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1. A Generalized and Efficient Control-Oriented Modeling Approach for Vibration-Prone Delta 3D Printers Using Receptance Coupling

   https://doi.org/10.1109/TASE.2022.3197057  

   Edoimioya, Nosakhare; Okwudire, Chinedum E. (August 2022, IEEE Transactions on Automation Science and Engineering)

   Delta 3D printers can significantly increase throughput in additive manufacturing by enabling faster and more precise motion compared to conventional serial-axis 3D printers. Further improvements in motion speed and part quality can be realized through model-based feedforward vibration control, as demonstrated on serial-axis 3D printers. However, delta machines have not benefited from model-based controllers because of the difficulty in accurately modeling their position-dependent, coupled nonlinear dynamics. In this paper, we propose an efficient framework to obtain accurate linear parameter-varying models of delta 3D printers at any position within their workspace from a few frequency response measurements. We decompose the dynamics into two sub-models–(1) an experimentally-identified sub-model containing decoupled vibration dynamics; and (2) an analytically-derived sub-model containing coupled dynamics–which are combined into one using receptance coupling. We generalize the framework by extending the analytical model of (2) to account for differing mass profiles and dynamic models of the printer’s end-effector. Experiments demonstrate reasonably accurate predictions of the position-dependent dynamics of a commercial delta printer, augmented with a direct drive extruder, at various positions in its workspace. Note to Practitioners—This work aims to equip high-speed 3D printers, like delta machines, with model-based controllers to complement their speed with high-accuracy. Due to the coupled kinematic chains of the delta, complex control methodologies, some of which require real-time state measurements, are often used to achieve satisfactory control performance. Our modeling approach provides an efficient methodology for obtaining accurate linear models without the need for real-time measurements, thus enabling practitioners to design linear model-based feedforward controllers to achieve the high throughput and accuracy desired in additive manufacturing (AM). The models we develop in this paper are intended for use with feedforward vibration compensation methods, which can be beneficial for both industrial-scale AM machines that have high-powered servo motors and feedback controllers, as well as consumer-grade AM machines which use stepper motors in feedforward control. 

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2. A nonlinear analysis of a Duffing oscillator with a nonlinear electromagnetic vibration absorber–inerter for concurrent vibration mitigation and energy harvesting

   https://doi.org/10.1007/s11071-023-09163-6  

   Kakou, Paul; Gupta, Sunit Kumar; Barry, Oumar (April 2024, Nonlinear Dynamics)

   Abstract Several investigators have taken advantage of electromagnetic shunt-tuned mass dampers to achieve concurrent vibration mitigation and energy harvesting. For nonlinear structures such as the Duffing oscillator, it has been shown that the novel nonlinear electromagnetic resonant shunt-tuned mass damper inerter (NERS-TMDI) can mitigate vibration and extract energy for a wider range of frequencies and forcing amplitudes when compared to competing technologies. However, nonlinear systems such as the NERS-TMDI are known to exhibit complex stability behavior, which can strongly influence their performance in simultaneous vibration control and energy harvesting. To address this problem, this paper conducts a global stability analysis of the novel NERS-TMDI using three approaches: the multi-parametric recursive continuationWe emphasize that these assume method, Floquet theory, and Lyapunov exponents. A comprehensive parametric analysis is also performed to evaluate the impact of key design parameters on the global stability of the system. The outcome indicates the existence of complex nonlinear behavior, such as detached resonance curves, and the transition of periodic stable solutions to chaotic solutions. Additionally, a parametric study demonstrates that the nonlinear stiffness has a minimal impact on the linear stability of the system but can significantly impact the nonlinear stability performance, while the transducer coefficient has an impact on the linear and nonlinear stability NERS-TMDI. Finally, the global sensitivity analysis is performed relative to system parameters to quantify the impact of uncertainty in system parameters on the dynamics. Overall, our findings show that simultaneous vibration control and energy harvesting come with a considerable instability trade-off that limits the range of operation of the NERS-TMDI. 

