Patent attributes
A test device includes a base plate configured to move on a slipping floor in X-Y directions substantially parallel to the slipping floor by an air bearing, and rotate around an axis substantially perpendicular to the slipping floor, and a platform connected to the base plate by a movement connecting mechanism. The base plate is between the slipping floor and the platform. The movement mechanism connected pivotally with the base plate is configured to move on the slipping floor in the X-Y directions, and rotate around the axis. When the base plate is at substantially a center of the slipping floor's upper surface, the tips of the movement mechanism are directed to points on a circle C or points close to C, and a central angle between a line from C's center to one of the tips and a line from C's center to another tip is 120°.