Electric motor simulator and method for testing motor driver devices

• US 8,108,191 B1
• Filed: 11/13/2006
• Issued: 01/31/2012
• Est. Priority Date: 12/08/2005
• Status: Expired due to Fees

• Current Assignee: Advanced Testing Technologies, Inc.
• Original Assignee: Advanced Testing Technologies, Inc.
• Inventors: Britch, Peter F.
• Primary Examiner(s): Shah, Kamini S
• Assistant Examiner(s): PATEL, SHAMBHAVI K
• Application Number:
  US11/559,061
• Time in Patent Office: 1,905 Days
• Field of Search: 703/13, 703/2, 703/3, 703/4, 703/6, 703/7, 703/14, 703/18, 703/23, 318/139, 318/490, 318/560, 324/76.11, 324/511, 388/805, 388/812, 388/813
• US Class Current: 703/13
• CPC Class Codes: G01M 13/02 Gearings; Transmission mechanisms
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30

Abstract

Apparatus to exercise electrical motor drivers by electrically simulating a geared electric or electrical motor by providing an electronic load for the power signals that are applied to it. Current levels in the load are monitored in real-time using gate array logic and digital signal processing (DSP) algorithms to determine torque, acceleration, velocity and/or position data of the motor and gear train. Motor and gear train positional signals are generated and fed back to the motor driver device to close the servo loop. Control algorithms within the gate array and DSP accurately simulate the motor inertia and act to simulate a physical motor under varying load conditions. A control interface modifies critical motor parameters such as inertia, losses, gear ratio, and loading.

Claims

1. An apparatus to electrically simulate, in real-time, a plurality of different electro-mechanical motor systems for testing a motor driver for the motor systems, the motor driver being controlled by a processor, the apparatus comprising:

at least one electrical load fixture adapted to be coupled to the motor driver, said at least one load fixture being electronically controlled by the motor driver to provide a plurality of different electrical loads;

said at least one load fixture comprising at least one current detector, each of said at least one current detector being arranged to detect current of a respective drive phase of the motor driver when said at least one load fixture is providing a specific electrical load upon control by the motor driver; and

a digital signal processing unit that processes current readings from said at least one current detector to generate motor characteristic signals indicative of characteristics of the simulated motor system in the presence of the same current readings when said at least one load fixture is providing the specific load,

said digital signal processing unit including at least one mathematical algorithm configurable by the processor to simulate different motor systems by receiving control commands or signals from the processor, generating the motor characteristic signals based on the at least one mathematical algorithm after having been configured by said digital signal processing unit to simulate a particular motor system based on the received control commands and signals, and providing the generated motor characteristic signals as feedback signals to the processor representative of the operation of the simulated motor system upon control by the motor driver without construction of the simulated motor system,

the processor controlling the motor driver and said digital signal processing unit based on the feedback signals.

2. The apparatus of claim 1, wherein said at least one load fixture comprises a plurality of load fixtures, each of said load fixtures including resistive and inductive elements for each drive phase of the motor driver.

3. The apparatus of claim 1, wherein the motor driver is multi-phase, said at least one current detector comprising a plurality of current detectors.

4. The apparatus of claim 1, wherein said digital signal processing unit comprises an analog-to-digital (A/D) converter that converts current information from said at least one current detector into digital format for processing by said digital signal processing unit, and digital-to-analog (D/A) converters that convert the motor characteristic signals into analog signals and into the feedback signals being directed to the processor for use in providing a response to the motor driver for a given excitation provided by the motor driver.

5. The apparatus of claim 4, wherein said digital signal processing unit further comprises a field programmable gate array (FPGA) arranged between said A/D converters and said D/A converters.

6. The apparatus of claim 5, wherein said FPGA is programmed to apply an offset value to null at least one of the A/D input reading to said FPGA and the D/A output value from said FPGA, the offset value being directable to the motor driver during a calibration process.

7. The apparatus of claim 1, wherein the motor characteristic signals include a motor position signal and a motor torque signal in addition to position and velocity of a mass being simulated such that said digital signal processing unit is arranged to derive the motor torque signal from current readings from said at least one current detector and the motor position signal.

8. The apparatus of claim 7, wherein the motor system being simulated includes two brushless direct current (DC) motors coupled to a movable shaft that rotates a mechanical mass and said digital signal processing unit is arranged to derive at least one of motor rotor acceleration, motor rotor velocity, motor rotor position, output shaft acceleration, output shaft velocity and output shaft position signals from the motor torque signal and intrinsic motor parameters selected from a group consisting of inertia, losses, loading and gear-train ratios.

9. The apparatus of claim 1, wherein said digital signal processing unit comprises a field programmable gate array (FPGA).

10. The apparatus of claim 8, further comprising an input system that inputs characteristics to said FPGA to provide said FPGA with calibration offsets for analog-to-digital converters and digital-to-analog converters, and motor characteristic parameters.

11. The apparatus of claim 10, further comprising a storage system that stores a plurality of system offsets, motor characteristic values and characterization data transferred via said input system.

12. The apparatus of claim 10, further comprising a storage system that stores the gate array design implementation data and DSP software algorithms.

13. A method for simulating, in real-time, a plurality of different electro-mechanical motor systems for testing a motor driver for the motor systems, the motor driver being controlled by a processor, the method comprising:

coupling at least one electrical load fixture to the motor driver to be electronically controlled thereby to provide a plurality of different electrical loads;

providing the at least one load fixture with at least one current detector, each current detector being arranged to detect current of a respective drive phase of the motor driver when the at least one load fixture is providing a specific electrical load upon control by the motor driver;

configuring at least one mathematical algorithm in a digital signal processing unit by means of the processor to simulate the motor system by receiving control commands or signals from the processor;

directing current readings from the at least one current detector to the digital signal processing unit which generate motor characteristic signals indicative of characteristics of the simulated motor system in the presence of the same current readings when said at least one load fixture is providing the specific load, the motor characteristic signals being generated based on the at least one mathematical algorithm after having been configured by the processor to simulate a particular motor system based on the received control commands and signals without construction of the simulated motor system; and

directing the motor characteristic signals as feedback signals to the processor representative of the operation of the simulated motor system upon control by the motor driver to ascertain the functionality of the motor driver such that the processor controls the motor driver and the digital signal processing unit based on the feedback signals.

14. The method of claim 13, further comprising selectively configuring the digital signal processing unit to simulate different motor systems.

15. The method of claim 14, further comprising adjusting motor parameters to enable the simulation of the different motor systems, the motor parameters being inertia, losses, loading and gear-train ratios.

16. The method of claim 13, wherein the motor system being simulated includes two brushless direct current (DC) motors coupled to a movable shaft that rotates a mechanical mass, the at least one mathematical algorithm in the digital signal processing unit being configured by means of the processor to simulate the motor system by receiving control commands or signals from the processor thereby, modifying a transfer function of the simulator and mass combination.

17. The method of claim 13, further comprising adjusting the motor driver based on the feedback signals.

18. The method of claim 13, further comprising converting the current readings from the at least one current detector into digital form for processing by a field programmable gate array in the digital signal processing unit.

19. The method of claim 18, further comprising representing the simulated motor system by a plurality of mathematical algorithms embedded in the digital signal processing unit.

20. The method of claim 19, further comprising designing the algorithms to derive angular velocity and position of an antenna mass upon excitation by the motor drivers based on input of the detected current readings and stored motor rotational position.