upper platform, the bottom platform, six parallel link type reciprocation piston rods and
the connect gemels,etc.
Fig.1 Manipulator based on Stewart platform
The upper platform is moveable, the bottom platform is the base one. The two
platforms are connected with sixsingle piston rod hydraulic cylinders and twelve universal
joints at the two ends of the cylinders. At the upperplatform side, there are S shape pull and
press force sensors used to sense the force feedback, and through whichthe hydraulic
cylinders are connected to the upper platform. The displacement sensors are fixed between
thehydraulic cylinders and the rods to detect the displacements of the cylinders. The
manipulation handle is bolted to the centre of upper platform.
Electro-hydraulic servo driven is applied to this system for its heavy density of driven
power and quick response, stable and reliable work performance. So it can realize accurate
displacement control. Because of the limited work space, the structure of the movement
system and the requirement of economy, the symmetrical valve controls asymmetrical
cylinder method is adopted in the system. The asymmetrical cylinder has a single rod in
- 4 -