A four-degree-of-freedom parallel robot capable of displacing a traveling
plate with four degrees of freedom at a high speed and a high acceleration
and positioning the traveling plate with high rigidity and high precision.
The four-degree-of-freedom parallel robot has four actuators fixed to a
base, four parallel linkages each of which is coupled at its upper end to
a tip end of an arm of each of the actuators through a kinematic element
such as a universal joint, and a traveling plate whose four corners are
coupled to lower ends of the parallel linkages through kinematic elements.
By controlling the actuators, a main member of the traveling plate is
displaced with four degrees of freedom, i.e., translated in all directions
and rotated around a predetermined axis. Only axial forces are applied to
rods constituting the parallel linkages. Thus, the traveling plate can be
positioned at a high speed and with high rigidity as well as high
precision.