This paper demonstrates that a hydraulically acting Helmholtz resonator can exist in a piezoelectric–hydraulic pump (PHP) based hybrid actuator, which in turn affects the volumetric efficiency of the PHP. The simulation and experimental results illustrate the effect of Helmholtz resonance on the flow rate performance of the PHP. The study also shows how to shift the Helmholtz resonant frequency...

Hydro-mechanical transmission (HMT) based hybrid hydraulic vehicle architecture is potentially more efficient than other architectures because: 1) it uses the efficient mechanical transmission for partial power transfer, 2) it allows the engine to operate at its most efficient point. The input coupled power split hybrid vehicle being developed is one such example. The increase in degrees of fre...

In this document the design, control and simulation of a hydraulic model for grasping an object is presented. The principal equations that constraint such a system are first investigated through the presentation of the hydraulic components which constitute the model. Their intrinsic characteristics are discussed as well as their interactions with each other. The controller that best fit this ap...

The Center for Transportation Research (CTR) Vehicle Systems team modified a Nissan CK-2 Continuously Variable Transmission (CVT) for a diesel hybrid powertrain application. Mechanical and electrical modifications were made to the CVT, both internal and external to the transmission. The goal of this experiment was to investigate and demonstrate the potential of CVT for diesel engines hybrid ele...

Hybrid mechanical press is an innovative sheet metal stamping press that has the advantages of both mechanical press and the hydraulic press. This paper focuses on the control of the hybrid mechanical press, including trajectory planning, trajectory optimization and real time feedback control. The trajectory planning is based on inverse kinematics and cubic spline interpolation. The trajectory ...

This paper simplifies the energy recovery process in the series hydraulic hybrid bus’ energy regeneration system into a process in which the main axle’s moment of inertia drives the secondary element variable delivery pump/motor and brings hydraulic oil from the oil tank to the accumulator. This process enables braking of the vehicle and also allows recovery of energy to the accumulator. Based ...

This paper deals with a hybrid actuator composed by a piezo and a hydraulic part and with a cascade PID-PD control structure for camless engine motor applications. The idea is to use the advantages of both, the high precision of the piezo and the force of the hydraulic part. In fact, piezoelectric actuators (PEAs) are commonly used for precision positionings, despite PEAs present nonlinearities...

This paper simplifies the energy regeneration based vehicle velocity system of the hydraulic hybrid bus into a process in which the extension rod of the hydraulic cylinder drives the secondary-element variable delivery pump/motor to change its displacement. This process enables braking of the vehicle and also allows recovery of energy. The stability, energy efficiency and other characteristics ...