2,215 research outputs found
Feedforward of sampled-data system for high-precision motion control using basis functions with ZOH differentiator
No full textFeedforward control has an important role in high-precision mechatronic systems. The aim of this research is to design a discrete-time feedforward controller to improve on-sample and intersample errors. The developed approach is parameterized using a linear combination of parameters and basis functions, which results in a parameterization that has intuitive physical meaning. The basis functions are designed with a differentiator that considers the sampled-data and zero-order-hold aspects. The performance improvement is demonstrated by comparing the developed approach with a conventional basis function design for a motion system.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Jan-Willem van Wingerde
Direct versus indirect penalties for supply contracts in high-tech industry
No full textUnlike consumer goods industry, a high-tech manufacturer (OEM) often amortizes new product development costs over multiple generations, where demand for each generation is based on advance orders (i.e., known demand) and additional uncertain demand. Also, due to economic regulatory reasons, high-tech OEMs usually source from a single supplier. Relative to the high retail price, the costs for a supplier of producing high-tech components are low. Consequently, incentives are misaligned: the OEM faces relatively high under-stock costs and the supplier faces high over-stock costs. In this paper, we examine supply contracts that are intended to align the incentives between a high-tech OEM and a supplier so that the supplier will invest adequate and yet non-verifiable capacity to meet the OEM’s demand. When focusing on a single generation, the manufacturer can coordinate a decentralized supply chain and extract all surplus by augmenting a traditional wholesale price contract with a “contingent penalty” should the supplier fail to fulfill the OEM’s demand. When the resulting penalty is too high to be enforceable, we consider a new class of “contingent renewal” wholesale price contracts with a stipulation: the OEM will renew the contract with the incumbent supplier for the next generation only when the supplier can fulfill the demand for the current generation. By using non-renewal as an implicit penalty, we show that the contingent renewal contract can coordinate the supply chain. While the OEM can capture the bulk of the supply chain profit, this innovative contract cannot enable the OEM to extract the entire surplus
Contingent Penalty and Contingent Renewal Supply Contracts in High-Tech Industry
No full textUnlike consumer goods industry, a high-tech manufacturer (OEM) often amortizes new product development costs over multiple generations, where demand for each generation is based on advance orders and additional uncertain demand. Also, due to economic reasons and regulations, high-tech OEMs usually source from a single supplier. Relative to the high retail price, the wholesale price for a supplier to produce high-tech components is low. Consequently, incentives are misaligned: the OEM faces relatively high under-stock costs and the supplier faces high over-stock costs. In this paper, we examine supply contracts that are intended to align the incentives between a high-tech OEM and a supplier so that the supplier will invest adequate and yet non-verifiable capacity to meet the OEM's uncertain demand. When focusing on a single generation, the manufacturer can coordinate a decentralized supply chain and extract all surplus by augmenting a traditional wholesale price contract with a "contingent penalty" should the supplier fail to fulfill the OEM's demand. When the resulting penalty is too high to be enforceable, we consider a new class of "contingent renewal" wholesale price contracts with a stipulation: the OEM will renew the contract with the incumbent supplier for the next generation only when the supplier can fulfill the demand for the current generation. By using non-renewal as an implicit penalty, we show that the contingent renewal contract can coordinate the supply chain. While the OEM can capture the bulk of the supply chain profit, this innovative contract cannot enable the OEM to extract the entire surplus
Long-Term Resource Planning in the High-Tech Industry: Capacity or Inventory?
