a new base isolation method for reducing the destructive effect of earthquake is proposed in this method mushroom shaped basements are used under structures as base isolation. these basements have spherical surface and are located on foundations. basements have pinned arms that are connected. when the length of the arm is less then the radius of spherical surface, the action of them is similar ...

This paper discusses the stability of 2D frictionless grasps and combining stability of frictional and frictionless grasps from the viewpoint of potential energy method. In many works related to the frictionless grasp, each finger is replaced by one directional virtual spring along the normal at the contact point. However, this condition is not accurate, because the frictionless condition does ...

But this is not real life! Suppose next that we are still moving in a straight line but the force is variable: indeed, the typical example of this is that of a spring: suppose we have a mass M on a spring, and we stretch the mass a distance of x units from its equilibrium position. The spring will pull back in the opposite direction, and the early British scientist Robert Hooke formulated a sim...

We present a hydro-elastic actuator that has a linear spring intentionally placed in series between the hydraulic piston and actuator output. The spring strain is measured to get an accurate estimate of force. This measurement alone is used in PI feedback to control the force in the actuator. The spring allows for high force fidelity, good force control, minimum impedance, and large dynamic ran...

Internally-balanced Magnetic Unit (IB Magnet) has been developed as a fundamental technique of wall climbing robots. This unit comprises of a permanent magnet which generates a strong sticking force, and a spring unit which cancels the internal force so that the unit can provide easy sticking and releasing actions. In this paper, the authors aim to enlarge usefulness of IB Magnet by several app...

This study presents a photo-driven micro-lever fabricated to multiply optical forces using the two-photon polymerization 3D-microfabrication technique. The micro-lever is a second class lever comprising an optical trapping sphere, a beam, and a pivot. A micro-spring is placed between the short and long arms to characterize the induced force. This design enables precise manipulation of the micro...

Series elastic actuators have a spring intentionally placed at the actuator output. Measuring the spring strain gives an accurate measurement for closed-loop actuator force control. The low spring stiffness allows for high control gain while maintaining actuator stability. This gives series elastic actuators many desirable properties including high bandwidth at moderate force amplitudes, low ou...

During locomotion, major muscle groups are often activated cyclically. This alternate stretch-shorten pattern of activity could enable muscle to function as a spring, storing and recovering elastic recoil potential energy. Because the ability to store and recover elastic recoil energy could profoundly affect the energetics of locomotion, one might expect this to be an adaptable feature of skele...

This paper presents a micrograting-based force sensor integrated with a surface micromachined silicon-nitride probe suitable for characterizing microsurgery force on a single cell or embryo. The probe is supported by springs of a known spring constant, and the surgical penetration force is determined from displacement measurements. The opticalencoder force sensor exhibits conŽgurable sensitivit...

This study presents effects of the vane spring stiffness on frictional power characteristics of a refrigeration compressor. Comparisons on the compressor performance are investigated for different vane spring stiffnesses with compressors designed with high and low shell pressures. Results show that while compressors with a low shell pressure using a higher spring stiffness combination may reduc...