Patent ID: 12204293

BEST MODE

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical idea of the present invention is not limited to some embodiments to be described, but may be implemented in various forms, and within the scope of the technical idea of the present invention, one or more of the constituent elements may be selectively combined or substituted between embodiments.

In addition, the terms (including technical and scientific terms) used in the embodiments of the present invention, unless explicitly defined and described, can be interpreted as a meaning that can be generally understood by a person skilled in the art, and commonly used terms such as terms defined in the dictionary may be interpreted in consideration of the meaning of the context of the related technology.

In addition, terms used in the present specification are for describing embodiments and are not intended to limit the present invention.

In the present specification, the singular form may include the plural form unless specifically stated in the phrase, and when described as “at least one (or more than one) of A and B and C”, it may include one or more of all combinations that can be combined with A, B, and C.

In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are merely intended to distinguish the components from other components, and the terms do not limit the nature, order or sequence of the components.

And, when a component is described as being ‘connected’, ‘coupled’ or ‘interconnected’ to another component, the component is not only directly connected, coupled or interconnected to the other component, but may also include cases of being ‘connected’, ‘coupled’, or ‘interconnected’ due that another component between that other components.

In addition, when described as being formed or arranged in “on (above)” or “below (under)” of each component, “on (above)” or “below (under)” means that it includes not only the case where the two components are directly in contact with, but also the case where one or more other components are formed or arranged between the two components. In addition, when expressed as “on (above)” or “below (under)”, the meaning of not only an upward direction but also a downward direction based on one component may be included.

FIG.1illustrates a production process of a control parameter measuring device according to a comparative example with a first embodiment of the present invention.

For the control board that forms the controller and the motor that is the load controlled by the control board, quality determination is performed whether the control board and the motor satisfy the design specifications before shipment. In order to determine whether the control board21or the motor22is a good product, the control parameters of the control board21and the motor22are measured using the control parameter measuring equipment10, and the quality determination on the control board21and the motor22is performed using the measured control parameters. As for the motor, as shown inFIG.1(A), control parameters such as resistance and inductance in a single unit state of the motor22are measured, it is judged whether the measured control parameters satisfy the good product criterion, and the good products are shipped. The control board21is shipped after calibration and quality determination for each sample in a single product state, in setting the control parameters of the control board21before shipment, it is assumed that the control parameters of the motor are the same as those of the development sample, and the controller values (P, I, D, gain, and filter) are applied as one and the same value before shipment.

After quality determination on the motor22and the control board21, as shown inFIG.1(B), it may be determined as defective when the connection state between the control board21and the motor22is poor. In the case of good products that have passed the response test, since all the same controller values are applied as described above, there may be a difference in performance between products that have been determined as good products.

In this way, when performing quality determination by measuring control parameters for each of the control board21and the motor22separately, when an actual control board21is applied to the motor22, it may not be suitable for the operation of the motor220to which the control parameter of the control board21is connected. For more accurate quality determination and control parameter setting in the production process, the production equipment according to an embodiment of a first embodiment of the present invention uses frequency response analysis. Hereinafter, production equipment according to an embodiment of a first embodiment of the present invention will be described in detail.

FIG.2is a block diagram of a production equipment according to an embodiment of a first embodiment of the present invention.

The production equipment100according to an embodiment of a first embodiment of the present invention comprises a frequency response analysis unit110and a processing unit120. A communication unit for transmitting and receiving signals or a memory for storing control parameters may be included.

The frequency response analysis unit110transmits a sine wave of variable frequency to the controller210connected to the load220, receives a sensing current sensing a current being outputted from the load220to which the sine wave is applied from the controller210, and the applied sine wave and the received sensing current are analyzed.

More specifically, in order to measure the control parameters for the controller210and the load220, the frequency response analysis unit110transmits a sine wave of variable frequency to the controller210connected to the load220. That is, the controller210and the load220are connected, and a sine wave of a variable frequency is transmitted to the controller210while the controller210and the load220are connected.

Here, the sine wave means a signal whose waveform is a sine curve, also referred to as a sine wave. The frequency response analysis unit110transmits a sine wave having a variable frequency, but one frequency may be outputted in one cycle or more. As shown inFIG.3, a sine wave having a variable frequency may be transmitted. At this time, as shown inFIG.3(A). A sine wave can be outputted so that the frequency gradually increases or the frequency gradually decreases. Or, it may gradually increase and decrease, or decrease and increase, or may vary randomly. The varying frequencies may vary linearly or exponentially. In addition, the frequency may be varied in various ways. At this time, a signal having one of the variable frequencies can be outputted for more than one cycle. Since the control parameter is measured using the response in one cycle, the frequency response analysis unit110may output a waveform being formed of one frequency in one cycle or more.

Or, as shown inFIG.3(B), a signal whose frequency is continuously changed may be outputted in one cycle or more. As shown inFIG.3(B), the frequency may be varied so that the frequency gradually increases from the start time fS(Start) to the end time fE(End) as time elapses. For example, it may be in the form of a chirp signal. The frequency may gradually increase or decrease gradually, and may change linearly or exponentially as shown inFIG.3(B). Or, it may increase and then decrease, or may vary randomly. In addition, the frequency may be varied in various ways.

The frequency response analysis unit110may transmit the sine wave to the controller210using communication or a digital analog converter (DAC). The frequency response analysis unit110may use communication or a digital analog converter (DAC) in transmitting a sine wave of variable frequency to the controller210. The frequency response analysis unit110may convert a sine wave signal into a communication signal in accordance with the communication to which the sine wave is to be transmitted and transmit it to the controller210. At this time, the frequency response analysis unit110transmits a communication signal corresponding to a sine wave of variable frequency using a variety of wired and wireless communication, and the controller210may receive it, convert it back into a sine wave, or convert it into another form and apply it to the load220.

