Linear positioner based on pneumatic muscle

The main goal of the work is to investigate the technical possibilities of creating a linear positioner on the basis of pneumatic muscle with acceptable characteristics for positioning. The experimental study of the power characteristics of the pneumatic muscle of the MAS 10-300 series of “FESTO” company is carried out. The physical essence of the cylindrical membrane operation is considered, on the basis of which the pneumatic muscle is constructed and a method for calculating the parameters of the positioning spring has been developed. It is shown that if the positional component is present in the load of pneumatic muscle then its rigidity (the dependence of the force on displacement) allows solving the task of positioning by controlling the pressure in the internal cavity of pneumatic muscle. If there is no positional component in the load or it is too small, then a positioning spring is needed to solve the positioning problem. Methods for determining the parameters of the positioning spring for positioners created on the basis of MAS pneumatic muscles of “FESTO” company are given. It has been established that the pneumatic muscle, which is used as a linear pneumatic motor, generates a pulling force which, with zero reduction of the pneumatic muscle, is 12 ... 14 times greater than the force developed on the return stroke by a pneumatic cylinder of equal working area of the piston and the specific force (force referred to the mass of the pneumatic motor) of pneumatic muscle is 100 times larger. This makes it possible to use pneumatic muscle as a loading device for brake, clamping and tensioning devices of transport systems and mobile units. To use the positioner in the tracking position control system, it must be provided with an analog feedback sensor. The static characteristic of the created physical layout of the positioner, obtained experimentally, has a quasilinear section in the range of the control pressure change of 2.5 ... 5 bar and agrees well with the calculation results. The nature of the transient process with respect to the input effect makes it possible to treat the positioner as an aperiodic link of the first order with a time constant T = 2 ... 5 s. As an example, the possibility of using a positioner in solving problems related to the need to stabilize a cargo platform in a horizontal position, in the case of a shift of the center of gravity of the cargo relative to the vertical axis of the platform, was investigated. The results of the work can be used and implemented in solving problems of linear and angular positioning of the load in flexible production systems, in executive devices of industrial robots, etc.

linear positioner, pneumatic muscle, cylindrical membrane, diamond-shaped cell