The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 16, 1996
Filed:
Feb. 07, 1995
Kazuo Hiroi, Tokyo, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A set point value SV(s) and a process value PV(s) are supplied to a deviation arithmetic operation circuit, and thereby a deviation E(s) is obtained. The deviation E(s) is input to a control arithmetic operation circuit, and at least a PI control arithmetic operation is executed to obtain a manipulative value MV(s) such that the deviation E(s) is set at zero. An disturbance D(s) is added to the manipulative value MV(s) and the result of the addition is supplied to the object to be controlled. A process value filter having a lead/lag time proportional to an integral time T.sub.I of the PI control arithmetic operation is inserted in a feedback line of the process value PV(s) to the deviation arithmetic operation circuit. The transfer function of the filter is (1+.alpha..multidot..beta..multidot.T.sub.I .multidot.s)/(1+.beta..multidot.T.sub.I .multidot.s). Although the optimal values of coefficients .alpha. and .beta. are 2.5 and 0.54, these values are variable in the range of 2 to 4 and the range of 0 to 1, respectively, depending on a first-order delay time T and a dead time L of the object. By setting .alpha. and .beta. in this way, the gain of the filter can be set at 1 at steady state and more than 1 at the transition state, so that both set point values following characteristic and disturbance suppression characteristics are improved.