Test system and method for controlling test system

Abstract

To provide a testing system that enables real-time simulation including a model and an actual machine with higher accuracy by eliminating response delays in a loading system caused by an actuator or the like that actuates a product under test.SOLUTION: A testing system 1 includes: a product under test 40 as a part of an actual machine to be tested; an actuator 30 that operates the product under test 40; a virtual model 11 that operates in association with the product under test 40; a control device 20 that controls the actuator 30; a computing device 10 that computes the virtual model 11; a communication unit between the product under test 40, the actuator 30, and the control device 20; and an inverse transfer function correction unit 50 that corrects a signal from the virtual model by a proper inverse transfer function obtained based on a transfer function of a system including the communication unit between the computing unit 10 and the control device 20. The testing system is configured such that the control device 20 controls the actuator 30 based on the signal corrected by the inverse transfer function correction unit 50.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a test system and a control method for a test system, and more particularly to a test system using a virtual model and a test object as a part of an actual machine. [Background technology]

[0002] By using this type of system to develop new vehicles, etc., it is possible to reduce the cost and time required for development. In this test system, for example, parts or assemblies that are difficult to model can be substituted with real parts and used as test specimens, or parts of prototyped actual vehicles can be used as test specimens. The characteristics of the test specimens or models other than the test specimens are verified using so-called HILS (Hardware In the Loop Simulation).

[0003] In such a test system, some error may exist between the behavior of the actual machine and the requirements from the model. Regarding the correction of this error, Patent Document 1 discloses a trajectory data correction device that is attached to an NC machine tool or the like and that eliminates contour cutting errors caused by servo characteristics that occur in a numerical control device that performs contour cutting. The contour error correction disclosed in Patent Document 1 involves creating command data in which errors have been corrected in advance for a known command value using an inverse transfer function corrector and providing the command data to the control device. Patent Document 2 also discloses a test system that uses a model consisting of a tire, a lower mass, and an upper mass, and a shock absorber specimen, and performs a load test by an actuator applying a load to the shock absorber based on a signal from the model. Patent Document 2 describes that the control waveform is corrected and updated so that the error (response delay) between the control waveform used by the controller and the reference waveform from the model is reduced, but the input waveform to the model is constant (for example, a time waveform of several tens of seconds), and each time a test is completed, the output of the model (i.e., the input to the load device) is compared with the previous output, and the error is corrected offline using an inverse transfer function. The corrected data is used for testing again, and once the error has been reduced, a formal verification test is performed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 63-233402 [Patent Document 2] JP 2004-53452 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the HILS test system, the input signal to the model changes in real time, and the input from the model to the load device (control device) and the feedback signal from the load device to the model also change in real time. In this way, the model and the feedback of the test piece by the actual load device form a closed loop and act on each other in real time. If the feedback signal is delayed or has a different magnitude due to the frequency characteristics of the load device, the result may differ from the original characteristics or may diverge, making it impossible to verify by simulation. In contrast, both Patent Document 1 and Patent Document 2 require correction calculations to be performed in advance using an inverse transfer function, and problems caused by delays in the load device cannot be solved in real time. In Patent Document 1, since a model is not involved, the command signal is predetermined and there is no need to calculate it in real time.

[0006] In addition, in Patent Document 2, the output signal from the model at the same time is not used during the simulation, but the signal corrected in the previous step is used, so that it is an open loop, and when one simulation is completed, the signal for the next step is created offline, so that it is a non-real-time HILS system that cannot handle HILS verification in which the input signal to the model changes in real time. In other words, Patent Document 2 does not have an inverse transfer function that can be calculated with high accuracy in real time in the time domain, so there is a problem that correction can only be made to predetermined signals.

