Mohan Rajesh Elara

Exploration of adaptive gait patterns with a reconfigurable linkage mechanism

Legged robots are able to move across irregular terrains and some can be energy efficient, but are often constrained by a limited range of gaits which can limit their locomotion capabilities considerably. This paper reports a reconfigurable design approach to robotic legged locomotion that produces a wide variety of gait cycles, opening new possibilities for innovative applications. In this paper, we present a distance-based formulation and its application to solve the position analysis problem of a standard Theo Jansen mechanism. By changing the configuration of a linkage, our objective in this study is to identify novel gait patterns of interest for a walking platform. The exemplary gait variations presented in this work demonstrate the feasibility of our approach, and considerably extend the capabilities of the original design to not only produce novel cum useful gait patterns but also to realize behaviors beyond locomotion.

On a Jansen leg with multiple gait patterns for reconfigurable walking platforms

Legged robots are able to move across irregular terrains and those based on 1-degree-of-freedom planar linkages can be energy efficient, but are often constrained by a limited range of gaits which can limit their locomotion capabilities considerably. This article reports the design of a novel reconfigurable Theo Jansen linkage that produces a wide variety of gait cycles, opening new possibilities for innovative applications. The suggested mechanism switches from a pin-jointed Grübler kinematic chain to a 5-degree-of-freedom mechanism with slider joints during the reconfiguration process. It is shown that such reconfigurable linkage significantly extend the capabilities of the original design, while maintaining its mechanical simplicity during normal operation, to not only produce different useful gait patterns but also to realize behaviors beyond locomotion. Experiments with an implemented prototype are presented, and their results validate the proposed approach.

Hinged-Tetro: A self-reconfigurable module for nested reconfiguration

Nested reconfiguration is an emerging research area in modular robotics. Such a novel design concept utilizes individual robots with distinctive reconfiguration characteristics (intra-reconfigurability) capable of combining with other homogeneous/heterogeneous robots (inter-reconfigurability). The objective of this approach is to generate more complex morphologies for performing specific tasks that are far from the capabilities of a single module or to respond to programmable assembly requirements. The two-level reconfiguration process in nested reconfigurable robotic system implies several technical challenges in hardware design, planning algorithms, and control strategies. In this paper, we discuss the theory, concept, and initial mechanical design of Hinged-Tetro, a self-reconfigurable module conceived for the study of nested reconfiguration. Hinged-Tetro is a mobile robot that uses the principle of hinged dissection of polyominoes to transform itself into any of the seven one-sided tetrominoes, the Tetris pieces, in a straightforward way. The robot can also combine with other modules for shaping complex structures or giving rise to a robot with new capabilities. Some preliminary experiments of intra-reconfigurability with an implemented prototype are presented.

Energy Based Position Control of Jansen Walking Robot

Theo Jansen mechanism is gaining attention among legged robotics researchers due to its scalable design, energy efficiency, low payload to machine load ratio, bio-inspired locomotion, and deterministic foot trajectory. In this paper, we present a novel position control strategy for Jansen walking robot derived using projection method for which energy based control forms the core. Numerical simulations are done to validate the efficacy of the designed controller. This work identifies an appropriate controller gain that decreases the overshoot necessary for successful real world deployments.

ON THE REDEFINITION OF FAN OUT METRIC FOR HUMAN ROBOT INTERACTIONS WITH HUMANOID SOCCER ROBOTS

Fan out (FO) is adopted as a general index among human robot interaction researchers in predicting the maximum number of robots a single operator can handle simultaneously while maintaining performance at acceptable levels. Neglect tolerance model forms the basis for FO metric that assumes ideal conditions wherein the operator switches control between robots sequentially based on acceptable performance ignoring any false alarms due to erroneous interactions. In this article, we redefine the FO metric to account for any additional demands due to the occurrence of false alarms, as these additional demands could lead to task failure. Experiments with our virtual and real humanoid soccer robots across tele-operation and semi-autonomous modes of autonomy showed significant drop in FO predictions with inclusion of demands due to false alarms for all experimental cases.

