Method and apparatus for controlling servomechanism by use of model reference servo-control system

• US 4,437,045 A
• Filed: 01/20/1982
• Issued: 03/13/1984
• Est. Priority Date: 01/20/1982
• Status: Expired due to Term

• Current Assignee: Agency of Industrial Science & Technology
• Original Assignee: Agency of Industrial Science & Technology, Ministry of International Trade & Industry (Government of Malaysia)
• Inventors: Mitsuoka, Toyokazu
• Primary Examiner(s): Dobeck, B.
• Application Number:
  US06/340,966
• Time in Patent Office: 783 Days
• Field of Search: 318/561, 364/148
• US Class Current: 318/561
• CPC Class Codes: G05B 13/04 involving the use of models or simulators

Abstract

A method and an apparatus for controlling servomechanism by use of a model reference adaptive system in which adjusting parameters so determined that the difference between the outputs from the final control element and the reference model is eliminated are set. An adaptive control input is produced by multiplying the adjusting parameters respectively by an instruction input, load value and load variation value of the final control element and is given to the final control element together with the instruction input thereby controlling the final control element with high accuracy without being affected even by the load variation.

Claims

1. An apparatus for model reference adaptive servo-control, which comprises in combination:

a final control element to be driven on the basis of an instruction input and to be controlled by feeding back the output of the final control element to the instruction input;

a reference model provided with the performance characteristics the same as those of the final control element;

a detector for detecting a load value and a load variation value of said final control element;

a comparator for comparing the outputs of said final control element and said reference model thereby obtaining the difference therebetween;

at least one adaptive control coefficient circuit having stored therein an adaptive control coefficient which is so prescribed that the difference between the outputs of the final control element and reference model is eliminated, and adapted to produce an adjusting parameter by multiplying one of the instruction input, load value and load variation value by said adaptive control coefficient;

at least one multiplier for multiplying at least one adaptive control coefficient by at least one of the instruction input, load value and load variation value thereby to obtain an adaptive control input; and

an adder for adding said adaptive control input to said instruction input and feeding these inputs to the final control element.

2. The apparatus for model reference adaptive servo-control according to claim 1, further comprising at least one multiplying circuit for multiplying at least one of the instruction input, load value and load variation value by the difference between the outputs of the final control element and the reference model, at least one adaptive performance coefficient circuit having stored therein a coefficient of adaptive performance and adapted to multiply a product fed from said multiplying circuit by said coefficient of adaptive performance, and at least one other multiplying circuit for producing and outputting to said adder an adjusting parameter by multiplying the sum of the outputs fed from said adaptive performance coefficient circuit and said adaptive control coefficient circuit by the corresponding one of the instruction input, load value and load variation value.

3. The apparatus for model reference adaptive servo-control according to claim 1, further comprising at least one multiplying circuit for multiplying at least one of the instruction input, load value and load variation value by the difference between the outputs of the final control element and reference model, at least one integrator for integrating a product fed from said multiplying circuit according to an integration having predetermined multiplier, and at least one other multiplying circuit for producing and outputting to said adder an adjusting parameter by multiplying the sum of the outputs fed from said adaptive performance coefficient circuit and said adaptive control coefficient circuit by the corresponding one of the instruction input, load value and load variation value.

4. The apparatus for model reference adaptive servo-control according to claim 1, further comprising at least one multiplying circuit for multiplying at least one of the instruction input, load value and load variation value by the difference between the outputs of the final control element and the reference model;

at least one adaptive performance coefficient circuit having stored therein a coefficient of adaptive performance and adapted to multiply a product fed from said multiplying circuit by said coefficient of adaptive performance;

at least one integrator for integrating the product fed from said multiplying circuit according to an integration having predetermined multiplier;

at least one adding circuit for adding the sum of the outputs from said at least one adaptive performance coefficient circuit and said at least one integrator to the corresponding adaptive control coefficient; and

at least one other multiplying circuit for producing and outputting to said adder an adjusting parameter by multiplying the sum of the outputs fed from said adaptive performance coefficient circuit and said adaptive control coefficient circuit by the corresponding one of the instruction input, load value and load variation value.

5. An apparatus for model reference adaptive servo-control, comprising in combination:

a final control element,

a model system for receiving an instruction input,

a comparator for comparing the outputs of said final control element and reference model and determining the difference e between the two outputs,

a first coefficient circuit for receiving said instruction input, processing the reference input in accordance with the following formula, and producing a first adjusting parameter K₁ (t,e) as an output, ##EQU5## (wherein, K₁, B₁, and C₁ are coefficients), a second coefficient circuit for receiving a load value m from said final control element, processing said load value in accordance with the following formula, and producing a second adjusting parameter K₂ (t,e) as an output, ##EQU6## (wherein, K₂, B₂, and C₂ are coefficients), a third coefficient circuit for receiving a load variation value m from said final control element, processing said load variation value in accordance with the following formula, and producing a third adjusting parameter K₃ (t,e) as an output, ##EQU7## (wherein, K₃, B₃, and C₃ are coefficients), an adder for totalling said first, second, and third parameters from said first, second, and third coefficient circuits thereby producing an adaptive control input, and

an adder for totalling said adaptive control input and said reference input and delivering the resultant sum to said final control element, whereby said first, second, and third adjusting parameters are fixed so as to eliminate the difference between the output from said final control element and that from said reference model.

