A vacuum robot adapted to grip and transport a substrate. The robot includes a robot drive coupled to an arm and having an end-effector adapted to support the substrate. A robot gripper system includes a front support having at least one hard stop, a movable contact element coupled to the end-effector, a bias device and at least one actuator coupled to the end-effector configured to move the contact element between a release position and a grip position. The bias device is configured to passively bias the contact element in the grip position such that the contact element contacts an edge of the substrate to urge the substrate against the at least one hard stop to secure the substrate in the grip position and to passively bias the contact element in the release position such that the contact element is retained in the release position.