# US 11,906,475 B2 · Material testing machine and method for controlling material testing machine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,475 B2 - Document ID: US11906475B2 - Status: Granted - Kind: B2 - Application number: 17/414,945 - Filed: 2019-06-25 - Published: 2022-02-24 - Granted: 2024-02-20 - Earliest claimed: 2018-12-21 - Assignees: Shimadzu Corporation - Applicants: Shimadzu Corporation - Inventors: Tohru Matsuura - Web page: https://patentgrep.com/patent/US11906475B2 ## CPC - G01N 3/06: Special adaptations of indicating or recording means - G01N 3/08: by applying steady tensile or compressive forces (G01N3/28 takes precedence) - G05B 11/42: for obtaining a characteristic which is both proportional and time-dependent, e.g. P. I., P. I. D. - G05B 13/042: {in which a parameter or coefficient is automatically adjusted to optimise the performance} - G05B 19/404: characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia (G05B19/19, G05B19/41 take precedence) - G01N 2203/0017: Tensile - G01N 2203/0037: involving a rotating movement, e.g. gearing, cam, eccentric, or centrifuge effects - G01N 2203/0202: Control of the test - G01N 2203/0208: Specific programs of loading, e.g. incremental loading or pre-loading - G01N 2203/0617: Electrical or magnetic indicating, recording or sensing means - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) ## Abstract In a case where control input is performed via a low-pass filter, a control gain more appropriate for both stability and responsiveness is set according to setting of the low-pass filter. A control unit (21) performs control input for a load mechanism (40) via a low-pass filter, discriminates a stability of a control system including the load mechanism (40) and the low-pass filter when setting of the low-pass filter is changed, sets an appropriate control gain based on a maximum control gain at which an excess amount of a measured value with respect to a target value is equal to or less than a predetermined value within a range where that the control system is stable, and controls an operation of the load mechanism (40) by using the appropriate control gain. ## Claims ### Claim 1 A material testing machine comprising: a load mechanism which applies a test force to a test target; a measuring instrument which measures a physical quantity of the test target which changes according to the test force or the application of the test force; and a control unit which performs a material test on the test target by controlling the test force, the physical quantity of the test target, or a physical quantity acting on the test target to reduce a difference between a predetermined target value and a value measured by the measuring instrument, wherein the control unit performs control input for the load mechanism via a low-pass filter, determines, when setting of the low-pass filter is changed, an appropriate control gain based on a control gain within a range where a control system including the load mechanism and the low-pass filter is stable, and controls an operation of the load mechanism by using the appropriate control gain. ### Claim 2 (depends on 1) The material testing machine according to claim 1, wherein the control unit controls the test force by proportional control and integral control, the control gain is an integral gain and a proportional gain, and an appropriate proportional gain and an appropriate integral gain are determined as the appropriate control gain. ### Claim 3 (depends on 2) The material testing machine according to claim 2, wherein in a discriminant of an equation with a denominator of a transfer function of the control system as 0, the control unit extracts a point at which a value of the discriminant becomes maximum when the proportional gain is used as a variable and determines the appropriate proportional gain on a basis of the proportional gain at the extracted point. ### Claim 4 (depends on 3) The material testing machine according to claim 3, wherein when the appropriate proportional gain is substituted into the discriminant, and the integral gain is used as a variable, the control unit determines the appropriate integral gain on a basis of the maximum integral gain in a range where a value of the discriminant is 0 or more. ### Claim 5 (depends on 3, 4) The material testing machine according to claim 3 or 4, wherein when an order of a denominator of the transfer function is a fourth order or higher, the control unit uses, as the discriminant, a discriminant of an equation obtained by approximating the denominator to a third order or less. ### Claim 6 A method for controlling a material testing machine carried out in the material testing machine which includes a load mechanism which applies a test force to a test target, a measuring instrument which measures a physical quantity of the test target which changes according to the test force or the application of the test force, and a control unit which performs a material test on the test target by controlling the test force, a physical quantity of the test target, or a physical quantity acting on the test target to reduce a difference between a predetermined target value and a value measured by the measuring instrument, the method comprising: a step of the control unit performing control input for the load mechanism via a low-pass filter; a step of the control unit determining, when setting of the low-pass filter is changed, an appropriate control gain based on a control gain within a range where a control system including the load mechanism and the low-pass filter is stable; and a step of the control unit controlling an operation of the load mechanism by using the appropriate control gain.