Or, the frequency response analysis unit110may transmit a sine wave through a DAC. The DAC is a device that converts digital signals to analog signals. The frequency response analysis unit110may apply a sine wave of variable frequency through the DAC, and transmit the sine wave to the controller210through the conversion in the DAC. The controller210senses the current being outputted from the load220according to the sine wave of variable frequency transmitted from the frequency response analysis unit110to the controller210, and the frequency response analysis unit110receives the sensed sensing current from the controller210. The controller210may receive a sine wave from the frequency response analysis unit110, convert it into a voltage signal, and apply it to the load220. The load220being connected to the controller210may be an actuator. Here, the actuator is a driving device that operates the device using power, and refers to a motor that forms a predetermined controller, or a piston or cylinder mechanism operated by hydraulic or pneumatic pressure. That is, the load220may be a motor, and the controller210may be a motor driving controller that drives the motor.

The controller210converts a sine wave of variable frequency into a voltage signal and applies it to the load220, and the load220operates according to the applied voltage signal and outputs a current. The controller210measures the current being outputted from the load220, and the controller210transmits the measured current to the frequency response analysis unit110. The controller210may measure the current being outputted from the load220using a current measuring device such as a shunt resistor. Or, the current being outputted from the load220may be measured using various devices such as a current mirror circuit and a voltage measuring device.

The frequency response analysis unit110analyzes the sensed sensing current. In order to derive control parameters for the controller210and the load220from the sensed sensing current, the frequency response analysis unit110analyzes the sensing current sensed by the controller210and received by the frequency response analysis unit110from the controller210.

In analyzing the sensing current, the frequency response analysis unit110may analyze the received sensing current by performing a fast Fourier transform. Fast Fourier transform (FFT) is a method of processing the Fourier transform of discrete data at high speed and is used to analyze a signal. When using the fast Fourier transform, fast processing is possible by reducing the number of times of multiplication that takes time through changing the order of the data by using sequential decomposition of the discrete Fourier transform of a long signal sequence into a discrete Fourier transform of a shorter signal sequence, and by using symmetry and periodicity of rotation factors.

The frequency response analysis unit110may perform fast Fourier transform using the received sensing current and the sine wave transmitted to the controller210. The sine wave transmitted from the frequency response analysis unit110to the controller210is stored in the memory, and when a sensing current corresponding to the stored sine wave is received, fast Fourier transform can be performed using the received sensing current and the stored sine wave. The frequency response analysis unit110may know the frequency response characteristic of the controller210to which the load220is connected through a fast Fourier transform. Frequency response means measuring what kind of response is outputted when an input signal of various frequencies are applied to a certain system, and is used to analyze a corresponding system. The amplitude of the signal may be constant or may vary. The frequency response may represent amplitude and phase of a signal being outputted from a system as a curve with respect to frequency.

The frequency response analysis unit110may be implemented as a frequency response analyzer. Frequency response analyzer (FRA) is a high-precision measuring device used to analyze components, circuits, or systems in the frequency domain, and generates a sine wave signal and applies it to the test object. The sine wave signal is measured at the injection point using one of the input channels of the frequency response analyzer, the injected signal passes through the object under test and the output signal is measured in another channel to analyze the frequency response. At this time, the frequency response analyzer can perform a fast Fourier transform. The frequency response of the test object can be analyzed using sine wave.

The processing unit120receives the result of analyzing the sensing current from the frequency response analysis unit110and performs quality determination on the controller210or the control parameters of the controller210are calculated and transmitted to the controller210.

More specifically, the processing unit120receives a result of analyzing the sensing current from the frequency response analysis unit110. As described above, the frequency response analysis unit110analyzes the sensing current through the fast Fourier transform, and transmits the analyzed result to the processing unit120. The processing unit120may perform quality determination on the controller210using the result received from the frequency response analysis unit110. By performing quality determination on the controller210in the state in which the load220is connected, accurate quality determination on the controller210and the load220that are actually connected together and being installed and driven in the system can be performed. The problem that may occur in practical application, in the case when performing quality determination without connecting the controller210and the load220, in which quality determination is performed by assuming control parameters for the other part, does not occur in the production equipment according to an embodiment of a first embodiment of the present invention in which the load220is connected to the controller210, and the control parameters are measured for the controller210to which the load220is connected. The processing unit120may perform quality determination on the load220as well as the controller210. Since the load220is connected to the controller210, the processing unit120may perform quality determination on the load220as well as the controller210. That is, it may perform quality determination on each of the controller210and the load220, or perform quality determination on the controller210and the load220as one set.

The processing unit120may perform quality determination on the controller210or the load220using a result of analyzing the sensing current. Quality determination on the controller210or the load220may be performed on the basis of whether the control parameter according to the result of analyzing the sensing current satisfies the quality determination criterion. The quality determination criterion may have a lower limit and an upper limit, or may be set in a predetermined range having a lower limit or an upper limit. The quality determination criterion is set according to the design specifications of the controller210and the load220, or may be set according to safety or safety level, or may be set by a user. The quality determination criterion may be stored in a memory. It may be stored as a lookup table (LUT).

The processing unit120may derive an inductance value L and a resistance value R or an impedance value Z from the result of analyzing the sensing current. Quality determination on the controller210or the load220may be performed using the derived inductance value, resistance value, or impedance value. That is, quality determination on the controller210and the load220may be performed by determining whether it is within the reference range of the inductance value and the resistance value or the impedance value is within the inductance reference range.

The processing unit120may determine the cause of the failure of the load220using a result of analyzing the sensing current. The processing unit120not only performs quality determination on the load220using the result of analyzing the sensing current, but also may determine the cause of the failure of the load220when determining that the load220is defective. By determining which failure cause the load220is defective, and storing and accumulating the failure cause information, it is possible to know the cause of the defect that frequently occurs during production for the load220at present time, and it is possible to know which defects are occurring at which rate in which production line. That is, the management of the production line or the production system can be performed using the defect cause information.

The processing unit120may derive an inductance value and an impedance value through analysis of the sensing current, and may determine a cause of a failure using the inductance value and the impedance value. At this time, the criteria for determining the cause of failure and classification may vary depending on the type of the load220. For example, when the load220is a three-phase motor and the controller210drives the motor using a three-phase power source, the processing unit120may determine disconnection, short circuit, contact resistance increase, magnet demagnetization, coil insulation reduction, and the like as cause of defects.

