Browsing by Author "Blümlein, Nikolaus"

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Open Access
Function-based cost estimation for service robot prototypes in early design phases
(2014) Blümlein, Nikolaus; Verl, Alexander (Univ.-Prof. Dr.-Ing. Dr. h. c. mult.)
Early cost estimation is a common prerequisite for the profitability assessment of the development of complex products. Thereby, the combination of numerous technical and economic factors poses a particular challenge for system developers when little more than the desired functionality of the product is known. In the field of service robotics, this issue is acerbated by the lack of empirical values and experience as the according technologies are comparatively novel. The presented work proposes an approach which facilitates the estimation process for various cost aggregates of service robot prototypes in early development phases. To this end, typical components and functionalities are structurally mapped and related to statistical cost models. Additionally, the presented approach offers the possibility of unit cost estimation for small lot sizes. Core elements of this work are the development of a design-structure-matrix for service robots and the modeling of hardwareand software costs. Robot functions mapped to hardware and software components via structure matrix facilitate the derivation of essential prototype parts from desired service robot capabilities. For hardware components, central characteristics serve as a basis for non-parametric regression derivation of individual cost models. For software components, the approach applies the principle of analogy-based estimation. To this end, several hundred modules of an existing open-source software framework for robots were analyzed and costs of their development and reuse deduced using heuristic data. The models' statistical foundation allow the calculation of expectation value, standard deviation and interquartile range and thus facilitate the assessment of the of estimation uncertainty. In order to support the estimation process a software application was developed. The approach was verified using to different datasets. On the one hand, estimations for robot prototypes outlined inthe EFFIROB study were calculated applying the proposed methodology and consecutively compared with the original estimates and assessed by experts. On the other hand, costs estimated for a built prototype, the corresponding original estimate as well as the actual costs were juxtaposed and critically reviewed by one of the developers involved in the prototype's development.