[0007] An object of the present invention is to provide a test system and a control method for a test system that eliminates the response delay of a load system such as an actuator that operates a test specimen, and enables simulation including a model and an actual device in real time with higher accuracy. [Means for solving the problem]

[0008] In order to solve the above problems, a test system according to an embodiment of the present invention comprises a specimen as part of an actual machine to be tested, an actuator for operating the specimen, a virtual model that operates in association with the specimen, a control device that controls the actuator, a calculation device that calculates the virtual model, and an inverse transfer function correction unit that corrects a signal from the virtual model using a proper inverse transfer function obtained based on a transfer function of a system including the specimen, a communication unit between the actuator and the control device, and a communication unit between the calculation device and the control device, and the control device controls the actuator based on the signal corrected by the inverse transfer function correction unit.

[0009] In addition, a control method for a test system according to an embodiment of the present invention is a control method for a test system including a specimen as part of an actual machine to be tested, an actuator for operating the specimen, a virtual model that operates in association with the specimen, a control device for controlling the actuator, and a calculation device for calculating the virtual model, and includes the steps of: correcting a signal from the virtual model using a proper inverse transfer function obtained based on a transfer function of a system including the specimen, the actuator, the control device, and a communication unit between the calculation device and the control device; and controlling the actuator based on the signal corrected in the inverse transfer function correction step. Effect of the Invention

[0010] According to the above-described embodiment, in the test system, it is possible to eliminate the response delay of the load system caused by the actuator that operates the test specimen, and to perform a simulation including a model and an actual device in real time with higher accuracy. [Brief description of the drawings]

[0011] [Figure 1] Fig. 1(a) is a functional block diagram showing a known test system that does not perform correction using a transfer function, and Fig. 1(b) is a functional block diagram for explaining a test system that performs correction using an inverse transfer function according to the present embodiment. [Diagram 2] FIG. 2 is a diagram for explaining the virtual model shown in FIG. [Diagram 3] 2 is a flowchart for explaining a method for creating an inverse transfer function used in the inverse transfer function correction unit of FIG. 1. [Figure 4] FIG. 2 is a diagram showing an example of actual measurement of a transfer function from the output section of the arithmetic device shown in FIG. 1(a) to a load device including a control device, an actuator, and a test specimen. [Diagram 5] 5 is a graph showing a comparison of the transfer characteristic approximated by a third-order polynomial with the actually measured transfer characteristic (FIG. 4), where FIG. 5(a) shows the gain and FIG. 5(b) shows the phase. [Figure 6] 6A and 6B are diagrams for comparing a theoretical inverse transfer function with an inverse transfer function generated by approximation in this embodiment, where FIG. 6A shows the gain and FIG. 6B shows the phase. [Figure 7] FIG. 7(b) is an enlarged view of a portion of FIG. 7(a), showing a comparison between an input signal to an actuator control device without correction by an inverse transfer function correction unit and an input signal to an actuator control device that has passed through an inverse transfer function correction unit. [Figure 8]FIG. 8 is a diagram showing an example in which the test system of this embodiment is applied to a HILS test of a vehicle. FIG. 8(a) is a diagram showing the displacement input from the road surface shown in FIG. 2 to the virtual model of FIG. 1(a) and FIG. 1(b). FIG. 8(b) and FIG. 8(f) show the calculation results of the input signal to the load device of FIG. 1(a) and FIG. 1(b) (the displacement difference between Y2 and Y1 calculated by the model of FIG. 2), and FIG. 8(c) and FIG. 8(g) show the load of the test specimen fed back from the test specimen of FIG. 1(a) and FIG. 1(b) to the virtual model. FIG. 8(d), (e), (h), and (i) are enlarged views of parts of FIG. 8(b), (c), (f), and (g), respectively. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings used in the description of the present embodiment are intended to explain the configuration of the present embodiment, the positional relationship of each part included in the configuration, the action, the effect, and the technical concept, and are not intended to limit the present invention to the specific configuration of the present embodiment.

[0013] 1(a) and 1(b) are functional block diagrams for explaining the test system of this embodiment. FIG. 1(a) shows a test system 100 as a comparative example in which correction is not performed using a transfer function, and FIG. 1(b) shows a test system 1 in which correction is performed using an inverse transfer function of this embodiment. Both the test system 100 of the comparative example and the test system 1 of this embodiment include a specimen 40 as a part of the actual machine to be tested, an actuator 30 that operates the specimen 40, a virtual model 11 that operates in relation to the specimen, a control device 20 that controls the actuator 30, and a calculation device 10 that calculates the virtual model 11. The control device 20, the actuator 30, and the specimen 40 constitute a load device (system) 60.

