friction is a nonlinear phenomenon which has destructive effects on performance of control systems. to obviate these effects, friction compensation is an effectual solution. in this paper, an adaptive technique is proposed in order to eliminate limit cycles as one of the undesired behaviors due to presence of friction in control systems which happen frequently. the proposed approach works for n...

In this paper, the nonlinear optimal control problem is formulated for the position control of an electrohydraulic servo system. The optimal control is given by the solution to the Hamilton-Jacobi-Bellman equation, which in this case cannot be solved explicitly. An alternative method, based upon successive Galerkin approximation, is used to obtain an approximate optimal solution. Preliminary si...

The positioning stand could help the surgeon to position and lock endoscopic tools without the need for an assistant surgeon. The kinematic con guration of the positioning stand is comprised of two main parts, the arm (for positioning) and the wrist (for orienting the tool). The main requirement of the wrist is to perform spherical movements around the incision point. A concentric multi-link sp...

background: long-term tunneled catheters are used for the hemodialysis or chemotherapy in many patients. proper placement of the catheter tip could reduce early and late catheter related complications. aim of the present study was to evaluate a new formula for proper placement of tunneled hemodialysis or infusion port device by using an external anatomic landmark. materials and methods: a total...

OBJECTIVE Automobile head restraints, when used properly, have been shown to decrease the incidence and severity of whiplash injuries to the neck. Before the development of a public campaign on proper head restraint positioning, the authors assessed head restraint positioning and public understanding. DESIGN Over a one month period, the position of the vehicle head restraint of drivers was ob...

introduction: the use of panoramic radiography has shown a remarkable expansion over the past 20 years. accurate positioning and preparation of patients is needed to avoid image distortion. the aim of this study was to evaluate the common errors on panoramic radiographs taken in the radiology department of rasht dental school. materials and methods: the study sample included 390 digital panoram...

The method of compensation elastic vibrations electric drives industrial positioning mechanisms, as well methods for assessing the level these are shown. It is proposed to choose parameters motor and mechanism optimal according criterion minimum at design stage displacement mechanisms. Positioning mechanisms "actuator" type with screw –nut transmission make it possible implement this approach

We present a novel method for the autonomous positioning of surgical lamps in open surgeries. The basic idea is to use an inexpensive depth camera to track all objects and the surgical staff and also generate a dynamic online model of the operation situs. Based on this information, our algorithms continuously compute the optimal positions for all surgical lamps. These positions can then be comm...