Fig 6 - uploaded by Jakub Lengiewicz

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# A scheme of the internal data organization in a module. Send and receive message boxes are denoted by S t i and R t i , respectively, for each direction i = 0, 1, 2, 3.

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Module localization is an important aspect of the operation of self-reconfigurable robots. The knowledge of spatial positions of modules, or at least of the overall shape which the modules form, is the usual prerequisite for reconfiguration planning. We present a general, decentralized algorithm for determining the positions of modules placed on a...

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**Context 1**

... proposed internal localization algorithm is presented in Fig. 7. It assumes that each module can store individual state variables, grouped into the respective data structures, as depicted in Fig. 6, where C m,t is a list of possible coordinates of the module m at time step t, R m,t i is a list of possible pairs {p, q} of coordinates taken from the i-th neighbor, and S m,t i is a list of possible pairs {p, q} of coordinates that is to be sent to the i-th neighbor at the next time step; see further explanation for details. It also ...

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... The goal is to transform the ensemble from the initial to the final shape using the mechanisms introduced in Sect. 2. Remark The subdivision of space into discrete cells requires from each meta-module of a robot to determine its position in the system, which must be done in a distributed manner (the so-called internal localization problem). As discussed in Hołobut et al. (2016), it may in general pose a difficult task, but it greatly simplifies if the meta-structure of the present kind is considered. ...

We propose a methodology of planning effective shape shifting and locomotion of large-ensemble modular robots based on a cubic lattice. The modules are divided into two groups: fixed ones, that build a rigid porous frame, and mobile ones, that flow through the frame.Mobile modules which flow out of the structure attach to the frame, advancing its boundary. Conversely, a deficiency of mobile modules in other parts of the boundary is corrected by decomposition of the frame. Inside the structure, appropriate module flow is arranged to transport the modules in a desired direction, which is planned by a special distributed version of a maximum flow search algorithm. The method engages a volume of modules during reconfiguration, which is more efficient than common surface-flow approaches. Also, the proposed interpretation as a flow in porous media with moving boundaries seems particularly suitable for further development of more advanced global reconfiguration scenarios. The theoretical efficiency of the method is assessed, and then partially verified by a series of simulations. The method can be possibly also applied to a wider class of modular robots, not necessarily cubic-lattice-based.
Full text: http://rdcu.be/HbA4

... • Modules can store information and compute. Fig. 1; we disregard the orientation-detection problems discussed in [20]). • Modules know (can sense or have a good model of) forces acting on them. ...

We discuss selected mechanical aspects of self-reconfiguration of densely-packed modular robots. The change of connection topology and transport of modules are fundamental mechanisms for these systems, which determine their desired emergent behavior, e.g., movement, shape change or interaction with their surroundings. At the same time, reconfiguration affects the forces between modules. We present a distributed procedure by which a robot can predict if the next planned reconfiguration step will overstress intermodular connections. We use a Finite Element model of a modular robot, with one-node-per-module discretization and beam elements representing intermodular connections. The analysis is restricted to static loads and linear elasticity. We present a distributed procedure of aggregation of the stiffness matrix and iterative solution of the resulting equations of elasticity. The procedure is illustrated with numerical examples and analyzed in terms of its efficiency.

... The goal is to transform the ensemble from the initial to the final shape using the mechanisms introduced in Sect. 2. Remark The subdivision of space into discrete cells requires from each meta-module of a robot to determine its position in the system, which must be done in a distributed manner (the so-called internal localization problem). As discussed in Hołobut et al. (2016), it may in general pose a difficult task, but it greatly simplifies if the meta-structure of the present kind is considered. ...

We propose a new class of modular-robotic structures, intended to produce forces which scale with the number of modules. We adopt the concept of a spherical catom and extend it by a new connection type which is relatively strong but static. We examine analytically and numerically the mechanical properties of two collective-actuator designs. The simulations are based on the discrete element method, with friction and elastic deformations taken into account. One of the actuators is shown to generate forces proportional to its volume. This property seems necessary for building modular structures of useful strength and dimensions.