If the impedance of the phase where the disconnection occurred suddenly decreases to zero, it can be determined that a winding disconnection has occurred. Conversely, if the impedance of the phase in which the short circuit occurs suddenly increases compared to the existing value, it may be determined that a winding short circuit has occurred. In addition, if the resistance of a specific phase among the measured impedances increases, it can be determined as an increase in the contact resistance due to the increased contact resistance for that phase.

When the magnitude of a measured current becomes larger than before at a frequency, a predetermined frequency, for example in a region less than 100 Hz, of the voltage being applied at the same temperature and rotational speed, it can be determined that the magnet is demagnetized. In addition, when the current is large, while the winding temperature increases, and if the inductance measured in a region where the frequency of the applied voltage is 100 Hz or more becomes smaller than the existing value, it can be determined that the magnet is demagnetized. When the resistance and inductance of the coil whose insulation is being reduced progress in a direction in which the insulation is reduced slightly, it can be determined that the insulation reduction of the coil has occurred. In addition, various causes of failure may be determined.

In addition, the processing unit120may estimate the temperatures of the stator and the rotor being included in the load by determining whether the magnetic flux strength, resistance, or inductance of the load changes by using the result of analyzing the sensing current. The load, like a motor, may include a stator and a rotor, and the load including the stator and rotor is greatly affected by temperature. Therefore, in measuring the temperature of the stator and rotor, the result of analyzing the sensing current can be used. The temperature of the stator and rotor can be estimated by determining at least one of a change in the magnetic flux strength of the load, a change in resistance, or a change in inductance by using the result of analyzing the sensing current. In this way, it is possible to determine whether or not a failure occurs or the probability of occurrence of a failure according to the estimated temperature.

The processing unit120may not only perform the quality determination on the controller210or the load220, but also calculate a control parameter of the controller210using the result of analyzing the sensing current. The calculated control parameter may be transmitted to the controller210to change or set the control parameter of the controller210. The controller210sets a control parameter to control the load220. The control parameters of the controller210that are to be set according to the type and characteristics of the controller210may vary.

The processing unit120may calculate a PI control parameter, a PID control parameter, or a filter coefficient of the controller210using a result of analyzing the sensing current.

The processing unit120calculates a PI control parameter when the controller210is a PI controller, calculates the PID control parameters when the controller210is a PID controller, and may calculate a filter coefficient when a filter is included. The controller210may be an automatic controller, and may be controlled using a combination of P, I, and D.

Here, P means proportional, I means integral, and D means differential. Proportional (P) control is a control that makes the control amount proportional to the difference between the target value and the current position, and as it approaches the target value, the difference of the control values decreases and thus fine control becomes possible. When performing proportional control, when the control amount approaches the target value, the control amount becomes too small and it becomes impossible to finely control it, so that there are residual deviations that remain uncontrollable anymore. PI control is a control using proportional and integral, and a residual deviation can be removed by using PI control. Minute residual deviation is accumulated over time to increase the control amount according to the accumulated residual deviation, thereby eliminating the deviation, and since it is a control in which an integral operation is added to a proportional operation, it is called a PI control. In case of PI control, it is possible to control close to the actual target value, but as it approaches the target value, the control amount decreases, and an operation for a certain period of time or longer is required. At this time, if the integer is large, the response performance may deteriorate when there is an external disturbance. That is, it may be difficult to quickly respond to the external disturbance and it may be difficult to return to the target value. To solve this, a differentiation operation may be performed. By observing the deviation for a sudden disturbance, and if the difference from the previous deviation is large, the manipulated value is increased to respond. Observing the deviation difference from the previous time corresponds to differentiation, and PID control is performed by applying differential to proportional and integral. Even if the control amount deviates from the target value, it is determined as a deviation from the previous time and the target value can be quickly reached by applying the control amount.

The PID control may be expressed as a PID control equation, and the PID control parameters may be expressed as Kp, Ki, and Kd. The PID parameter may be calculated through optimization by using a step response method or a limit reduction method. The PI control may correspond to this, and calculate the PI control parameters Kp and Ki.

The processing unit120may transmit the calculated control parameters to the controller210so that the controller210sets or changes the control parameters with the calculated control parameter. Since the control parameters calculated by the processing unit120are control parameters calculated in a state in which the load220is connected, they are the control parameters adaptively calculated in a state in which the load220and the controller210are connected, and correspond to the optimal control parameters of the controller210.

The processing unit120may calculate the control parameters of the controller210at the same time as the quality determination or after the quality determination. When the controller210and the load220are good products, the control parameters may be calculated in order to set optimal parameters for the controller210in a state in which the load220is connected. When the controller210or the load220is defective, the control parameter calculation may not be performed. Or, the result according to the control parameters set in the current controller210is bad, but when it is determined to be bad within the range that may be determined to be good when the control parameters are changed, the quality determination result for the controller210or the load220may be changed by changing the control parameters thereof. Or, quality determination may be performed again after changing the control parameters. Through this, it may prevent the cases that may be determined to be defective even when they may be determined to be good when the control parameters are changed. When performing individual quality determination on the load220using a fixed control parameter, a case may occur in which a defective determination is made on a load220even though the load220can be used as a good product when the control parameters are changed. However, in the production equipment according to an embodiment of a first embodiment of the present invention, not only performs the quality determination on a controller210to which the load220is connected, but also increases the possibility and accuracy of quality determination on the load220by changing the result for the load220using the change of the control parameters.

The processing unit120may control the frequency response analysis unit110by transmitting a mode entry signal to the frequency response analysis unit110. The processing unit120transmits a mode entry signal to the frequency response analysis unit110for quality determination or control parameter calculation for the controller210to which the load220is connected, so that the frequency response analysis unit110may transmit a sine wave of variable frequency to the controller210. That is, the processing unit120may transmit a mode entry signal to the frequency response analysis unit110in order to start a series of processes of quality determination or control parameter calculation. The frequency response analysis unit110may receive a mode entry signal from the processing unit120and transmit a sine wave of a variable frequency to the controller210. Or, the frequency response analysis unit110may transmit a sine wave of a variable frequency to the controller210when the controller210is positioned at a predetermined position without receiving a mode entry signal. Or, a sine wave of variable frequency may be periodically transmitted to the controller210.

