Siamak Arzanpour

A Novel Semi-active Magnetorheological Bushing Design for Variable Displacement Engines:

This study introduces the concept of smart materials, namely magnetorheological (MR) fluids, to the design of automotive engine isolation systems. Hydraulic bushings and mounts are widely used in the automobile industry to isolate the engine and chassis from each other. The simplicity and low cost associated with these types of bushing, in addition to their dual frequency response characteristics, are the main reasons for their industrial popularity. Recently with the introduction of variable displacement engines (VDE), the conventional bushings have reached their performance limits. A more versatile isolator is therefore required to handle the additional vibration and disturbances in VDE, associated with the change in the engine displacement whenever the automobile does not use its full displacement capacity for maintaining the desired speed. The realization is that the appropriate isolator should be half as stiff in the operating frequency range of the three cylinder mode of the engine. In addition, in the full cylinder mode the isolator must maintain the performance levels comparable to existing conventional products. This study introduces a cost-effective semi-active bushing for the VDE isolation problem. After a study of the VDE systems, different modes of engine performances in those systems are discussed, and the ideal isolator features for this type of engine are identified. The hydraulic bushing frequency response is then obtained experimentally. Based on the experimental results, a simple semi-active bushing proof-of-concept design is developed and tested, which utilizes a short inertia track to satisfy the soft isolator requirement in VDE mode. A mathematical model of the semi-active system is generated, and its validity is verified experimentally. The damping requirement of this semi-active isolator is produced by utilizing a MR compliance chamber. This innovative solution reduces the amount of expensive MR fluid requirements of the bushing. The experimental results on the semi-active bushing system, using a magnetic shaker, show the merit of the system for the VDE application.

A Piezoelectric Energy Harvester for Rotary Motion Applications: Design and Experiments

This paper investigates the analysis and design of a vibration-based energy harvester for rotary motion applications. The energy harvester consists of a cantilever beam with a tip mass and a piezoelectric ceramic attached along the beam that is mounted on a rotating shaft. Using this system, mechanical vibration energy is induced in the flexible beam due to the gravitational force applied to the tip mass while the hub is rotating. The piezoelectric transducer is used to convert the induced mechanical vibration energy into electricity. The equations of motion of the flexible structure are utilized along with the physical characteristics of the piezoelectric transducer to derive expressions for the electrical power. Furthermore, expressions for the optimum load resistance and maximum output power are obtained and validated experimentally using PVDF and PZT transducers. The results indicate that a maximum power of 6.4 mW at a shaft speed of 138 rad/s can be extracted by using a PZT transducer with dimensions 50.8 mm × 38.1 mm × 0.13 mm. This amount of power is sufficient to provide power for typical wireless sensors such as accelerometers and strain gauges.

Flexible fixture design with applications to assembly of sheet metal automotive body parts

Purpose – To design a reconfigureable flexible fixture for the assembly of a set of sheet metal automotive body parts. Reconfigureable fixturing permits different parts to be grasped for assembly by a fixture without the need to conduct costly redesign and fabrication of hardware fixtures, which is an industry standard in widespread use in industry. While somewhat more complex than fixtures in current use, reconfigureable fixtures provide one solution to the problem of costly redesign of fixtures due to changes in dimensions, or geometry of parts to be assembled.Design/methodology/approach – We propose a novel reconfigureable fixture for robotic assembly of a number of different parts. Motivated by the marine organism, O. vulgaris, commonly referred to as an octopus, which grasps different objects or prey using suction cups, the proposed fixture has three fingers, each equipped with a suction cup, to facilitate the grasping process and increase grasp flexibility. Using this design approach, the fixture is...

Real-Time Adaptive VVO/CVR Topology Using Multi-Agent System and IEC 61850-Based Communication Protocol

This paper proposes a new approach for real-time and adaptive Volt/VAr optimization (VVO)/conservation voltage reduction (CVR) system using Intelligent Agents, communicating through IEC 61850 Goose Messaging Protocol. The paper also proposes new real-time adaptive VVO/CVR algorithms tailored for different service level targets and system topologies. The paper argues that each of these variations requires different Intelligent Agent Systems, data structures, and communication requirements. To test the applicability of the VVO/CVR optimization engine, a modified IEEE 34 Node system is used as case study.

Modeling and Analysis of a Piezoelectric Energy Scavenger for Rotary Motion Applications

This paper presents modeling and analysis of a piezoelectric mounted rotary flexible beam that can be used as an energy scavenger for rotary motion applications. The energy harvester system consists of a piezoelectric bimorph cantilever beam with a tip mass mounted on a rotating hub. Assuming Euler-Bernoulli beam equations and considering the effect of a piezoelectric transducer, equations of motion are derived using the Lagrangian approach followed by relationships describing the harvested power. The equations provide a quantitative description of how the hub acceleration and gravity due to the tip mass contribute power to the energy harvester. In particular, expressions describing optimum load resistance and the maximum power that can be harvested using the proposed system are derived. Numerical simulations are performed to show the performance of the harvester by obtaining tip velocities and electrical output voltages for a range of electrical load resistances and rotational speeds. It is shown that by proper sizing and parameter selection, the proposed system can supply enough energy for operating wireless sensors in rotating mechanisms such as tires and turbines.