6. A method for model reference adaptive servo-control for a servomechanism composed of a final control element to be driven on the basis of an instruction input and to be controlled by feeding back the output of the final control element to the instruction input and a reference model provided with performance characteristics the same as those of the final control element, which comprises the steps of:

detecting a load value and a load variation value of said final control element;

multiplying at least one of the instruction input load value and load variation value by the difference between the outputs of the reference model and the final control element so as to eliminate said difference, and multiplying at least one product thus obtained by at least one prescribed coefficient of adaptive performance to obtain at least one adaptive control coefficient;

multiplying said at least one adjusting coefficient by the corresponding one of the instruction input, load value and load variation value thereby to obtain an adaptive control input; and

feeding said adaptive control input together with said instruction input to the final control element.

7. A method for model reference adaptive servo-control for a servomechanism composed of a final control element to be driven on the basis of an instruction input and to be controlled by feeding back the output of the final control element to the instruction input and a reference model provided with performance characteristics the same as those of the final control element, which comprises the steps of:

detecting a load value and a load variation value of said final control element;

multiplying at least one of the instruction input load value and load variation value by the difference between the outputs of the reference model and the final control element so as to eliminate said difference, and integrating at least one product thus obtained according to an integration having a predetermined multiplier to obtain at least one adaptive control coefficient;

multiplying said at least one adjusting coefficient by the corresponding one of the instruction input, load value and load variation value thereby to obtain an adaptive control input; and

feeding said adaptive control input together with said instruction input to the final control element.

8. A method for model reference adaptive servo-control for a servomechanism composed of a final control element to be driven on the basis of an instruction input and to be controlled by feeding back the output of the final control element to the instruction input and a reference model provided with performance characteristics the same as those of the final control element, which comprises the steps of:

detecting a load value and a load variation value of said final control element;

multiplying at least one of the instruction input load value and load variation value by the difference between the outputs of the reference model and the final control element so as to eliminate said difference thereby obtaining at least one first value, integrating said at least one product according to an integration having a predetermined multiplier thereby obtaining at least one second value, and adding the sum of said first and second values to the corresponding adaptive control coefficient thereby to obtain at least one adjusting coefficient;

multiplying said at least one adjusting coefficient by the corresponding one of the instruction input, load value and load variation value thereby to obtain an adaptive control input; and

feeding said adaptive control input together with said instruction input to the final control element.

9. A method for model reference adaptive servo-control for a servomechanism composed of a final control element to be driven on the basis of an instruction input and to be controlled by feeding back the output of the final control element to the instruction input and a reference model provided with performance characteristics the same as those of the final control element, which comprises the steps of:

detecting a load value of said final control element;

subjecting the load value thus detected to approximate differentiation thereby obtaining a load variation value;

multiplying at least one of the instruction input, load value and load variation value by at least one adaptive control coefficient which is so prescribed that the difference between the outputs of the reference model and the final control element is eliminated, thereby to obtain at least one adjusting coefficient;

multiplying said at least one adjusting coefficient by the corresponding one of the instruction input, load value and load variation value thereby to obtain an adaptive control input; and

feeding said adaptive control input together with said instruction input to the final control element.

10. A method for model reference adaptive servo-control for a servomechanism composed of a final control element to be driven on the basis of an instruction input and to be controlled by feeding back the output of the final control element to the instruction input and a reference model provided with performance characteristics the same as those of the final control element, which comprises the steps of:

detecting a load value of said final control element;

subjecting the load value thus detected to approximate differentiation thereby obtaining a load variation value;

multiplying at least one of the instruction input, load value and load variation value by the difference between the outputs of the reference model and the final control element so as to eliminate said difference, and multiplying at least one product thus obtained by at least one prescribed coefficient of adaptive performance to obtain at least one adaptive control coefficient;

multiplying said at least one adjusting coefficient by the corresponding one of the instruction input, load value and load variation value thereby to obtain an adaptive control input; and

feeding said adaptive control input together with said instruction input to the final control element.

11. A method for model reference adaptive servo-control for a servomechanism composed of a final control element to be driven on the basis of an instruction input and to be controlled by feeding back the output of the final control element to the instruction input and a reference model provided with performance characteristics the same as those of the final control element, which comprises the steps of:

detecting a load value of said final control element;

subjecting the load value thus detected to approximate differentiation thereby obtaining a load variation value;

multiplying at least one of the instruction input, load value and load variation value by the difference between the outputs of the reference model and the final control element so as to eliminate said difference, and integrating at least one product thus obtained according to an integration having a predetermined multiplier to obtain at least one adaptive control coefficient;

multiplying said at least one adjusting coefficient by the corresponding one of the instruction input, load value and load variation value thereby to obtain an adaptive control input; and

feeding said adaptive control input together with said instruction input to the final control element.

12. A method for model reference adaptive servo-control for a servomechanism composed of a final control element to be driven on the basis of an instruction input and to be controlled by feeding back the output of the final control element to the instruction input and a reference model provided with performance characteristics the same as those of the final control element, which comprises the steps of:

detecting a load value of said final control element;

subjecting the load value thus detected to approximate differentiation thereby obtaining a load variation value;

multiplying at least one of the instruction input, load value and load variation value by the difference between the outputs of the reference model and the final control element so as to eliminate said difference thereby obtaining at least one product;

multiplying said product thus obtained by at least one prescribed coefficient of adaptive performance thereby obtaining at least one first value, integrating said at least one product according to an integration having a predetermined multiplier thereby obtaining at least one second value; and

adding the sum of said first and second values to the corresponding adaptive control coefficient thereby to obtain at least one adjusting coefficient;

multiplying said at least one adjusting coefficient by the corresponding one of the instruction input, load value and load variation value thereby to obtain an adaptive control input; and

feeding said adaptive control input together with said instruction input to the final control element.