JP5136247B2 - Dynamometer control method for engine bench system - Google Patents

Description

  The present invention relates to an engine bench system for measuring various characteristics of an engine by connecting a dynamometer to an engine with a shaft, and more particularly to a dynamometer control system for suppressing resonance of a two-inertia mechanical system.

  FIG. 11 shows a configuration example of the engine bench system. The engine E / G and the transmission T / M are combined (AT or MT, or with a clutch in the case of MT), and connected to the dynamometer DY via the shaft. ing. The engine E / G side controls the engine output by adjusting the throttle opening by the throttle actuator ACT.

  On the other hand, a rotation detector PP and a torque detector (load cell) LC are provided on the dynamometer DY side, and speed and torque are controlled based on detection signals from these detectors. This control is PID controlled by the controller C (s). The figure shows the case of speed control, and the controller C (s) performs a PID calculation on the deviation between the speed setting input and the speed detection value of the dynamometer DY, and the inverter (power converter) uses this calculation result. To control the speed of the dynamometer DY.

  In such an engine bench system based on PID control of a dynamometer, there is a risk of causing a resonance breakage of the shaft due to pulsating torque generated by the engine. In order to prevent this, the resonance point of the mechanical system of the dynamometer, the shaft, and the engine is set to be equal to or less than the frequency of the pulsation torque generated by the engine, and the PID control of the dynamometer is performed.

As another control method of the dynamometer speed of the engine bench system that requires resonance suppression, there is a speed control method using a μ design method which is one of robust control design theories (for example, see Patent Document 1).
JP 2003-121308 A

  The speed control method proposed in Patent Document 1 is intended for a system in which the engine bench system to be controlled does not have large nonlinearity such as play and hysteresis. On the other hand, a general engine bench system has a clutch between the engine and the dynamometer. There is play in the clutch, and it is difficult to apply the control method of Patent Document 1 to such an engine bench system.

  Further, the control method of Patent Document 1 is based on the μ design method, and in order to obtain a controller circuit, roughly two operations of modeling a control target and determining a weight function are required. In particular, the determination of the weight function requires trial and error. For this reason, when the specimen engine is changed, it takes time to design the controller circuit, making it difficult to perform an efficient test.

  In addition, a general engine bench system with a clutch has a resonance characteristic due to the clutch. However, since the resonance characteristic is not considered in the currently applied speed control method, the shaft torque is particularly detected from the engine torque. In the characteristic, a resonance point of the mechanical system appears greatly, and it is difficult to estimate the vibration waveform of the engine torque by observing the shaft torque.

  An object of the present invention is to provide a dynamometer control method for an engine bench system that can suppress shaft torque and speed from becoming oscillating and can efficiently perform a stable engine test.

  In order to solve the above-mentioned problems, the present invention uses a two-inertia engine bench model as the mechanical system of the engine bench system, and appropriately applies the equation of motion and the fifth-order polynomial P (s) of the closed loop characteristic of the dynamometer control characteristic. By determining the dynamometer control parameters so as to have the characteristics of the fifth-order polynomial set in the above, the dynamometer torque command for suppressing the resonance operation of the mechanical system is obtained. To do.

(1) In an engine bench system for measuring various characteristics of an engine by connecting a dynamometer to the engine with a shaft,
The controller of the dynamometer outputs a dynamometer torque command T2ref,
T2ref = (Ki / s + Kp) * (w2ref−w2)
+ (B1 * s + b0) / (a1 * s + 1) * T12
However, T12 is a combined shaft torsion torque (shaft torque), w2ref is a dynamometer speed command, w2 is a dynamometer angular speed, and Ki, Kp, b1, b0, and a1 are parameters.
It is characterized by having a configuration obtained by the above calculation.

