Compression of servo control logging entries
First Claim
1. A method for logging motion-related data obtained from a system, comprising:
- providing a memory space;
obtaining an initial complete value of a motion-related parameter of an initial physical state of a system;
saving the initial complete value as an initial absolute value in a first field of a first absolute log entry in the memory space, the first field having a first length;
periodically obtaining a first group of additional complete values of the parameter with the system in a then current state;
determining the difference between each additional complete value and the preceding complete value; and
saving each difference as a relative value in a first field of a respective relative log entry in the memory space, the first field of the relative log entry having a second length shorter than the first length.
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Accused Products
Abstract
In controlled mechanical hardware, such as servo-controlled hardware, data from the control algorithm is obtained and logged for possible later analysis. Loss-less compression is provided without increasing the size of the storage memory. Instead of continuously storing the complete (absolute) value of a monitored control parameter, an absolute value is stored in an absolute entry and one or more values of the parameter which are relative to each preceding value are stored in a sequence of associated relative entries. The space required to store a relative value is less than the space required to store an absolute value. Updated absolute values and groups of associated relative values may also be recorded periodically or when a relative value is too large for the allotted space. The size of relative values may be variable and appropriate information data entries may be generated to indicate the size of associated relative entries.
54 Citations
35 Claims
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1. A method for logging motion-related data obtained from a system, comprising:
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providing a memory space; obtaining an initial complete value of a motion-related parameter of an initial physical state of a system; saving the initial complete value as an initial absolute value in a first field of a first absolute log entry in the memory space, the first field having a first length; periodically obtaining a first group of additional complete values of the parameter with the system in a then current state; determining the difference between each additional complete value and the preceding complete value; and saving each difference as a relative value in a first field of a respective relative log entry in the memory space, the first field of the relative log entry having a second length shorter than the first length. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for logging servo data obtained from a servo-controlled system, comprising:
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providing a memory space; obtaining an initial complete value of each of a plurality servo parameters representative of an initial physical state of a servo-controlled system; saving the initial complete values as absolute values in a corresponding plurality of fields of a first absolute log entry in the memory space, each field having a respective first length; periodically obtaining a first group of additional complete values of at least one of the plurality of parameters; determining the difference between each additional complete value and the preceding complete value; saving each difference as a relative value in a corresponding field of a periodic relative log entry in the memory space, the field of the relative log entry having a first length shorter than the length of the field of the absolute log entry; periodically obtaining an updated complete value of each parameter; saving each updated complete value as an absolute value in a field of a new absolute log entry in the memory space; periodically obtaining a new group of additional values of the at least one parameter; determining the difference between each additional complete value and the preceding complete value; and saving each difference as a relative value in a field of a respective relative log entry in the memory space. - View Dependent Claims (10, 11)
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12. A system for logging servo data from a servo-controlled system, comprising:
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a memory; a data structure of a first type having a first length; a data structure of a second type having a second length less than the first length; a servo loop to control a first parameter of a mechanical subsystem of the servo-controlled system according to a selected servo profile defining a sequence of first parameter values; means for obtaining a first complete value of the first parameter and a first group of associated periodic complete values of the first parameter; a first servo log entry comprising a data structure of the first type in which the first complete value of the first parameter is stored as a first absolute value; means for determining the difference between each associated periodic complete value of the first group and the preceding complete value; and a plurality of second servo log entries, each comprising a data structure of the second type in which the differences are stored as a first group of relative values. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A computer program product of a computer readable storage medium usable with a programmable computer, the computer program product having computer-readable code embodied therein for logging mechanical-based parameters from a system, the computer-readable code comprising instructions for:
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providing a memory space; obtaining an initial complete value of a motion-related parameter of an initial physical state of a system; saving the initial complete value as an initial absolute value in a first field of a first absolute log entry in the memory space, the first field having a first length; periodically obtaining a first group of additional complete values of the parameter with the system in a then current state; determining the difference between each additional complete value and the preceding complete value; and saving each difference as a relative value in a first field of a respective relative log entry in the memory space, the first field of the relative log entry having a second length shorter than the first length. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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28. A method for deploying computing infrastructure, comprising integrating computer readable code into a computing system, wherein the code, in combination with the computing system, is capable of performing the following:
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providing a memory space; obtaining an initial complete value of a motion-related parameter of an initial physical state of a system; saving the initial complete value as an initial absolute value in a first field of a first absolute log entry in the memory space, the first field having a first length; periodically obtaining a first group of additional complete values of the parameter with the system in a then current state; determining the difference between each additional complete value and the preceding complete value; and saving each difference as a relative value in a first field of a respective relative log entry in the memory space, the first field of the relative log entry having a second length shorter than the first length. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35)
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Specification