Previous research has shown that an increase in hamstring activation may compensate for anterior tibial transalation (ATT) in patients with anterior cruciate ligament deficient knee (ACLd); however, the effects of this compensation still remain unclear. The goals of this study were to quantify the activation of the hamstring muscles needed to compensate the ATT in ACLd knee during the complete ...

This paper presents a new teleoperation approach using a virtual spring, and local contact force control on the slave robot. The operational space framework provides the control structure needed to achieve decoupled task dynamics. A virtual spring connects the master and slave systems and a closed-loop force controller compensates for the dynamics of the slave system, rendering transparent the ...

A novel low-cost impedance control structure is proposed for monitoring the contact force between end-effector and environment without installing an expensive force/torque sensor. Theoretically, the end-effector contact force can be estimated from the superposition of each joint control torque. There have a nonlinear matrix mapping function between each joint motor control input and end-effecto...

The problem of force distribution in systems involving multiple frictional contacts between actively coordinated mechanisms and passive objects is examined. The special case in which the contact interaction can he modeled by three components of forces (zero moments) is particularly interesting. The Moore-Penrose Generalized Inverse solution for such a model (point contact) is shown to yield a s...

The aim of this study was to evaluate the effect of bicycle pedal design on the mechanics of the patellofemoral joint. Previous research determined that for certain riders the non-driving varus and internal knee moments could be reduced by switching from fixed to free floating pedals (Ruby and Hull, 1993). It was postulated that the presence of varus and internal knee moments during fixed pedal...

BACKGROUND Arthrofibrosis in the suprapatellar pouch and anterior interval can develop after knee injury or surgery, resulting in anterior knee pain. These adhesions have not been biomechanically characterized. METHODS The biomechanical effects of adhesions in the suprapatellar pouch and anterior interval during simulated quadriceps muscle contraction from 0 to 90° of knee flexion were assess...

Contact probing is the preferable method for studying mechanical properties of thin two-dimensional (2D) materials. These studies are based on analysis of experimental force-displacement curves obtained by loading of a stretched membrane by a probe of an atomic force microscope or a nanoindenter. Both non-adhesive and adhesive contact interactions between such a probe and a 2D membrane are stud...

PURPOSE The purpose of this study is to evaluate the effect of change in tibial posterior slope on contact force and ligament stress using finite element analysis. MATERIALS AND METHODS A 3-dimensional finite element model for total knee arthroplasty was developed by using a computed tomography scan. For validation, the tibial translations were compared with previous studies. The finite eleme...

A successful catch of a falling ball requires an accurate estimation of the timing for when the ball hits the hand. In a previous experiment in which participants performed ball-catching task in virtual reality environment, we accidentally found that the weight of a falling ball was perceived differently when the timing of ball load force to the hand was shifted from the timing expected from vi...

To be successful at manipulating objects one needs to apply simultaneously well controlled movements and contact forces. We present a computational theory of how the brain may successfully generate a vast spectrum of interactive behaviors by combining two independent processes. One process is competent to control movements in free space and the other is competent to control contact forces again...