Design principles for robot inclusive spaces: a case study with roomba

Research focus on service robots that deals with applications related to healthcare, logistics, residential, search and rescue are gaining significant momentum in the recent years. Their social and economic relevance is more than evident. Yet, while much has been researched about “designing robots” focusing on sensing, actuation, mobility and control of service robots, little work has been done on “design for robots” that looks at designing preferred artefacts or environments for such robots. In this work, we propose a new philosophy of robot inclusive spaces, a cross disciplinary approach that brings together roboticians, architects and designers to solve numerous unsettled research problems in robotics community through design of inclusive interior spaces for robots where the latter live and operate. With a residential floor cleaning robot as a case study, we inductively derived a set of four design principles namely observability, accessibility, activity and safety that guides the realization of an inclusive space for these service robots. Also, the suggested principles are further defined, analysed and validated for their merits in this paper.

Observer-based state estimation of snake-like robot with rotational elastic actuators

The long-term goal of this study is to realize a locomotion control for snake-like robots on various environments. A key point for the locomotion control is the normal direction friction force of each link of the robot. Because, a real snake can locomote by utilizing the difference of frictions in the propulsive and in the normal direction. In previous our study, a locomotion control of the snake-like robot considering side-slipping has been proposed. However, there are some problems to realize the control by a real machine. As the problems, all state of the snake-like robot is supposed to be observed, and computational load of the control law is too large to be real-time. To solve these problems, this paper aims to develop a state estimation of the snake-like robot in consideration of side-slipping by utilizing an observer. Moreover, a rotational elastic actuator consisting of a motor and a spring is installed for the robot to adapt to various environments. Motion equations of the snake-like robot with rotational elastic actuators and side-slipping effect are derived. Constraint forces of the normal direction of each link are also formulated in the modeling process. A type-I observer based on State Dependent Riccati equation: SDRE is utilized to detect a slipping link of the robot. This detection is based on the generalized coordinate of the robot link estimated by the observer. Numerical simulations are given to verify the effectiveness of the proposed method.

Virtual game approach for rehabilitation in autistic children

With the changes in diagnostic procedures and public awareness, the number of individuals diagnosed with autism are rising dramatically in recent years. This project presents virtual games developed as an augmentative aid to engage autistic students in rehabilitative and academic training. It is an attempt to show the cost effectiveness, safety and time-efficiency of building a platform for pilot study, using virtual agent and robot without any hardware. Following an iterative and incremental model for software development life cycle, an interactive quiz programme which employs virtual avatar to pose academic related questions to autistic students is developed. Additionally, drawing on a Sumo wrestling game using robotics agent iRobot Create to hone motor skill is evaluated. Experiments conducted at a Singapore-based autistic school with a sample of nine students had garnered a mixed result. The degree of assistance required to guide them through the game can range from minimal to gesture and contact guidance. Experimental results showed that the deployment of virtual games hold great potential in motivating and exciting the children in their learning process, as well as providing valuable insights to related rehabilitative industries.

Effects of Adapted Model-Rival Method and parrot-inspired robot in improving learning and social interaction among children with autism

Educating children with autism is becoming a highly challenging task due to the nature of the disorder and limited interest of these children in interacting with people. Nevertheless, it is observed that most of the children with autism are good observers. This paper put forward and evaluates a novel teaching technique, Adapted Model-Rival Method (AMRM and a parrot-inspired robot for children with autism to help improve learning and social interaction abilities through qualitative and quantitative analysis. We begin by discussing various medications, therapy, and teaching methods used in treating autism and emphasizing the importance and benefits of implementing an indirect teaching method. We then present our novel indirect teaching method, AMRM and the benefits of using a parrot-inspired robot as an intervention tool. Finally, we discuss the results of our study conducted for five consecutive days with nine participants.

Experimental evaluation of parrot-inspired robot and adapted model-rival method for teaching children with autism

The use of biologically inspired robots in therapeutic settings could offer new possibilities for improving learning and social interaction abilities of children with autism. This paper introduces a novel teaching method, Adapted Model-Rival Method, together with a parrot-inspired robot (KiliRo) to help children with autism in learning and social interaction. The proposed indirect teaching method and the parrot-like robot morphology were tested with 9 children identified with autism. The test was conducted for 5 consecutive days for the same participants at the same place. In this study, the emotions of participating children during the experiment were analyzed using an automated emotion recognition and classification system, Oxford emotion API through facial images. Totally, 580 pictures were taken to obtain 2360 individual facial emotion values for evaluation. The results show that the happiness of subjects improved from day 1 through day 5 of the study through interacting with the robot. It is also reported that the participating children were attracted to the robot when it was exhibiting its learning abilities. Our study also indicates that the children with autism are not afraid of parrot-like robots and are happy to interact with it.