During the everyday usage of an automobile, only 10–16% of the fuel energy is used to drive the car—to overcome the resistance from road friction and air drag. One important loss is the dissipation of vibration energy by shock absorbers in the vehicle suspension under the excitation of road irregularity and vehicle acceleration or deceleration. In this paper we design, characterize and test a retrofit regenerative shock absorber which can efficiently recover the vibration energy in a compact space. Rare-earth permanent magnets and high permeable magnetic loops are used to configure a four-phase linear generator with increased efficiency and reduced weight. The finite element method is used to analyze the magnetic field and guide the design optimization. A theoretical model is created to analytically characterize the waveforms and regenerated power of the harvester at various vibration amplitudes, frequencies, equilibrium positions and design parameters. It was found that the waveform and RMS voltage of the individual coils will depend on the equilibrium position but the total energy will not. Experimental studies of a 1:2 scale prototype are conducted and the results agree very well with the theoretical predictions. Such a regenerative shock absorber will be able to harvest 16–64 W power at 0.25–0.5 m s − 1 RMS suspension velocity.

https://iopscience.iop.org/article/10.1088/0964-1726/19/4/045003/pdf

Design and characterization of an electromagnetic energy harvester for vehicle suspensions

Research on shunted piezoelectric transducers, performed mainly over the past decade, has generated new opportunities for control of vibration and damping in flexible structures. This is made possible by the strong electromechanical coupling associated with modern piezoelectric transducers. In vibration control applications, a piezoelectric transducer is bonded to, or embedded in a base structure. As the structure deforms, the piezoelectric element strains and converts a portion of the structural vibration energy into electrical energy. By shunting the piezoelectric transducer to an electrical impedance, a part of the induced electrical energy can be dissipated. Hence, the impedance acts as a means of extracting mechanical energy from the base structure. This paper reviews recent research related to the use of shunted piezoelectric elements for vibration damping and control. In particular, the paper presents an overview of the literature on piezoelectric shunt damping and discusses recent observations on the feedback nature of piezoelectric shunt damping systems.

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A survey of recent innovations in vibration damping and control using shunted piezoelectric transducers

Research on shunted piezoelectric transducers, per- formed mainly over the past decade, has generated new opportuni- ties for control of vibration and damping in flexible structures. This is made possible by the strong electromechanical coupling associ- ated with modern piezoelectric transducers. In vibration control applications, a piezoelectric transducer is bonded to, or embedded in a base structure. As the structure deforms, the piezoelectric el- ement strains and converts a portion of the structural vibration energy into electrical energy. By shunting the piezoelectric trans- ducer to an electrical impedance, a part of the induced electrical energy can be dissipated. Hence, the impedance acts as a means of extracting mechanical energy from the base structure. This paper reviews recent research related to the use of shunted piezoelec- tric elements for vibration damping and control. In particular, the paper presents an overview of the literature on piezoelectric shunt damping and discusses recent observations on the feedback nature of piezoelectric shunt damping systems.

A Survey of Recent Innovations in Vibration Damping

A method of on-demand energy delivery to an active suspension system comprising an actuator body, hydraulic pump, electric motor, plurality of sensors, energy storage facility, and controller is provided. The method comprises disposing an active suspension system in a vehicle between a wheel mount and a vehicle body, detecting a wheel event requiring control of the active suspension; and sourcing energy from the energy storage facility and delivering it to the electric motor in response to the wheel event.

Active vehicle suspension system

Energy-harvesting shock absorbers are able to recover the energy otherwise dissipated in the suspension vibration while simultaneously suppressing the vibration induced by road roughness. They can work as a controllable damper as well as an energy generator. An innovative design of regenerative shock absorbers is proposed in this paper, with the advantage of significantly improving the energy harvesting efficiency and reducing the impact forces caused by oscillation. The key component is a unique motion mechanism, which we called ?mechanical motion rectifier (MMR)?, to convert the oscillatory vibration into unidirectional rotation of the generator. An implementation of a MMR-based harvester with high compactness is introduced and prototyped. A dynamic model is created to analyze the general properties of the motion rectifier by making an analogy between mechanical systems and electrical circuits. The model is capable of analyzing electrical and mechanical components at the same time. Both simulation and experiments are carried out to verify the modeling and the advantages. The prototype achieved over 60% efficiency at high frequency, much better than conventional regenerative shock absorbers in oscillatory motion. Furthermore, road tests are done to demonstrate the feasibility of the MMR shock absorber, in which more than 15 Watts of electricity is harvested while driving at 15?mph on a smooth paved road. The MMR-based design can also be used for other applications of vibration energy harvesting, such as from tall buildings or long bridges.