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3. Proprioceptive Origami Sleeves Using Embedded Fold Sensors

   Jamal, Saima; Zheng, Ryan; Bruder, Daniel (April 2026, 2026 IEEE International Conference on Soft Robotics (RoboSoft))

   Origami structures offer lightweight, compact, and highly deformable architectures that can be used for a variety of different applications. However, their adoption has been constrained by the lack of low-cost, scalable, and generalizable sensing solutions. Existing proprioceptive approaches often rely on complex fabrication or external tracking systems, limiting accessibility and integration. In this work, we present the Origami Sensing Sleeve (OSS), a low-cost, crease-embedded sensing architecture fabricated using commercial off-the-shelf (COTS) inkjet printing technology, enabling low-cost, rapid, scalable, and geometry-agnostic manufacturing. We demonstrate and validate this approach on a four-sided Yoshimura-pattern, selected as a representative origami sleeve due to its large range of motion and geometric versatility. Each crease integrates an inkjet printed fold sensor that provides low-profile feedback of local bending angles within the origami structure. A kinematic model of the OSS is coupled with sensor feedback to reconstruct its geometry and track its kinematic state in real time. The embedded sensors measure fold angles within ±5° with a 20-60 s settling time. Paired with a kinematic model, sensors estimate the position of one end of an origami sleeve relative to the other with an RMSE error of 2.32 cm for static poses and 4.06 cm for transient trajectories, given a nominal extended sleeve length of 12.18 cm. This work establishes a low-cost, manufacturable, and generalizable pathway toward scalable proprioceptive control for compliant robotic systems using origami-based designs. 

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4. Parametric Analysis of Negative Capacitance Circuit for Enhanced Vibration Suppression Through Piezoelectric Shunt

   https://doi.org/10.1115/DETC2022-90616  

   Wang, Ting; Tang, Jiong (August 2022, Proceedings of the ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference)

   Abstract Piezoelectric transducers are widely employed in vibration control and energy harvesting. The effective electro-mechanical coupling of a piezoelectric system is related to the inherent capacitance of the piezoelectric transducer. It is known that passive vibration suppression through piezoelectric LC shunt can be enhanced with the integration of negative capacitance which however requires a power supply. This research focuses on the parametric investigation of a self-sustainable negative capacitance where the piezoelectric transducer is concurrently used in both vibration suppression and energy harvesting through LC shunt. The basic idea is to utilize the energy harvesting functionality of the piezoelectric transducer to aid the usage of negative capacitance in terms of power supply. Specifically, the power consumption and circuitry performance with respect to negative capacitance circuit design is analyzed thoroughly. Indeed, the net power generation is the difference between available power in the shunt circuit and the power consumption of the negative capacitance circuit. There exists complex tradeoffs between net power generation and the vibration suppression performance when we use different resistance values in the negative capacitance circuit. It is demonstrated through correlated analytical simulation and experimental study that the proper selection of the resistance values in the negative capacitance circuit can result in vibration suppression enhancement as well as improved net power generation, leading to a self-sustainable negative capacitance scheme. 

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5. Clean Vibes: Hand Washing Monitoring Using Structural Vibration Sensing

   https://doi.org/10.1145/3511890  

   Fagert, Jonathon; Bonde, Amelie; Srinidhi, Sruti; Hamilton, Sarah; Zhang, Pei; Noh, Hae Young (January 2022, ACM Transactions on Computing for Healthcare)

   We present a passive and non-intrusive sensing system for monitoring hand washing activity using structural vibration sensing. Proper hand washing is one of the most effective ways to limit the spread and transmission of disease, and has been especially critical during the COVID-19 pandemic. Prior approaches include direct observation and sensing-based approaches, but are limited in non-clinical settings due to operational restrictions and privacy concerns in sensitive areas such as restrooms. Our work introduces a new sensing modality for hand washing monitoring, which measures hand washing activity-induced vibration responses of sink structures, and uses those responses to monitor the presence and duration of hand washing. Primary research challenges are that vibration responses are similar for different activities, occur on different surfaces/structures, and tend to overlap/coincide. We overcome these challenges by extracting information about signal periodicity for similar activities through cepstrum-based features, leveraging hierarchical learning to differentiate activities on different surfaces, and denoting “primary/secondary” activities based on their relative frequency and importance. We evaluate our approach using real-world hand washing data across 4 different sink structures/locations, and achieve an average F1-score for hand washing activities of 0.95, which represents a 8.8X and 10.2X reduction in error over two different baseline approaches. 

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