Swapping Modularity Research Articles

LMI-Based Design of Distributed Controllers to Achieve Component Swapping Modularity

Component swapping modularity (CSM) refers to distributed modular control design in networks of swappable smart components. CSM reduces control design effort and complexity in platform-based systems. Existing CSM methods achieve promising results for low order multi-input-multi-output systems. However, the lack of generalization, heavy computational burden, and to a lower extent, designer’s involvement limit the applications of the existing CSM methods. Thus, this brief utilizes linear matrix inequalities (LMIs) to present an almost automatic CSM algorithm which converges rapidly and is easy to generalize to an arbitrary linear system. The LMI-based CSM is designed to maintain both disturbance attenuation and quadratic stability. Also, it is desired to satisfy specific time response criteria. Thus, the proposed algorithm combines $\mathcal {H}_{2}$ optimization and robust $\mathcal {H}_\infty $ optimization to obtain a distributed control composed of parts with prescribed orders and partially tunable parameters. The designer’s involvement is dramatically reduced to the iterative tuning of two scalar parameters to optimize the fixed part of the controller. The proposed algorithm incorporates reference tracking. Also, stability measures and design criteria are checked numerically at each step. The LMI-based CSM algorithm has been numerically verified using an engine idle speed control example.

Smart product design for automotive systems

Automobiles evolved from primarily mechanical to electro-mechanical, or mechatronic, vehicles. For example, carburetors have been replaced by fuel injection and air-fuel ratio control, leading to order of magnitude improvements in fuel economy and emissions. Mechatronic systems are pervasive in modern automobiles and represent a synergistic integration of mechanics, electronics and computer science. They are smart systems, whose design is more challenging than the separate design of their mechanical, electronic and computer/control components. In this review paper, two recent methods for the design of mechatronic components are summarized and their applications to problems in automotive control are highlighted. First, the combined design, or co-design, of a smart artifact and its controller is considered. It is shown that the combined design of an artifact and its controller can lead to improved performance compared to sequential design. The coupling between the artifact and controller design problems is quantified, and methods for co-design are presented. The control proxy function method, which provides ease of design as in the sequential approach and approximates the performance of the co-design approach, is highlighted with application to the design of a passive/active automotive suspension. Second, the design for component swapping modularity (CSM) of a distributed controller for a smart product is discussed. CSM is realized by employing distributed controllers residing in networked smart components, with bidirectional communication over the network. Approaches to CSM design are presented, as well as applications of the method to a variable-cam-timing engine, and to enable battery swapping in a plug-in hybrid electric vehicle.

Component Swapping Modularity for Distributed Precision Contouring

Prior works use numerical simulations to verify component swapping modularity (CSM) for various systems. Moreover, current CSM algorithms do not investigate control parameter allocation for a realistic control configuration when the control consists of multiple parts. Thus, this work primarily focuses on presenting and experimentally validating an empirical methodology to allocate and calibrate various parts of the controller to improve CSM in a precision multiaxis servo-system. As a secondary contribution, the concept of the modified reference contour is introduced to simplify control allocation and to improve the modularity of the cross-coupling control (CCC), which is utilized to achieve high-precision contouring. First, the unified linear CCC algorithm is presented for multiaxis servo-systems. Initially, the sensitivity of the contouring algorithm versus the control parameters is studied numerically. Then, empirical calibration and sensitivity analysis are conducted to obtain the optimal set of control parameters. Hence, the lowest feasible contour error is obtained for possible configurations of the servo-system. It is shown that the results of the empirical analysis are consistent with those of the numerical analysis. Despite dramatic differences between the servo-system variants, experimental results show that full CSM is achieved with the same controller for the variants of the servo-system.

