Pneumatic Cylinder System Research Articles

Modeling and Fuzzy FOPID Controller Tuned by PSO for Pneumatic Positioning System

A pneumatic cylinder system is believed to be extremely nonlinear and sensitive to nonlinearities, which makes it challenging to establish precise position control of the actuator. The current research is aimed at reducing the overshoot in the response of a double-acting pneumatic actuator, namely, the IPA positioning system’s reaction time. The pneumatic system was modeled using an autoregressive with exogenous input (ARX) model structure, and the control strategy was implemented using a fuzzy fractional order proportional integral derivative (fuzzy FOPID) employing the particle swarm optimization (PSO) algorithm. This approach was used to determine the optimal controller parameters. A comparison study has been conducted to prove the advantages of utilizing a PSO fuzzy FOPID controller over PSO fuzzy PID. The controller tuning algorithm was validated and tested using a pneumatic actuator system in both simulation and real environments. From the standpoint of time-domain performance metrics, such as rising time (tr), settling time (ts), and overshoot (OS%), the PSO fuzzy FOPID controller outperforms the PSO Fuzzy PID controller in terms of dynamic performance.

Finite-Time Trajectory Tracking Control for Rodless Pneumatic Cylinder Systems With Disturbances

In this article, a finite-time trajectory tracking control problem is studied for a rodless pneumatic cylinder system with disturbance in an inner outer loop framework. In the inner loop system, the generalized nonlinear extended state observer and the inner loop controller are designed to estimate and compensate the matched disturbances, respectively. The generalized nonlinear extended state observer designed in this article achieves desired convergence performance under relaxed existence conditions. In the outer-loop system, a super twisting extended state observer and an outer loop controller are designed to estimate and compensate the unmatched disturbances, respectively. The super twisting extended state observer is designed to realize finite-time stable by using the super twisting technology. Finally, experiment results are shown that finite-time control performances are obtained by the proposed control strategy.

Contribution to the Assessment of the Quality of the Pre-Analytical Phase of Medical Biology Tests at the Ibn Sina University Hospital in Rabat

The study of the nonconformities (NC) literatures in medical biology report that between 60-85% of laboratory errors are produced during the pre-analytical phase, which are often external and escapes the biologist's control. The objective of our study was to identify the factors at the origin of non-conformities during this phase at the University Hospital of Rabat. A mixed analytical descriptive study realized between August 2019 and August 2020 based on a non-compliance form, a self-questionnaire, an observation grid, focus groups and semi-structured interviews. We also set up the Deming wheel PDCA as well as the work tools (BRAINSTORMIN, 5M, ISHIKAWA). Our results show that 22 % of the prescriptions of biologic tests are drafted by nurses and not doctors this in the absence of an updated list of biological exams. The samples are taken at 88,1% by unqualified personnel and 95 % without any guide or manual. For the traceability aspect, the name of the sampler is never placed on the sheet of examination, age, sex of the patient; time and nature of the sample are often not mentioned in the label vials of samples. Transportation is made by pneumatic cylinder system and sometimes by unqualified staff in absence of procedures for packaging and transportation equipment without traceability. The reception of samples is carried out by untrained staff on the error management of the pre-analytical phase. They result at first from a major defect of coordination between the laboratory and the services, then by the lack of continuing education and the weak competence of the staff involved in this process and finally compounded by the lack of manual sampling, procedures for packaging, transport, reception and triage.

Study of the effects of relative humidity and velocity on the friction characteristics of pneumatic cylinders

The movement of a piston rod in a pneumatic cylinder is directly affected by the air humidity in the atmosphere, especially in the case of piston rods without any means of protection or grease on their surfaces. In a pneumatic cylinder system, the friction between the piston rod and the rod seal is sliding friction, and it has a significant value that varies with the variation in the moisture on the piston rod’s surface. In this paper, an investigation of the friction characteristics of piston rods and rod seals in a pneumatic cylinder was carried out with different humidity and velocity values to understand the effect of lubricants on the moving parts of pneumatic systems in humid environments, where the friction characteristics of the displacements corresponding to the static and dynamic friction forces were displayed on a measuring device. The research results showed that the static friction forces tended to decrease by [Formula: see text] and that the dynamic friction forces tended to decrease by [Formula: see text] when the relative humidity increased from 51% to 99% at different velocities between 5 and 100 mm/s.

Position control of a rodless cylinder in pneumatic servo with actuator saturation

In this paper, positioning control of a rodless cylinder in pneumatic servo systems with actuator saturation is investigated via an active disturbance rejection control. A linear extended state observer is designed to estimate and compensate strong friction force and other nonlinearities in the pneumatic rodless cylinder system. An actuator saturation linear feedback control law is developed to further improve the control performance. Furthermore, a linear matrix inequality-based optimization algorithm is employed to estimate a strictly invariance set for the closed-loop system. Experiment results with response time 0.5 s and accuracy 0.005 mm for a 200 mm step signal demonstrate the effectiveness of the proposed control strategy.

