Energy harvesting from a vehicle suspension system

Hundreds of piezoelectric ultrasonic motors (PUSMs) have been proposed for scientific researches and developed for commercial applications in the past decade. They are surveyed and mainly classified into three types: standing wave motor (SWM), traveling wave motor (TWM) and hybrid modes motor (HMM), according to their operating principles. These different types of PUSMs are discussed in detail, in terms of their operating principles, structures, features and performances. The methods to realize the multi-degree-of-freedom (multi-DOF) motions of the PUSMs are also investigated based on the basic operating principles of the SWM, TWM and HMM. Some practical applications and representative designs of the PUSMs are introduced briefly. Finally, further efforts and research perspectives of the PUSM are summarized. This review contributes to a comprehensive understanding of the state of arts of the PUSM.

A review on piezoelectric ultrasonic motors for the past decade: Classification, operating principle, performance, and future work perspectives

In this paper, the current technologies of the regenerative shock absorber systems have been categorized and evaluated. Three drive modes of the regenerative shock absorber systems, namely the direct drive mode, the indirect drive mode and hybrid drive mode are reviewed for their readiness to be implemented. The damping performances of the three different modes are listed and compared. Electrical circuit and control algorithms have also been evaluated to maximize the power output and to deliver the premium ride comfort and handling performance. Different types of parameterized road excitations have been applied to vehicle suspension systems to investigate the performance of the regenerative shock absorbers. The potential of incorporating nonlinearity into the regenerative shock absorber design analysis is discussed. The research gaps for the comparison of the different drive modes and the nonlinearity analysis of the regenerative shock absorbers are identified and, the corresponding research questions have been proposed for future work.

A Comprehensive Review of the Techniques on Regenerative Shock Absorber Systems

Piezoelectric energy harvesting from vibrations of a beam subjected to multi-moving loads

Hybrid electric vehicles (HEVs) have been developed extensively thanks to the inherent merits of both internal combustion engine vehicles (ICEVs) and battery electric vehicles (BEVs). In HEVs, batteries and electric motors are introduced to help internal combustion engines improve fuel efficiency and reduce greenhouse gas (GHG) emissions. Accordingly, HEVs provide opportunities for energy harvesting methods that are suitable for both ICEVs and BEVs. With these energy harvesting methods, more energy can be harvested from HEVs and lower GHG emissions can be achieved. Therefore, energy harvesting methods are investigated in this critical overview and discussed from four perspectives, namely waste heat recovery from exhaust gas, mechanical energy recovery from braking, vibration and/or shock, alternative fuels and renewable energy integration, with emphasis on thermoelectric generators, the organic Rankine cycle, regenerative shock absorbers, regenerative braking and solar roofs. Specifically, the working principles, distinct features, current research, and challenges of various energy harvesting methods in HEVs are discussed. In the conclusion, recommendations for future research are provided. This study provides a comprehensive overview of energy harvesting and emission reduction technologies in HEVs.

Overview of energy harvesting and emission reduction technologies in hybrid electric vehicles

Only ∼20% of a vehicle's fuel consumption is used for overcoming air drag force and friction with the road. Vibration energy produced during driving is dissipated by shock absorbers in the vehicle suspension. A new Piezoelectric Energy-Harvesting Shock Absorber (PEHSA) system for vehicles has been developed to act as an energy harvester that converts vibration energy to electrical energy. Cylindrical piezoelectric transducers are combined with the cylinder of the shock absorber to generate electricity from changes in fluid pressure produced by piston vibrations. A multiphysics simulation was performed using COMSOL Multiphysics to determine the characteristics of the PEHSA system.

Design of a Piezoelectric Energy-Harvesting Shock Absorber System for a Vehicle

A micro-viscometer for measuring viscosity changes in small amount of liquid in real time is designed and fabricated. The merits of the device are to use minimal liquid and to increase the sensitivity for measuring the viscosity. The micro-viscometer is composed of two chambers connected by several micro-channels. Each chamber has a unimorphic piezoelectric diaphragm for driving and sensing sound waves. The micro-channel plays a role as a waveguide and an attenuator of sound waves. Attenuation of sound wave is a function of the viscosity of the liquid. So, the output voltage of sensor is also changed as the viscosity of liquid is changed. After fabrication through micromachining, the device was tested on several viscous liquids, and then it was demonstrated that the device can play a role of a viscometer with high sensitivity. In this paper, we mainly discuss on the comparison between experimental results and newly simulated results.

Design and fabriction of micro-viscometer using the propagation of acoustic waves in micro-channel

In this paper, a new omnidirectional driving system is proposed that is composed of an ultrasonic motor, a sphere wheel, and ball bearings. The sphere wheel is driven by an ultrasonic motor, which is a Λ-type motor developed in the previous research. If the piezo-ceramic plates of the ultrasonic motor vibrate at the resonant frequency, the displacement of the ellipse orbit is generated at a sharp end of Λ-type. Modal analysis and time domain analysis were performed. The proposed omnidirectional driving system was validated by analyzing its motion characteristics.

Hongseok Lee

Papers

Design of a Piezoelectric Energy-Harvesting Shock Absorber System for a Vehicle

Design and fabriction of micro-viscometer using the propagation of acoustic waves in micro-channel

Design and Analysis of Ultrasonic Motor for Driving Sphere Wheel