Gantry robots and anthropomorphic arms of various sizes have already been studied and, while they are in use in some parts of the world for automated construction, a new kind of wide workspace machinery, cable-driven parallel robots (CDPR), has emerged. These robots are capable of automated movement in a very wide workspace, using cables reeled in and out by winches as actuation members, the other elements being easily stacked for easy relocation and reconfiguration, which is critical for on-site construction. The motivation of this paper is to showcase the potential of a CDPR operating solely on motor position sensors and showing limited collisions from the cables for large-scale applications in the building industry relevant for additive manufacturing, without risk of collisions between the cables and the building. The combination of the Cogiro CDPR (Tecnalia, LIRMM-CNRS 2010) with the extruder and material of the Pylos project (IAAC 2013) opens the opportunity to a 3D printing machine with a workspace of 13.6 9 9.4 9 3.3 m. The design patterns for printing on such a large scale are disclosed, as well as the modifications that were necessary for both the Cogiro robot and Pylos extruder and material. Two prints, with different patterns, have been achieved with the Pylos extruder mounted on Cogiro: the first spanning 3.5 m in length, the second, reaching a height of 0.86 m. Based on this initial experiment, plans for building larger parts and buildings are discussed, as well as other possible applications for CDPRs in construction, such as the manipulation of assembly processes (windows, lintels, beams, floor elements, curtain wall modules, etc.) or brick laying.

Picturing the interest of research institutions and industrial actors, the list of research and demonstration parallel cable-driven robot prototypes is growing by the day. LIRMM and Tecnalia have decided to put knowledge in common in order to develop novel concepts for cable-driven parallel robotics and demonstrate its capabilities in industrial tasks. We have developed together a reconfigurable cable robot for this purpose. The robot main characteristics, e.g. footprint, mobile platform geometry and drawing point layout can be modified at will, making it particularly suitable for studying in good conditions new configurations or novel control laws, as well as any scenario suggested by our partners. The present paper first provides an overview of the robot. Afterwards, a more specific view on the different components and the capabilities of reconfiguration are presented, as well as examples of layouts meant for various research and industrial projects.

In order to use a cable-driven parallel robot to inspect an existing surface, a straightforward solution consists in fixing the robot components on this surface. In most cases, however, there are conditions that limit these fixations, for example structural reasons since the frame of the surface has probably not been specifically calculated to withstand the forces generated by the parallel cable-driven robot. In the particular case of inspection of the façade of a building, civil engineering specifications apply, which may drastically reduce the engineering possibilities from the point of view of the parallel cable-driven robot designers. This paper introduces a detailed example of implementation of a parallel cable-driven robot on the Media-TIC building located in Barcelona in Spain. In this highly technological building, the main façade parallel cable-driven robot in intended to work as a sensor for monitoring the environment, but also as an interface between the building and its occupiers. The various constraints-due to normative, structural and aesthetic reasons-that were tackled are described in the paper, along with the elected detailed design of the robot that complies with these constraints.

A continuous collision checking method for a cable-driven parallel robot with an embarked robotic arm is proposed in this paper. The method aims at validating paths by checking for collisions between any pair of robot bodies (mobile platform, cables, and arm links). For a pair of bodies, an upper bound on their relative velocity and a lower bound on the distance between the bodies are computed and used to validate a portion of the path. These computations are done repeatedly until a collision is found or the path is validated. The method is integrated within the Humanoid Path Planner (HPP) software, tested with the cable-driven parallel robot CoGiRo, and compared to a discretized validation method.

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The maximum cable tension is a crucial parameter in the design of a cable-driven parallel robot (CDPR) since the various mechanical components of the CDPR must be designed to safely withstand the loads induced by this maximum tension. For CDPRs having a number of cables at least equal to its number of DOFs, this paper deals with the determination of the smallest maximum cable tension vectors allowing a required wrench set to be feasible. The problem is formulated as the minimization of the maximum cable tension infinity norm under linear inequality constraints which include the wrench-feasibility constraints. The solution to this minimization problem is not unique, and the solution set is shown to be a convex polytope in the maximum tension space. Hence, various smallest maximum tension vectors generally exist and the computations of two different solution vectors are introduced. The first vector has all its components equal to the minimum infinity norm which can be directly obtained from the minimization problem inequality constraints. An algorithm is proposed to determine the second vector as the solution vector having the least possible value for each of its components. The computation of the smallest maximum tension vectors for general required wrench sets are then presented. The cases of particular wrench set definitions relevant to heavy payload manipulation applications are also introduced. Finally, these contributions are applied to the configuration (geometry) optimization of a large-dimension 6-DOF CDPR installed on a building facade to manipulate heavy payloads.

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The installation of curtain wall modules (CWMs) is a risky activity carried out in the heights and often under unfavorable weather conditions. CWMs are heavy prefabricated walls that are lifted normally with bindings and cranes. High stability is needed while positioning in order not to damage the fragile CWMs. Moreover, this activity requires high precision while positioning brackets, the modules, and for that reason, intensive survey and marking are necessary. In order to avoid such inconveniences, there were experiences to install façade modules in automatic mode using robotic devices. In the research project HEPHAESTUS, a novel system has been developed in order to install CWMs automatically. The system consists of two sub-systems: a cable driven parallel robot (CDPR) and a set of robotic tools named as Modular End Effector (MEE). The platform of the CDPR hosts the MEE. This MEE performs the necessary tasks of installing the curtain wall modules. There are two main tasks that the CDPR and MEE need to achieve: first is the fixation of the brackets onto the concrete slab, and second is the picking and placing of the CWMs onto the brackets. The first integration of the aforementioned system was carried out in a controlled environment that resembled a building structure. The results of this first test show that there are minor deviations when positioning the CDPR platform. In future steps, the deviations will be compensated by the tools of the MEE and the installation of the CWM will be carried out with the required accuracy automatically.