Linear positioning apparatus for memory disc pack drive mechanisms

Claim 2

Apparatus for precisely positioning one member with respect to another at a desired one of two adjacent relative positions selected from a plurality of such positions comprising means for mechanically moving one of said members with respect to the other; means for generating a control signal for said mechanical moving means having two states respecTively representative of said two adjacent positions with each of said states having a characteristic in a different condition than the other, servo means responsive to said control signal by regulating said mechanical moving means to cause the same to position said one of said members at the desired position with respect to the other, said servo means providing said positioning of said member at the desired position only in response to said characteristic of the signal state representative of the desired position having one of said different conditions; means for determining the condition of said characteristic of the signal state representative of the desired position; and means responsive to a determination that said condition is different than that to which the servo means properly responds by converting said characteristic to the correct condition prior to introduction of said control signal to said servo means, whereby said servo responds to said control signal to provide proper regulation of said mechanical moving means irrespective of the condition of said characteristic of the signal state representative of the desired position.

Claim 3

The apparatus of claim 1 for precisely positioning one member with respect to another wherein said characteristic of each of said generated signal states is in a condition which is opposite to that of the other and said means for converting the same reverses the condition if necessary for proper regulation of said mechanical moving means.

Claim 4

The apparatus of claim 2 for precisely positioning one member with respect to another wherein said control signal is a cyclic signal with said characteristic of said signal states being the slope of said signal at the location of said states, said opposite conditions thereof being the opposite polarities of the slope.

Claim 5

The apparatus of claim 1 for precisely positioning one member with respect to another wherein said plurality of relative positions of said members are equally spaced apart and said means for generating said control signal generates such a signal having a plurality of states which are equally spaced apart therealong and each of which is representative of a corresponding one of said positions whereby the spacing of said signal states is linearly proportional to the spacing of said plurality of relative positions.

Claim 6

The apparatus of claim 4 for precisely positioning one member with respect to another wherein said means for generating a control signal generates such a signal which is cyclic with one half of any whole waveform shape thereof symmetric with the other half thereof to provide said equally spaced states representative of said equally spaced relative positions along the plane of symmetry thereof.

Claim 7

The apparatus of claim 5 for precisely positioning one member with respect to another wherein said control signal has a triangular waveform.

Claim 8

The apparatus of claim 5 for precisely positioning one member with respect to another wherein said means for generating a control signal includes a pair of transducer means, each of which is responsive to a relative movement of said two members by generating a cyclic position signal having one half of any whole waveform thereof symmetric with respect to the other half thereof and being 180* out of spatial phase with respect to the other position signal, and summing means for combining said position signals to form a composite signal for said control signal having equally spaced null points representative of said equally spaced relative positions.

Claim 9

The apparatus of claim 5 for precisely positioning one member with respect to another wherein said servo means includes means for producing a signal from said control signal representative of the velocity of movement of said two members relative to one another, and means for comparing said control signal with said signal representative of such velocity to produce an output signal which will regulate said mechanical moving means to provide said precise positioning of one mEmber with respect to another at a desired one of said relative positions.

Claim 10

The apparatus of claim 8 for precisely positioning one member with respect to another wherein one of said members is a data transfer device of a memory storage mechanism and the other of said members is a data storage device thereof, and said adjacent relative positions of one with respect to another coincide with positions on said data storage device at which it is desired to transfer information between said data transfer device and said data storage device.

Claim 11

The apparatus of claim 9 for precisely positioning one member with respect to another wherein said means for generating a control signal includes a pair of transducer means, each of which is responsive to relative movement of said two members by generating a cyclic position signal having one half of any whole waveform thereof symmetric with respect to the other half thereof and being 180* out of spatial phase with respect to the other position signal, and comparator means for combining said position signals to form a composite signal for said control signal having equally spaced null points representative of said equally spaced relative positions.

Claim 12

In a position sensing and servo control mechanism for precisely positioning a data transfer device with respect to a data storage device at any one of a plurality of generally equally spaced relative positions, means for mechanically moving one of said devices with respect to the other through said relative positions, transducer means responsive to said movement through said relative positions by generating a position signal having a plurality of states respectively a portion of which states are representative of a portion of said relative positions, means to alter said position signal such that it includes states representative of the remainder of said relative positions, said states of said control signal being equally spaced apart therealong to be linearly proportional to the spacing between said relative positions and thereby truly representative of the locations of said relative positions, and means responsive to said position signal by regulating said mechanical moving means to cause the same to locate said one of said devices at a selected one of said positions with respect to the other.

