This paper describes the modelling and testing of mm-scale hydrodynamic bearings which are being developed to improve the efficiency of a cm-scale turbine energy harvester, whose efficiency was previously limited by poorly lubricated commercial jewel-bearings. The bearings were fabricated using DRIE and their performance was assessed using a custom built MEMS tribometer. Results demonstrate tha...

This paper describes the modelling and testing of mm-scale hydrodynamic bearings which are being developed to improve the efficiency of a cm-scale turbine energy harvester, whose efficiency was previously limited by poorly lubricated commercial jewel-bearings. The bearings were fabricated using DRIE and their performance was assessed using a custom built MEMS tribometer. Results demonstrate tha...

We review the state of the art in friction estimation and rendering for haptic interfaces and present a method based on a modified Karnopp friction model. We illustrate some of the advantages of this approach and show how it can be used to create accurate and convincing displays of sliding friction, including pre-sliding displacement and stick-slip behavior. We also present the results of human...

A spanwise array of surface hot-film shear-stress sensors and a traversing hot-wire located directly above one of these sensors are used to examine the relationship between skin-friction fluctuations and the velocity fluctuations in the boundary layer. Experiments are performed in a high Reynolds number turbulent boundary layer at Reθ ≈ 39000. The shear-stress data indicate the presence of larg...

This paper describes friction compensation based control of an industrial pneumatic actuator used for the variable geometry turbocharger (VGT). Adaptive LuGre model for friction has been used in this work. Friction force that is responsible for hysteresis and hunting phenomenon in the position control is compensated with two different control strategies designed to improve low velocity position...

BACKGROUND AND OBJECTIVES Therapeutic laparoscopy was incorporated into surgical practice more than 25 y ago. Several modifications have since been developed to further minimize surgical trauma and improve results. Minilaparoscopy, performed with 2- to 3-mm instruments was introduced in the mid 1990s but failed to attain mainstream use, mostly because of the limitations of the early devices. Bu...

The aims of this study were to determine and compare frictional resistance obtained by low-friction and conventional elastomeric ligatures in the presence of artificial saliva, and observe whether this variable changed after 21 days. Super Slick® low-friction elastomeric ligatures and conventional ligatures of the brands TP conventional® and Unitek® were placed on standard edgewise maxillary ce...

This paper presents experimental investigations to actively modulate the nanoscale friction properties of a self-assembled monolayer (SAM) assembly using an external electric field that drives conformational changes in the SAM. Such "friction switches" have widespread implications in interfacial energy control in micro/nanoscale devices. Friction response of a low-density mercaptocarboxylic aci...

introduction: the purpose of this study was to compare the accuracy of the torque wrenches used in different dental implant systems. methods: we evaluated 42 torque wrenches used in different dental clinics in mashhad, iran, using a digital torque meter (mark 10). high (25, 30 and 35 n·cm) and low (15 n·cm) levels of torque were examined. ten tests were performed on each wrench, and the mean va...

In this paper we present two controllers for robots that combine terms for the compensation of gravity forces, and the forces of friction of motors and gearboxes. The Low-Friction Zero-Gravity controller allows a guidance of the robot without effort, allowing small friction forces to reduce the free robot motion. It can serve to aid users providing kinesthetic demonstrations while programming b...