FIGS.4and5are diagrams for explaining the operation of a production equipment according to a first embodiment of the present invention. The frequency response analysis unit may be implemented using a frequency response analyzer (FRA)110, and the processing unit may be production equipment120. A load being connected to the controller210may be a motor220. In the process of setting the control parameters by analyzing the frequency response for the controller210to which the motor220is connected, as shown inFIG.4, first, the production equipment120transmits a mode entry signal to the FRA equipment110using communication or the like. When it is entered in a mode, a sine wave of variable frequency is generated in the FRA device110, and this signal is transmitted to the controller through communication or DAC. Here, the signal of variable frequency must be outputted one cycle or more. For example, if 1 Hz and 10 Hz signals are being outputted, after 1 Hz signal is outputted for 1 cycle or more, 10 Hz signal should be outputted for 1 cycle or more. The controller210may receive a sine wave of a variable frequency through communication or ADC. A sine wave of variable frequency received from the controller210is converted into a voltage signal to be applied to the motor220to apply a voltage to the motor220. At this time, variable frequency may change, but the frequency does not change. A current according to the input voltage flows, and the current value is measured by the controller210. The controller210transmits the signal of the measured current to the FRA equipment through communication or DAC. The FRA equipment110may receive the signal of the measured current through communication or ADC. The FRA equipment110performs fast Fourier transform (FFT) using the variable frequency sine wave signal outputted by the controller210and the current signal received from the controller, and delivers the result to the production equipment120. The production equipment120receiving the FFT signal may design an optimal control value (P, I, D, gain or filter coefficient) and transmit it to the controller210to set the control parameters of the controller210. Through this, it is possible to set the control parameters for each sample and to reduce the deviation between products by compensating for the deviation between products using P, I, D, gain or filter.

In addition, the production equipment120may make quality determination based on the FFT signal, as shown inFIG.5. Through this, quality determination on a motor220and a controller210is possible in a state in which the controller210and the motor220are connected. In addition, it is possible to measure controller stability (phase margin and gain margin) in the frequency domain without repeated testing according to the step response in the time domain.

FIG.6is a flowchart of a production method according to an embodiment of a first embodiment of the present invention; andFIG.7is a flowchart of a production method according to another embodiment of a first embodiment of the present invention. A detailed description of each step ofFIGS.6and7corresponds to the detailed description of the production equipment ofFIGS.1to5, and thus overlapping descriptions will be omitted. Each step ofFIGS.6and7may be configured in one processor included in the production equipment.

In step S11, a mode entry signal is transmitted to the frequency response analysis unit, and in step S12, the frequency response analysis unit generates a sine wave of variable frequency and transmits it to the controller connected to the load. The sine wave is a sine wave with a variable frequency, and a signal having one of the variable frequencies may be outputted in one cycle or more, or a signal having a continuously changing frequency may be outputted in one cycle or more. Thereafter, in step S13, a sensing current sensing the current being outputted from the load to which the sine wave is applied from the controller is received, and in step S14, the frequency response analysis unit analyzes the received sensing current. In analyzing the received sensing current, fast Fourier transform may be performed for analysis using the received sensing current and a sine wave transmitted to the controller.

After that, in step S15, a result of analyzing the sensing current from the frequency response analysis unit is received, and in step S16, a control parameter of the controller is calculated using a result of analyzing the sensing current. In calculating the control parameters of the controller, PI control parameter, PID control parameter, or filter coefficient of the controller can be calculated using the result of analyzing the sensing current. When the control parameters are calculated, in step S17, the calculated control parameter is transmitted to the controller.

In addition, after step S15, quality determination on the controller or the load may be performed in step S21. In performing the quality determination on the controller or the load, a cause of the failure of the load may be determined using a result of analyzing the sensing current.

As described above, the production equipment and production method according to a first embodiment of the present invention have been described with reference toFIGS.1to7. Hereinafter, a control device and a control parameter setting method according to a second embodiment of the present invention will be described with reference toFIGS.8to19. Detailed description of the control device and control parameter setting method according to the second embodiment of the present invention, and production equipment and production methods, names, terms, or functions according to the first embodiment of the present invention are based on the detailed description of each embodiment, and may be the same as or different from each other.

Hereinafter, a configuration of a control device and a control parameter setting method according to a second embodiment of the present invention will be described with reference to the drawings.

FIG.8illustrates an operation of a controller according to a comparative example with a second embodiment of the present invention. In a controller that drives a load such as a motor, the controller2010applies a voltage for driving the motor to the motor2021through the voltage output2015in the position/speed/current control logic2011, senses the current flowing according to the applied voltage in the current measurement2015, and uses to drive the motor2021in the position/speed/current control logic2011using the sensed sensing current. In the position/speed/current control logic2011, control parameters for driving the motor2021are set, and the control parameters are set using characteristic values or design values of the motor.

At this time, when using design values, since deviations between design values and manufactured products may occur and the characteristic values of the motor may change with temperature change or aging, it may be difficult to achieve optimal control performance with the previously set control parameters of the position/speed/current control logic2011.

In order to achieve optimal control performance even when errors or changes in load characteristics occur according to the characteristics of the load, a control device according to an embodiment of a second embodiment of the present invention may use frequency response analysis to set or change control parameters. Hereinafter, a production equipment according to an embodiment of a second embodiment of the present invention will be described in detail.

FIG.9is a block diagram of a control device according to an embodiment of a second embodiment of the present invention.

The control device1100according to an embodiment of the second embodiment of the present invention comprises: a controller1110, a sine wave generation unit1120, an analysis unit1130, and a processing unit1140, and may include a voltage output unit1150, a current measurement unit1160, a storage unit1131, and an FFT conversion unit1132.

The controller1110transmits a control signal for controlling the load1210to the load1210.

More specifically, the controller1110controls the load1210according to the set control parameter, and transmits a control signal to the load1210to control the load1210. The load1210being connected to the control device1100may be an actuator. Here, the actuator is a driving device that operates the device using power, and refers to a motor operated by a predetermined controller, or a piston or cylinder mechanism operated by hydraulic or pneumatic pressure. The load1210may be a motor, and the control device1100may be a motor driving device for driving the motor.

