Browsing by Author "Abeykoon, S"

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item: Conference-Abstract
3D Environmental force : position impedance variation for different motion parameters
Ruwanthika, RMM; Harsha, AM; Abeykoon, S
The skill preservation of an expert has been a serious problem for countries with aging population because decrease of the number of successors. The concepts of haptic database and force sensor recorder which have been developed recently suggests solutions of using third multimedia type of haptic communication. Haptic information is a bilateral information of the law of action and reaction. The reaction from real world includes not only position and force information but also environmental impedance. In this paper, the behavior of environmental impedance has been studied with the changes of the different motion parameters like applied force, velocity, position and depth on the object 3D space. This idea is exemplified using a rubber balloon and a rubber sponge which is often modeled using simple linear equations. The experimental results show the importance of considering motion parameters when abstracting haptic information for a haptic database. Nonlinear impedance variations against the motion parameters suggest the necessity of adopting complex haptic abstraction techniques.
item: SRC-Report
Position detecting module
Dunuweera, MS; Fonseka, M; Gunasekara, RT; Gunasekara, P; Harcha, AM; Abeykoon, S; Udawatta, L
This invention relates to a method of sensing positions in application such as mobile robotic applications. The main objective of this invention is to overcome certain issues related to position detection mechanisms available in mobile robotic applications and other relevant applications that have position detection methods. Specifically the invention related to moving application to identify its distance traveled with a new optical design to PAN 3101 low cost CMOS optical sensor. PAN 3101 sensor process the images that are taken through the optical design and gives the position in terms of relative distances traveled in vertical and horizontal directions. Microcontroller that utilize this technology. So this module can be used in applications that needs smooth position detection capabilities.
item: Conference-Full-text
Simulation of online human arm inertia estimation for robot-aided rehabilitation
(IEEE, 2018-05) Harischandra, PAD; Harsha, AM; Abeykoon, S; Chathuranga, D
Most of the studies on rehabilitation robots consider the human arm inertia and the gravity torque as system disturbances. Individual anthropometry varies from patient to patient, and therefore human limbs are not modelled. Some studies used the Disturbance Observer (DOB) as a method of disturbance rejection. However, if the inertia and gravity torque parameters of the human arm could be estimated, they could be effectively used in the controller loop to achieve precise motion control. This paper proposes a novel Reaction Torque Observer (RTOB) based estimation technique which updates parameters using learning and recursive algorithms in real-time. The proposed method is applicable to many robot systems where the load inertia or the load is not known. A simulation was carried out with realistic parameters to compare the performance of two competing methods proposed namely, Adaptive Linear Neuron (ADALINE) and Recursive Least Squares (RLS). Results show that the RLS method outperforms the ADALINE method based on the performance criteria of accuracy, precision and convergence speed for estimating the inertia.