Method for correcting the deviation of a predetermined stop position in a loom

Claim 1

A method for braking a rotatable shaft coupled to the driving mechanism of a loom, so that the shaft stops at a predetermined crank angular stop position during successive braking operations occurring at randomly spaced time intervals by means of a braking device cooperating with and being connected with a motor for driving said loom, said method comprising the steps of: (a) determining the positional deviation between the actual stop position obtained during the last conducted braking operation and said predetermined stop position and storing the value of said positional deviation in a read/store enable memory, said positional deviation being determined according to the relation e←c-b where the symbol c denotes a crank angle, as digital data, corresponding to the predetermined stop position, the symbol b denotes a crank angle, as digital data, corresponding to an angular range through which the braking operation is completed, and the symbol e denotes resultant digital data derived from the operation of "c-b", indicating the positional deviation; (b) reading the positional deviation from said read/store enable memory and determining a resultant crank angle numerical value according to the relationship g←(e-a)γ+a where the symbol a denotes a crank angle, as digital data, at which the braking operation commences, the symbol γ has a value less than 1 and denotes a predetermined correction factor, and the symbol g denotes a resultant crank angle digital value; (c) determining whether the resultant crank angle value g is positive or negative; (d) determining the crank angle value a' at which the next succeeding braking operation is to be initiated, (i) according to the relationship a'←g when g is positive and (ii) according to the relationship a'←g+360° when g is negative, thereby effecting correction of the position for commencing the braking operation; (e) initiating said next succeeding braking operation by means of said braking device immediately when the crank angle coincides with the crank angle value a'; and (f) repeating steps (a) through (e) automatically every time the next following braking operation is performed.

Claim 2

A method for braking a rotatable shaft coupled to the driving mechanism of a loom, so that the shaft stops at a predetermined crank angular stop position during successive braking operations occurring at randomly spaced time intervals by means of a braking device cooperating with and being connected with a motor for driving said loom, said method comprising the steps of: (a) determining the positional deviation between the actual stop position obtained during the last conducted braking operation and said predetermined stop position and storing the value of said positional deviation in a read/store enable memory, said positional deviation being determined according to the relation e←c-b where the symbol c denotes a crank angle, as digital data, corresponding to the predetermined stop position, the symbol b denotes a crank angle, as digital data, corresponding to an angular range through which the braking operation is completed, and the symbol e denotes resultant digital data derived from the operation of "c-b", indicating the positional deviation; (b) reading the positional deviation from said read/store enable memory and determining a resultant crank angle numerical value according to the relationship g←(e-a)γ+a where the symbol a denotes a crank angle, as digital data, at which the braking operation commences, the symbol γ has a value less than 1 and denotes a predetermined correction factor, and the symbol g denotes a resultant crank angle digital value; (c) determining whether the resultant crank angle value g is positive or negative; (d) determining the crank angle value a' at which the next succeeding braking operation is to be initiated, (i) according to the relationship a'←g when g is positive and (ii) according to the relationship a'←g+360° when g is negative, thereby effecting correction of the position for commencing the braking operation; (e) initiating said next succeeding braking operation by means of said braking device immediately when the crank angle coincides with the crank angle value a'; and (f) repeating steps (a) through (e) automatically every time the next following braking operation is performed.