The sine wave generation unit1120generates a sine wave of variable frequency and transmits it to the load1210.

More specifically, the sine wave generation unit1120generates a sine wave of variable frequency and transmits it to the load1210in order to determine the characteristics of the load1210.

Here, the sine wave means a signal whose waveform is a sine curve, also referred to as a sine wave. The sine wave generation unit1120transmits a sine wave having a variable frequency, but one frequency may be outputted in one cycle or more. As shown inFIG.3, the sine wave generation unit1120may transmit a sine wave having a variable frequency, which is formed of a sinusoidal curve. At this time, as shown inFIG.3(A). A sine wave can be outputted so that the frequency gradually increases or the frequency gradually decreases. Or, it may gradually increase and then decrease, or decrease and increase, or may vary randomly. The varying frequencies may vary linearly or exponentially. In addition, the frequency may be varied in various ways. At this time, a signal having one of the variable frequencies can be outputted for one cycle or more. Since the control parameter is measured using the response in one cycle, the sine wave generation unit1120may output a waveform formed with one frequency for one cycle or more.

Or, as shown inFIG.3(B), a signal whose frequency is continuously changed may be outputted in one cycle or more. As shown inFIG.3(B), the frequency may be varied so that the frequency gradually increases from the start time fS(Start) to the end time fE(End) as time elapses. For example, it may be in the form of a chirp signal. The frequency may gradually increase or decrease gradually, and may change linearly or exponentially as shown inFIG.3(B). Or, it may increase and then decrease, or may vary randomly. In addition, the frequency may be varied in various ways.

The sine wave generation unit1120may receive a mode operation signal from the controller1110to generate a sine wave of variable frequency. When it is necessary to reset or change the control parameter, the controller1110may control the sine wave generation unit1120to generate a sine wave of variable frequency. Or, the high level controller1220may enable the sine wave generation unit1120to generate a sine wave of variable frequency through a mode operation signal. When a control parameter is set in the production process, the production device1220may control the sine wave generation unit1120to generate a sine wave of variable frequency. Upon receiving the mode operation signal, the sine wave generation unit1120generates a sine wave of variable frequency and transmits it to the load1210.

Or, the sine wave generation unit1120may periodically generate the sine wave. Even if the mode operation signal is not received from the controller1110, the high level controller1220, or the production equipment1220, a sine wave of a variable frequency may be periodically generated for periodic control parameter update. The period for generating a sine wave of variable frequency may be set in units of months or years for updating control parameters, and may be set in units of seconds, minutes, hours, and days for failure determination of the load1210. In addition, it is natural that various periods may be set. The variable frequency sine wave generation period may vary according to the characteristics of the load1210being connected to the control device1100or the characteristics of the control device1100, and may be set by a user. Or, the sine wave generation unit1120may continuously change the frequency to generate a sine wave.

The load1210receives a control signal from the controller1110and receives a sine wave of variable frequency from the sine wave generation unit1120. The load1210may receive a control signal and a sine wave of variable frequency together. At this time, the frequency of the sine wave may be different from that of the control signal of the controller. Since the frequency of the control signal for driving the load1210and the frequency of the sine wave for setting the control parameter should be distinguished, the sine wave generation unit1120may generate a sine wave having a frequency different from that of the control signal. The sine wave generation unit1120may generate a sine wave by varying the frequency to include at least one frequency different from the control signal. In generating the variable frequency, the sine wave generation unit1120may vary the frequency except for a sine wave having the same frequency as the frequency of the control signal. A response to an already corresponding frequency may be received from the control signal and analyzed. Or, the frequency may be varied by including the same frequency as the frequency of the control signal. Or, the load1210may receive the control signal and the sine wave of variable frequency independently through a separate input line, or may be applied with different input periods.

The control signal of the controller and the sine wave of variable frequency may be transmitted to the load1210through the voltage output unit1150. The voltage output unit1150may convert a control signal of the controller1110and a sine wave of the sine wave generation unit1120into a voltage signal and transmit it to the load1210. The load1210may be a device that receives a voltage and operates, for example, a motor, and the voltage output unit1150receives a control signal and a sine wave in order to apply a voltage to the load1210, and the voltage output unit1150may transmit voltage corresponding to the frequency to the load1210according to the frequency of the control signal and sine wave. The voltage output unit1150may be a bridge circuit formed of a plurality of switches. The upper switch and the lower switch forming the bridge are conducted complementarily to each other and may transmit a three-phase voltage to the load1210with a phase difference in each bridge circuit.

The analysis unit1130analyzes the sensing current sensed by the current being outputted from the load1210.

More specifically, in order to set the control parameters, a sine wave is generated by the sine wave generation unit1120and applied to the load1210, and the analysis unit1130analyzes the sensing current sensing the current being outputted from the load1210according to the applied sine wave.

The current measuring unit1160senses the current being outputted from the load. The current measuring unit1160is connected to the output line of the load1210to sense the current. The current may be formed by a current measuring element such as a shunt resistor. Or, the current being outputted from the load1210may be sensed using various devices such as a current mirror circuit and a voltage measuring device.

The sensing current sensed by the current measuring unit1160may be used by the controller1110to generate a control signal, and the analysis unit1130may be used to analyze a frequency response to a control parameter.

In analyzing the sensing current, the analysis unit1130may analyze the received sensing current by performing a fast Fourier transform. Fast Fourier transform (FFT) is a method of processing the Fourier transform of discrete data at high speed and is used to analyze a signal. When using the fast Fourier transform, fast processing is possible by reducing the number of times of multiplication that takes time through changing the order of the data by using sequential decomposition of the discrete Fourier transform of a long signal sequence into a discrete Fourier transform of a shorter signal sequence, and by using symmetry and periodicity of rotation factors.

The analysis unit1130may perform fast Fourier transform using the received sensing current and the sine wave transmitted from the sine wave generation unit1120to the load1210. In performing fast Fourier transform, the analysis unit1130may comprise a storage unit1131for storing the sine wave or the sensing current, and an FFT transform unit1132for performing fast Fourier transform using the sine wave and the sensing current.