[0014] Furthermore, the test system 1 differs from the test system 100 according to the comparative example in that an inverse transfer function correction unit 50 for correcting a signal from the virtual model 11 is provided between the virtual model 11 and the control device 20. The inverse transfer function of the inverse transfer function correction unit 50 is a proper inverse transfer function obtained based on a transfer function of a system including a communication unit between the test piece 40, the actuator 30, and the control device 20, and a communication unit between the arithmetic device 10 and the control device 20. Although the communication unit between the test piece 40, the actuator 30, and the control device 20, and the communication unit between the arithmetic device 10 and the control device 20 are not shown, it is clear that there is a communication unit between the test piece 40, the actuator 30, and the control device 20 because the signals S1 and S2 are transmitted from the control device 20 to the actuator 30 and the test piece 40 in sequence. It is also clear that there is a communication unit between the arithmetic device 10 and the control device 20 because the signals S0, S1, and S2 are transmitted from the arithmetic device 10 to the control device 20 in sequence.

[0015] The inverse transfer function that the inverse transfer function correction unit 50 has as a function is basically an inverse transfer function of a transfer function established between a signal S0 output from the virtual model 11 and a signal Sf1 indicating the displacement of the specimen 40 driven by the actuator 30 in the test system 100 shown in Fig. 1(a). This inverse transfer function is an approximation of the inverse transfer function found from the above transfer function of the test system 100 as a proper inverse transfer function.

[0016] The test system 1, 100 is related to testing of a suspension including a tire of a vehicle. As a shock absorber A (FIG. 2), a shock absorber of an actual test piece 40 is used instead of a virtual model 11, and the shock absorber A is operated by an actuator 30 controlled by a control device 20. Elements other than the shock absorber A, that is, a spring, an unsprung tire, and a sprung vehicle body, are used as the virtual model 11. The virtual model 11 is implemented in a real-time calculation device 10 capable of high-speed calculation, and its operation is executed. A signal S3 input to the virtual model 11 indicates a displacement given to the tire due to unevenness of a road surface Z when the vehicle is traveling. The displacement is generated by another road surface model (not shown) in the calculation device 10. Moreover, the contents describing the virtual model 11 shown in FIGS. 1(a) and (b) are a schematic representation of an equation expressing the virtual model 11, and do not represent an actual equation.

[0017] FIG. 2 is a diagram showing the physical system of the virtual model 11 shown in FIG. 1(a) and 1(b). In the virtual model 11, the sprung mass M1 corresponds to the mass of the vehicle body above the spring Sp, and the unsprung mass M2 corresponds to the mass below the spring Sp, such as the axle and the tire T. A shock absorber A is disposed between the sprung mass M1 and the unsprung mass M2. The lower surface of the tire T is in contact with the road surface Z, and the position Y0 of the lower end of the tire T is a displacement caused by the unevenness of the road surface Z when the vehicle is traveling. When the position of the unsprung mass M2 is Y2 and the position of the sprung mass M1 is Y1, the input to the shock absorber A is a displacement caused by the difference between the position Y2 and the position Y1. The output from the shock absorber A is a load, and the load acts on the unsprung mass M1 and the sprung mass M1.

[0018] In the case of a HILS that uses an actual machine instead of a theoretical model, the difference between position Y2 and position Y1 is applied to the load device 60, and the load generated by shock absorber A driven by the load device 60 is fed back to the virtual model 11, whereby shock absorber A plays a role similar to that of shock absorber A of the virtual model 11, and calculations for the virtual model 11 are performed.

[0019] Referring again to Figures 1(a) and (b), the calculation device 10 performs sampling at regular time intervals (e.g., 0.5 ms) and calculates a signal S0(Y2-Y1) indicating the displacement (Y1, Y2) of each mass in the virtual model 11 and the displacement of the shock absorber A due to an input Y0 from the road surface Z.

