- Front Matter: Volume 9517
- Harvesting
- Materials and Processes
- Resonators
- Optical Devices
- Modeling
- Devices
- Characterization
- Systems
- Chemical Sensors
- Poster Session
- Energy Harvesting and Low Power Design
- Embedded Systems Applications
- Networking and Embedded Computing
Energy Harvesters (EH) are devices that convert environmental energy (i.e. thermal, vibrational, solar or electromagnetic) into electrical energy. One of the most promising solutions consists in transforming energy from vibrations using a piezoelectric material placed onto a mechanical resonator. The intrinsic drawback of this solution is the typically high quality factor of the device and so the device works effectively only within a narrow bandwidth. To overcome this limitation it is possible to tune the mechanical resonance of the device, to introduce non-linear elements (e.g. magnets) or to design the mechanical resonator with a multimodal behavior. In Ultra Low Power (ULP) applications the aspect of integration is of utmost importance and so MEMS-based (micro electro-mechanical systems) EHs are preferable. Within this scenario the multimodal solution is the more suitable considering the technological constraints imposed by the micro machining manufacturing process.
In this paper we optimize a given multimodal mechanical geometry in order to maximize the number of resonances within a certain frequency band. In the particular case of piezoelectric energy harvesting, the strain distribution of each modes is critical and has to be taken into consideration for the designing of efficient device. The proposed optimization is FEM-based and it uses modal and harmonic simulations for both select the useful modes and then to design the device in a way that presents those modes within a predefined frequency range. This mechanical optimization could be considered the first step for maximizing the output power of a multimodal piezoelectric energy harvester. The second step focuses on the geometry optimization of the piezoelectric transducer element, starting from the desired resonant mode configuration defined in the first stage. The number of modes stimulated applying a vertical acceleration increases in number in the desired frequency range (i.e. around 1 kHz). As the output power is proportional to the stress of the flexible device, these promising results show clearly how an optimization of the geometry could significantly boost the performance of such devices.
Expanding the design to up to ten bit elements would offer a passive microsensor able to detect 1023 off-limit conditions. A mechanical binary microcounter is presented that does not require electrical energy supply. It is suitable for counting any physical event that can be converted into an adequate force-travel-characteristic.
Cyber physical systems (CPS) enable applications not previously possible by networking components incorporating tightly connected physical and computational (cyber) functions.
We propose a method for studying and optimizing such systems at an early development stage by using simulation. Models, which mimic the cyber physical components behaviour, combine analytical models for the physical part with neural network models for the cyber part. Such models are computationally efficient, can be easily upgraded and can be networked to simulate even large scale cyber physical systems.
Applications for studying architectural issues, overall reliability and commercial aspects of cyber physical energy systems will be discussed.
This paper discusses the Model-Based design approach in the applicative design of Cyber Physical Systems and, in particular, focuses upon the abstraction of the Communications resources used in such systems. Two relevant cases are considered in the discussion, namely the HTTP protocol and the ModBUS-RTU protocol.
The discussed approach has been implemented in an existing Model-Based technology, TaskScript. The above mentioned protocols, among others, have been made available to the applicative designer at the Model Level, abstracted according to the presented approach. Results are reported, demonstrating the effectiveness of the approach: real case applications have been effectively developed in less than one day.