A Simple Design Approach for an Electro- Hydraulic Stewart Platform Through Matlab Simulation

A Stewart platform has been designed by selecting commercially available components. Each of its six legs has spherical and universal joints respectively at the bottom and top ends of a piston-cylinder arrangement with the piston rod protruding out of the cylinder top. By a universal joint at the cap end at the bottom of each cylinder, the legs are mounted on a fixed horizontal frame. By electrical actuation of the valve for each cylinder, a six-DOF motion could be imparted to a cylindrical payload fixed on a circular disc. The motion is transferred through a spherical joint fitted between each piston rod and the disc. Corresponding to the specified payload pose range from its horizontal neutral, the inverse kinematic model has been used for simultaneously searching the piston stroke, the distance between the frame and the disc along with the locations of the joints, assuming each type arranged in a semi-regular hexagonal pattern. The discharge and pressure of a power pack feeding all the cylinders have been estimated by Matlab simulation of the inverse dynamic model for different velocity, acceleration and weight of the payload. Keywords—Inverse model, kinematics, dynamics, Six-DOF motion