Page 49 - ASME DSCC 2015 Program

Technical Program

nitudes. It is found that superior vibration control is achieved with combined Performances of Energy-Harvesting Shock Absorbers on Various Types
paths, provided all powertrain paths are aligned with the torque roll axis of Vehicles
coordinates. Additionally, successful control is dependent on which paths Invited session paper. DSCC2015-9772
are selected as a combination of active and passive mounts, dictated by the Sijing guo, Lin xu, xuexun guo, Wuhan University of Technology, Wuhan,
interaction between active control forces and the passive system dynamics. Hubei, China, Yilun liu, lei Zuo, Virginia Tech, Blacksburg, VA, United
Active and Passive Vibration Control using Compact Damping Patches: States
Assessment of a Reduced order Model for an Euler Beam Energy-Harvesting Shock Absorber (EHSA), as a large-scale energy-harvest-
Contributed regular paper. DSCC2015-9636 ing mechanism for recovering suspension vibration energy, has been stud-
Joseph Plattenburg, Jason T. Dreyer, Rajendra Singh, The Ohio State ied for years. A design of the regenerative shock absorber with Mechanical
University, Columbus, OH, United States Motion Rectifier (MMR) has been proved to be more reliable and efficient.
This paper reports a comprehensive study of the influence of MMR-based
Concurrent placement of compact active and passive damping patches for
Energy-Harvesting Shock Absorber (MMR-EHSA) on vehicle dynamics
vibration reduction is a developing area of research. Analytical and compu-
performances. Models of MMR-EHSA and vehicle with MMR-EHSA with two
tational models to evaluate alternate patch configurations and structural ge-
degrees of freedom are created. Simulations are conducted on five typical
ometries are not widely available. To overcome this void, this paper presents
vehicles, including passenger car, bus and three types of trucks. The ride
a simplified discrete-system model for vibrations of a beam-like structure. A
characteristics of comfort, road handling and energy recovery are evaluat-
disturbance input is included in the model, along with a control input from
ed on these vehicles under various MMR rotational inertia and harvesting
an active patch. Localized structural damping resulting from a passive patch
damping. The simulation results show that MMR-EHSA is able to improve
is modeled with an equivalent loss factor. Results from the simplified model
both the ride comfort and road handling simultaneously under certain condi-
are verified using a more detailed analytical formulation, which is based on
tions over the traditional shock absorbers, which broadens our knowledge
the Ritz approximation. Verification studies include the effect of a passive
of MMR-EHSA’s applicable scenarios.
damping patch on modal loss factors and broadband attenuation. Finally, a
few case studies are proposed which show the efficacy of the reduced-or- Vibrations of Curved and Twisted Beam
der model for parametric design studies. These studies include determin- Invited session paper. DSCC2015-9880
ing the effect of localized damping on the control system parameters that Yiming Zhao, Halliburton, Houston, TX, United States, Jason Dykstra,
are required for attenuation of localized and global motions. The effect of Halliburton Energy Services, Spring, TX, United States
patch locations on system response is also studied. This work has potential
This paper studies the vibration of beams in 3D space with arbitrary shape.
applications in industry since compact damping patches are attractive NVH
Based on results from differential geometry of curves, a set of beam
treatments that add minimal weight and complexity.
vibration dynamics equations is developed, comprising six partial differen-
Proof-of-Concept Experimental Validation of a new Active tial equations (PDE). The beam dynamics equations account for both the
Hydrodynamic Bearing in-plane and out-of-plane beam vibrations simultaneously. In addition, the
Contributed regular paper. DSCC2015-9675 equations explicitly capture the coupling between different vibration mode
neal Rivenbark, Cullen Walsh, Marcio de Queiroz, Louisiana State types, which occur when the beam exhibits geometric irregularities such as
University, Baton Rouge, LA, United States bending, torsion, and twisting. The proposed beam dynamics equations are
solved numerically. Comparison between experimental results and numer-
Flow-induced instabilities known as ‘whirl’ and ‘whip’ are the main contribu-
ical results obtained by solving the PDEs proposed in this paper shows a
tors to self-excited vibrations in fluid-film bearings. In this paper, we exper-
good match for in-plane and out-of-plane curved beam vibrations.
imentally evaluate a new active hydrodynamic bearing designed to lessen
flow-induced vibrations in rotating machines. The active system consists of Control Design for a Hand Tremor Suppression Pen
a fluid-film bearing with a motor-actuated rotating bushing that serves as Invited session paper. DSCC2015-9962
the control input. This input is used to adjust the mean flow velocity in the Che ou, Andrew Gouldstone, Beverly Jaeger, Rifat Sipahi,
bearing and indirectly control the whirl vibration. A PID-type control law is Northeastern University, Boston, MA, United States
used to adjust the bushing speed. An experimental test rig that realizes the
Active feedback control is utilized in this study in order to regulate pen-tip
active bearing concept is introduced. Experimental results are presented
deviations in a novel pen design with the aim to minimize the effects of hand
comparing the active bearing with PID-type control and open-loop control to
tremors on handwriting. The pen comprises a pendulum-like pen-rod that
the passive bearing operation. The results show that the active bearing with
swings inside a tubular shaped pen casing, and between the pen and the
feedback control is effective in eliminating whirl vibrations.
casing, certain compliance and active actuation is considered. Since by the
nature of the system dynamics, arbitrary pole placement is not possible in
the design of the controller, a nonlinear optimization scheme is construct-
ed to design the controller gains. With these gains, pen-tip deviations are
minimized (~ -47 dB) when the pen casing is subjected tremor-induced cyclic
disturbances, and pen-tip response against impulsive perturbations is sat-
isfactorily improved (settling time ~ 1 sec) while keeping the controller effort
around 2 N. Simulation studies are presented comparing the efficacy of the
proposed controller with respect to a passively controlled pen, along with 49
trade-offs within the design parameter space.