Abstract: A treating period T=L.sub.0 /V is determined from a preset treating length L.sub.0 and a stock running speed V. An advancing acceleration is made as small as possible consistent with a requirement that an advancing time T.sub.F of the treating machine (=advancing positioning interval t.sub.1 +settling time t.sub.s +treating interval t.sub.c +retracting deceleration interval t.sub.2) is equal to or less than T/2 and a requirement that (t.sub.1 /2+t.sub.s) V assumes a given value. Both a retracting acceleration and a retracting speed are made as small as possible consistent with a requirement that an advanced distance is equal to a retracted distance and a requirement that a stop positioning interval t.sub.6 is made as close to a minimum value as possible.

Abstract: During a remaining time which is defined by excluding a positioning settling time t.sub.s and a cutting time interval t.sub.T during which a cutting edge is brought into contact with a stock from a period of time T allotted to a cutting operation which is determined by a preset length L.sub.0 and a stock running speed V.sub.A, the cutting edge maintains a speed difference .DELTA. which is as small as possible relative to V.sub.A during a fraction of the remaining time which is as long as possible. An acceleration which causes the speed difference .DELTA. is chosen to be as less as possible below a maximum acceleration which is demanded by the machine specification.

Abstract: In a rotary shear line in which sheet stock is fed by a feeder to a rotary shear for fly cutting by its rotating cutting edges, a synchronous speed and a synchronization length are calculated by an arithmetic unit which are supplied with the cutting length and the average feed rate of the sheet stock. Reference pulses of a frequency corresponding to the synchronous speed and the synchronization length are provided to a first numerical controller for controlling the feeder and a second numerical controller for controlling the rotary shear. The first numerical controller controls the feeder to feed the sheet stock at a speed higher or lower than the synchronous speed in such a manner that when the sheet stock is fed at the synchronous speed, the length of the sheet stock short or excessive of the cutting length before its cutting is compensated for within a cutting period.

Abstract: A sheet stock feed line in which sheet stock is leveled and fed by a leveler to a feeder and each time the feeder feeds the sheet stock by a predetermined length, the feed by the feeder is stopped for working the sheet stock. While the feed by the feeder is stopped, the leveler feeds the sheet stock at a very low feed rate to form a loop of the sheet stock between the leveler and the feeder. When the loops reaches a predetermined size, the feeder resumes the feed of the sheet stock and the leveler is controlled so that its feed amount follows that by the feeder.