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As automated construction processes require large workspaces and high payloads, the use of cables is a reasonable approach to span wide distances and share loads. Therefore, a cable-driven parallel robot is a suitable choice for automated masonry construction. Another possible robotic system for this task consists of a set of cooperative drones, each connected to the end effector and the payload by a cable. Because of the similarities between the two robotic systems, the same object-oriented programmed software can be used for trajectory planning and subsequent investigations, making minor adjustments. The implemented optimizing path planning algorithm takes into account the physical boundaries, motion time, collision avoidance and energy requirements. Thus, a simulation-based comparison of the characteristics of both systems can be made. In this paper, the necessary physical models for both the drone system and the cable robot are derived in detail. Based on the common framework, this paper presents a comparison between the two robotic systems, defining two different scenarios. The first scenario demonstrates the functioning of the optimizer approach. The second scenario is used to compare the two systems. For this purpose, the trajectories for all 1720 masonry units of the first floor of a house are optimized. The analysis of the results shows that both systems can transport heavy loads, with the cable robot having advantages on smaller sites, while the drone system covers larger distances for the price of slower performance and higher energy consumption.

Cable failure is an extremely critical situation in the operation of cable-driven parallel robots (CDPR), as the robot might be instantly outside of its predefined workspace. Therefore, the calculation of a cable force distribution might fail and, thus, the controller might not be able to master the guidance of the system anymore. However, as long as there is a remaining set of cables, the dynamic behavior of the system can be influenced to prevent further damage, such as collisions with the ground. The paper presents a feasible algorithm, introduces the models for dynamical multi-body simulation and verifies the algorithm within control loop closure.

Under special circumstances, a cable-driven parallel robot (CDPR) may leave its wrench-feasible-workspace. Standard approaches for the computation of set-point cable forces are likely to fail in this case. The novel nearest corner method for calculating appropriate cable forces when the CDPR is outside of its wrench-feasible-workspace was introduced in former work of the authors. The obtained cable force distributions aim at continuity and generate wrenches close to the desired values. The method employs geometrical operations in the cable force space and promises real-time usability because of its non-iterative structure. In a simplified simulation, a cable break scenario was used to carry out more detailed testing of the method regarding different parameters, a higher number of cables, and the numerical efficiency. A brief discussion about the continuity of the method when entering the wrench-feasible-workspace is presented.