(2) The parameters (Ki, Kp, b1, b0, a1) are
J1 * s * w1 = T1 + T12
T12 = K12 / s * (w2-w1)
J2 * s * w2 = −T12 + T2
T2ref = (Ki / s + Kp) * (w2ref−w2)
+ (B1 * s + b0) / (a1 * s + 1) * T12
However, J1 is an engine moment of inertia, J2 is a dynamometer moment of inertia, K12 is a coupled shaft spring stiffness, T12 is a coupled shaft torsion torque (axial torque), w1 is an engine angular velocity, w2 is a dynamometer angular velocity, T1 is an engine torque, T2 Is the dynamometer torque.
And a means for determining Ki, Kp, b1, b0, a1 so that the coefficients of the fifth-order polynomial P (s) having the closed-loop characteristics are appropriately set to the coefficients c1 to c5 of the fifth-order polynomial. And

(3) When the shaft has nonlinear characteristics and the resonance frequency changes depending on the magnitude of the shaft torque,
An engine torque map for obtaining a measured value of output torque with respect to the engine speed and throttle opening;
A T2f table having a relationship of a resonance frequency generated in a mechanical system from the engine to the dynamometer with respect to an output of the torque map as a torsion torque (shaft torque) value of the shaft;
The spring stiffness K12 is obtained from the resonance frequency wc obtained from the T2f table, the engine inertia J1 and the dynamometer inertia J2, and the coefficients c1 to c5 of the fifth order polynomial P (s) appropriately set. Means is provided for determining Ki, Kp, b1, b0, a1 so as to be c5.

(4) In an engine bench system for measuring various characteristics of an engine by connecting a dynamometer to the engine with a shaft,
The controller of the dynamometer outputs a dynamometer torque command T2ref,
T2ref = ((Ki / s) * (w2ref−w2) −Kp * w2) * (1 / (a1 * s + 1)) − ((bl * s + 1) / (a1 * s + 1) * T12) * Kt12
However, T12 is a coupling shaft torsion torque (shaft torque), w2ref is a dynamometer speed command, w2 is a dynamometer angular speed, and Ki, Kp, Kt12, b1, and a1 are parameters.
It is characterized by having a configuration obtained by the above calculation.

(5) The parameters (Ki, Kp, Kt12, b1, a1) are
J1 * s * w1 = T1 + T12
T12 = K12 / s * (w2-w1)
J2 * s * w2 = −T12 + T2
T2ref = ((Ki / s) * (w2ref−w2) −Kp * w2) * (1 / (a1 * s + 1)) − ((bl * s + 1) / (a1 * s + 1) * T12) * Kt12
However, J1 is an engine moment of inertia, J2 is a dynamometer moment of inertia, K12 is a coupled shaft spring stiffness, T12 is a coupled shaft torsion torque (axial torque), w1 is an engine angular velocity, w2 is a dynamometer angular velocity, T1 is an engine torque, T2 Is the dynamometer torque.
And a means for determining Ki, Kp, Kt12, b1, a1 so that the coefficients of the fifth-order polynomial P (s) of the closed-loop characteristic are the coefficients c1 to c5 of the appropriately set fifth-order polynomial. And

(6) When the shaft has non-linear characteristics and the resonance frequency varies depending on the magnitude of the shaft torque,
An engine torque map for obtaining a measured value of output torque with respect to the engine speed and throttle opening;
A T2f table having a relationship of a resonance frequency generated in a mechanical system from the engine to the dynamometer with respect to an output of the torque map as a torsion torque (shaft torque) value of the shaft;
The spring stiffness K12 is obtained from the resonance frequency wc obtained from the T2f table, the engine inertia J1 and the dynamometer inertia J2, and the coefficients c1 to c5 of the fifth order polynomial P (s) appropriately set. Means is provided for determining Ki, Kp, Kt12, b1, a1 so as to be c5.

