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Facing the energy crisis and environmental problems, saving energy of construction machinery, especially in the hydraulic excavator is very important. Regeneration of the potential energy is an effective solution to save energy. However, the conventional hybrid excavator can't regenerate the potential energy. This paper proposes a new structure of hydraulic excavator as well as a control strategy...
Mechanics modeling for joints is a challenging problem for the complex multi-scale, multi-physics behaviors of contact interface, which will induce additional flexibility and damping to the assembled structure. In this paper, Iwan model was applied to describe the nonlinear softening stiffness and hysteresis behaviors of joint interface. The dynamic governing equations of vibration system are conducted...
There is a lack of system-level finite element (FE) model which can directly predict the performance of a piezoelectric energy harvester connected with interface circuits and electric load. This work developed a system-level model of piezoelectric strain energy harvesting system by directly coupling the finite element and electrical circuits. The strain energy harvester (SEH) is a macro fibber composite...
The behavior of scissor action dry friction damper under harmonic loading has been presented. Finite element model was developed in PTC CREO and then imported in ANSYS to check the response with varying values of normal force (100N, 120N and 150N). A constant force of 20N is applied to excite the damper harmonically. Moreover the experiments are performed after fabricating the device to validate the...
Gas insulated switchgear (GIS) is widely used for its good economic benefits. But mechanical faults caused by electromagnetic force occur occasionally. The conducting wire and the metal shell are exposed in the alternating electromagnetic field, which is caused by the load current and vortex. This leads to electromagnetic force because of electromagnetic induction. So it is necessary to analyze the...
The most critical part of the induction machines which determines on their life time operation are rolling element bearings. To ensure reliable drive with an induction machine requires deep insight in electro-mechanical dynamics during its operation. The flexible multibody modeling technique enables the simulation of dynamic loads on all drive components. This paper focuses on complex dynamic modeling...
Ultrasound elasticity imaging (UEI) is a noninvasive method for characterizing mechanical properties of soft tissue. This technique potentially provides important feedback for making treatment decision for advanced tendinopathies, such as posterior tibial tendon dysfunction (PTTD). Highly variable lateral strain along the length of the tendon has been observed during human experiments. To better understand...
This paper presents a co-rotational concept for large-deflection formulation of cardiac catheters. Using this approach, the catheter is first discretized with a number of equal length beam elements and nodes, and the rigid body motions of an individual beam element are separated from its deformations. Therefore, it is adequate for modelling arbitrarily large deflections of a catheter with linear elastic...
This report describes the development of a force platform based on instrumented load cells with built-in conditioning circuit and strain gages to measure and acquire the components of the force that is applied to the bike crank arm during pedaling in real conditions, and save them on a SD Card. To accomplish that, a complete new crank arm 3D solid model was developed in the SolidWorks, with dimensions...
Orthodontic force simulation is very important for the guidance of clinical orthodontic treatment. Previous works were mainly conducted by directly loading the force on a single or a few teeth. However, in clinic, the orthodontic force is provided by loading orthodontic appliances, and there currently is no appropriate way to measure the force on the teeth provided by the loaded appliances. This study...
Postural instability affects a large number of people and can compromise even simple activities of the daily routine. Therapies for balance training can strongly benefit from auxiliary devices specially designed for this purpose. In this paper, we present a system for balance training that uses the metaphor of a game, what contributes to the motivation and engagement of the patients during a treatment...
To determine a force-closure grasp, current grasp synthesis algorithms either assume a deterministic model to compute a desired finger placement without noise, or model the end-effector position as a free-floating rigid body whose noise in pose is independent of the kinematic chain formed by the robot arm. In this work we instead explore a probabilistic approach that explicitly models noise in joint-angles...
In recent years the control of Wave Energy Conversion (WEC) systems has been a challenging research topic. A 1/50th scale buoy system has been constructed at the University of Hull for modelling, verification and control. This study focuses on the time-varying state space model development of this direct-drive WEC with a tubular permanent magnet linear generator (TPMLG). A new form of control is developed,...
A novel, homogeneous and continuous analytical model of cyclist pedaling torque angular distribution is presented in the article. The model is dedicated for use in an unique pedaling-by-wire system. The motivation to the research is to obtain a model for use in control system with compensation. Applying nonlinear compensation of cyclist load torque results in pedals speed ripples reduction — particularly...
The preload of bolt is very important for bolt connection, because it affects the reliability and tightness of the connection. The best bolt mounting method for the control of preload is through a hydraulic stretching device. However, the initial tensile bolt preload is not equal to the final, as a result of elastic rebound deformation of bolt. This paper analyses the tensile resilience of hydraulic...
Due to the existence of clearances, contact-impact events are liable to cause lower transmission precision and slower dynamic response of the mechanism involving revolute joints. Based on the elastic-damping method, the continuous contact force (CCF) model is widely used in explicating the contact-impact phenomena. As part of storing and releasing strain energy in the CCF model, the elastic force...
The use of minimally invasive procedures for breast tumor diagnosis and treatment, such as needle biopsy and radio frequency ablation (RFA), is steadily increasing. Accurate needle insertion requires solving the problems of tissue deformation and target displacement. Breast needle insertion guided by imaging techniques such as ultrasound is widely used to evaluate suspicious masses within the breast...
This paper describes the basic theoretical knowledge of piezoelectric ceramic materials, analyzes piezoelectric bimorph deformation theory, sums up the common way of working of the piezoelectric bimorph as a driving source. Based on the internal energy analysis of three layers structure piezoelectric bimorph, we establish a model of output force and output displacement under different loading conditions...
Precision centrifuge is an important test equipment in inertial navigation. In this paper, the problem of the accuracy of 2-DOF precision centrifuge is investigated and the unbalance balancing problem is completed while the precision centrifuge rotor unbalance exists. Firstly, based on the institutional arrangements of precision balancing centrifuge system, the existing forms of the unbalance of the...
Pneumatic Artificial Muscles (PAMs) are used in robotic and prosthetic applications due to the high power to weight ratio, controllable compliance, and simple design. Contractile PAMs are typically used in traditional hard robotics in place of heavy electric motors. As the field of soft robotics grows, extensile PAMs are beginning to have increased usage. This work experimentally tests, models, and...
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