Method and system for control and co-simulation of physical systems

• US 10,296,706 B2
• Filed: 08/09/2016
• Issued: 05/21/2019
• Est. Priority Date: 08/25/2015
• Status: Active Grant

• Current Assignee: Volvo Car Corporation (AB Volvo)
• Original Assignee: Volvo Car Corporation (AB Volvo)
• Inventors: Drenth, Edo
• Primary Examiner(s): Johnson, Cedric
• Application Number:
  US15/232,261
• Publication Number:
  US 20170061069A1
• Time in Patent Office: 1,015 Days
• Field of Search: None
• CPC Class Codes: F02D 2041/1432 the system including a filter, e.g. a low pass or high pass filter
• CPC Class Codes: F02D 2041/1433 using a model or simulation of the system
• CPC Class Codes: F02D 2041/1437 Simulation
• CPC Class Codes: F02D 2041/288 for performing a transformation into the frequency domain, e.g. Fourier transformation
• CPC Class Codes: F02D 2250/14 Timing of measurement, e.g. synchronisation of measurements to the engine cycle
• CPC Class Codes: F02D 41/1401 characterised by the control or regulation method F02D41/1473, F02D41/1477 take precedence
• CPC Class Codes: G06F 30/15 Vehicle, aircraft or watercraft design
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30

Abstract

A method for control and co-simulation in a system having multiple subsystems, each representing a physical system, includes, in a first subsystem simulating a first physical system, providing a first time continuous output signal representing a property of the first physical system, and filtering the output signal using a continuous moving average (CMA) filter as an anti-aliasing filter to form a filtered time continuous signal. Filtering the output signal includes integrating the time continuous signal to form an integrated signal, sampling the integrated signal, for each sample, forming an average value from the current sample and a previous sample, and forming a filtered time continuous signal from the average values. The method also includes providing the filtered time continuous signal to a second subsystem simulating a second physical system. A system for performing the method is also provided.

Claims

1. A method performed by a processor for control and co-simulation in a system comprising a plurality of subsystems, each subsystem representing a physical system, the method comprising:

in a first subsystem simulating a first physical system, providing a first time continuous output signal representing a property of the first physical system;

filtering the output signal using a continuous moving average filter as an anti-aliasing filter to form a filtered time continuous signal, wherein filtering the output signal comprises;

integrating the time continuous signal to form an integrated signal,

sampling the integrated signal,

for each sample, forming an average value from the current sample S₀ and a previous sample S<sub>0−

n</sub>, where n>

0, divided by total sample time h*n, where h is sample period, and

forming a filtered time continuous signal from the average values; and

providing the filtered time continuous signal to a second subsystem simulating a second physical system.

2. The method according to claim 1 wherein n=2.

3. The method according to claim 1 wherein the first time continuous output signal represents a flow of the first subsystem.

4. The method according to claim 1 wherein each of the plurality of subsystems is characterized by a flow and an effort.

5. The method according to claim 1 wherein the first subsystem represents a first physical system having a higher impedance than the second physical system.

6. The method according to claim 1 further comprising, in the second subsystem:

receiving the filtered time continuous signal from the first subsystem;

simulating a behavior of the second physical system based on the received signal;

providing a second time continuous output signal representing a property of the second subsystem;

filtering the second output signal using a continuous moving average filter as an anti-aliasing filter to form a second filtered time continuous signal;

wherein filtering the output signal comprises;

integrating the second time continuous signal to form an integrated signal;

sampling the integrated signal;

for each sample, forming an average value from the current sample S₀ and a previous sample S<sub>0−

n</sub>, where n>

0, divided by the total sample time h*n, where h is the sample period;

forming a second filtered time continuous signal from the average values; and

providing the second filtered time continuous signal to the first subsystem.

7. The method according to claim 6 wherein, if the first physical system has a higher impedance than the second physical system, the first output signal represents a flow and the second output signal represents an effort.

8. The method according to claim 6 wherein, if the first physical system has a lower impedance than the second physical system, the first output signal represents an effort and the second output signal represents a flow.

9. A method performed by a processor for control and co-simulation in a system comprising a plurality of subsystems, each subsystem representing a physical system, the method comprising:

in a first subsystem simulating a first physical system, providing a first time discrete output signal representing a property of the first physical system, the first discrete output signal having a first sample rate;

filtering the output signal using a continuous moving average filter as an anti-aliasing filter to form a filtered time continuous signal, wherein filtering the output signal comprises

summing the time discrete signal to form a summed signal,

sampling the summed signal using a second sample rate lower than the first sample rate,

for each sample, forming an average value from the current sample S₀ and previous samples S<sub>−

1</sub> . . . S<sub>−

(n+1)</sub>, where n>

0, divided by total number of samples n, and

forming a filtered time discrete signal from the average values; and

providing the filtered time continuous signal to a second subsystem simulating a second physical system.

10. The method according to claim 9 wherein n is equal to the ratio between the first sample rate and the second sample rate.

11. The method according to claim 10 wherein the first sampling rate is a variable sampling rate.

12. A control and co-simulation system comprising a plurality of subsystems, each subsystem representing a physical system, the co-simulation system implemented in a processor and comprising:

a first subsystem simulating a first physical system and configured to provide a time continuous output signal representing a velocity or a torque of the first physical system;

an anti-aliasing filter connectable to an output of the first subsystem and configured to form a filtered time continuous signal, wherein the anti-aliasing filter comprises;

an integrator configured to integrate the time continuous signal to form an integrated signal,

a sampling module configured to continuously sample the integrated signal, and

an averaging module configured to form an average value for each sample from the current sample S₀ and a previous sample S<sub>0−

n</sub>, where n>

0, divided by total sample time h*n, where h is sample period;

an output module configured to form a time continuous output signal from the average values formed by the averaging module; and

a second subsystem simulating a second physical system, the second subsystem connectable to the anti-aliasing filter to receive the filtered time continuous signal.

13. The system according to claim 12 wherein, if the first physical system has a higher impedance than the second physical system, the first output signal represents a flow and the second output signal represents an effort, and if the first physical system has a lower impedance than the second physical system, the first output signal represents an effort and the second output signal represents a flow.

14. The system according to claim 12 wherein, if the first physical system has a higher inertia than the second physical system, the first output signal represents a velocity and the second output signal represents a torque, and if the first physical system has a lower inertia than the second physical system, the first output signal represents a torque and the second output signal represents a velocity.