https://iopscience.iop.org/article/10.1088/0964-1726/22/2/025008/pdf

Energy-harvesting shock absorber with a mechanical motion rectifier

A tilting suspension system is provided for two wheels (2, 3) of a vehicle (200) disposed on a common axle with said module comprising a rigid frame (17) adapted to be firmly fixed to the chassis of the vehicle so as to be tilted together with the whole vehicle and a tilting arm (14) pivotally linked to said rigid frame. The tilting of the rigid frame is obtained as a result of the counter torque arising when activating hydraulic actuating means (101, 102) pivotally interposed between said tilting arm (14) and said rigid frame (17), with said tilting arm being pivotally connected to shock absorbers (18). The tilting module further comprises suspension arms (10, 11, 12, 13) pivotally connected to the rigid frame, with said suspension arms supporting, in cooperation with supporting uprights, the two wheels thus allowing both tilting and steering of said two wheels. The hydraulic actuating means (101, 102) are actuated by an hydraulic pump (112) driven by an electric motor (108).

A suspension tilting module for a wheeled vehicle and a wheeled vehicle equipped with said suspension tilting module

Along with the fourth industrial revolution, different tools coming from optimization, Internet of Things, data science, and artificial intelligence fields are creating new opportunities in production management. While manufacturing processes are stochastic and rescheduling decisions need to be made under uncertainty, it is still a complicated task to decide whether a rescheduling is worthwhile, which is often addressed in practice on a greedy basis. To find a tradeoff between rescheduling frequency and the growing accumulation of delays, we propose a rescheduling framework, which integrates machine learning (ML) techniques and optimization algorithms. To prove the effectiveness, we first model a flexible job-shop scheduling problem with sequence-dependent setup and limited dual resources (FJSP) inspired by an industrial application. Then, we solve the scheduling problem through a hybrid metaheuristic approach. We train the ML classification model for identifying rescheduling patterns. Finally, we compare its rescheduling performance with periodical rescheduling approaches. Through observing the simulation results, we find the integration of these techniques can provide a good compromise between rescheduling frequency and scheduling delays. The main contributions of the work are the formalization of the FJSP problem, the development of ad hoc solution methods, and the proposal/validation of an innovative ML and optimization-based framework for supporting rescheduling decisions.

/pdf/machine-learning-and-optimization-for-production-1ynkp5rfz7.pdf

Machine learning and optimization for production rescheduling in Industry 4.0

High efficiency linear power amplifier for active magnetic bearings

A modified class-G linear amplifier has been developed to improve the overall efficiency of a transconductance amplifier loaded with the high inductance and low resistance typical of the magnetic bearing coils. A simple theoretical characterization has been used to provide some diagrams to optimize the power efficiency as a function of a nonconstant load such as that due to a rotor unbalance. Experimental results are reported that show a more than satisfactory agreement with the expected results and the developed theory.

High-efficiency linear power amplifier for active magnetic bearings

A suspension system for a wheeled vehicle is provided, the suspension system being adapted to support at least one wheel of the vehicle and comprising at least one shock absorbing device adapted to be activated as a result of the motion of the at least one wheel in a substantially vertical direction, the suspension system further comprising electrical power generating means in fluid connection with the at least one shock absorbing device so that the activation of said at least one shock absorbing device results in electrical power being generated. Furthermore, the suspension system comprises means for absorbing at least partially the electrical power generated, the absorption of electrical power resulting in the stiffness of said at least one shock absorbing device being varied as a function of the electrical power absorbed.

Stefano Carabelli

Papers

A suspension tilting module for a wheeled vehicle and a wheeled vehicle equipped with said suspension tilting module

Machine learning and optimization for production rescheduling in Industry 4.0

High efficiency linear power amplifier for active magnetic bearings

High-efficiency linear power amplifier for active magnetic bearings

Suspension system for a wheeled vehicle and a wheeled vehicle equipped with such a suspension system