Using two servovalves to improve pneumatic force control in industrial cylinders

Carneiro, João Falcão; Almeida, Fernando Gomes de

doi:10.1007/s00170-012-4324-8

Cited by 20 publications

(8 citation statements)

References 16 publications

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“…The force division block used in this work provides force references so that pneumatic force saturation is avoided in both chambers, as it has been shown that this strategy may improve pneumatic force control [32]. The equations used to implement this strategy are given in Eqs.…”

Section: Pneumatic Connectionsmentioning

confidence: 99%

Accurate motion control of a servopneumatic system using integral sliding mode control

Carneiro

Almeida

2014

Int J Adv Manuf Technol

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Pneumatic systems are a simple and readily available technology that presents high force to volume ratios. Their use is nevertheless restricted to simple motion tasks, given the complexity in its modelling and control. One of the main aspects contributing to this panorama is the difficulty in accurately predicting friction forces. In fact, although it is possible to find in literature complex friction models that suit well a particular experimental set-up, its practical use becomes hindered given the diversity of pneumatic actuated systems found in industry. This paper presents a new controller that achieves very good results even without a friction model. The controller architecture includes a robust motion control loop and a non-linear state feedback pneumatic force loop. The motion controller law is based on integral sliding control and takes into account the pneumatic dynamics, using it as a natural filter of the discontinuous part of the control law. Experimental results show that the proposed approach leads to low tracking and positioning errors. These results are obtained without including a friction model and even in the presence of parameter disturbances caused by a fivefold payload change, without any controller retuning or excessive control action activity.

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Section: Pneumatic Connectionsmentioning

confidence: 99%

Accurate motion control of a servopneumatic system using integral sliding mode control

Carneiro

Almeida

2014

Int J Adv Manuf Technol

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“…Thanks to kinesthesia, haptic training, and in particular kinesthetic focused training, extends vision based training. Some haptic simulators are now available on the market and are used in various medical sectors [7], such as endovascular surgery [8] or laparoscopy [9].…”

Section: Introductionmentioning

confidence: 99%

A Review of Pneumatic Actuators Used for the Design of Medical Simulators and Medical Tools

Senac

Lelevé

Moreau

et al. 2019

MTI

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Simulators have been traditionally used for centuries during medical gestures training. Nowadays, mechatronic technologies have opened the way to more evolved solutions enabling objective assessment and dedicated pedagogic scenarios. Trainees can now practice in virtual environments representing various kind of patient and body parts including physio-pathologies issues. Gestures, to be mastered, vary according to each medical specialty (e.g., ultrasound probe orientations, or forceps installation during assisted delivery). Hence, medical students need kinesthetic feedback in order to significantly improve their learning capabilities. Gesture simulators require haptic devices with variable stiffness actuators. Existing solutions do not always fit the requirements because of their significant size. Contrary to electric actuators, pneumatic technology is low-cost, available off-the-shelf and offers a better mass–power ratio. However, it presents two main drawbacks: nonlinear dynamics and need for a compressed air supply. During the last decade, we have developed several haptic solutions based on pneumatic actuation (e.g., birth simulator, epidural needle insertion simulator) and, recently, in a joint venture with Prisme laboratory, a pneumatic probe master device for remote ultrasonography. This paper recalls literature scientific approaches on pneumatic actuation developed in the medical context and illustrated with the aforementioned applications to highlight the benefits.

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“…However, the use of two three-port valves becomes suitable for compliance control because each cylinder chamber can be individually controlled. A study [15] showed that the use of only one five-port servo valve may lead to very steep variation of the fluidic stiffness around zero velocity; independent pneumatic force control in each chamber, using two servo valves, surpasses this drawback. A zero-lap condition is desirable for precise control with three-port valves.…”

Section: Introductionmentioning

confidence: 99%

Development of a Poppet-Type Pneumatic Servo Valve

et al. 2018

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In pneumatic positioning and force-control systems, spool-type servo valves are widely used for obtaining quick responses and precise control. However, air leakage from these valves results in increased energy consumption. To address this problem, we developed a three-port poppet-type servo valve to reduce air leakage. The developed valve consists of a camshaft, two orifices, two metal balls, and a housing with two flow channels. The metal ball is pushed by fluid, and spring force closes the orifice. The port opens when the cam rotates and pushes the ball. The cam shape and orifice size were designed to provide the desired flow rate. The specifications of the DC motor for rotating the camshaft were determined considering the fluid force on the ball. Static and dynamic characteristics of the valve were measured. We experimentally confirmed that air leakage was 0.1 L/min or less. The ratio of air leakage to maximum flow rate was only 0.37%. Dynamic characteristic measurements showed that the valve had a bandwidth of 30 Hz. The effectiveness of the valve was demonstrated through experiments involving pressure and position control.

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Using two servovalves to improve pneumatic force control in industrial cylinders

Cited by 20 publications

References 16 publications

Accurate motion control of a servopneumatic system using integral sliding mode control

Accurate motion control of a servopneumatic system using integral sliding mode control

A Review of Pneumatic Actuators Used for the Design of Medical Simulators and Medical Tools

Development of a Poppet-Type Pneumatic Servo Valve

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