A motion seat using pneumatic membran actuators in a hexapod system structur

Abstract

The development process of a pneumatic powered motion seat is being outlined as an example for mechatronic design. The fluid muscle of Festo AG provides stick slip free motion and is being used as displacement and pressure controlled actuator in a hexapod system for the first time. The process of design is supported by 3D-CAD with the software tool SolidEdge. It provides the necessary data to use Rigid Body Simulation with the software tool CAMeLView. Actuator behaviour is acquired by using a test bench with similar environment to the designed application. An 80486 process controller system with modular periphery called PS-1 made by Beck-IPC is beeing used. The programming is done by defining the control structure in a block oriented simulation environment followed by automated C++ code generation and compilation for the DOS 6.22 operating system. The displacement control of the fluid muscle was possible due to the development of an incremental in-tube length measuring system. For this purpose the miniaturized magnetic linear encoder system had to be integrated into the membrane of the actuator. By using a six-actuator structure it is possible to move a person in the seat in three translatorical directions as well as three rotatorical orientations-all six degrees of freedom are available respective limited working ranges. By using the inverse transformation formalism for hexapod structures only forward position control of the motion seat is available. It is scheduled to implement the hexapod forward transformation to calculate the seat position and orientation in real-time in order to improve the control accuracy. The motion simulator will be an example for an interesting application of fluid muscles launched by Festo AG. It is the intention to present the simulator at the next Hanover fair.