No full textVolatile and non-stationary demand, very complex production processes, long production and capacity acquisition leadtimes, and extremely high and rarely reversible capacity acquisition costs make capacity planning in the high-tech industry a particularly challenging managerial task. To cope with demand surges and hedge against its uncertainty, firms can invest in order to expand their capacity for the long-term. For the short-term, however, demand is often fixed due to committed orders, and excess capacity might be available that may be used to build up inventory as a complementary means of hedging against these demand surges and uncertainty. In multi-echelon systems, these decisions need to be made simultaneously and must be aligned over the echelons. We address the strategic problem of determining the optimal inventory buildup and capacity expansion timing and amount across locations of a multi-echelon supply chain, as well as the operational problem of production planning. We model the problem as a two-stage stochastic program (SP), with strategic decisions at the first stage and operational decisions at the second stage. We enumerate the capacity expansion timing and use the deterministic equivalent formulation to optimize the other strategic decisions. Through an extensive numerical study, we provide practical managerial insights into the system behavior
A closed-loop perspective on fault detection for precision motion control: With application to an overactuated system
No full textFault diagnosis is crucial in high-tech production equipment to minimize operational downtime and to facilitate targeted maintenance. Future high-tech systems have numerous complex closed-loop control systems and require compatible fault diagnosis systems. The aim of this paper is to develop a procedure for decentralized fault detection in the presence of additional feedback interconnections. The influence of the additional feedback interconnections on the fault diagnosis system is investigated by means of an illustrative experimental study that resembles a next generation flexible motion system
Bode Analysis of Uncertain Multivariable Systems
No full textBode plots are crucial for frequency domain analysis of SISO systems. The aim of this paper is to develop a complete approach for Bode plots of multivariable uncertain systems for both the magnitude and phase. The magnitude is based on the singular values. The phase is based on the phase spread of the numerical range. An IQC-based approach is pursued to provide both the magnitude and phase. A simulation example shows that the presented approach allows the generation of multivariable Bode plots of multivariable uncertain systems
Conjugate Gradient MIMO Iterative Learning Control Using Data-Driven Stochastic Gradients
No full textData-driven iterative learning control can achieve high performance for systems performing repeating tasks without the need for modeling. The aim of this paper is to develop a fast data-driven method for iterative learning control that is suitable for massive MIMO systems through the use of efficient unbiased gradient estimates. A stochastic conjugate gradient descent algorithm is developed that uses dedicated experiments to determine the conjugate search direction and optimal step size at each iteration. The approach is illustrated on a multivariable example, and it is shown that the method is superior to both the earlier stochastic gradient descent and deterministic conjugate gradient descent methods. Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Jan-Willem van Wingerde
Frequency Response Data-driven LPV Controller Synthesis for MIMO Systems
No full textThe linear parameter-varying framework enables systematic control design approaches to meet increasing performance requirements and complexity of systems. The aim of this paper is to develop local frequency response data-based analysis and synthesis conditions for multiple-input multiple-output linear parameter-varying systems to facilitate fast tuning. Key advantages are local stability and performance guarantees and a global controller parameterization. The effectiveness of the proposed methods are evaluated based on a simulation example.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Jan-Willem van Wingerde
An AR-Enabled Interactive Car Door to Extend In-Car Infotainment Systems for Rear Seat Passengers
No full textModern cars create a high-tech interactive space by providing entertainment and information functionalities to the driver and partly to the passengers. By introducing rear-seat infotainment systems especially in luxury cars, manufacturers started to also focus on the passenger’s experience. However, such systems offer mainly standard entertainment and internet-based services. To enhance the user experience of rear seat passengers, we present the concept of an interactive car door that enables passengers to engage with and explore their surroundings. Our system consists of an interactive door panel that shows points of interest along the progressing route, more detailed information is shown on the AR-enabled side window in addition to the rear seat display. Results from a pilot study (n=11) show that our concept leads towards a positive user experience. The qualitative feedback reveals that such an interactive car door helps to make riding as a passenger more attractive and pleasant
Feedforward with acceleration and snap using sampled-data differentiator for a multi-modal motion system
No full textSampled-data control requires both on-sample and intersample performance in high-precision mechatronic systems. The aim is to design a discrete-time linearly parameterized feedforward controller to improve both on-sample and intersample performance in a multi-modal motion system. The continuous-time performance is considered as state compatibility by a multirate zero-order-hold differentiator. The developed approach enables the linearly parameterized feedforward controller design for sampled-data systems with physically intuitive tuning parameters. The performance improvement is validated by comparing the developed approach with a conventional approach using a backward differentiator for a multi-modal motion system
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