An experimental study on the bypass-type DPF using pneumatic cylinder systems

An experimental study on the bypass-type DPF using pneumatic cylinder systems

Experimental analysis of electro-pneumatic optimization of hot stamping machine control systems with on-delay timer

The sustainability criterion in the manufacturing industries is imperative, especially in the automobile industries. Currently, efforts are being made by the industries to mitigate CO2 emission by the total vehicle weight optimization, machine utilization and resource efficiency. In lieu of this, it is important to understudy the manufacturing machines adopted in the automobile industries. One of such machine is the hot stamping machine that is used for about 35% of the manufacturing operations within the automobile industries. Therefore, the standardization and optimization of the hot stamping process could reduce the carbon footprint within the automobile industries. This work understudied the on-delay timer functional valve of the hot stamping machine in order to determine various process parameters affecting it. The detailed physical model of the pneumatic and electro-pneumatic cylinder systems for the control is simulated and optimized for both the pneumatic and electro-pneumatic cylinder systems. Experimental and simulation model were established at the FESTO work station and FESTO FluidSIM® 5.1 respectively to evaluate the effective velocity, accelerations, displacement, and flow rate for the pneumatic and electro-pneumatic actuator on both systems. Comparisons were made between pneumatic and electro-pneumatic cylinder systems on their characteristic curve in order to optimize the process variables. The result favours the electro-pneumatic cylinder systems in stability and in designing hot stamping machines. The result obtained could elucidate the understanding of the pressing arm of a hot stamping machine.

近接スイッチを利用した空気圧シリンダの繰返し位置決め

Applications requiring accurate position control of cylinders are in increasing use in industry. Pneumatic cylinder systems have the potential to fulfill this requirement due to their high speed and reliability at a relatively low cost. This paper outlines a technique of repeated positioning of a pneumatic cylinder. The system runs with a sequential on-off action of air valves as its basic control algorithm. To acquire accurate positioning at the time of each operation, three proximity switches are installed for one desired stop position to detect the slider passing as well as its velocity. In this scheme, less deviation of the stop position can be obtained by braking within a certain range of velocity which can affect the positioning performance. It is experimentally suggested that there is an optimal velocity for starting to apply the braking. The results are analyzed by simulation to validate that the existence of an optimal velocity is strongly related to the frictional fluctuation and the braking characteristics. Finally, experiments of repeated positioning are conducted to show the effectiveness of the proposed braking method.

ON/OFF VALVE IMPLEMENT OF CONTINUOUS VSC TO A PNEUMATIC CYLINDER

A pneumatic cylinder system has been diffcult in position control due to the nonlinearity of the air, friction on packing seal, and parameter variations. Variable Structure Control (VSC) with a proportion valve has been used to overcome the diffcult. However, VSC with an ON/OFF valve is not extensively investigated so far. Therefore, friction compensation using VSC with an ON/OFF valve is proposed in this research. VSC with an ON/OFF valve is designed based on VSC for the proportional one. The experimental results provided the accuracy with 0.1mm as same as using a proportional valve with chattering reduction. The results imply that the ON/OFF valve controlled by VSC is a possible replacement of proportional valve for conventional pneumatic cylinder control system.

ON/OFF Valve Implement of Continuous VSC to a Pneumatic Cylinder

A pneumatic cylinder system has been diffcult in position control due to the nonlinearity of the air, friction on packing seal, and parameter variations. Variable Structure Control (VSC) with a proportion valve has been used to overcome the diffcult. However, VSC with an ON/OFF valve is not extensively investigated so far. Therefore, friction compensation using VSC with an ON/OFF valve is proposed in this research. VSC with an ON/OFF valve is designed based on VSC for the proportional one. The experimental results provided the accuracy with 0.1mm as same as using a proportional valve with chattering reduction. The results imply that the ON/OFF valve controlled by VSC is a possible replacement of proportional valve for conventional pneumatic cylinder control system.

1A2-C05 フィードバック階層制御による空気圧駆動システムの軌道追従制御実験(アクチュエータの機構と制御)

1A2-C05 フィードバック階層制御による空気圧駆動システムの軌道追従制御実験(アクチュエータの機構と制御)

A Study of Gas Economizing Pneumatic Cylinder

The pneumatic cylinder is the most typical actuator in the pneumatic equipment, and its mechanism is so simple that it is often used to operate point to point driving without the feedback loop in various automatic machines. But, the energy efficiency of pneumatic system is very poor compared with electrical systems and hydraulic systems. So, it is very important to discuss the energy saving for the pneumatic cylinder systems. In this thesis, we proposed three methods to apply the reduction in the air consumed for pneumatic cylinder systems. An air charge accumulator is used to absorb the exhausted compress air and a boost valve boosted the air to the higher pressure for used again. From the experiments, the direct used cylinder exhaust air may save about 40% of compress air.

CONTROLLER DESIGN FOR PNEUMATIC SYSTEM WITH CONNECTION PORT RESTRICTION: AN LMI APPROACH

This paper presents an approach to designing a nonlinear pressure controller for a pneumatic cylinder system for which the connection port comprises a non negligible restriction. The pressure chamb...

신경회로망을 이용한 공압서보 XY-플로터의 운동제어

This paper deals with the issue of Neural Network-based control for a rodless pneumatic cylinder system which is utilized for a pneumatic XY-plotter. In order to identify the system design parameters, the open loop response of a pneumatic rodless cylinder controlled by a pneumatic servovalve is investigated by applying a self-excited oscillation method. Based on the system design parameters, the<br/> PD feedback compensator is designed and then Neural Network is incorporated with it. The<br/> experiment of a trajectory tracking control using a PD-NN has been performed and proved its excellent performance by comparing with that of a PD feedback compensator.

Measurement of friction force in pneumatic cylinders

AbstractAlthough the performance and reliability of pneumatic cylinders depend to a great extent on the friction generated at the seals, the friction characteristics have not been widely studied. Both the literature and manufacturers' catalogues rarely discuss the friction characteristics of pneumatic cylinders, and the lack of friction models limits the design, optimisation, and analysis of pneumatic cylinder systems. In seeking to improve the characteristics of pneumatic cylinders and to clarify the friction phenomenon, this paper describes friction force measurement tests carried out in pneumatic cylinders of six different diameters, from 32 to 100 mm. An experimental apparatus was designed to assess the effect of a broad range of operating conditions, where the velocity and pressure of the cylinder chambers are controlled independently. Measurements of friction force are shown for velocities of up to 0.5 m/s and pressures of up to 0.8 MPa. The data obtained will be useful for developing a suitable friction model, and the experimental apparatus will allow study of the effects on the friction force of different types of seal, lubricant, and cylinder barrel.

Block-oriented approximate feedback linearization for control of pneumatic actuator system

A block-oriented approximate feedback linearization methodology is presented in this paper. Accurate force control and high-precision positioning, 5 μm, of a rodless pneumatic cylinder system can be easily achieved with the presented techniques, despite the existence of high friction and substantial nonlinearities. Since the linearization is manipulated on block level, it only requires that some specific blocks are invertible or approximately invertible. This feature is favorable for a class of high order and extremely nonlinear systems. Experimental results, including force control, short distance (0.5 mm), low velocity (1 cm/s) and normal positioning are presented.

サンプル値&lt;i&gt;H&lt;/i&gt;&lt;SUB&gt;&amp;infin;&lt;/SUB&gt;制御による空気圧シリンダの制御

A sampled-data H∞ control is applied for a pneumatic cylinder system and its effectiveness is examined experimentally. Compared to the conventional continuous-based H∞ control, the experimental results show that the sampled-data control achieves superior performance not only for long sampling periods but also for short sampling periods.

PID Controller of Knee Orthoses using Fuzzy Curve Fitting

In this paper, we discuss the mode ling and control of a pneumatic cylinder system for attaining high human-friendliness of active knee orthoses. First, we develop a linear modeling by applying first-order Taylor series expansion about the initial values of the controller. Second, we design a self-tuning PID controller by applying real-time system identification with fuzzy curve fitting. Finally, we conclude with some remarks on the future work directions

A practical control strategy for servo-pneumatic actuator systems

A practical control strategy with a simple controller structure is proposed for servo-pneumatic cylinder actuator systems. Theoretical analysis reveals that the acceleration of the piston indirectly represents the cylinder chamber pressure difference so it is possible to employ acceleration feedback instead of pressure feedback in the construction of servo-pneumatic actuator control systems. The main features of the control strategy developed in the paper are (1) using acceleration feedback to improve the stability of the system; and (2) introducing time-delay minimisation and optimised null offset compensation to address the problem of time delay and dead zone, which are mainly caused by the compressibility of air and friction. The experimental studies have been conducted using an asymmetric pneumatic cylinder system and the results show that the system performance has been much improved when compared with a conventional PID controller.

Position control and repeatability of a pneumatic rodless cylinder system for continuous positioning

Pneumatic cylinder systems have the potential to provide high output power to weight and size ratios at a relatively low cost. However, they are mainly employed in open-loop control applications where positioning repeatability is not of great importance. In this paper the repeatability of a pneumatic rodless cylinder system under closed-loop PD control is examined for its potential use in robotic applications. Our analysis shows that the linearized continuous time dynamics is dependent on the trimmed and operating conditions. This can cause positioning problems when a controller is designed based upon the transfer function obtained at a particular trimmed point. Furthermore, there are uncertainties associated with the dynamics which can lead to precision errors in both transient and steady-state responses. Due to these complexities, a pragmatic gain tuning methodology is proposed to achieve satisfactory nominal transient response characteristics over the range of loading requirements. With this scheme, it is suggested that the performance of the conventional controller be evaluated in terms of its repeatability. The repeatability of the system under different start–stop positions and loading conditions is experimentally found to be less than ±0.3 mm. This repeatability value is within typical industrial requirements.