[0020] The control device 20 includes a comparison unit 21 and a control unit 22. The comparison unit 21 calculates the difference between a signal S0 (signal S1: the absorber displacement Y2-Y1) from the model 11 (via an inverse transfer function unit 50 in FIG. 1(b)) and a signal Sf1 fed back from the test piece 40, and outputs the difference to the control unit 22. The control unit 22 performs, for example, PID control based on the difference signal from the comparison unit 21, and controls the operation amount of the actuator 30, etc. Note that the control device 20 can be, for example, an ECU (Electronic Control Unit) in a HILS test.

[0021] The actuator 30 operates in accordance with a signal S2 from the control unit 22 so that the specimen 40 (shock absorber A) performs an operation (displacement Y2-Y1) related to the test evaluation item. This actuator 30 can be a hydraulic actuator, an actuator driven by a motor, or the like. The specimen 40 operates when driven by the actuator 30. This operation is detected by a predetermined sensor (not shown), and the detected signal Sf1 is output to the comparison unit 21 and used to control the actuator. The signal Sf2 (load) is output to the virtual model 11 and used for calculation of the next step.

[0022] When simulating shock absorber A using only a model, rather than an actual machine, the displacement S0 of the absorber calculated on the model is input to the model absorber at the same time, and the load calculated by the model absorber is used to perform the calculation of the next step. However, in a HILS system using the actual shock absorber A, a delay and amplitude change occurs between the signal Sf1 indicating the displacement of shock absorber A and the signal S0 due to the control device 20 and actuator 30. For this reason, the load signal generated from the actual shock absorber A is also delayed compared to the original signal, making it impossible to perform an accurate simulation. Depending on the conditions, the simulation may diverge.

[0023] In the test system 1 of this embodiment, the inverse transfer function correction unit 50, which functions as this inverse transfer function, corrects the signal S0 from the virtual model 11, so that the signal S1 input to the comparison unit 21 can be advanced by the same amount as the delay caused by the load device 60 including the control device 20 and the actuator 30 relative to the signal S0. This makes it possible for the test system 1 to eliminate the time delay of the signal Sf1 indicating the displacement of the shock absorber A caused by the actuator 30 etc. relative to the signal S0 from the virtual model 11, thereby enabling a more accurate simulation to be performed.

[0024] That is, in the system of Fig. 1(a), S0 = S1, and signal Sf1 lags signal S1 by, for example, δt seconds. Therefore, signal Sf2 also lags behind signal S1 by δt seconds compared to a simulation using only the model. In Fig. 1(b), signal S1 is advanced by δt seconds compared to signal S0 due to the correction by inverse transfer function correction unit 50. Since the relationship between signal Sf1 and signal S1 does not change, signal Sf1 lags behind signal S1, which is advanced by δt seconds compared to signal S0, by δt seconds, so the delay with respect to signal S0 is eliminated, and the delay of signal Sf2 indicating the load input to virtual model 11 is also eliminated. In FIG. 1(b), for the sake of explanation, the inverse transfer function correction unit 50 is shown between the calculation device 10 and the control device 20 of the load device 60, but in actual practice, it is implemented in either the calculation device 10 or the control device 20.

[0025] (Generating the inverse transfer function) Fig. 3 is a flowchart showing the process of creating an inverse transfer function in the inverse transfer function correction unit 50 in Fig. 1. This process is performed prior to the operation of the test system 1 in Fig. 1. First, in step S101, without being connected to the virtual model 11, the control device 20 inputs a signal S2 indicating input data for each of a plurality of frequencies to the actuator 30 to apply a vibration input to the test piece 40 (shock absorber), and obtains the displacement Sf1 of the shock absorber A at that time. The vibration can be applied using a sine wave sweep excitation or a random wave excitation in a predetermined frequency range. The predetermined frequency range is determined by the characteristics of the test piece 40 to be simulated. In the case of a vehicle absorber, it can be, for example, higher than 0 Hz and up to 100 Hz.