The sine wave generated by the sine wave generation unit1120and transmitted to the load1210is branched and stored in the storage unit1131, and when the sensing current corresponding to the stored sine wave is received, the FFT transform unit1132may perform fast Fourier transform using the received sensing current and the stored sine wave. The FFT transform unit1132may know the frequency response characteristic of the load1210through the fast Fourier transform. Frequency response means measuring what kind of response is outputted when an input signal of various frequencies are applied to a certain system, and is used to analyze a corresponding system. The amplitude of the signal may be constant or may vary. The frequency response may represent amplitude and phase of a signal being outputted from a system as a curve with respect to frequency.

The processing unit1140sets the control parameters of the controller1110by using the result of analyzing the sensing current.

More specifically, the processing unit1140receives a result of analyzing the sensing current from the frequency response analysis unit1130. As described above, the analysis unit1130analyzes the sensing current through the fast Fourier transform, and transmits the analyzed result to the processing unit1140. The processing unit1140may calculate control parameters of the controller1110using a result of analyzing the sensing current. The calculated control parameters may be transmitted to the controller1110to change or set the control parameters of the controller1110. The controller1110sets control parameters to control the load1210. The control parameters of the controller1110may be different parameters to be set according to the characteristics of the type of the controller1110.

The processing unit1140may calculate a PI control parameter, a PID control parameter, or a filter coefficient of the controller1110using a result of analyzing the sensing current.

The processing unit1140calculates a PI control parameter when the controller1110is a PI controller, calculates the PID control parameters when the controller1110is a PID controller, and may calculate a filter coefficient when a filter is included. The controller1110may be an automatic controller, and may be controlled using a combination of P, I, and D.

Here, P means proportional, I means integral, and D means differential. Proportional (P) control is a control that makes the control amount proportional to the difference between the target value and the current position, and as it approaches the target value, the difference of the control values decreases and thus fine control becomes possible. When performing proportional control, when the control amount approaches the target value, the control amount becomes too small and it becomes impossible to finely control it, so that there are residual deviations that remain uncontrollable any more. PI control is a control using proportional and integral, and a residual deviation can be removed by using PI control. Minute residual deviation is accumulated over time to increase the control amount according to the accumulated residual deviation, thereby eliminating the deviation, and since it is a control in which an integral operation is added to a proportional operation, it is called a PI control. In case of PI control, it is possible to control close to the actual target value, but as it approaches the target value, the control amount decreases, and an operation for a certain period of time or longer is required. At this time, if the integer is large, the response performance may deteriorate when there is an external disturbance. That is, it may be difficult to quickly respond to the external disturbance and it may be difficult to return to the target value. To solve this, a differentiation operation may be performed. By observing the deviation for a sudden disturbance, and if the difference from the previous deviation is large, the manipulated value is increased to respond. Observing the deviation difference from the previous time corresponds to differentiation, and PID control is performed by applying differential to proportional and integral. Even if the control amount deviates from the target value, it is determined as a deviation from the previous time and the target value can be quickly reached by applying the control amount.

The PID control may be expressed as a PID control equation, and the PID control parameters may be expressed as Kp, Ki, and Kd. The PID parameter may be calculated through optimization by using a step response method or a limit reduction method. The PI control may correspond to this, and calculate the PI control parameters Kp and Ki.

The processing unit1140may transmit the calculated control parameters to the controller1110so that the controller1110sets or changes the control parameters of the controller1110with the calculated control parameters. The control parameters calculated by the processing unit1140is control parameters calculated while the load1210is connected. That is, the control parameters that are adaptively calculated by reflecting a characteristic value according to temperature or aging of the load1210, and corresponds to the optimal control parameters of the controller1110.

The processing unit1140may perform quality determination on the controller1210and the control device1100or the load1210using the result received from the analysis unit1130. In performing quality determination in the production process, accurate quality determination can be performed by performing quality determination on the controller1110in a state in which the load1210is connected. The problem that may occur in practical application, in the case when performing quality determination without connecting the controller1110and the load1210, in which quality determination is performed by assuming control parameters for the other part, does not occur in the production equipment according to an embodiment of a second embodiment of the present invention in which the load1210is connected to the controller1110, and the control parameters are measured for the controller1110to which the load1210is connected. The processing unit1140may perform quality determination on the load1210as well as the controller1110. Since the load1210is connected to the controller1110, the processing unit1140may perform quality determination on the load1210as well as the controller1110. That is, it may perform quality determination on each of the controller1110and the load1210, or perform quality determination on the controller1110and the load1210as one set.

The processing unit1140may perform quality determination on the controller1110or the load1210using a result of analyzing the sensing current. Quality determination on the controller1110or the load1210may be performed on the basis of whether the control parameter according to the result of analyzing the sensing current satisfies the quality determination criterion. The quality determination criterion may have a lower limit and an upper limit, or may be set in a predetermined range having a lower limit or an upper limit. The quality determination criterion is set according to the design specifications of the controller1110and the load1210, or may be set according to safety or safety level, or may be set by a user. The quality determination criterion may be stored in a memory. It may be stored as a lookup table (LUT).

The processing unit1140may derive an inductance value L and a resistance value R or an impedance value Z from the result of analyzing the sensing current. Quality determination on the controller1110or the load1210may be performed using the derived inductance value, resistance value, or impedance value. That is, quality determination on the controller1110and the load1210may be performed by determining whether it is within the reference range of the inductance value and the resistance value or the impedance value is within the inductance reference range.

The processing unit1140not only performs quality determination on the load1210using the result of analyzing the sensing current, but also may determine the cause of the failure of the load1210when determining that the load1210is defective. By determining which failure cause the load220is defective, and storing and accumulating the failure cause information, it is possible to know the cause of the defect that frequently occurs during production for the load1210at present time, and it is possible to know which defects are occurring at which rate in which production line. That is, the management of the production line or the production system can be performed using the defect cause information.

