| Pneumatic actuators offer a low-cost alternative to conventional servo technologies. Like electromagnetic actuators, pneumatics offer clean and reliable operation. Like hydraulic actuators, pneumatics can be coupled directly to a payload, without the need for power or motion conversion. Unlike electromagnetics and hydraulics, a pneumatic actuator exhibits significant nonlinear behavior. These nonlinear characteristics prevent linear control systems, such as PID, from providing acceptable servo control of the pneumatic actuator. Relatively recent developments in control strategies, though, allow for improved control of servopneumatics, making them competitive with traditional servo technologies.; The objective of this research is to explore advanced control strategies for proportionally controlled pneumatic actuators. A significant constraint applied to this study is that the strategies developed must work within the architecture of an industrial programmable logic controller (PLC). Two control systems were developed, and their performance compared to that of a PI controller. A simulation allows for investigation of phenomena not directly measurable with the experimental apparatus. This research demonstrates the capabilities and limitations of advanced control strategies with a PLC. |
