Modular Redesign of Mechatronic Systems: Formulation of Module Specifications Guaranteeing System Dynamics Specifications
Lars A. L. Janssen, Rob H. B. Fey, Bart Besselink, Nathan van de Wouw
TL;DR
The paper tackles the challenge of guaranteeing system-level dynamic specifications for complex, modular mechatronic systems when components are designed by separate teams. It develops a modular redesign framework that models modules with FRFs $G^{(j)}(i\\omega)$, interconnects them via a fixed structure $\\mathcal{K}$, and defines system-level FRF bounds through $\\mathcal{E}_A(\\omega)$ using $V_A(\\omega)$ and $W_A(\\omega)$ such that $\\|V_A(\\omega)(G_A(i\\omega)-\\hat{G}_A(i\\omega))W_A(\\omega)\\|<1$. A central theorem links module-level specifications $\\mathcal{E}^{(j)}(\\omega)$ to the assembly specification $\\mathcal{E}_A(\\omega)$ via a nominal system $N(i\\omega)$ and a positive-definite condition on a Schur-complement-like matrix, enabling an alternating-LMI algorithm to automatically synthesize module FRF specifications. The workflow supports fully parallel redesign: engineers modify their module to satisfy $\\hat{G}^{(j)}(i\\omega)\\in\\mathcal{E}^{(j)}(\\omega)$, and, if all modules comply, the assembled system satisfies $\\hat{G}_A(i\\omega)\\in\\mathcal{E}_A(\\omega)$. Demonstrations on a two-DOF mass-spring-damper, a pillar-plate benchmark, and an industrial wire bonder show the method’s scalability, the trade-off between conservatism and redesign freedom, and the computational advantages of modular verification over full-system reanalysis. The approach offers a practical path toward faster, cost-effective modular redesign for complex mechatronic systems with rigorous FRF-based guarantees.
Abstract
Complex mechatronic systems are typically composed of interconnected modules, often developed by independent teams. This development process challenges the verification of system specifications before all modules are integrated. To address this challenge, a modular redesign framework is proposed in this paper. Herein, first, allowed changes in the dynamics (represented by frequency response functions (FRFs)) of the redesigned system are defined with respect to the original system model, which already satisfies system specifications. Second, these allowed changes in the overall system dynamics (or system redesign specifications) are automatically translated to dynamics (FRF) specifications on module level that, when satisfied, guarantee overall system dynamics (FRF) specifications. This modularity in specification management supports local analysis and verification of module design changes, enabling design teams to work in parallel without the need to iteratively rebuild the system model to check fulfilment of system FRF specifications. A modular redesign process results that shortens time-to-market and decreases redesign costs. The framework's effectiveness is demonstrated through three examples of increasing complexity, highlighting its potential to enable modular mechatronic system (re)design.
