Raghavan Kunigahalli

Motion planning for automated construction

Abstract Increasing research and development in the area of construction robotics and computer-aided-construction has resulted in a large number of automated construction equipment applications. Full potential of such construction equipment can be realized by providing the collision avoidance motion planning capabilities. Models used in motion planning can be categorized into two types: (1) planning with complete information and (2) planning with incomplete information. State-of-the-art general algorithms appropriate for the motion planning process are highlighted. Motion planning with complete information is typically NP-complete and hence requires approximate approaches or exploitation of special conditions to generate solutions. Motion planning with incomplete information requires sensory feedback. An algorithm for motion planning in an automated conrete placement operation that exploits the special conditions provided by structural engineering floor design theory is described.

Framework for development of CAD/CAC systems

Abstract This paper provides a framework for the development of Computer-Aided-Design/Computer-Aided-Construction (CAD/CAC) systems. A description of the proposed CAD/CAC systems is provided. The proposed system contains software tools related to (1) conceptual design, (2) structural and foundation analysis, (3) design of structural components, (4) routine geometric, mathematical, and optimization functions, (5) construction management, (6) Computer Aided Process Planning (CAPP), (7) process simulation, and (8) constructability analysis. On-going research work in areas related to CAD/CAC systems are highlighted. Incorporation of Group Technology (GT) paradigm for civil engineering structures to enhance the efficiency and effectiveness of the proposed systems is investigated. Issues related to algorithm development are also discussed. Possible extension of Automatically Programmed Tools (APT) language to include construction industry processes are examined. Specifically, the programming level syntax of APT can be extended by adding construction related vocabulary and features to only two out of five statement types and processor-level syntax can be extended by incorporating additional modular features.

Visibility Graph Approach to Detailed Path Planning in CNC Concrete Placement

An algorithm that employs visibility graph approach to generate a minimal L1-metric obstacle avoidance path in CNC concrete placement is presented . A set of pseudo-obstacles that represent nodes in a relational structure called Rectangle Adjacency Graph (RAG) is introduced during construction of visibility graph. Shrinking of pseudo -obstacles and growing of primary obstacles such as elevator shafts results in an efficient network for generating minimal L1-metric paths from a given source location to a target location in concrete floors. Secondary obstacles such as column bars are avoided using geometric and topological relationships stored in the RAG.

OPSALC: A computer-integrated operations planning system for autonomous landfill compaction☆

Construction workers and operators associated with sanitary waste landfilling operations face significant health risks because of high levels of exposure to harmful solids and gases. Automation of the spreading and compacting processes of a landfilling operation using an autonomous compactor can reduce exposure of workers to the harmful environment, and thereby lead to improved safety of workers. This paper describes a computer-integrated operations planning system that facilitates (1) the design of landfill cells and (2) the generation of area-covering path plans for spreading and compaction processes by the autonomous compactor. The partitioning of a given landfill site into three-dimensional cells is accomplished by a recursive spatial decompostion technique in which the cell sizes are determined using a probabilistic model for waste generation. A recursive sub-division of each cell into monominoes facilitates the system to automatically deal with any differences between the actual amount of waste generated on a particular day and the amount predicted by the probabilistic model. The partitioned configuration of the landfill site is used to generate the path plan for the autonomous compactor using three motion models, namely straight-up, straight-down, and zig-zag. The computer-integrated system is implemented using PHIGS graphics standard and MOTIF toolkit with C-program binding.

Managing multiple construction robots with a computer

Abstract The Construction Robotic Equipment Management System (CREMS) prototype presented in this paper has been applied to the evaluation of performance of ten diverse construction robots. individual task characteristics along with the robot physical parameters have been analyzed in arriving at appropriate effectiveness and productivity parameters. The wall inspection, clean room inspection and concrete placement tasks were analyzed using a uniform analysis procedure. The number of erected units has been the primary focus of beam and column erection evaluation. Consistency and relative density were considered as parameters associated with productivity of a robotic excavation control system. Underground utilities encountered during excavation imposed limits on the speed of progress and interruptions along the delivery path of concrete distribution. These are regarded as major project-specific constraints for these tasks. An example application of CREMS to robotic excavation has been provided.

Concplanner: An Automated Process Planning System for Concrete Construction

This paper presents Concplanner , a Computer Aided Process Planning system capable of generating pictorial construction process plans for automated concrete construction. Concplanner provides an efficient userinterface by adopting interactive computer graphic programming techniques. International Standards Organization computer graphic functional interface standard PHIGS has been employed to: (1) obtain graphical input through logical input devices and (2) display pictorial construction process plans. An additional capability of generating an obstacle avoidance path plan for automated concrete placement has also been incorporated into the system. The output corresponding to obstacle avoidance path plan can be used to provide equipment-level instructions to Computer Numerically Controlled concrete

Motion Planning for Automated Construction

Increasing research and development in the area of construction robotics and computer -aided -construction has resulted in a large number of automated construction equipment applications . Full potential of such construction equipment can be realized by providing the collision avoidance motion planning capabilities . Models used in motion planning can be categorized into two types : ( 1) planning with complete information and (2) planning with incomplete information . State-of-the -art general algorithms appropriate for the motion planning process are highlighted . Motion planning with complete information are typically NP-complete and hence are modeled by approximate approaches or by exploitation of special conditions. Motion planning with incomplete information requires sensory feedback. An algorithm for motion planning in an automated concrete placement operation that exploits the special conditions provided by structural engineering floor design theory is also provided.