The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Linear motor has potential applications in electric vehicles because of high efficiency and convenient maintenance. However, existing researches are mainly about linear motors, rarely focusing on its loading system. Actually its complicated motion pattern requires accurate and multi-mode load simulation to evaluate output performance comprehensively. In this paper, a novel multi-mode and accurate...
In this paper we present an electro-hydraulic load simulation method for the helicopter booster. Based on electro-hydraulic servo control technology, we construct the load simulation system. And then, the mathematical model of load simulation system for the booster is built. The position servo system controller is combined of hysteresis compensation with PI controller and the force servo system controller...
In this paper, an ongoing work for verifying the behavior of a twisted string actuator in contact with a sliding surface or guided through a sheath is presented. The twisted string actuation system is particularly suitable for very compact and light-weight robotic devices, like artificial limbs and exoskeletons, since it allows the implementation of powerful tendon-based driving systems, based on...
We present a new palm design that features a dense array of micro-spines for the JPL Robosimian human-scale climbing robot. A linearly-constrained spine mechanism is introduced and analyzed using adhesion and stiffness models. This mechanism achieves a spine density of 19/cm2 and a mean adhesion of 67N (207kPa) on coarse concrete surfaces. The models are validated on two different surfaces with two...
Robots with Variable Stiffness Actuators (VSA) are intrinsically flexible in the joints. The built-in mechanical spring has the advantage of a higher peak performance, in some extend increased safety for humans interacting physically with the robot, and promises a more energy efficient robot for certain trajectories. This paper shows the modeling process of a VSA including energy losses on the example...
A kind of closed hydraulic system controlled by servo motor and constant pump is introduced for controlling the experimental press. By using AMESim and Adams, the hydraulic system model and motion model of the beam of the experimental press are established and co-simulation is carried out. PID controller is used in this hydraulic system to improve the control performance. Simulation results indicate...
In order to improve the control accuracy and adaptive ability of electro-hydraulic loading system, a back-stepping adaptive friction compensation method based on LuGre-model is presented here. The dynamic model of electro-hydraulic loading system is established, and the friction characteristics based on LuGre model are described. For adapting to the change of frictional model parameters of the system,...
In order to provide highly compliant and powerful force, a series elastic actuator (SEA) has been developed and are now widely utilized. In spite of this characteristics as an ideal force source for safe human-robot interactions, SEA is considered difficult to design and control as its mechanical structure is complicated, namely it consists of a motor, a reduction gear, an elastic element and load,...
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...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.