Spring-like leg behavior is found in both humans and animals when running. In a spring-mass model, running proves to be self-stable in terms of external perturbations or variations in leg properties (for example, landing angle). However, biological limbs are not made of springs, rather, they consist of segments where spring-like behavior can be localized at the joint level. Here, we use a two-s...

The shape memory alloy (SMA) based actuators are replacing huge and bulky because of its ability to provide high work per unit mass serves as active prismatic joint develop precise robotic manipulators. It also helps in developing a light weight manipulators with simple actuation process. Here, the study presents relationship between contraction Nitinol SMA prings input variables such current t...

An H∞ synthesis method for control of a flexible joint, with non-linear spring characteristic, is proposed. The first step of the synthesis method is to extend the joint model with an uncertainty description of the stiffness parameter. In the second step, a non-linear optimisation problem, based on nominal performance and robust stability requirements, has to be solved. Using the Lyapunov shapi...

In this study, the improvement of energy harvesting from wideband vibration with random change by using a combination of linear and nonlinear spring system is investigated. The system consists of curved beam spring for non-linear buckling, which supports the linear mass-spring resonator. Applying shock acceleration generates a snap through action to the buckling spring. From the FEM analysis, w...

in this study, application of adaptive neuro-fuzzy inference system (anfis) in forecasting three perspectives (1, 2, and 4 years) ahead of iran’s agricultural products export was compared with arima as the most common econometrics linear forecasting method. for this purpose, iran’s agricultural products export revenues related to 1959-2010, and forecast performance measures such as r2, mad, and...

In this paper we present a newmethod for approximating non-linear dynamics in deformable simulations based on a full cubic polynomial formulation of the inter-particle force. The proposed approach is a non-physical extension of the well known St Venant Kirchhoff force, focusing on practical considerations about the behavior of the deformable model. Therefore it is very useful for simulating and...

Vibration signals of non-linear systems can be locally represented by a frequency and a spread about that frequency on the base of the Wigner-Vie Distribution as distribution of energy in time and frequency. They can also be represented via the instantaneous frequency as the first derivative of the instantaneous phase of the analytic signal. Frequency estimations of non-linear systems are time ...

This paper presents the initial investigation of nonlinear control for a magnetic spring. The combination of a magnet pair in repulsion and a magnet pair in attraction create a spring with a quadratic force curve. At its nominal position, it is a marginally stable system that has interesting vibration isolation properties. Non-linear control is shown to be effective in stabilising the system.