  As described above, according to the present invention, the mechanical system of the engine bench system is a two-inertia engine bench model, and the equation of motion and the fifth-order polynomial P (s) of the closed loop characteristic of the dynamometer control characteristic are appropriately set. By determining the dynamometer control parameters so that the characteristic of the fifth-order polynomial is obtained, the torque command of the dynamometer that suppresses the resonance operation of the mechanical system is obtained, so that the shaft torque and speed become oscillating. Can be suppressed, and a stable engine test can be efficiently performed.

  First, mechanical characteristics of the engine bench system targeted by the present invention will be described. In general, the mechanical system configuration of the engine bench system is expressed as a multi-inertia mechanical system model having two or more inertia systems. The present invention is directed to an engine bench system that can be approximated to a two-inertia system.

  FIG. 12 shows a target engine bench model of a two-inertia mechanical system. The physical values in this engine bench model are expressed as J1: engine inertia moment, J2: dynamometer moment of inertia, K12: coupling shaft spring stiffness, T12: coupling shaft torsion torque (shaft torque), w1: engine angular velocity, w2: dynamometer angular velocity. , T1: engine torque, T2: dynamometer torque, the equation of motion of the engine bench can be expressed by the following equation, where Laplace operator is s.

J1 * s * w1 = T1 + T12 (1)
T12 = K12 / s * (w2-w1) (2)
J2 * s * w2 = −T12 + T2 (3)
FIG. 13 and FIG. 14 show characteristic examples of the engine bench system of FIG. 11 when J1 = 0.3, K12 = 1500, and J2 = 0.7. FIG. 13 is a Bode diagram of T1 (engine torque) → T12 (shaft torque), and FIG. 14 is a Bode diagram of T1 (engine torque) → w2 (dynamometer speed). Thus, the mechanical system of a general engine bench system has a resonance point (about 11 Hz in FIG. 13) at a certain frequency.

(Embodiment 1)
FIG. 1 is a configuration diagram of an engine bench system according to the present embodiment. The engine 1 and the transmission 2 are connected to a dynamometer 4 through a shaft 3, the engine 1 controls the output by the throttle opening, and the dynamometer 4 is provided with a rotation detector 5 and a shaft torque detector 7. The system configuration is such that the speed control of the dynamometer 4 is performed by the inverter 8 based on the detection signal of each detector.

  In this system configuration, the controller 9 that gives a torque command to the inverter 8 sets the dynamometer torque T2 according to the following equation (4) when the dynamometer speed command value (command value of w2) is w2ref. It is controlled by T2ref.

T2ref = (Ki / s + Kp) * (w2ref−w2) + (b1 * s + b0) / (a1 * s + 1) * T12 (4)
The first term on the right side of the equation (4) calculates the speed deviation obtained by the subtraction element 9A by the proportional integration (PI) element 9B, and the second term calculates the shaft torque T12 by the filter element 9C. The addition element 9D adds the calculation results of the elements 9B and 9C to obtain a torque command T2ref. The parameters (Ki, Kp, b1, b0, a1) in the equation (4) are determined as follows.

  When the closed loop characteristic polynomial P (s) of the above equations (1) to (3) and (4) is obtained, the following quintic polynomial is obtained.

The coefficients of the terms s, s ² , s ³ , s ⁴ , and s ⁵ of this polynomial P (s) can be arbitrarily determined by (Ki.Kp, b1, b0, a1). That is,

By solving the simultaneous equations (6) to (10) with respect to (Ki.Kp.b1.b0.a1), the closed-loop polynomials of (1) to (4) are

It can be.

  In this embodiment, since (Ki, Kp, b1, b0, a1) in the expression (4) is determined, the expressions (6) to (10) (c5, c4, c3, c2.c1) are changed to 5 Set to the coefficient of the characteristic polynomial of the second-order low-pass filter.

  For example, for binomial coefficient type, c5 = 1. c4 = 5. Set c3 = 10, c2 = 10, and c1 = 5.

  In order to obtain the Butterworth type, c5 = 1. It is assumed that c4 = 3.23606797749979, c3 = 5.23606797779979, c2 = 5.23606797779979, c1 = 3.23606797779979.

