Research Papers - Department of Mechanical Engineering
Permanent URI for this collectionhttps://rda.sliit.lk/handle/123456789/604
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Publication Embargo An Embedded System for a High-Speed Manipulator With Single Time Scale Visual Servoing(American Society of Mechanical Engineers, 2017-07-01) Liyanage, M. H; Krouglicof, NThis study presents the development of an embedded system for controlling a high-speed robotic manipulator. Three different types of controllers including hardware proportional derivative (PD), software PD, and single time scale visual servoing are considered in this study. Novel field programmable gate array (FPGA) technology was used for implementing the embedded system for faster execution speeds and parallelism. It is comprised of dedicated hardware and software modules for obtaining sensor feedback and control signal (CT) estimation, providing the control signal to the servovalves. A NIOS II virtual soft processor system was configured in the FPGA for implementing functions that are computationally expensive and difficult to implement in hardware. Quadrature decoding, serial peripheral interface (SPI) input and output modules, and control signal estimation in some cases was carried out using the dedicated hardware modules. The experiments show that the proposed controller performed satisfactory control of the end effector position. It performed single time scale visual servoing with control signal updates at 330 Hz to control the end effector trajectory at speeds of up to 0.8 ms1 . The FPGA technology also provided a more compact single chip implementation of the controller.Publication Embargo Optimization of controller gains for FPGA-based multivariable motion controller using response surface methodology(IEEE, 2015-05-03) Sekaran, H. P; Liyanage, M. H; Krouglicof, NField Programmable Gate Arrays (FPGA) have become increasingly popular in recent years for control applications. Using contemporary FPGA technology, a powerful virtual processor can be synthesized and integrated with custom hardware to create a dedicated controller that outperforms conventional microcontroller and microprocessor based designs. The FPGA based controller takes advantage of both hardware features and virtual processor technology. This study details the development of a cascaded type PD controller for an inverted pendulum system implemented on a single FPGA device. The controller includes a hardware based implementation of the IO modules including quadrature decoders/counters and a Pulse Width Modulation (PWM) controller for the motor driver. The NIOS II processor was synthesized to implement the cascaded PID controller algorithm. This study also proposes a novel method for obtaining the optimal controller gains for the system. It uses the Central Composite Design (CCD) in Response Surface Methodology (RSM) for obtaining these gains. A classic inverted pendulum system was selected to demonstrate the applicability of the proposed approach. The gains provided by the RSM were verified experimentally to validate the proposed controller tuning method.Publication Embargo A single time scale visual servoing system for a high speed SCARA type robotic arm(IEEE, 2014-05-31) Liyanage, M. H; Krouglicof, NA high speed image based visual servoing (VS) technique is developed in this study for a Selective Compliant Assembly Robotic Arm (SCARA) manipulator with rotary hydraulic actuators. This study has developed a 2D position measuring system which comprise a high speed camera with a position sensitive detector as the image sensor. The input output interface and the controller for the VS system was implemented using a field programmable gate array (FPGA) providing a single chip solution for the embedded system. This camera was capable of providing position measurements of the end effector (EE) with an accuracy of up to 0.95 mm at a frequency of 1340 Hz. The proposed control strategy produced a better tracking performance with an EE payload of 12 kg with speeds of up to 1.3 m/s.Publication Embargo High speed electro-hydraulic actuator for a scara type robotic arm(IEEE, 2010-10-18) Liyanage, M. H; Krouglicof, N; Gosine, RThis study details the development of a high performance servo-hydraulic actuator for a Selective Compliant Assembly Robotic Arm (SCARA). The arm is intended for high speed food processing applications; specifically on-line poultry deboning. The system is mathematically modeled and simulated. Based on the simulation results, the hydraulic actuators are sized for optimal performance. A prototype actuator is subsequently designed, manufactured and experimentally evaluated. The tests results demonstrate that the prototype actuator is capable of producing unprecedented torques and associated accelerations relative to its size and mass. Comparable performance is not feasible with contemporary electrical actuators of similar size.Publication Embargo Development and testing of a novel high speed SCARA type manipulator for robotic applications(IEEE, 2011-05-09) Liyanage, M. H; Krouglicof, N; Gosine, RThis paper proposes using servo hydraulics for high speed robotic manipulation. It details the development of a novel double vane rotary type actuator custom designed for use in a Selective Compliant Assembly Robotic Arm (SCARA). The system, which is mathematically modeled and simulated, consists of an electro-hydraulic servo valve, double vane rotary actuator, manipulator and a controller. Based on the simulation results, hydraulic actuators were sized for optimal performance. A prototype of the proposed manipulator was built and tested. The test results show that the proposed actuator is capable of reaching torques of up to 860 Nm. The end effector of the manipulator is capable of reaching average velocities in excess of 2.7 ms -1 with a payload capability of 5.3 kg. Comparable performance is not feasible with contemporary SCARA type robots with electric motors.Publication Embargo Design and control of a high performance SCARA type robotic arm with rotary hydraulic actuators(IEEE, 2009-05-03) Liyanage, M. H; Krouglicof, N; Gosine, RThis study proposes a selective compliant assembly robotic arm (SCARA) with two revolute joints for poultry deboning. The joints of the arm are based on two high performance rotary type hydraulic actuators. These actuators are operated by servo valves, which control hydraulic fluid flow and direction. A PID based independent joint control system is considered for controlling the position of each joint. The system was modelled using the MATLAB-SIMULINK toolbox. The simulation results show that the arm was capable of covering a work envelope of 0.9 m times 0.9 m, reaching controlled velocities of up to 7.5 m/s with an average of 5.8 m/s. Obtaining such high speeds and torques would be a difficult task with electrical actuators of the capacity as the hydraulic counterparts considered here.