Topology and size optimization methods are used to design compliant mechanisms that produce a constant output force for a given actuator characteristic of linearly decreasing force versus displacement. The design procedure consists of two stages: (i) topology optimization using two-dimensional (2-D) continuum parametrization, and (ii) size optimization of the beam-element abstraction derived fr...

A statistical mechanical description of flexible and semiflexible polymer chains in a poor solvent is developed in the constant force and constant distance ensembles. We predict the existence of many intermediate states at low temperatures stabilized by the force. A unified response to pulling and compressing forces has been obtained in the constant distance ensemble. We show the signature of a...

Quantitative force measurements performed using the atomic force microscope AFM inherently rely on calibration of the AFM cantilever spring constant to convert the measured deflection into a force. Here, we examine the effect of cantilever tilt and induced torque on the effective normal spring constant resulting from variable placement of the tip probe, as is frequently encountered in practice....

In colloidal probe atomic force microscopy (AFM) surface forces cannot be measured without an accurate determination of the cantilever spring constant. The effective spring constant k depends upon the cantilever geometry and therefore should be measured in situ; additionally, k may be coupled to other measurement parameters. For example, colloidal probe AFM is frequently used to measure the sli...

Muscle produces force by forming cross-bridges, using energy released from ATP. While the magnitude and duration of force production primarily determine the energy requirement, nearly a century ago Fenn observed that muscle shortening or lengthening influenced energetic cost of contraction. When work is done by the muscle, the energy cost is increased and when work is done on the muscle the ene...

Series Elastic Actuators have linear springs intentionally placed in series between the motor and actuator output. The spring strain is measured to get an accurate estimate of force. Despite using a transmission to achieve high force/mass and high power/mass, the spring allows for good force control, high force fidelity, minimum impedance, and large dynamic range. A second order linear actuator...

The aim of the present study was to investigate memory effects, force accuracy, and variability during constant isometric force at different force levels, using auditory biofeedback. Two types of transition trials were used: a biofeedback-no biofeedback transition trial and a no biofeedback-biofeedback transition trial. The auditory biofeedback produced a low- or high-pitched sound when partici...

Muscle force during active lengthening was characterized for scaphognathite levator muscle L2B from the crab Carcinus maenas. The muscle was tetanically stimulated and, during the peak of the contraction, stretched at constant velocity. The total strain was approximately 4 %, the strain rates ranged from 0.03 to 1.6 muscle lengths s-1 (L s-1), and the temperature was 15 degreesC. Force increase...

a portable and light pneumatic branch shake system was designed and manufactured in this research for harvesting fruits that can be harvested by shaking branch. required air flow and electric current are provided for operating system from category containing electrical generator and air compressor on wheelbarrows and portable chassis. vibration is equipped by programmable logic controller (plc)...