Design and Development of a Vision System Interface for Three Degree of Freedom Agricultural Robot

In this study, a vision system interfaced 3DOF agricultural harvester robot was designed, developed and tested. The robot was actuated by hydraulic power for heavy tasks such as picking and harvesting oil palm FFB. The design was based on the task of that robot, the type of actuators and on the overall size. Attention was given to the stability, portability and kinematic simplicity in relation to the hydraulic actuators. The derivation of the kinematic model was based on the Matrix Algebra for the forward kinematics, and the inverse kinematics problem was based on analytical formulation. The D-H representation was used to carry out the coordinates of the end-effector as the function of the joint angles. The joint angles of the robot were computed as the function of the end-effector coordinates to achieve the inverse kinematic model. A mathematical model that related the joint angles and the actuators length was derived using geometric and trigonometric formulations. A differential system was derived for the manipulator. This differential system represents the dynamic model, which describes relationships between robot motion and forces causing that motion. The Lagrange-Euler formulation with the D-H representation was applied to formulate the differential system. The importance of the derivation of the kinematic model arises in the development of the control strategy. While the derivation of the dynamic model helps in real time simulation. The robot was enhanced by a CCD camera as a vision sensor to recognise red object as a target. Red object was to exemplify the matured oil palm FFB . The recognition process was achieved by using C++ programming language enhanced by MIL functions. An algorithm based on empirical results was developed in order to convert the target coordinates from the image plane (pixel) into the robot plane (cm). The image plane is two-dimensional while the robot plane is three-dimensional. Thus at least one coordinate of the target in the robot plane should be known. An Interface program has been developed using Visual Basics to control and simulate 2D motion of the manipulator

Simulation of a four-car elevator operation using MATLAB

The design and simulation of a four-cars-elevator controller in a nine storey building is described in this paper. The design and simulation were accomplished using MATLABTM fuzzy logic toolbox. The logic of the controller of a multi-car elevator has to be designed in such a way that the average waiting time is minimized while keeping the energy consumption of the system optimum. This is a multi-criteria optimization problem in stochastic environment and is best approached through Artificial Intelligent techniques. The work here focuses mainly on extracting the rules to minimize factors (i.e. waiting time, travelled distance and riding time) in order to minimize the energy consumed by the system. In this paper a detailed algorithm is presented to achieve the multiple objectives of minimizing the waiting time and the distance travelled simultaneously. This was accomplished by distributing different weightage to different quantities and then minimizing a combined cost. A simulator has been built with interactive GUI in Matlab to evaluate the efficacy of the algorithm

Simulation of a four-car elevator operation using MATLAB

The design and simulation of a four-cars-elevator controller in a nine storey building is described in this paper. The design and simulation were accomplished using MATLABTM fuzzy logic toolbox. The logic of the controller of a multi-car elevator has to be designed in such a way that the average waiting time is minimized while keeping the energy consumption of the system optimum. This is a multi-criteria optimization problem in stochastic environment and is best approached through Artificial Intelligent techniques. The work here focuses mainly on extracting the rules to minimize factors (i.e. waiting time, travelled distance and riding time) in order to minimize the energy consumed by the system. In this paper a detailed algorithm is presented to achieve the multiple objectives of minimizing the waiting time and the distance travelled simultaneously. This was accomplished by distributing different weightage to different quantities and then minimizing a combined cost. A simulator has been built with interactive GUI in Matlab to evaluate the efficacy of the algorithm

Improved Optimal Power Flow for a Power System Incorporating Wind Power Generation by Using Grey Wolf Optimizer Algorithm

In this paper, an efficient Grey Wolf Optimizer (GWO) search algorithm is presented for solving the optimal power flow problem in a power system, enhanced by wind power plant. The GWO algorithm is based on meta-heuristic method, and it has been proven to give very competitive results in different optimization problems. First, by using the proposed technique, the system independent variables such as the generators’ power outputs as well as the associated dependent variables like the bus voltage magnitudes, transformer tap setting and shunt VAR compensators values are optimized to meet the power system operation requirements. The Optimal power flow study is then performed to assess the impact of variable wind power generation on system parameters. Two standard power systems IEEE30 and IEEE57 are used to test and verify the effectiveness of the proposed GWO method. The obtained results are then compared with others given by available optimization methods in the literature. The outcome of the comparison proved the superiority of the GWO algorithm over other meta-heuristics techniques such as Modified Differential Evolution (MDE), Enhanced Genetic Algorithm (EGA), Particle Swarm Optimization (PSO), Biogeography Based Optimization (BBO), Artificial Bee Algorithm (ABC) and Tree-Seed Algorithm (TSA)