The processing unit1140may derive an inductance value and an impedance value through analysis of the sensing current, and may determine a cause of a failure using the inductance value and the impedance value. At this time, the criteria for determining the cause of failure and classification may vary depending on the type of the load1210. For example, when the load1210is a three-phase motor and the controller1110drives the motor using a three-phase power source, the processing unit1140may determine disconnection, short circuit, contact resistance increase, magnet demagnetization, coil insulation reduction, and the like as cause of defects.

The processing unit1140may calculate the control parameters of the controller1110at the same time as the quality determination or after the quality determination. When the controller1110and the load1210are good products, the control parameters may be calculated in order to set optimal parameters for the controller1110in a state in which the load1210is connected. When the controller1110or the load1210is defective, the control parameter calculation may not be performed. Or, the result according to the control parameters set in the current controller1110is bad, but when it is determined to be bad within the range that may be determined to be good when the control parameters are changed, the quality determination result for the controller1110or the load1210may be changed by changing the control parameters thereof. Or, quality determination may be performed again after changing the control parameters. Through this, it may prevent the cases that may be determined to be defective even when they may be determined to be good when the control parameters are changed. When performing individual quality determination on the load1210using a fixed control parameter, a case may occur in which a defective determination is made on a load1210even though the load1210can be used as a good product when the control parameters are changed. However, in the production equipment according to an embodiment of a first embodiment of the present invention, not only performs the quality determination on a controller1110to which the load1210is connected, but also increases the possibility and accuracy of quality determination on the load1210by changing the result for the load1210using the change of the control parameters.

The processing unit1140may determine whether the load1210has failed using a result of analyzing the sensing current. The process of determining whether there is a failure may correspond to the process of performing quality determination. Quality determination is performed in the production process, and failure determination can be performed in the process of controlling a load by being installed in a device or system. The processing unit1140may determine whether there is a failure according to the failure determination criterion. The failure determination criterion may be different from the quality determination criterion. The quality determination is a determination for sale, and the failure determination is a determination for whether to stop the operation according to a failure during the current operation, so the failure determination criterion may be weaker than the quality determination criterion. If it is not a fatal failure, it may not be determined as a failure when determining whether there is a failure, even if it is within the range that is determined to be defective during quality determination. That is, the range of criteria determined as normal rather than faulty may be wider than the criteria for determining good products. Or, it is natural that the failure determination criterion may be the same as the quality determination criterion. The failure determination criterion may be set according to the design specifications of the controller1110and the load1210, may be set according to safety or safety grade, or may be set by a user. The failure determination criterion may be stored in the storage unit1131. It may be stored as a lookup table (LUT).

In addition, the processing unit1140may determine not only whether there is a failure, but also a cause of the failure. The load1210can determine what cause of the failure caused the failure, and provide the failure cause to the system or the high level controller1220through an alarm, so that it can be used to quickly deal with the failure.

The processing unit1140may derive an inductance value and an impedance value through analysis of the sensing current, and may determine a failure cause using the inductance value and the impedance value. At this time, failure cause determination criteria and classification may vary depending on the type of load1210. For example, when the load1210is a three-phase motor and the controller1110drives the motor using a three-phase power source, the processing unit1140may determine an open circuit, a short circuit, and an increase in contact resistance as the cause of the failure of the load1210, and as shown inFIG.11, and may determine the magnetic demagnetization, coil insulation reduction, and the like as shown inFIG.12. The process of determining the cause of failure may correspond to the process of determining the cause of failure in quality determination.

If the impedance of the phase where the disconnection occurred suddenly decreases to zero, it can be determined that a winding disconnection has occurred. Conversely, if the impedance of the phase in which the short circuit occurs suddenly increases compared to the existing value, it may be determined that a winding short circuit has occurred. In addition, if the resistance of a specific phase among the measured impedances increases, it can be determined as an increase in the contact resistance due to the increased contact resistance for that phase.

When the magnitude of a measured current becomes larger than before at a frequency, a predetermined frequency, for example in a region less than 100 Hz, of the voltage being applied at the same temperature and rotational speed, it can be determined that the magnet is demagnetized. In addition, when the current is large, while the winding temperature increases, and if the inductance measured in a region where the frequency of the applied voltage is 100 Hz or more becomes smaller than the existing value, it can be determined that the magnet is demagnetized. When the resistance and inductance of the coil whose insulation is being reduced progress in a direction in which the insulation is reduced slightly, it can be determined that the insulation reduction of the coil has occurred. In addition, various causes of failure may be determined.

In addition, the processing unit1140may estimate the temperatures of the stator and the rotor being included in the load by determining whether the magnetic flux strength, resistance, or inductance of the load changes by using the result of analyzing the sensing current. The load, like a motor, may include a stator and a rotor, and the load including the stator and rotor is greatly affected by temperature. Therefore, in measuring the temperature of the stator and rotor, the result of analyzing the sensing current can be used. The temperature of the stator and rotor can be estimated by determining at least one of a change in the magnetic flux strength of the load, a change in resistance, or a change in inductance by using the result of analyzing the sensing current. In this way, it is possible to determine whether or not a failure occurs or the probability of occurrence of a failure according to the estimated temperature.

The controller is a micro controller unit (MCU), and the sine wave generation unit, analysis unit, and processing unit may be implemented as a processor in the MCU. That is, the sine wave generation unit, the analysis unit, and the processing unit may be implemented as software on a processor included in an MCU embedded in a vehicle or the like, or may be implemented in the form of hardware of a companion chip. When implemented in the form of hardware, it may be formed as one piece of hardware or as separate pieces of hardware.

FIGS.13and14are diagrams for explaining the operation of production equipment according to a second embodiment of the present invention. As shown inFIG.13, the controller1100may be a control device including an FRA online calibration function that drives a motor1210serving as a load and performs a frequency response using a variable frequency sine wave. The controller1100receives a calibration operation signal from the production device or the high level controller1220and applies a voltage including a sine wave of variable frequency to operate the motor1210. The controller1100is connected to the motor1210, and when the motor is a three-phase motor, three-phase is connected, and in the case of a DC motor, + and − may be connected. When the current according to the voltage applied to the motor1210is outputted, quality determination may be performed through frequency response analysis using the sensing current sensed by the current, and control parameters of the controller in the controller1100may be set. The quality determination information may be transmitted to the production device or high level controller1220.