[0026] Table 1 below shows an example of actual measurements of this embodiment. It shows the gain and phase (deg) of signal Sf1 relative to signal S0 for each vibration frequency. The gain is shown both in dB and in real numbers. Gain is the amplitude ratio of signal Sf1, and a negative phase means a time delay.

[0027] [Table 1]

[0028] Figure 4 shows the Bode plot of the transfer function represented by the measurement data in Table 1. In Figure 4, G and P show the frequency characteristics of gain and phase, respectively. When the measurement data in Table 1 above is expressed in complex numbers, it becomes the following Table 2. That is, the relationship between gain and phase in Table 1 above can be expressed in complex numbers as in the following formula. G(jω k )=Ae jφ =A(cosφ+jsinφ)=Acosφ+jAsinφ =R m +jI m Here, A is the gain (actual quantity) and φ is the phase (deg), so the values ​​in Table 1 become the contents of Table 2 according to the above formula.

[0029] [Table 2]

[0030] JPEG0007620600000003.jpg127167

[0031] JPEG0007620600000004.jpg133150

[0032] JPEG0007620600000005.jpg178150

[0033] JPEG0007620600000006.jpg91150

[0034] Figures 5(a) and (b) are Bode plots of the transfer function approximated by the third-order polynomial shown in equation (17) above, and the gain and phase are shown in comparison with the gain G and phase P calculated based on the measured data shown in Figure 4. Rg and Rp shown in Figures 5(a) and (b) respectively indicate the gain and phase obtained by measurement, while Ng and Np respectively indicate the gain and phase obtained by calculation. As shown in Figures 5(a) and (b), the gain error at 100 Hz is about 1 dB, and the phase error is within 5 deg, which is sufficient accuracy for simulating the absorber. If the accuracy is insufficient for a certain system, it is possible to increase n and approximate using a similar calculation.

[0035] JPEG0007620600000007.jpg118166

[0036] JPEG0007620600000008.jpg194150

[0037] JPEG0007620600000009.jpg91150

[0038] In equation (25), the parameter ω a1 , ω a2 , ω b1 , ω b2 , ζ a , ζ b In this embodiment, by adjusting such parameters, the proper inverse transfer function of the formula (25) is obtained so as to approach the inverse transfer characteristic of the transfer function of the test system while considering the influence of the first-order lag element (low-pass filter) and the second-order vibration element. Each parameter may be determined manually or automatically. Conditions for determining the parameters are shown below as examples. (1) Regarding the denominator of equation (25), in order to reduce the effect of phase lag, a1 , ω a2 is set to be four times or more of ω1 and ω2, or the maximum frequency that the computing device can simulate. (2) Similarly, in order to reduce the effect of phase lag in the denominator, ζ a Set it to 0.2 or less. (3) Regarding the numerator of equation (25), the phase is slightly delayed and the gain is reduced due to the quadratic and linear terms in the denominator. b1 , ω b2 is set to a small value relative to ω1 and ω2. (4) The parameters are adjusted as described above, and the Bode plot (gain and phase frequency characteristics) of the inverse transfer function for the parameters is obtained. The above adjustments are then repeated until the difference between the obtained gain and the required gain is within 3 dB, and the phase difference is within 10 deg. Here, the "required gain or phase" refers to the gain and phase frequency characteristics represented by the inverse transfer function of the transfer function obtained as equation (24) (hereinafter referred to as the "theoretical inverse transfer function"). The above settings are merely a guideline, and the present embodiment is not limited to adjusting parameters according to such procedures or settings.

[0039] 6(a) and (b) are Bode diagrams showing the inverse transfer function obtained in this embodiment in comparison with the theoretical inverse transfer function, where FIG. 6(a) shows the frequency characteristics of gain (dB) and FIG. 6(b) shows the frequency characteristics of phase (deg). Curves Ig and Ip in FIG. 6(a) and (b) show the gain and phase of the theoretical inverse transfer function, respectively, and curves Mg and Mp show the gain and phase of the inverse transfer function obtained in this embodiment, respectively. As described above, the difference between the frequency characteristics of the obtained gain and phase and the theoretical inverse transfer function is within 3 dB for gain and within 10 deg for phase, and the response delay (phase delay) in the test system of this embodiment is sufficiently suppressed.