  Then, equations (6) to (10) are solved to obtain control parameters (Ki, Kp, b1, b0, a1) of equation (4).

  According to the present embodiment, the resonance can be suppressed while improving the speed control response. This will be explained. First, the control result by PI control currently generally applied to the speed control of an engine bench system is shown in FIGS.

  FIG. 2 is a Bode diagram of engine torque (T1) → shaft torque (T12). As shown in FIG. 13, the engine bench system has resonance characteristics, and it can be seen that substantially the same resonance characteristics remain as shown in FIG. 2 even when speed control is performed by PI control. FIG. 3 is a Bode diagram of engine torque (T1) → speed detection (w2). As shown in FIG. 14, the engine bench system has a resonance characteristic, and it can be seen that the resonance characteristic remains as shown in FIG. 3 even when the speed is controlled by the PI control. FIG. 4 is a Bode diagram of speed command value (w2ref) → speed detection (w2). From this figure, it can be seen that the general PI control is controlled to a speed control response of about 4 Hz.

  From FIG. 2 and FIG. 3, in the speed control by PI control that is generally applied at present, when the frequency of the torque generated by the engine is close to the mechanical resonance frequency, the shaft torque and the speed may become oscillating. Recognize.

  5 to 7 show control results according to the present embodiment. FIG. 5 is a Bode diagram of engine torque (T1) → shaft torque (T12). As shown in FIG. 2, resonance characteristics remain in general PI control, but in this embodiment, resonance is suppressed as shown in FIG. FIG. 6 is a Bode diagram of engine torque (T1) → speed detection (w2). As shown in FIG. 3, the resonance characteristics remain in general P1 control, but in this embodiment, resonance is suppressed as shown in FIG. FIG. 7 is a Bode diagram of speed command value (w2ref) → speed detection (w2). From this figure, it is understood that the speed control response of about 8 Hz is controlled in this embodiment.

  As can be seen from FIGS. 5 to 7, according to the present embodiment, the speed control response is improved and the resonance is suppressed as compared with the speed control result by the general PI control. In addition, the controller circuit can be easily designed as compared with the μ design method. Therefore, according to the present embodiment, even in a situation where the shaft torque and speed are oscillating according to the current technology, the present embodiment is controlled non-oscillating and can efficiently perform a stable engine test.

(Embodiment 2)
This embodiment is applied to a mechanical system (a spring has a non-linear characteristic) in which the resonance frequency changes depending on the magnitude of the shaft torque. In the case where the coupling shaft portion of the engine bench model shown in FIG. 12 is a non-linear spring such as a clutch (a spring whose spring stiffness value changes according to the torsion angle), the speed control system is configured as follows.

  (S1) The relationship of (revolution, opening) → (torque) of the specimen engine is measured in advance by some means, and this is prepared as an engine torque map.

  (S2) A table (T2f table) representing the relationship between the torsional torque (shaft torque) value in the model of FIG. Any means can be obtained by calculation when the characteristics of the nonlinear spring are known, and when the characteristics are not known, the resonance frequency when the torsion torque is a certain value can be measured. Good.

(S3) For the resonance frequency wc [rad / s] obtained from the T2f table, from the engine inertia J1 and the dynamometer inertia J2 obtained in advance by some means,
K12 = J1 * J2 * wc ² / (J1 + J2) (12)
As a result, a clutch (coupled shaft) spring stiffness K12 is obtained. The engine inertia J1 and the dynamometer inertia J2 may be calculated from design values of each part or may be values measured by some means.

  (S4) As in the first embodiment, the parameters (Ki, Kp, b1, b0, a1) are obtained, and the dynamometer torque T2 is controlled according to the equation (4).

  FIG. 8 is a block diagram of the controller of this embodiment. In this embodiment, in addition to the elements 9A to 9D of the controller 9 of FIG. 1, the speed command (w2ref) and the throttle opening of the engine are input to the engine torque map 9E, and the output torque is input to the T2f table 9F. The resonance frequency wc in the operation state at that time is calculated by the T2f table 9F. The calculation element 9G obtains the spring stiffness K12 from the resonance frequency wc, the engine inertia J1 and the dynamometer inertia J2 by calculation according to the equation (12), and the setting element 9H is the relationship between the coefficients c1 to c5 according to the equations (6) to (10). Equation (6) to (10) are solved by calculation element 9I to calculate speed control parameters (Kp, Ki, b1, b0, a1), proportional integral (PI) element 9B and filter element Adjust the value of 9C.

  According to the present embodiment, the resonance frequency of the Bode diagrams shown in FIGS. 13 and 14 is also shown in a mechanical system (the spring has nonlinear characteristics) in which the resonance frequency changes depending on the magnitude of the axial torque. With the controller configuration of 8, the gain parameters (Ki, Kp, b1, b0, a1) that are always adapted to the resonance frequency can be selected, and even non-linear engine bench systems are non-vibrating Controlled and stable engine testing can be done efficiently.

(Embodiment 3)
In the present embodiment, in the speed control based on the dynamometer speed command value w2ref, the dynamometer torque command T2ref is
T2ref = ((Ki / s) * (w2ref−w2) −Kp * w2) * (1 / (a1 * s + 1)) − ((bl * s + 1) / (a1 * s + 1) * T12) * Kt12 (13) )
And control.

  FIG. 9 shows a circuit diagram of the controller 10 equivalent to the equation (13). The first term on the right side of the equation (13) is the integral calculation of the speed deviation obtained by the subtraction element 10A by the integral (I) element 10B, and the speed is calculated. Proportional calculation is performed by the proportional (P) element 10C, and the delay is added by the delay element 10E to the result of subtraction by the subtraction element 10D from the calculation result of the integration element 10B. In the second term, the shaft torque T12 is calculated by the filter element 10F, multiplied by the coefficient Kt12 by the multiplication element 10G, and this is subtracted by the subtraction element 10H from the calculation result of the delay element 10E to obtain the torque command T2ref.

  The coefficient (Ki, Kp, Kt12, b1, a1) in the equation (13) is 5 when the closed loop characteristic polynomials of the equations (1) to (3) and the equation (11) are obtained as in the first embodiment. It turns out that it becomes a polynomial, and the characteristic can be arbitrarily set by (Ki, Kp, Kt12, b1, a1).

  Expressions (14) to (18) below are used to calculate (Ki, Kp, Kt12, b1, a1) of the closed loop characteristic polynomial.

  In this embodiment, in order to determine (Ki, Kp, Kt12, b1, al) in the equation (13), (c5, c4, c3, c2, c1) in the equations (14) to (18) Set to the coefficient of the characteristic polynomial of the low-pass filter.

  For example, for the binomial coefficient type, c5 = 1, c4 = 5, c3 = 10, c2 = 10, and c1 = 5 are set.

  In order to obtain the Butterworth type, c5 = 1, c4 = 3.23606797779979, c3 = 5.23606797779979, c2 = 5.23606679779979, and c1 = 3.23606797479979.

  Then, the equations (14) to (18) are solved to obtain the control parameters (Ki, Kp, Kt12, b1, a1) of the equation (13).

  According to the present embodiment, similarly to the first embodiment, the speed control response can be improved and the resonance can be suppressed.

(Embodiment 4)
This embodiment is applied to a mechanical system (a spring has a non-linear characteristic) in which the resonance frequency changes depending on the magnitude of the shaft torque. In the case where the coupling shaft portion of the engine bench model shown in FIG. 12 is a non-linear spring such as a clutch (a spring whose spring stiffness value changes according to the torsion angle), the speed control system is configured as follows.

  (S1) The relationship of (revolution, opening) → (torque) of the specimen engine is measured in advance by some means, and this is prepared as an engine torque map.

  (S2) A table (T2f table) representing the relationship between the torsional torque (shaft torque) value in the model of FIG. Any means can be obtained by calculation when the characteristics of the nonlinear spring are known, and when the characteristics are not known, the resonance frequency when the torsion torque is a certain value can be measured. Good.

(S3) For the resonance frequency wc [rad / s] obtained from the T2f table, from the engine inertia J1 and the dynamometer inertia J2 obtained in advance by some means,
K12 = J1 * J2 * wc ² / (J1 + J2) (19)
As a result, a clutch (coupled shaft) spring stiffness K12 is obtained. The engine inertia J1 and the dynamometer inertia J2 may be calculated from design values of each part or may be values measured by some means.

  (S4) As in the third embodiment, parameters (Ki, Kp, Kt12, b1.a1) are obtained, and the dynamometer torque T2 is controlled according to the equation (13).

  FIG. 10 shows the controller of this embodiment. In this embodiment, in addition to the elements 10A to 10H of the controller 10 of FIG. 9, the speed command (w2ref) and the throttle opening of the engine are input to the engine torque map 10I, and the output torque is input to the T2f table 10J. The clutch spring rigidity K12 in the operation state at that time is calculated by the T2f table 10J. The calculation element 10K obtains the spring stiffness K12 by calculation according to the equation (19) from the resonance frequency wc, the engine inertia J1 and the dynamometer inertia J2, and the setting element 10L has the relationship between the coefficients c1 to c5 according to the above equations (14) to (18). Formulas are set, and the speed control parameters (Kp, Ki, Kt12, b1, a1) are calculated by solving the formulas (14) to (18) by the calculation element 10M, and the elements 10, 10C, 10E, 10F, 10GB are calculated. Adjust the value of.

  According to the present embodiment, similarly to the second embodiment, even in a mechanical system (the spring has a nonlinear characteristic) in which the resonance frequency changes depending on the magnitude of the shaft torque, the gain parameter always adapted to the resonance frequency. (Ki, Kp, Kt12, b1, a1) can be selected, and even a non-linear engine bench system is controlled in a non-vibrating manner, and a stable engine test can be efficiently performed.

The block diagram of the engine bench system which shows Embodiment 1 of this invention. The control result by the conventional PI control (the 1). The control result by the conventional PI control (the 2). The control result by the conventional PI control (the 3). The control result by Embodiment 1 (the 1). The control result by Embodiment 1 (the 2). The control result by Embodiment 1 (the 3). The block diagram of the controller which shows Embodiment 2 of this invention. The block diagram of the controller which shows Embodiment 3 of this invention. The block diagram of the controller which shows Embodiment 4 of this invention. Configuration example of an engine bench system. A two-inertia mechanical engine bench model. An example of conventional mechanical properties. An example of conventional mechanical properties.

Explanation of symbols

1 Engine 2 Transmission 3 Coupling shaft 4 Dynamometer
7-axis torque meter 8 Inverter 9, 10 Controller

Claims (6)