FIG.14is a block diagram for each specific function of the controller1100, may comprise: a position/speed/current control logic that is a controller for driving the motor1210that is a load; a voltage output unit1150; a current measuring unit1160, and in addition to these, include a sine wave generation unit for detecting the characteristics of the motor1210using a sine wave of variable frequency, a voltage and current signal storage memory1131, an FFT conversion unit1132for performing FFT on the stored signal, and an FRA online calibration including a processing unit1140that performs design and analysis of control parameters.

When the production device or the high level controller1220transmits the calibration operation signal to the sine wave generation unit, the sine wave generation unit generates a sine wave signal of variable frequency, and the voltage output unit1150converts a sine wave signal of variable frequency into a voltage along with the control signal being outputted from the position/speed/current control logic to apply a voltage to the motor1210. Here, the signal of variable frequency should be outputted one cycle or more. For example, if 1 Hz and 10 Hz signals are outputted, after 1 Hz signal is outputted for 1 cycle or more, 10 Hz signal should be outputted for 1 cycle or more. In addition, this variable frequency means a frequency different from the rotation frequency of the motor. For example, when the motor rotates at 600 rpm and the pole pair is 4, the voltage is applied at 40 Hz. However, in the FRA online calibration function, a variable signal including 40 Hz is added and applied. When a current according to the applied voltage is outputted from the motor1210, the current measuring unit1160senses the current, and a fast Fourier transform (FFT) is performed using a pre-stored voltage and current signal according to a sine wave of variable frequency. The stored data is data corresponding to the same frequency, and the number of data of voltage and current is the same. The gain and phase values are calculated through FFT, the gain and phase values according to the frequency are transmitted to the processing unit1140, the processing unit1140designs and analyzes control parameters accordingly to calculate quality determination or control parameters. The quality determination information is transmitted to the production device or the high level controller1220, and the control value of the position/speed/current control logic is changed using the calculated control parameters. Through this, it is possible to perform quality determination in a state in which the motor, the controller, and the controller and the motor are connected. In addition, it is possible to measure the controller stability (phase margin, gain margin) in the frequency domain. In addition, it is possible to design the optimal controller value (P, I, D, gain, and filter) by analyzing the characteristics of the desired frequency through the sine wave generation unit inside the control device. In addition, even if the motor characteristics change as the motor usage environment (temperature, aging, and the like) changes, the motor characteristics are measured online to obtain the optimum control values, the control performance (ripple in steady state, responsiveness in transient, and the like) can always be kept optimal.

In addition, the mutual interference component for the dual motor1700ofFIG.15may be measured by using a sine wave generation unit. Sine waves having different frequencies are applied to different motors1710and720, respectively, and the mutual interference components of the two motors1710and720can be calculated through frequency response analysis according to the currents being outputted, respectively. Through this, it is possible to accurately compensate the mutual interference component by calculating an accurate mutual interference component.

FIG.16is a flowchart of a control parameter setting method according to an embodiment of a second embodiment of the present invention; andFIGS.17to19are flowcharts of a control parameter setting method according to another embodiment of a second embodiment of the present invention. A detailed description of each step ofFIGS.16to19corresponds to a detailed description of a method for setting a control parameter in the control device ofFIGS.8to15, and an overlapped description will be omitted below.

In step S11, the sine wave generation unit generates a sine wave of variable frequency, and in step S12, the sine wave is transmitted to the load together with the control signal generated by the controller. Thereafter, the current being outputted from the load is sensed in step S13, and the sensed sensing current is analyzed in step S14. In analyzing the sensing current, a fast Fourier transform may be performed using the sine wave and the sensing current.

Then, in step S15, control parameters of the controller are set using the result of analyzing the sensing current in step S14.

In setting the parameters of the controller, the control parameters of the controller may be set using the inductance and impedance of the load being derived from the analysis result of the sensing current.

In addition, in step S21, quality determination on the load or the controller may be performed using the result of analyzing the sensing current in step S14.

In generating the sine wave, the sine wave may be generated by receiving a mode operation signal from the controller, a production device, or a high level controller, or the sine wave may be generated periodically, and the frequency of the sine wave may be different from the control signal and frequency of the controller.

In addition, in analyzing the sensed sensing current, in step S31, it may be determined whether the load is disconnected, short circuited, increased contact resistance, magnetic demagnetization, or reduced coil insulation using the result of analyzing the sensing current in step S14.

In addition, in analyzing the sensed sensing current, in step S41, the temperatures of the stator and rotor being included in the load can be estimated by determining whether the magnetic flux strength, resistance, or inductance of the load changes by using the result of analyzing the sensing current in step S14.

The control parameter setting method according to a second embodiment of the present invention may be performed in a processor of an embedded controller (MCU) formed in a vehicle or the like. That is, by using the frequency response analysis (FRA), it is possible to find the optimal control parameters (PID/PI/filter coefficients). By using frequency response analysis, it is possible to find the optimal control parameters (PID/PI/filter coefficients) in real time or periodically on the online (or runtime) during vehicle operation.

A modified embodiment according to the present embodiment may include some configurations of a first embodiment and some configurations of a second embodiment together. That is, the modified embodiment may include the first embodiment, but some configurations of the first embodiment may be omitted, and may include some configurations of the corresponding second embodiment. Or, the modified embodiment may include the second embodiment, but some configurations of the second embodiment are omitted and include some configurations of the corresponding first embodiment.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment, and are not necessarily limited to only one embodiment. Furthermore, features, structures, effects, and the like illustrated in each embodiment can be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the embodiments.

Meanwhile, the embodiments of the present invention can be implemented as computer-readable codes on a computer-readable recording medium. The computer-readable recording medium includes all types of recording devices in which data readable by a computer system is stored.

As examples of computer-readable recording media there are ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage devices, and in addition, they are distributed across networked computer systems in a distributed manner in which computer-readable code can be stored and executed. And functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers in the technical field to which the present invention belongs.

As described above, in the present invention, specific matters such as specific components, and the like; and limited embodiments and drawings have been described, but these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and various modifications and variations are possible from these descriptions by those of ordinary skill in the art to which the present invention belongs.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention.