Study on positioning accuracy of automated pneumatic drive with an outer brake

Abstract

The work objective is to introduce a design of the automated pneumatic drive (APD) with an external braking gear. It is a controlled pneumo-mechanic brake providing the process time reduction, the positioning accuracy increase, and the reliable positioning of the stop mechanism in the setpoints. The application of the prototype drive with the automated measurement complex creates conditions for the oscillographic testing of the positioning process in real time and space, and it also provides reliable experiment results. The authors have created a special stand - a model of the proposed drive that allows investigating the effect of its positional accuracy under different parameters of its operation. Kinematic and power characteristics of the drive in the automatic operation by the compressed air flow are identified. The effect of the positioning speed and the brake control pressure on the drive accuracy is resulted. Recommendations for the development of real positional drives with increased performance and positioning accuracy are formulated. It is found that the introduction of an outer braking device - the controlled pneumo-mechanic brake - improves the positioning accuracy of these drives by 1,25-2,25 times.

Mathematical model of the pneumatic actuator follower system

“…But this, in turn, leads to higher requirements for drive dynamics and positioning accuracy of actuators. Simulation of pneumatic system processes is complicated by non-stationarity of compressed gas flows [1][2][3][4][5][6][7][8]. Because of that, assumptions were made when forming the mathematical model of the actuator: -The compressed air source characteristic is assumed constant pM -const, since the pressure line of the pneumatic actuator is connected to a receiver of sufficient volume through a pressure regulator; -The thermodynamic process of gas state change is assumed to be adiabatic, as it proceeds in a short period of time; -An ideal gas model is used in the description of pneumatic devices, since the pressure of compressed air is below 10 bar; -Flow coefficients µ of control devices are assumed constant.…”

“…the difference between the output quantity and the reference value, the second part ( ) -is integral in time of the error of the output quantity, and the third part ( ) -is derivative of the error. The equation of the classical PID controller is [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]:…”

Improving the energy efficiency of the pipeline system by ensuring its linear flow characteristic

“…An important area of research in this area is improving the positioning accuracy of pneumatic actuators. To solve this problem, it is necessary to study the dynamic characteristics and search for the optimal structure of the drive [2][3][4].…”

Effect of recuperative volume parameters on dynamic characteristics of pneumatic drive underbraking

“…Такие особенности, как сжимаемость рабочей среды и инерционность выходных звеньев, затрудняют безударное торможение, усложняют управление и конструкцию привода [1,3,4]. Управлять законом торможения пневмопривода можно как воздействием на регулирующее устройство [1,2,5,6], так и выбором рационального способа торможения [7][8][9].…”

“…Альтернативой является подключение в момент торможения к тормозной полости пневмодвигателя рекуперативного объема. Задавая его начальные параметры до торможения, возможно влиять на конечное давление в тормозном объеме и тормозной путь выходного звена пневматического привода [8].…”