding machinery. The agricultural sector is currently facing labor shortages and high labor costs, especially seasonal labor shortages for broadcasting and transplanting operations. However, the primary constraint in adopting existing broadcasting seeders for small-scale farmers in developing countries is the high initial purchase costs. Therefore, developing locally commercial accessible technology for small-scale farmers is an urgent requirement. In this regard, attempt was taken to develop a new low-cost 3D printed seeder that can be used for multi-crop seed broadcasting operations when integrated with an autonomous terrain vehicle. A new seed metering mechanism was proposed for seed broadcasting that can be controlled electronically from the autonomous terrain vehicle. Positional sensors based on the real time kinematics—global navigation satellite system (RTK-GNSS) were used ...

Research paper thumbnail of Autonomous Robots in Orchard Management: Present Status and Future Trends

IoT and AI in Agriculture, 2023

Research paper thumbnail of IoT × AI: Introducing Agricultural Innovation for Global Food Production

IoT and AI in Agriculture, 2023

Research paper thumbnail of Recognition and Counting of Apples in a Dynamic State Using a 3D Camera and Deep Learning Algorithms for Robotic Harvesting Systems

Sensors

Recognition and 3D positional estimation of apples during harvesting from a robotic platform in a... more Recognition and 3D positional estimation of apples during harvesting from a robotic platform in a moving vehicle are still challenging. Fruit clusters, branches, foliage, low resolution, and different illuminations are unavoidable and cause errors in different environmental conditions. Therefore, this research aimed to develop a recognition system based on training datasets from an augmented, complex apple orchard. The recognition system was evaluated using deep learning algorithms established from a convolutional neural network (CNN). The dynamic accuracy of the modern artificial neural networks involving 3D coordinates for deploying robotic arms at different forward-moving speeds from an experimental vehicle was investigated to compare the recognition and tracking localization accuracy. In this study, a Realsense D455 RGB-D camera was selected to acquire 3D coordinates of each detected and counted apple attached to artificial trees placed in the field to propose a specially design...

Research paper thumbnail of Pulse-Width-Modulation Control of a Heat Pump Dryer with Cascade Evaporators and Parallel-Flow Condensers

Tropical Agricultural Research, 2021

Heat pump drying systems require a method to change the inflow air temperature of the drying cham... more Heat pump drying systems require a method to change the inflow air temperature of the drying chamber. Pulse-widthmodulation (PWM) technique with duty cycle provides a measure of controlling the voltage supplied to the electric motors. Therefore, we conducted this research to PWM control a heat pump dryer to change the air circuit parameters. In the Parallel-Flow condensers, inlet and outlet temperatures, and relative humidity, data were collected, and the average temperature values were recorded. The duty cycle was changed by developing a program using the Python programming language. An Excel-based psychrometric calculator was developed to analyze the collected data. The average condenser outlet temperatures were 56.6±0.1 ℃, 54.9±0.1 ℃, and 52.6±0.1℃, and the average condenser inlet temperatures were 43.2±0.0 ℃, 42.8±0.1 ℃, and 41.2±0.1 ℃ for 60%, 80%, and 100% duty cycles, respectively. The power consumption rate of the condenser reduced with an increasing duty cycle. The results concluded that the PWM control system is a viable method to control the inflow air temperature to the drying chamber.

Research paper thumbnail of Industrial Robotic Arm for Chilli Milling Process

Regular, 2020

Chilli (Capsicum annuum), one of the essential ingredients in Sri Lankan cuisine, is widely culti... more Chilli (Capsicum annuum), one of the essential ingredients in Sri Lankan cuisine, is widely cultivated for producing dried chilli. The narrow conical-shaped chilli pods with wrinkled surface do not support much of the existing common mechanical feeding systems such as augers or bucket conveyorsin the chilli processing plants. Therefore, the objective of this study is to design and develop a robotic arm with a proper grabbing technique to feed chilli into the grinding mill. Furthermore, it is intended to install the developed robotic arm in an industrial level processing plant to test the feasibility of theindustrial application.The industrial robot designed in this study is primarily composed of three parts: the base, the arm and the wrist. These components connect with joints to form a unit. At the end of the wrist, an end-effector, which is a gripper for grasping chilli pods, is located.ATmega328 microcontroller, micro switches and DC motors were used to operate the robotic arm. T...

Research paper thumbnail of Development of a 3D Printed New Metering Mechanism for a Multi-Crop Seed Broadcasting System Using an Autonomous Small-Scale Vehicle

Inventions

Developing countries in Asia widely use manual seed broadcasting methods due to a lack of appropr... more Developing countries in Asia widely use manual seed broadcasting methods due to a lack of appropriate seeding machinery. The agricultural sector is currently facing labor shortages and high labor costs, especially seasonal labor shortages for broadcasting and transplanting operations. However, the primary constraint in adopting existing broadcasting seeders for small-scale farmers in developing countries is the high initial purchase costs. Therefore, developing locally commercial accessible technology for small-scale farmers is an urgent requirement. In this regard, attempt was taken to develop a new low-cost 3D printed seeder that can be used for multi-crop seed broadcasting operations when integrated with an autonomous terrain vehicle. A new seed metering mechanism was proposed for seed broadcasting that can be controlled electronically from the autonomous terrain vehicle. Positional sensors based on the real time kinematics—global navigation satellite system (RTK-GNSS) were used ...

Research paper thumbnail of Autonomous Robots in Orchard Management: Present Status and Future Trends

IoT and AI in Agriculture, 2023

Research paper thumbnail of IoT × AI: Introducing Agricultural Innovation for Global Food Production

IoT and AI in Agriculture, 2023

Research paper thumbnail of Recognition and Counting of Apples in a Dynamic State Using a 3D Camera and Deep Learning Algorithms for Robotic Harvesting Systems

Sensors

Recognition and 3D positional estimation of apples during harvesting from a robotic platform in a... more Recognition and 3D positional estimation of apples during harvesting from a robotic platform in a moving vehicle are still challenging. Fruit clusters, branches, foliage, low resolution, and different illuminations are unavoidable and cause errors in different environmental conditions. Therefore, this research aimed to develop a recognition system based on training datasets from an augmented, complex apple orchard. The recognition system was evaluated using deep learning algorithms established from a convolutional neural network (CNN). The dynamic accuracy of the modern artificial neural networks involving 3D coordinates for deploying robotic arms at different forward-moving speeds from an experimental vehicle was investigated to compare the recognition and tracking localization accuracy. In this study, a Realsense D455 RGB-D camera was selected to acquire 3D coordinates of each detected and counted apple attached to artificial trees placed in the field to propose a specially design...

Research paper thumbnail of Pulse-Width-Modulation Control of a Heat Pump Dryer with Cascade Evaporators and Parallel-Flow Condensers

Tropical Agricultural Research, 2021

Heat pump drying systems require a method to change the inflow air temperature of the drying cham... more Heat pump drying systems require a method to change the inflow air temperature of the drying chamber. Pulse-widthmodulation (PWM) technique with duty cycle provides a measure of controlling the voltage supplied to the electric motors. Therefore, we conducted this research to PWM control a heat pump dryer to change the air circuit parameters. In the Parallel-Flow condensers, inlet and outlet temperatures, and relative humidity, data were collected, and the average temperature values were recorded. The duty cycle was changed by developing a program using the Python programming language. An Excel-based psychrometric calculator was developed to analyze the collected data. The average condenser outlet temperatures were 56.6±0.1 ℃, 54.9±0.1 ℃, and 52.6±0.1℃, and the average condenser inlet temperatures were 43.2±0.0 ℃, 42.8±0.1 ℃, and 41.2±0.1 ℃ for 60%, 80%, and 100% duty cycles, respectively. The power consumption rate of the condenser reduced with an increasing duty cycle. The results concluded that the PWM control system is a viable method to control the inflow air temperature to the drying chamber.

Research paper thumbnail of Industrial Robotic Arm for Chilli Milling Process

Regular, 2020

Chilli (Capsicum annuum), one of the essential ingredients in Sri Lankan cuisine, is widely culti... more Chilli (Capsicum annuum), one of the essential ingredients in Sri Lankan cuisine, is widely cultivated for producing dried chilli. The narrow conical-shaped chilli pods with wrinkled surface do not support much of the existing common mechanical feeding systems such as augers or bucket conveyorsin the chilli processing plants. Therefore, the objective of this study is to design and develop a robotic arm with a proper grabbing technique to feed chilli into the grinding mill. Furthermore, it is intended to install the developed robotic arm in an industrial level processing plant to test the feasibility of theindustrial application.The industrial robot designed in this study is primarily composed of three parts: the base, the arm and the wrist. These components connect with joints to form a unit. At the end of the wrist, an end-effector, which is a gripper for grasping chilli pods, is located.ATmega328 microcontroller, micro switches and DC motors were used to operate the robotic arm. T...