The authors describe practical sensor systems suitable for a mobile bricklaying robot for automated masonry construction on a building site. The major sources of error encountered during the automated masonry construction process as well as the required tolerances for the masonry process are described. Based on these considerations, two sensor strategies for positioning and orientating the robot are described in detail. An assessment of these strategies and a description of simulation results conclude this article.

This paper presents basic concepts and enabling technologies for a mobile plastering robot used on the construction site and controlled by a skilled operator. Economic aspects of the German plastering industry, requirements for semi-automated plastering, alternative robotic end-effectors, various kinematic structures as well as suitable drive technologies for a plastering robot are discussed in detail.

The definition of the excavation geometry in concrete removal has a considerable effect on the longevity of the subsequent replacement repair material . Also, when removing defective material, it is important to use methods that do not cause micro-cracking and other structural damge. The hydro -erosion concept , a controlled version of hydro-demolition. represents a means of excavating material to well definded gometry without causing such damage . To achieve a robotic solution for this, it is necessary to incorporate sensing and control strategies that are roboust in the harsh environment . An experimental robot has been devised for investigations into these issues . This work is being undertaken within a European Community project named HEROIC : Hydro Erosion for Repair Of Insitu Concrete.

The authors detail two servo-control strategies which improve the performance of servodriven electro-hydraulic robotic manipulators. The first servo-controller is pragmatic approach based on both empirical controller design and fuzzy logic and results presented demonstrate that its performance clearly surpasses that of the conventional Pcontroller. The second servo-controller is a robust state-space controller designed by applying the Ackermann parameter space method. This controller uses both the measured angular position and acceleration as state-variables to directly control the angular position of the revolute joints. In order to determine the angular acceleration, a contact free acceleration sensor based on the Ferraris principle has been developed and described in detail. Results are presented which clearly demonstrate the improvement of the servo-control quality through use of the acceleration sensor.

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