Claim 13

In a position sensing and servo control mechanism for precisely positioning a data transfer device with respect to a data storage device at any one of a plurality of generally equally spaced relative positions, means for mechanically moving one of said devices with respect to the other through said relative positions, transducer means responsive to said movement through said relative positions by generating a position signal having a plurality of states respectively a portion of which states are representative of a portion of said relative positions, means to alter said position signal such that it includes states representative of the remainder of said relative positions, said states of said control signal being equally spaced apart therealong to be linearly proportional to the spacing between said relative positions and thereby truly representative of the locations of said relative positions, and means responsive to said position signal by regulating said mechanical moving means to cause the same to locate said one of said devices at a selected one of said positions with respect to the other.

Claim 14

The position sensing and servo control mechanism of claim 11 wherein said transducer means is responsive to said movement by generating a position which is cyclic with one half of any whole waveform shape thereof symmetric with the other half thereof to provide said equally spaced states representative of said equally spaced relative positions along the plane of symmetry thereof.

Claim 15

In a position sensing and servo control mechanism for precisely positioning a data transfer device with respect to a data storage device at any one of a plurality of generally equally spaced relative positions, means for mechanically moving one of said devices with respect to the other through said relative positions, transducer means responsive to said movement through said relative positions by generating a position signal having a plurality of states respectively representative of said relative positions, said states of said control signal being equally spaced apart therealong to be linearly proportional to the spacing between said relative positions and thereby truly representative of the locations of said relative positions, and means responsive to said position signal by regulating said mechanical moving means to cause the same to locate said one of said devices at a selected one of said positions with respect to the other, said transducer means being responsive to said movement by generating a position which is cyclic with one half of any whole waveform shape thereof symmetric with the other half thereof to provide said equally spaced states representative of said equally spaced relative positions along the plane of symmetry thereof, said transfer means including a light source, an optical transducer for reception of light from said source, and means for varying the amount of light from said source permitted to be received by said transducer in a manner directly related to the positioning at any given time of said transfer device with respect to said storage device, said optical transducer being responsive to changes in the amount of light received thereby indicative of changes in said relative positioning by generating said cyclic position signal having one half of any whole waveform shape thereof symmetric with the other half thereof.

Claim 16

In a position sensing and servo control mechanism for precisely positioning a data transfer device with respect to a data storage device at any one of a plurality of generally equally spaced relative positions, means for mechanically moving one of said devices with respect to the other through said relative positions, transducer means responsive to said movement through said relative positions by generating a position signal having a plurality of states respectively representative of said relative positions, said states of said control signal being equally spaced apart therealong to be linearly proportional to the spacing between said relative positions and thereby truly representative of the locations of said relative positions, and means responsive to said position signal by regulating said mechanical moving means to cause the same to locate said one of said devices at a selected one of said positions with respect to the other, said transducer means being responsive to said movement by generating a position which is cyclic with one half of any whole waveform shape thereof symmetric with the other half thereof to provide said equally spaced states representative of said equally spaced relative positions along the plane of symmetry thereof, said transfer means including a light source, an optical transducer for reception of light from said source, and means for varying the amount of light from said source permitted to be received by said transducer in a manner directly related to the positioning at any given time of said transfer device with respect to said storage device, said optical transducer being responsive to changes in the amount of light received thereby indicative of changes in said relative positioning by generating said cyclic position signal having one half of any whole waveform shape thereof symmetric with the other half thereof.

Claim 17

The position sensing and servo control mechanism of claim 13 wherein said position signal has a triangular waveform.

Claim 18

The positioning sensing and servo control mechanism of claim 13 wherein said optical transducer is a photodiode connected in series through a high impedance buffering means with a high gain amplifier.

Claim 19

The position sensing and servo control mechanism of claim 13 wherein said optical transducer is a phototransistor connected to one of two input terminals of a difference amplifier, which terminals are normally biased equally, said phototransistor being responsive to the reception of light from said light source by generating a current causing a voltage change at said one terminal of said difference amplifier proportional to the intensity of light received by said phototransistor to thereby produce an output from said difference amplifier also representative of said light intensity, and a current generator responsive to said output by driving the base current of said phototransistor in a direction equal to and opposite to the current generated thereby by the light incident thereon to linearize the voltage output of said difference amplifier and make the same linearly proportional to the amount of light incident on said base of said phototransistor.