Shaft position controlling system
AssigneeRedactron Corporation
InventorsEdward H. Lau, John F. Tweedy, Jr.
Life of this patent
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Abstract
There is disclosed a typewriter using a single element print head wherein the tilt and rotate positions for character selection are obtained by servo systems driving tilt and rotate shafts. The system utilizes a digital multiplexing system whereby common elements in the servo channels are time shared. One common element is a binary arithmetic unit which compares binarily represented actual and desired position values of the shafts to fetch from a memory desired velocity information. The fetched velocity information in binary form is compared with the binarily represented actual velocity of the shafts to generate signals for energizing the servo motors which drive the shafts.
Claims13
Apparatus for controlably rotating first and second shafts comprising:
- first and second motor means connected respectively to the first and second shafts, first and second transducer means connected to the first and second shafts, first indicator means connected to said first transducer means for generating a first actual position value representing the actual position of the first shaft, second indicator means connected to said second transducer means for generating a second actual position value representing the actual position of the second shaft, source means for generating first and second desired position values representing desired positions of the first and second shafts, respectfully, comparing means for comparing a desired position value and an actual position value to generate a quantity which is a function of the difference between said desired and actual position values, first drive means for converting a received first quantity to an electrical current for driving said first motor means, second drive means for converting a received second quantity to an electrical current for driving said second motor means, and switching means for periodically and alternately feeding a first actual position value and a first desired position value to said comparing means whereby a first quantity is generated for transfer to said first drive means and a second actual position value and a second desired position value to said comparing means whereby a second quantity is generated for transfer to said second drive means, the operation of said switching means being such that the feeding of said first position values is interleaved with the feeding of said second position values to that said first and second motor means are simultaneously energized.
Apparatus for controllably rotating a shaft comprising transducer means connected to said shaft, first indicator means connected to said transducer means for generating an actual position valve representing the actual position of the shaft, source means for generating a desired position value representing the desired position of the shaft, comparing means receiving the desired and actual position values for comparing said desired position value and said actual position value to generate an address value, storage means having a plurality of addressable registers each storing desired velocity information related to a desired velocity for driving the shaft in view of the displacement between the desired and actual positions of the shaft, fetching means utilizing the generated address value to fetch the contents of the corresponding addressed register, converting means for converting the contents of said corresponding addressed register to an electrical drive signal, and motor means connected to said converting means for receiving the electrical drive signal for rotating the shaft.
Dependencies are inferred from the claim text.