Browsing by Author "Wijewardhana, WMTG"

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item: Conference-Full-text
Analysis of torque sensorless steer by wire system using the bilateral tele-operation concept
(Institute of Electrical and Electronics Engineers, Inc., 2021-09) Senevirathne, EH; Abeykoon, AMHS; Wijewardhana, WMTG; Abeykoon, AMHS; Velmanickam, L
The mechanical linkage of the steering column can ideally be replaced by a bilateral controller-based steer by wire system. This paper presents an intuitive method of designing a bilaterally controlled steer by wire system based on disturbance observers and reaction torque observers. The presented system can overcome the force sensing demerits of traditional force sensors as well as the demerits of existing steer by wire systems based on bilateral control systems. Feedback torque from the steering rack to the steering wheel conveys important data about the road conditions as well as the vehicle conditions to the driver. Hence, accurate feedback to the driver is vital for smooth vehicle handling. The presented method has the capability of tuning the system as per the desire. The validity of the proposed method has been verified through simulations using real-world vehicle and controller data.
item: Conference-Abstract
Interactive learning platform for programmable logic controllers with a web application
Anuradha, KBJ; Wijewardhana, WMTG; Pathirana, APAC; Bandaranayake, AMWKN; Samarakoon, SMPB; Jayasekara, AGBP
Programmable Logic Controllers (PLCs) are one of the most used controllers for automated facilities nowadays. Hence, knowledge of PLC programming and system implementation is essential for automation related education curricula. This paper proposes an Interactive Learning Platform (ILP) for PLCs. The design specifications of the proposed ILP have been identified based on the background study conducted. The proposed ILP for PLCs has been designed using Siemens S7- 1200 as the main controller. An object sorting mechanism that includes diverse types of sensors and actuators is proposed as laboratory exercises that could be performed using the proposed ILP. A web interface has been designed to control the object sorting process. This is the major value addition of the proposed ILP for PLCs compared to the existing learning facilities for PLCs. Simulation has also been carried out using SIMATIC STEP 7 Totally Integrated Automation (TIA) Portal V14 software to validate the operation of the ILP. Furthermore, laboratory exercises and tutorials have been designed to facilitate challenging learning goals. A prototype of the proposed ILP for PLCs has been developed and experiments have been conducted to evaluate the performance of the proposed ILP. Based on the results, the proposed ILP for PLCs facilitates better learning.
item: Conference-Full-text
Study of stability variations in reaction torque observer based force controllers
(IEEE, 2022-07) Wijewardhana, WMTG; Abeykoon, AMHS; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
An effective method for determining the environmental impedance is to use a reaction torque observer (RTOB), which is a variant of the disturbance observer (DOB) concept. A robust yet accurate force controller can be developed by implementing both RTOB and DOB. This study examines the potential instability of force controllers based on RTOB. Traditionally, a RTOB-based force controller is examined under the presumption that the two cut-off frequencies for DOB and RTOB should always be equal to one another. But in some circumstances, it fails to maintain stability. The stability of the system is determined by the interactions between the mechanical, environmental, and controller dynamics, which also add to design constraints. There has not been any analysis of unstable scenarios in terms of system dynamics. In this paper, a novel stability constraint is derived as a result of the new stability assessment approach that is proposed. A new stability guideline is also suggested. The simulation results are used to confirm the validity of the proposals.