This paper presents a comparative study among friction behavior of several double-acting pneumatic actuators available to industrial use. A brief review covering the manner that pneumatic actuator manufacturers and current literature approach friction force and its usual models also is presented. After depicting friction test methodology and test apparatus, the comparison work is carried out th...

This work presents a modeling and control design method for PWM-controlled pneumatic systems. Difficulties associated with servovalves typically used to continuously control pneumatic systems, in addition to a general lack of analytic control design techniques available for PWMcontrolled pneumatic systems, motivate the development> of a modeling and control design technique for PWM pneumatics. ...

Since 1972 the Hyogo Rehabilitation Centre has been developing a variable-resistance-type pneumatic control device, the HRC Adjustable Pneumatic Swing-Phase Control Knee. Successful field tests have been carried out on 20 cases with Model IV since 1973 with only a limited number of mechanical troubles. This paper introduces the HRC adjustable pneumatic swing-phase control knee with follow-up st...

BACKGROUND Intubation is frequently performed in intensive care unit patients. Overinflation of the endotracheal tube cuff is a risk factor for tracheal ischemia and subsequent complications. Despite manual control of the cuff pressure, overinflation of the endotracheal cuff is common in intensive care unit patients. We hypothesized that efficient continuous control of the endotracheal cuff pre...

Determination and analysis of vibration behavior of structures for at least first few natural frequencies and mode shapes needs several sensors to be connected at different non node points and exciting the structure at one point. Other method for determination of first few mode shapes is to excite several points of the structure at once and sensing the response from one point.  Both methods nee...

Controlling the occurrence of defects is a major challenge for manufacturing organizations that are seeking to enhance their competitive position in today’s global market. This paper considers the process of screen-printing T-shirts using hydraulic and pneumatic printing machines. Several defects in the output of this printing process have been observed, especially with multi colors printing as...

BACKGROUND Pneumatic dilatation or intrasphincteric botulinum toxin injection provide effective symptom relief for patients with achalasia. Although intrasphincteric botulinum toxin injection is simple and safe, its efficacy may be short-lived. Pneumatic dilatation lasts longer, but esophageal perforation is a risk. We compared treatment costs for pneumatic dilatation and intrasphincteric botul...

Parallel robots exhibit high stiffness, low weight and low dynamic forces, mostly because of the closed loop chains implied by their structure, and allow the positioning of the actuators on the truss. These characteristics outline the possibility of actuating such kind of robotic devices by means of pneumatic actuators. The position control of pneumatic cylinders through proportional valves sat...

This work describes a method for the simulation of multiple pneumatic actuators in a context of multi body mechanical systems. The model of the single actuator is based on elliptical approximation of non-linear pneumatic devices; friction and sticking phenomena are considered as well. Pneumatic devices introduce forces and new state variables into the complete multibody system: we developed a s...

OBJECTIVE To comprehensively review and critically assess the available gynecologic surgery venous thromboembolism prophylaxis literature and provide clinical practice guidelines. DATA SOURCES MEDLINE and Cochrane databases from inception to July 2010. We included randomized controlled trials in gynecologic surgery populations. Interventions and comparators included graduated compression stoc...