[0040] The gain and phase tolerances described herein are for the exemplary absorber and may not apply to all systems, but may vary depending on the characteristic frequency range of the system being evaluated.

[0041] In this embodiment, the parameter ω a1 , ω a2 By making the parameter ω b1 , ζ b , ω b2 can be approximated to the parameters ω1, ζ1, and ω2, and the theoretical inverse transfer function can be approximated up to higher frequencies. In this case, it is necessary to perform calculations with a shorter sampling time, which means that a more powerful computing device or control device is required. When the frequency range of the system evaluated by HILS is low, the agreement at the lower frequencies is sufficient, so the parameter ω a1 , ω a2 It is possible to lower the calculation load and build an inexpensive evaluation system.

[0042] Table 3 shows the parameters ω1, ω2, ζ1 of the theoretical inverse transfer function and the parameters ω of the inverse transfer function generated by approximation. a1 , ω a2 , ω b1 , ω b2 , ζ a , ζ b Shows.

[0043] [Table 3]

[0044] (Evaluation by inverse transfer function) 3 again, once the proper inverse transfer function is found, in step S105, this inverse transfer function is implemented in the test system 1 as shown in FIG. 1(b). This inverse transfer function can be implemented on the same computing device side as the model computation, or it can be implemented in a computing section (not shown) of the control device 20 of the actual device under test 40. The inverse transfer function is usually implemented on the side with higher computation power.

[0045] 7(a) and (b) and 8(a) to (i) are diagrams for explaining the effect of the inverse transfer function correction unit 50 functioning as the inverse transfer function of this embodiment. FIG. 7(a) is a diagram showing a comparison between a signal (command) c2 input to the actuator 30 without correction by the inverse transfer function correction unit 50 of the test system 100 of FIG. 1 and a signal (command) c1 input to the actuator 30 that has passed through the inverse transfer function correction unit 50 of the test system 1. FIG. 7(b) is a diagram showing an enlarged view of the signals c1 and c2 in the range of the horizontal axis 30s to 30.1s in FIG. 7(a). The horizontal axis of FIG. 7(a) and FIG. 7(b) indicates time (s), and the vertical axis indicates displacement (mm).

[0046] The relationship between the delay time and phase of a signal is expressed by the following equation (26), where F is the frequency and ΔT is the delay. Φ =360°×F×δT··· Formula (26) In the example shown in FIG. 7(a), when ΔT=0.0043 s and F=60 Hz, a delay (the time it takes for the signal Sf2 output from the specimen 40 to be input to the calculation device 10) of Φ=92.8° (approximately ¼ period) occurs, making it impossible to perform an accurate simulation. In this embodiment, as shown in FIG. 7(b), the displacement of the signal c1 changes at an earlier timing than the signal c2 (the signal c1 leads compared to the signal c2). In this embodiment, the signals Sf1 and Sf2 output from the specimen 40 also lead due to the lead of the signal c1, and there is no signal delay in the calculation device 10, making it possible to perform an accurate simulation.

[0047] Fig. 8(a) is a diagram showing a signal S0 indicating a displacement input from the road surface Z shown in Fig. 2 to the virtual model 11 of Fig. 1(a) and Fig. 1(b). Fig. 8(b) is a diagram showing a signal S1 input to the load device 60 of the test system 100, Fig. 8(c) is a diagram showing a signal Sf2 fed back from the test specimen 40 of the test system 100 to the virtual model 11, Fig. 8(d) is a diagram showing an enlarged view of region B of Fig. 8(b), and Fig. 8(e) is a diagram showing an enlarged view of region C of Fig. 8(c). The horizontal axis of Fig. 8(a) to (e) is time, the vertical axes of Fig. 8(a), (b), and (d) are displacement, and the vertical axes of Fig. 8(c) and (e) are load.

