Robotic Specialization in Autonomous Robotic Structural Assembly

Robotic in-space assembly of large space structures is a long-term NASA goal to reduce launch costs and enable larger scale missions. Recently, researchers have proposed using discrete lattice building blocks and co-designed robots to build high-performance, scalable primary structure for various on-orbit and surface applications. These robots would locomote on the lattice and work in teams to build and reconfigure building-blocks into functional structure. However, the most reliable and efficient robotic system architecture, characterized by the number of different robotic 'species' and the allocation of functionality between species, is an open question. To address this problem, we decompose the robotic building-block assembly task into functional primitives and, in simulation, study the performance of the the variety of possible resulting architectures. For a set consisting of five process types (move self, move block, move friend, align bock, fasten block), we describe a method of feature space exploration and ranking based on energy and reliability cost functions. The solution space is enumerated, filtered for unique solutions, and evaluated against energy and reliability cost functions for various simulated build sizes. We find that a 2 species system, dividing the five mentioned process types between one unit cell transport robot and one fastening robot, results in the lowest energy cost system, at some cost to reliability. This system enables fastening functionality to occupy the build front while reducing the need for that functional mass to travel back and forth from a feed station. Because the details of a robot design affect the weighting and final allocation of functionality, a sensitivity analysis was conducted to evaluate the effect of changing mass allocations on architecture performance. Future systems with additional functionalities such as repair, inspection, and others may use this process to analyze and determine alternative robot architectures

Autonomous In-Orbit Satellite Assembly from a Modular Heterogeneous Swarm

This paper presents a decentralized, distributed guidance and control scheme to combine a heterogeneous swarm of component satellites into a large satellite structure. The component satellites for the heterogeneous swarm are chosen to promote flexibility in final shape inspired by crystal structures and Islamic tile art. After the ideal fundamental building blocks are selected, basic nanosatellite-class satellite designs are made to assist in simulations involving attitude control. The Swarm Orbital Construction Algorithm (SOCA) is a guidance and control algorithm to allow for the limited type heterogeneity and docking ability required for in-orbit assembly. The algorithm consists of two parts, a distributed auction which uses barrier functions to ensure the proper agent selection for each target, and a trajectory generation portion which leverages model predictive control and sequential convex programming to achieve optimal collision-free trajectories to the desired target point even with nonlinear system dynamics. The optimization constraints use a boundary layer to determine whether the collision avoidance or the docking constraints should be applied. The algorithm was tested in a simulated perturbed 6-DOF spacecraft dynamic environment for planar and out-of-plane final structures and on two robotic platforms, including a swarm of frictionless spacecraft simulation robots

Design agency:prototyping multi-agent systems in architecture

This paper presents research on the prototyping of multi-agent systems for architectural design. It proposes a design exploration methodology at the intersection of architecture, engineering, and computer science. The motivation of the work includes exploring bottom up generative methods coupled with optimizing performance criteria including for geometric complexity and objective functions for environmental, structural and fabrication parameters. The paper presents the development of a research framework and initial experiments to provide design solutions, which simultaneously satisfy complexly coupled and often contradicting objectives. The prototypical experiments and initial algorithms are described through a set of different design cases and agents within this framework; for the generation of façade panels for light control; for emergent design of shell structures; for actual construction of reciprocal frames; and for robotic fabrication. Initial results include multi-agent derived efficiencies for environmental and fabrication criteria and discussion of future steps for inclusion of human and structural factors

Structure Assembly by a Heterogeneous Team of Robots Using State Estimation, Generalized Joints, and Mobile Parallel Manipulators

Autonomous robotic assembly by mobile field robots has seen significant advances in recent decades, yet practicality remains elusive. Identified challenges include better use of state estimation to and reasoning with uncertainty, spreading out tasks to specialized robots, and implementing representative joining methods. This paper proposes replacing 1) self-correcting mechanical linkages with generalized joints for improved applicability, 2) assembly serial manipulators with parallel manipulators for higher precision and stability, and 3) all-in-one robots with a heterogeneous team of specialized robots for agent simplicity. This paper then describes a general assembly algorithm utilizing state estimation. Finally, these concepts are tested in the context of solar array assembly, requiring a team of robots to assemble, bond, and deploy a set of solar panel mockups to a backbone truss to an accuracy not built into the parts. This paper presents the results of these tests

Are Autonomous Mobile Robots Able to Take Over Construction? A Review

Although construction has been known as a highly complex application field for autonomous robotic systems, recent advances in this field offer great hope for using robotic capabilities to develop automated construction. Today, space research agencies seek to build infrastructures without human intervention, and construction companies look to robots with the potential to improve construction quality, efficiency, and safety, not to mention flexibility in architectural design. However, unlike production robots used, for instance, in automotive industries, autonomous robots should be designed with special consideration for challenges such as the complexity of the cluttered and dynamic working space, human-robot interactions and inaccuracy in positioning due to the nature of mobile systems and the lack of affordable and precise self-positioning solutions. This paper briefly reviews state-ofthe-art research into automated construction by autonomous mobile robots. We address and classify the relevant studies in terms of applications, materials, and robotic systems. We also identify ongoing challenges and discuss about future robotic requirements for automated construction

Distributed Spatial Control and Global Monitoring of Mobile Agents

In this paper, we combine two frameworks in the context of an important application. The first framework, called artificial physics , is described in detail in a companion paper by Spears and Gordon (1999). The purpose of artificial physics is the distributed spatial control of large collections of mobile physical agents. The agents can be composed into geometric patterns (e.g., to act as a sensing grid) by having them sense and respond to local artificial forces that are motivated by natural physics laws. The purpose of the second framework is global monitoring of the agent formations developed with artificial physics. Using only limited global information, the monitor checks that the desired geometric pattern emerges over time as expected. If there is a problem, the global monitor steers the agents to self-repair. Our combined approach of local control through artificial physics, global monitoring, and steering for self-repair is implemented and tested on a problem where multiple agents from a hexagonal lattice pattern

Interpreting parametric-biomimicry design from cad тo bim software: digital modelling based on a sketch of nandi flame

This research represents an application of two digital modelling softwares, first digital modelling software, chosen as representative of Computer-Aided Design – CAD modelling tool was Fusion 360. The representative of Building Information Modelling (BIM) as second digital modelling software was ArchiCAD. The aim of the research was to translate the same parametric-biomimicry design methodology used in CAD process modelling into BIM environment. African species Spathodea campanulata P. Beauv, whose common name in Kenya is Nandi flame, has been selected for the purpose of this digital modelling processes. As one of the most spectacular flowering plants, Nandi flame is indigenous to the tropical dry forests in Kenya. The decorative flower of this species was the basic model, more precisely the botanical sketches of the flower. This sketches were implemented into digital modelling softwares and used for parametric modelling. The results of this processes were represented as urban models or installations (landscape-architectural elements) in open space. This approach of digitally generating conceptual solutions from nature elements has capability to boost the formulation of new creative inventions in the different fields. The unique geometric patterns found in the flower of Spathodea campanulata P. Beauv served as a good example of how we may transform these ideas into actual design installations– using CAD or BIM software tools. This research has been carried out with the aim to find the position of BIM tools in parametric biomimicry design