Broadening the Frequency Bandwidth of a Tire-Embedded Piezoelectric-Based Energy Harvesting System Using Coupled Linear Resonating Structure

The efficiency of single-degree-of-freedom (SDOF) vibration-based energy harvesters significantly drops when the resonance frequency of the harvester is different from that of the ambient vibration. In this study, a novel piezoelectric-based energy harvesting mechanism is introduced for rotary motion applications, which can generate power over a broad range of angular velocities of the wheel. The proposed design, which comprises a coupled spring-mass system attached to a PZT beam, has the advantage that it can easily be tuned in an off-line position by simply changing the tip mass and/or spring stiffness. A theoretical and experimental study is undertaken to check the performance of the proposed design for the range of speeds typical of commercial tires. It is shown that by tuning the resonance frequency of the mass-spring system the design can significantly increase the frequency bandwidth of the energy harvester.

Energy Harvesting From Pneumatic Tires Using Piezoelectric Transducers

The concept of harvesting energy in our surrounding has recently drawn global attention. Harvesting the ambient energy of the deflected tire and convert it to electricity is discussed in this paper. An Elastic pneumatic tire deflects due to the load it carries. This deflection appears as a contact patch to the road surface. Initially, the concept of the tire deflection will be discussed. This deflection is then related to the wasted energy used for deflection. The dependency of this energy to some important parameters such as the tire air pressure, vehicle speed and tire geometry and forces are primarily discussed. To harvest the deflection energy different well established methods are exists. Due to the tire environment, piezoelectric transducers can serve as the best option. Those transducers are traditionally used to produce mechanical motion due to the applied electrical charges. This material is also capable of generating electrical charges by mechanical motion and deflections. For the tire energy harvesting application, the piezoelectric stacks can be mounted inside a tire structure such that electric charge is generated therein as the wheel assembly moves along a ground surface. For this application, lead-zirconate-titanate (PZT) is selected. The PZT inside the tire is modeled as a cantilever beam vibration in its first mode of vibration. The frequency of vibration is calculated based on the car speed, tire size, and PZT stack length. A mathematical model for this energy harvesting application is derived. Based on this model, the optimum load of the electrical circuit is also found. Finally the amount of energy harvested from tire using PZT is calculated. Although this energy is not significantly high, it will be enough to provide power for wireless sensors applications.Copyright

Semi-active engine mount design using auxiliary magneto-rheological fluid compliance chamber

Engine mounts are used in the automotive industry to isolate engine and chassis by reducing the noise and vibration imposed from one to the other. This paper describes modelling, simulation and design of a semi-active engine mount that is designed specifically to address the complicated vibration pattern of variable displacement engines (VDE). The ideal isolation for VDE requires the stiffness to be switchable upon cylinder activation/deactivation operating modes. In order to have a modular design, the same hydraulic engine mount components are maintained and a novel auxiliary magneto-rheological (MR) fluid chamber is developed and retrofitted inside the pumping chamber. The new compliance chamber is a controllable pressure regulator, which can effectively alter the dynamic performance of the mount. Switching between different modes happens by turning the electrical current to the MR chamber magnetic coil on and off. A model has been developed for the passive hydraulic mount and then it is extended to include the MR auxiliary chamber as well. A proof-of-concept prototype of the design has been fabricated which validates the mathematical model. The results demonstrate unique capability of the developed semi-active mount to be used for VDE application.

Development of a bushing with an active compliance chamber for variable displacement engines

In this paper a novel active compliance chamber is designed, which can be used to control the dynamic stiffness of a common hydraulic bushing. This chamber offers a simple and cost-effective solution for the variable displacement engine (VDE) isolation problem. A VDE system requires a soft bushing for the half cylinder mode and a regular one for normal engine operations. A magnetic actuator is used to produce mechanical pulses. The linearisation technique is used for simplifying the nonlinear equation of motion. Different current sources are used to feed the magnetic actuator. The pressure inside the chamber follows linearly the current input signal. The phase shift in various current inputs is used in the form of the transfer functions to create the required pressure response pattern in the frequency domain. Since the dynamic stiffness of a conventional hydraulic bushing is a direct function of the pressure inside it, the active compliance chamber can be used to alter the pressure and consequently produce the required dynamic stiffness response. As a result, it can address the engine vibration problem for VDE situation.

Design of a solenoid valve based active engine mount

This paper describes the design of a versatile and fully controllable active engine mount. The proposed active mount is capable of addressing vibration isolation requirements at various driving conditions. This design addresses a better ride quality that has always been demanded by the automotive industry, as well as satisfying sophisticated vibration isolation requirements for the unconventional engines, i.e. variable displacement, and hybrids. The proposed engine mount replaces the decoupler of the original design with a solenoid actuator. The mathematical model of the active mount is obtained. The dynamic characteristics of the mount are shown to be highly controllable over the operating frequency range of excitation in engines. The effectiveness of the developed active engine mount for various working conditions of engine is also evaluated. Several driving conditions are investigated and proper control strategies are utilized to demonstrate the mounts capability to fulfill the isolation requirements for each condition. The promising results, in addition to compactness, low cost, fail safety, and durability are the main advantages of the proposed active engine mount, which makes it viable for automotive applications.