[0048] FIG. 8(f) shows the signal S1 input to the load device 60 of the test system 1, FIG. 8(g) shows the signal Sf2 fed back from the specimen 40 of the test system 1 to the virtual model 11, FIG. 8(h) shows an enlarged view of the region F of FIG. 8(f), and FIG. 8(i) shows an enlarged view of the region G of FIG. 8(g). The horizontal axis of FIG. 8(f) to (i) is time, the vertical axis of FIG. 8(f) and (h) is displacement, and the vertical axis of FIG. 8(g) and (i) is load. That is, FIG. 8(b) to FIG. 8(e) show the results of using the test system 100 of FIG. 1(a) without correction by the inverse transfer function correction unit 50. FIG. 8(f) to FIG. 8(i) show the results of using the test system 1 with correction by the inverse transfer function correction unit 50.

[0049] In this embodiment, the road surface input to the virtual model 11 is a simulated road surface with unevenness of ±50 mm, which varies sinusoidally along the vehicle travel direction as shown in Fig. 8(a). At the vehicle speed in the simulation, it fluctuates at a period of 0.5 Hz.

[0050] In this test, an actual shock absorber is used as the specimen 40. As shown in Figures 8(b) and (f), in response to a sine wave road input, the displacement input of the absorber to the actual shock absorber also fluctuates smoothly and is close to a sine wave, whereas the change gradient of the load on the absorber is discontinuous and contains strong nonlinearity and high frequency components. This load signal is fed back to the model (areas B and F in the figure).

[0051] As shown in Fig. 8(b) to (e), when there is no correction using the inverse transfer function, the influence of high-frequency components of about 40 Hz gradually increases in the areas shown in Fig. 8(b) and Fig. 8(c) as areas B and C, and in the range from time 2.4 s to time 3.0 s in Fig. 8(d) and Fig. 8(e), and the command to the actual machine calculated from the model is superimposed with vibration of high-frequency components that should not exist. This vibration command causes the shock absorber A to vibrate at a high frequency, and the load signal to the virtual model 11 also becomes oscillatory. This is due to an incorrect calculation result caused by the phase delay of the high-frequency components in the load signal described above. On the other hand, as shown in Fig. 8(f) to Fig. 8(i), when correction using the inverse transfer function is performed, the above-mentioned vibration disappears, and a correct HILS evaluation can be performed. In the case of this embodiment, since it is known that there is no vibration like that when the actual vehicle is running, it can be assumed that this is a simulation error, but in the case of a new product whose characteristics are not known, an incorrect result will be obtained if there is no correction using the inverse transfer function.

[0052] The timing, frequency, and magnitude of the vibration change depending on the test conditions and the characteristics of the test specimen and the load device. That is, oscillation occurs due to changes in the phase and amplitude of the frequency contained in the load component. Therefore, although the oscillating frequency and time are within the illustrated regions B and C in the examples shown in Figures 8(b) and (c), this embodiment is not limited to such examples, and the oscillation frequency and time (timing) change depending on the test conditions.

[0053] Here, the proper transfer function is a transfer function that can be realized strictly in the real world, specifically, a transfer function that satisfies the degree of s of the numerator≦the degree of s of the denominator. That is, an improper transfer function is divided into a proper term and an improper term. By expanding this, the output of the test system is obtained. When the transfer function is improper, the time derivative of the input is included in the output due to the action of the improper term. The time derivative is a factor that prevents the realization in the real world. As described above, in this embodiment, the output signal of the virtual model 11 is corrected by the inverse transfer function of the proper transfer function, that is, the proper inverse transfer function. As a result, in this embodiment, the response delay in the test system caused by the actuator 30 and the like is eliminated, and the simulation performed in the test system 1 can be performed with higher accuracy.

