Locomotion Gait Optimization For Modular Robots; Coevolving Morphology and Control

This study aims at providing a control-learning framework capable of generating optimal locomotion patterns for the modular robots. The key ideas are firstly to provide a generic control structure that can be well-adapted for the different morphologies and secondly to exploit and coevolve both morphology and control aspects. A generic framework combining robot morphology, control and environment and on the top of them optimization and evolutionary algorithms are presented. The details of the components and some of the preliminary results are discussed. (C) Selection and peer-review under responsibility of FET11 conference organizers and published by Elsevier B.V

Study of saturable absorber materials for Q-switching dye laser

Q-switching is a technology widely used in lasers to generate short pulses with high peak powers. In practice, Q-switching can be realized with various methods including mechanically by rotating mirror, actively either by acousto-optic or electrooptic method, or passively using a saturable absorber. The first two techniques have their own problems especially the spinning machine and the driver to get a shorter pulse duration. Therefore, passive Q-switch was chosen in this study because it requires less optical element inside the laser cavity and no outside driving circuitry and makes this technique simple and relatively cheaper compared to the other two techniques. Passive Q-switching is a better choice for those applications where compactness of the laser is a prime requirement. The objective of this project is to study and characterize the suitable material to be saturable absorber for passive Q-switching laser. The dye laser was utilized as a source of Q-switching laser. As a preliminary, the laser was calibrated to determine the best performance of laser beam. Various materials including 3, 3’- Diethyloxadicarbocyanine Iodide (DODCI), 1,3'-Diethyl-4, 2’-quinolyloxacarbocyanine Iodide (DQOCI) and 1,1'-Diethyl-4, 4’-carbocyanine Iodide (Cryptocyannine) and Chromium-doped Yttrium Aluminium Garnet (Cr4+: YAG) crystal are employed as a saturable absorber material. The pulse width, the single pulse energy and the peak power of the Q-switched laser output are measured. Two of the tested materials namely 1,3'- Diethyl-4, 2’-quinolyloxacarbocyanine Iodide (DQOCI) and Chromium-doped Yttrium Aluminium Garnet (Cr4+: YAG) crystal demonstrate a good performance to be a saturable absorber. The output characteristics of the passive Q-switch laser possess a uniphase of TEM00 mode

Learning to move in modular robots using central pattern generators and online optimization,”

Abstrac

Roombots: A hardware perspective on 3D self-reconfiguration and locomotion with a homogeneous modular robot

In this work we provide hands-on experience on designing and testing a self-reconfiguring modular robotic system, roombots (rb), to be used among others for adaptive furniture. In the long term, we envision that rb can be used to create sets of furniture, such as stools, chairs and tables that can move in their environment and that change shape and functionality during the day. In this article, we present the first, incremental results towards that long term vision. We demonstrate locomotion and reconfiguration of single and metamodule rb over 3d surfaces, in a structured environment equipped with embedded connection ports. Rb assemblies can move around in non-structured environments, by using rotational or wheel-like locomotion. We show a proof of concept for transferring a roombots metamodule (two in-series coupled rb modules) from the non-structured environment back into the structured grid, by aligning the rb metamodule in an entrapment mechanism. Finally, we analyze the remaining challenges to master the full roombots scenario, and discuss the impact on future roombots hardware

Locomotion through Reconfiguration based on Motor Primitives for Roombots Self-Reconfigurable Modular Robots.

We present the hardware and reconfiguration experiments for an autonomous self-reconfigurable modular robot called Roombots (RB). RB were designed to form the basis for self-reconfigurable furniture. Each RB module contains three degrees of freedom that have been carefully selected to allow a single module to reach any position on a 2-dimensional grid and to overcome concave corners in a 3-dimensional grid. For the first time we demonstrate locomotion capabilities of single RB modules through reconfiguration with real hardware. The locomotion through reconfiguration is controlled by a planner combining the well-known D ⋆ algorithm and composed motor primitives. The novelty of our approach is the use of an online running hierarchical planner closely linked to the real hardware.

An experimental study on the role of compliant elements on the locomotion of the self-reconfigurable modular robots Roombots

This paper presents the results of a study on the exploitation of compliance in structures made of self-reconfigurable modular robots - Roombots. This research was driven by the following three hypotheses: (1) compliance can improve locomotion performance; (2) different types of compliance will result in diverse locomotion behaviors; (3) control parameters optimized for a medium level of compliance will perform better for other values of compliance than parameters optimized for extremal compliance. Two types of in-series compliant elements were tested, with five different stiffness values for each of them, on a structure made of two Roombots modules. We ran dedicated on-line locomotion parameter optimizations for six different configurations and evaluated their performance for different stiffness values. Hypothesis 1 was confirmed for both types of compliant elements, with a peak of performance for an optimal level of compliance. The variety of locomotion strategies obtained for the different structures confirms hypothesis 2. Hypothesis 3 was only partially confirmed