Abstract
With all the advantages over other actuators, such as high power/weight ratio and intrinsic compliance, the use of a pneumatic cylinder is limited to simple tasks at present. This is because the pneumatic cylinder has stick-slip motions at low velocities caused by a nonlinear friction force due to the mechanical sealing parts.
However, electro-rheological fluid (ERF) has lately been attracting a great deal of attention as a new functional material. The ERF can increase the shearing stress when subjected to an electric field. Therefore, by making use of this characteristic, a functional damping device capable of controlling the damping force by controlling electric signal can be developed.
This paper centers on a compensatory method capable of achieving a constant, slow motion pneumatic cylinder by using an ERF damper. This method aims to overcome any decrease in the nonlinear friction force, i. e., the friction force against the increase in piston velocity, which may cause stick-slip motion. As a result of this study, this compensatory method was proven to be applicable to the pneumatic cylinders in a wide range of velocity controls.