A module configuration and valuation model for operational flexibility in ship design using contract scenarios

ABSTRACTModularity allows for affordable reconfiguration in operation. Thus, a single modular ship has flexibility and stakeholders have the option to delay investment decisions until more information and technology become available. However, previous design methods for modular ships have not considered the economic benefits of such operational flexibility. We therefore present an optimization model that involves both design and operation decisions related to modules. In creating design alternatives, we use component swapping modularity, in which designs are created by configuring modules to a main body through non-identical interfaces. In evaluation, we represent an operating context based on a set of contracts. We implemented the model in a case study in which both modular and non-modular ships were designed, evaluated, and compared. Moreover, a sensitivity analysis was performed for different contract scenarios. The case study shows that reconfiguration options are influential factors on the value robustness of ships under high uncertainty.

Direct Optimal Design for Component Swapping Modularity in Control Systems

This paper presents a new method for the design of distributed controllers that achieves component swapping modularity (CSM) in control systems. Our approach, referred to as the direct method, is based on solving a bilevel optimization problem to obtain the distributed controller gains directly. In the previously proposed three-step method, the distributed controllers were obtained by matching with a precomputed centralized controller. To illustrate our approach, we consider an engine idle speed control problem, where CSM is achieved with respect to the throttle actuator. The results indicate that the direct method can significantly improve the CSM metric compared to the three-step method. In addition, for a certain distributed control structure, the direct method enables the designer to tradeoff between desired system performance and CSM.

Distributed Supervisory Controller Design for Battery Swapping Modularity in Plug-In Hybrid Electric Vehicles

A distributed supervisory controller is proposed to achieve battery component swapping modularity (CSM) for a plug-in hybrid electric vehicle (PHEV). The CSM permits the designer to distribute a part of the supervisory controller to the battery module such that the PHEV can use a range of batteries while providing corresponding optimal fuel economy. A novel feedback-based controller for the charge sustaining mode is proposed to facilitate distributed controller design for battery CSM. The method based on sensitivity analysis of the control signals with respect to the battery hardware parameter is introduced to define the controller distribution architecture. The distributed controller gains are obtained by solving a bilevel optimization problem using the collaborative optimization and the augmented Lagrangian decomposition methods. The simulation results demonstrate that the proposed distributed controller can achieve battery CSM without compromising fuel economy compared to the centralized control case.

Swappable Distributed MIMO Controller for a VCT Engine

In the early days of computer control, only one centralized computer was responsible for executing the algorithms. Increasingly, computer control algorithms reside inside individual system components in a distributed fashion. Variable camshaft timing (VCT) is an appealing feature for automotive engines because it allows optimization of the cam timing over a wide range of operating conditions. In this paper, a method to distribute the discrete multiple-input mutiple-output controller for the VCT engine to improve the component swapping modularity of the VCT actuator and the EGO sensor components using network communications is presented. First, a discrete LQG controller is designed, and then this controller is distributed to the engine control unit, the VCT controller, and the EGO sensor controller in order to maximize the component swapping modularity of the system. A control oriented pre-optimization technique, which simplifies the optimization problem, and a candidate solution was devised to maximize component modularity.

Modularity, product variety, production volume, and component sourcing: theorizing beyond generic prescriptions

Research in operations management suggests that firms can mitigate the negative impact of product variety on operational performance by deliberately pursuing modularity in the design of product family architectures. However, modularity is not a dichotomous property of a product, as different types of modularity can be embedded into a product family architecture. The present paper explores how manufacturing characteristics affect the appropriate type of modularity to be embedded into the product family architecture, and how the types of modularity relate to component sourcing. The study is based on a qualitative research design involving a multiple case study methodology to examine six product families belonging to six European companies. The themes derived through case analyses are synthesized in the form of empirical generalizations. Insights from these empirical generalizations are subsequently developed into two propositions explaining why and under what conditions these empirical generalizations might hold for a product family outside of the original sample. The theoretical results formalize, first of all, a type of modularity (i.e. combinatorial modularity) not currently described in literature. Second, the theoretical propositions suggest that when the desired level of product variety is low (high) relative to total production volume, component swapping modularity (combinatorial modularity) helps to maximize operational performance. Finally, the complexity of component families outsourced to suppliers and the geographical proximity of component family suppliers affect the extent to which the product variety–operational performance trade-off can be mitigated through modularity.