[0054] The first aspect of the invention described above is a test system comprising: a specimen as part of an actual machine to be tested; an actuator for operating the specimen; a virtual model that operates in association with the specimen; a control device that controls the actuator; a calculation device that calculates the virtual model; and an inverse transfer function correction unit that corrects a signal from the virtual model using a proper inverse transfer function obtained based on a transfer function of a system including the specimen, a communication unit between the actuator and the control device, and a communication unit between the calculation device and the control device, wherein the control device controls the actuator based on the signal corrected by the inverse transfer function correction unit.

[0055] A second aspect of the present invention is the test system of the above aspect, wherein the inverse transfer function correction section is implemented in the arithmetic device.

[0056] A third aspect of the present invention is the test system according to the above aspect, wherein the inverse transfer function correction unit is implemented in an actual machine control and calculation unit that operates the specimen.

[0057] A fourth aspect of the invention is the test system of the above aspect, wherein the transfer function has a numerator that is a Laplace variable of order 0 and is an approximate transfer function.

[0058] A fifth aspect of the invention is the test system according to the above aspect, wherein the transfer function has a denominator that is a third-order Laplace variable and is an approximate transfer function.

[0059] A sixth aspect of the invention is a control method for a test system including a specimen as part of an actual machine to be tested, an actuator for operating the specimen, a virtual model that operates in association with the specimen, a control device for controlling the actuator, and a calculation device for calculating the virtual model, the control method for the test system including the steps of: correcting a signal from the virtual model using a proper inverse transfer function obtained based on a transfer function of a system including the specimen, the actuator, the control device, and a communication unit between the calculation device and the control device; and controlling the actuator based on the signal corrected in the inverse transfer function correction step.

[0060] A seventh aspect of the invention is a method for controlling the above-mentioned test system, which separates a transfer function of a system including the actuator and the test piece into a real part and an imaginary part, and determines the transfer function by an approximation formula using the least squares method.

[0061] An eighth aspect of the present invention is a method for controlling the above test system, which divides the transfer function into a first-order lag system and a second-order vibration system, and finds parameters of an approximate inverse transfer function. [Explanation of symbols]

[0062] 1,100 Test System 10 Arithmetic unit 11 Virtual Model 20 Control device 21 Comparison section 22 Control section 30 Actuator 40 Specimen 50 Inverse transfer function correction section 60 Loading device A. Shock absorber

Claims

1. An actuator for moving a specimen; a virtual model operating in conjunction with the specimen; A control device for controlling the actuator; A computing device that computes the virtual model; and an inverse transfer function correction unit that corrects a signal from the virtual model using a proper inverse transfer function obtained based on a transfer function of a system including the test piece, a communication unit between the actuator and the control device, and a communication unit between the arithmetic device and the control device; The control device controls the actuator based on the signal corrected by the inverse transfer function correction unit. Test system.

2. The test system according to claim 1 , wherein the inverse transfer function correction unit is implemented in the arithmetic device.

3. 2. The test system according to claim 1, wherein the inverse transfer function correction unit is implemented in an actual machine control and calculation unit that operates the device under test.

4. 2. The test system of claim 1, wherein the transfer function is an approximated transfer function with a numerator being a zeroth order Laplace variable.

5. 5. The test system of claim 4, wherein the transfer function is an approximate transfer function whose denominator is a third order Laplace variable.

6. A method for controlling a test system including an actuator for operating a specimen, a virtual model operating in association with the specimen, a control device for controlling the actuator, and a computing device for computing the virtual model, comprising: an inverse transfer function correction step of correcting a signal from the virtual model by a proper inverse transfer function obtained based on a transfer function of a system including the specimen, a communication unit between the actuator and the control device, and a communication unit between the arithmetic device and the control device; controlling the actuator based on the signal corrected in the inverse transfer function correction step; A method for controlling a test system comprising:

7. 7. The method for controlling a test system according to claim 6, wherein a transfer function of a system including the actuator and the test object is divided into a real part and an imaginary part, and the transfer function is calculated by an approximation formula using a least squares method.

8. 7. The method for controlling a test system according to claim 6, wherein the transfer function is divided into a first-order lag system and a second-order vibration system, and parameters of an approximate inverse transfer function are obtained.

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