Expert system-based approach to automate the design process of power electronics converters

The design of power electronics converters is still an ad-hoc process. Usually, this process is accomplished virtually using existing simulation packages before the real implementation. Despite, the use of these packages, the process is proved to be time consuming and bulky task. This paper describes an expert system approach to ease this cumbersome process by automating the design procedure. The present approach combines expert system techniques with object-oriented paradigm. The designer has firstly to choose the appropriate application of the converter. Then the system suggests the most appropriate (according to the user's specifications) topology that is formed in a schematic file accepted by the Pspice simulation package. The topology is displayed within the Schematic environment containing all the circuit parameters and components including the best (optimum) switching devices and control circuits, here the simulation is launched automatically in order to investigate the outputs. The topologies constitute the knowledge base of the system represented as objects. The switching devices are stored in database module accessed by the inference engine to select the optimum switch for a certain topology. This approach could be a kernel of a power electronics converters design aid tool, whereby the complexity of the design process can be reduced dramatically

Development of a Knowledge-Based System for Power Electronics Design

Various simulation packages are being widely used to design and simulate electrical and electronic circuits. These simulators require the user to be proficient in designing the circuits and need deep training to be familiar with. Moreover, the design is based on trial and error, till the user reaches the required outputs. Despite their long use, the existing general-purpose simulation packages are still time-consuming when they are used to design power converters especially for inexperienced designers. This is because of the ad-hoc nature of the design task. An approach to overcome the drawbacks of these packages and augment their functionality is to incorporate knowledge-based techniques along with these packages. In the present work an approach to automate the design process of power converters is introduced, explained, and implemented. The presented approach integrates object-oriented paradigm within expert system techniques to develop a user-friendly tool; power electronic converters design aid system (PEDAS). Benefiting from the class builder provided in Visual Basic programming language, various class modules with their properties and methods were implemented to constitute the inference engine and represent the knowledge base. Two types of knowledge were investigated; application-based knowledge which was implemented using fourteen (14) classes and subclasses and type based knowledge which was represented by one class having eleven (11) methods. Each topology was represented by either one subclass for the first type or one method for the second type. Additionally, the tool offers an automatic selection of switching devices for a specific converter topology. The selection process is conducted within a switching devices database built for this purpose. Further, this database can be seen as an independent unit where many functions such as searching for or adding, removing devices are provided. In using this tool, the designer has firstly to choose the appropriate application of his/her converter among a given list of applications. Then he/she has to pursue interaction process to input his/her requirements and answer some questions needed for facts insertion in order to come out with the most appropriate topology that meets the entered specifications. The topology suggested for the user is formed in a schematic file accepted by the Pspice simulation package. The topology is then displayed within Schematic environment containing all the circuit parameters including the best (optimum) switching devices and the control circuit. The switching devices are stored in database module accessed by the inference engine to select the optimum switch for a certain topology. General description of the system is presented, its architecture and interaction between its various modules is dealt with in details. Finally, the issue of validating the developed tool is accomplished through many design examples, both software and hardware. The developed system still can be improved, mainly in expanding its knowledge base in its two parts; converter topologies and switching devices

Knowledge-based design aid tool for power electronic converters

Purpose - The paper aims to develop a CAD tool power electronics converters. Design/methodology/approach - Integration of knowledge base techniques with OOP paradigm. Using Visual Basis class builder, 15 classes were built to form the kernel of the tool's KB. Findings - A knowledge-based CAD tool was developed to ease the design of power electronics converters. It can be considered a learning aid tool too. Research limitations/implications - The knowledge base of developed tool can be expanded to accommodate large number of topologies. The GUI can be also ameliorated to a better look and interaction process. Practical implications - With proper enhancements, the purpose of the developed tool can be upgraded from educational one to industrial one. Originality/value - Beside the methodology, the new thing in the paper is the specificity of the application of the tool (i.e. in power electronics)

Dynamic model and control for 3DOF agricultural robot

To endow great capabilities to an agricultural robot for harvesting operations to identify the fruits, a CCD camera mounted on its end-effector and an interfacing system for controlling the process was developed. This paper will discuss on a dynamic model of a 3DOF agricultural robot and control strategy that was used and on the hardware interfacing. The dynamic model is the mathematical formulations of the equations of the robot arm motion. The control strategy depends on the kinematics and dynamic derivation. The purpose of robot arm control is to maintain the dynamic response of the manipulator in accordance with some pre-specified performance criteria. Since hydraulic power is used to actuate the whole arm, the control method is based on the control of the length of linear actuators and of the revolution of the shaft of the rotary actuator according to the position of the end-effector to control the joint angles