Abstract: A cross-coupling control method for moving beam of gantry machine tool is disclosed, which relates to the technical field of CNC machine tool control. The cross-coupling control method includes: Step 1: establishing a crossbeam dynamics model considering a ram on the crossbeam, and at the same time simplifying the model for an observer design; step 2: realizing a PID control parameter adjustment of motors at both ends in accordance with a method of parameter tuning of a unilateral servo control system; using a servo system with the same control parameters to jointly drive the crossbeam up and down, realizing the synchronous control and realizing PID control parameter tuning for both end motors. The disclosure not only reduces the synchronization error caused by the torsion of the crossbeam, but also solves the synchronization error caused by the asymmetric load on both sides, and improves the system robustness and stability.

Abstract: An apparatus for forming a plasma may include one or more coupling ports to accept and RF current. The apparatus may additionally include a receptacle to accommodate one or more gases, in which the receptacle is oriented along a first axis. The apparatus may additionally include an RF coupling structure, oriented in a plane and substantially surrounding the receptacle, the RF coupling structure can be configured to conduct an RF current to bring about formation of the plasma within the receptacle. The apparatus may further include one or more linkages, coupled to the RF coupling structure, which may permit the plane of the RF coupling structure to pivot about a second axis so as to tilt the plane of the RF coupling structure toward the first axis.