International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 04 | Apr 2019 www.irjet.net p-ISSN: 2395-0072 © 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 1317 Comprehensive Review on Modular Self-Reconfigurable Robot Architecture Muhammad Haziq Hasbulah 1 , Fairul Azni Jafar 2 , Mohd. Hisham Nordin 2 1 Centre for Graduate Studies, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2 Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Self-reconfigurable modular robot is a new approach of robotic system which involves a group of identical robotic modules that are connecting together and forming structure that able to perform specific tasks. Such robotic system will allows for reconfiguration of the robot and its structure in order to adapting continuously to the current needs or specific tasks, without the use of additional tools. Nowadays, the use of this type of robot is very limited because it is at the early stage of technology development. This type of robots will probably be widely used in industry, search and rescue purpose or even on leisure activities in the future. Hence, this paper is written in order to review on self- reconfigurable modular robot technology that has been developed to this day for the purpose of the future researcher on this topic. This paper is structured as follows: modular robots hardware architecture, control architecture, modular robot challenges and open-source modular robot (Dtto) review. Key Words: modular, robot, architecture, self- reconfiguration, Dtto, technology, open-source 1. INTRODUCTION Mostly in natural disaster situations for example an earth- quake, we will face a situation where people get trapped and unable to be found as soon as possible due to the unpredictable terrain. Due to that situations, nowadays researchers all over the world work on robotics technology that will give an impact to the search and rescue field. According to Robin Murphy cited by Carol Hamilton, robots are being seen as scouts that able to adapt and perceive; and robot will be small and can fit into small subhuman confines as they able to move as snake throughout rubble [1]. Hence, the idea of modular self-reconfigurable robot (MSR) based on CEBOT in 1988 [2] spark an interest to the researchers to fit the search and rescue purpose. Self-reconfigurable modular robots can also be known as Modular Self-Reconfigurable (MSR) robotic system. Theoretically, MSR robots are able to change their own shape by rearranging the connectivity of their parts to adapt with a new circumstances or tasks. Conceptually, the best example of an MSR robot that shows how this robotic system works would be the robots called “Microbots” from the Big Hero 6 film directed by William Don Hall. In this movie, a character named Hiro create a lot of Microbots that able to be controlled by neurotransmitter. They are designed by Hiro to connect together to form various shapes and perform tasks cooperatively Hall and Williams [3]. The idea of that movie concept is multiple robots that able to change shape in group being controlled by human thought. The MSR robot is build based on the electronics components, computer processors, and memory and power supplies, and also they might have a feature for the robot to have an ability to connect and disconnect themselves to perform various tasks. Having the quality of being “modular”, in MSR robotic system, it is to have a basic intent to have an unrestricted number of identical modules or a specific small set of identical modules, in a mesh or matrix structure of self- reconfigurable modules. The advantage of combining multiple matrices into a single matrix is the ability to form larger or elongated, more complex structure. In the early 1990s, MSR robots were shown to have the ability to perform the task of locomotion. One MSR robot module by itself might not be able to move or locomote by itself, but the collective behaviour of the robots of many modules could move itself from place to place and achieve many different locomotion gaits [4] such as a slinky, caterpillar, or rolling. The development of prototypes for MSR robot derived from experience on basic locomotion. Majority of the module developed is based on available resource at specific time which sometimes restricted MSR capabilities due to slow technology advancements A review on multiple MSR robots hardware architecture in this paper is done so that a better understanding on MSR robot can be achieved with better solutions for MSR robot provided with the latest technologies. It can be generalized that, re- search on modular robots is one of the challenges that provide opportunities in robotics field in term of automation, control, motion planning and the creation of the modular robot itself. 2. MODULAR ROBOT HARDWARE ARCHITECTURE Nowadays, the MSR robots architecture is becoming better along with the technologies. As the first prototype MSR robot being developed called CEBOT, it is consisting of separate heterogenous units that capable of binding together. The