A vibration wave linear motor comprises a vibrator unit having two driving contacting parts which are respectively formed on top and bottom surfaces of the vibrator unit, two guide members guiding the running of the vibrator unit by sandwiching the vibrator unit in parallel with the running direction. The cooking grate is located within a cooking chamber of the barbecue grill and adjacent the heat source. A primary processing unit is in communication with the solenoid and configured to determine an intended position of the valve. The releasable latch prevents the bar frame from pivoting at the pivoting mount. In that embodiment, the processing hypothesizes a frequency shift in the received positioning signal. The stem slide apparatus further comprises a drive mechanism having an electric motor to move the slide base in the sliding direction.