In an engine bench system that connects a dynamometer to the engine with a shaft and measures various characteristics of the engine,
The controller of the dynamometer outputs a dynamometer torque command T2ref,
T2ref = (Ki / s + Kp) * (w2ref−w2)
+ (B1 * s + b0) / (a1 * s + 1) * T12
However, T12 is a combined shaft torsion torque (shaft torque), w2ref is a dynamometer speed command, w2 is a dynamometer angular speed, and Ki, Kp, b1, b0, and a1 are parameters.
A dynamometer control method for an engine bench system, characterized in that it is configured to be obtained by the above calculation. The parameters (Ki, Kp, b1, b0, a1) are
J1 * s * w1 = T1 + T12
T12 = K12 / s * (w2-w1)
J2 * s * w2 = −T12 + T2
T2ref = (Ki / s + Kp) * (w2ref−w2)
+ (B1 * s + b0) / (a1 * s + 1) * T12
However, J1 is an engine moment of inertia, J2 is a dynamometer moment of inertia, K12 is a coupled shaft spring stiffness, T12 is a coupled shaft torsion torque (axial torque), w1 is an engine angular velocity, w2 is a dynamometer angular velocity, T1 is an engine torque, T2 Is the dynamometer torque.
And a means for determining Ki, Kp, b1, b0, a1 so that the coefficients of the fifth-order polynomial P (s) having the closed-loop characteristics are appropriately set to the coefficients c1 to c5 of the fifth-order polynomial. The dynamometer control method for an engine bench system according to claim 1. When the shaft has non-linear characteristics and the resonance frequency changes depending on the magnitude of the shaft torque,
An engine torque map for obtaining a measured value of output torque with respect to the engine speed and throttle opening;
A T2f table having a relationship of a resonance frequency generated in a mechanical system from the engine to the dynamometer with respect to an output of the torque map as a torsion torque (shaft torque) value of the shaft;
The spring stiffness K12 is obtained from the resonance frequency wc obtained from the T2f table, the engine inertia J1 and the dynamometer inertia J2, and the coefficients c1 to c5 of the fifth order polynomial P (s) appropriately set. 2. A dynamometer control system for an engine bench system according to claim 1, further comprising means for determining Ki, Kp, b1, b0, a1 so as to be c5. In an engine bench system that connects a dynamometer to the engine with a shaft and measures various characteristics of the engine,
The controller of the dynamometer outputs a dynamometer torque command T2ref,
T2ref = ((Ki / s) * (w2ref−w2) −Kp * w2) * (1 / (a1 * s + 1)) − ((bl * s + 1) / (a1 * s + 1) * T12) * Kt12
However, T12 is a coupling shaft torsion torque (shaft torque), w2ref is a dynamometer speed command, w2 is a dynamometer angular speed, and Ki, Kp, Kt12, b1, and a1 are parameters.
A dynamometer control method for an engine bench system, characterized in that it is configured to be obtained by the above calculation. The parameters (Ki, Kp, Kt12, b1, a1) are
J1 * s * w1 = T1 + T12
T12 = K12 / s * (w2-w1)
J2 * s * w2 = −T12 + T2
T2ref = ((Ki / s) * (w2ref−w2) −Kp * w2) * (1 / (a1 * s + 1)) − ((bl * s + 1) / (a1 * s + 1) * T12) * Kt12
However, J1 is an engine moment of inertia, J2 is a dynamometer moment of inertia, K12 is a coupled shaft spring stiffness, T12 is a coupled shaft torsion torque (axial torque), w1 is an engine angular velocity, w2 is a dynamometer angular velocity, T1 is an engine torque, T2 Is the dynamometer torque.
And a means for determining Ki, Kp, Kt12, b1, a1 so that the coefficients of the fifth-order polynomial P (s) of the closed-loop characteristic are the coefficients c1 to c5 of the appropriately set fifth-order polynomial. The dynamometer control method for an engine bench system according to claim 4. When the shaft has non-linear characteristics and the resonance frequency changes depending on the magnitude of the shaft torque,
An engine torque map for obtaining a measured value of output torque with respect to the engine speed and throttle opening;
A T2f table having a relationship of a resonance frequency generated in a mechanical system from the engine to the dynamometer with respect to an output of the torque map as a torsion torque (shaft torque) value of the shaft;
The spring stiffness K12 is obtained from the resonance frequency wc obtained from the T2f table, the engine inertia J1 and the dynamometer inertia J2, and the coefficients c1 to c5 of the fifth order polynomial P (s) appropriately set. 5. A dynamometer control system for an engine bench system according to claim 4, further comprising means for determining Ki, Kp, Kt12, b1, a1 so as to be c5.

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