Appeal No. 1997-1111 Page 18 Application No. 08/105,899 (brief, page 17) that Hägglund does not suggest using a signal generator with a fuzzy logic controller, and that (reply brief, page 5) the fact that both Ueda and Hägglund mention the Ziegler-Nichols method does not suggest the claimed steps of appellant’s method. We find that Hägglund discloses the use of a non-linear circuit to provide a controlled induced oscillation for tuning a PID. However, in Hägglund (col. 3, lines 5-11) the system is brought into self oscillation by disconnecting the integrating and derivative units I and D of the regulator, and increasing the amplification of the proportional control unit P, by manually moving adjusting means 9. Hägglund further discloses (col. 4, lines 39-47) completely disconnecting the PID controller. In addition, Hägglund discloses (col. 4, lines 64 and 65) that “[a]lso the I- and D-units can be connected individually or in combination-also with the P- unit.” We are in general agreement with the examiner that PID controllers and fuzzy controllers are both well known in the art and that the Ziegler-Nichols method of tuning is used in both PID and fuzzy controllers. However, we find no suggestion to combine the teachings of Hägglund with Ueda forPage: Previous 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NextLast modified: November 3, 2007