Adjusting device and method for adjusting a steering angle of a vehicle

Abstract

The invention relates to a regulating device for regulating a steering angle of a vehicle, comprising a first regulator unit (2) with a regulating characteristic having at least one integral part, wherein the first regulator unit (2) is designed to receive a regulating difference between a first steering angle information derived from a steering angle target information and an actual steering angle and to provide a drive information for a motor (3) for actuating a steering device, wherein a compensating regulating loop (4) is provided which is superimposed on the first regulator unit (2), wherein the compensating regulating loop has a feedback path (4) which receives as input parameters the motor (3) drive information, a motor (3) output torque and / or an information dependent on the motor (3) output torque and provides a steering angle compensation information on the basis of these input parameters, wherein an adaptation of the steering angle target information relative to the first steering angle information is carried out on the basis of the steering angle compensation information, wherein the regulating characteristic of the compensating regulating loop can be changed in dependence on at least one control parameter (s), wherein the control parameter (s) is an influence parameter of a driver on the steering device and / or a measured parameter related to a driving situation.

Description

Technical Field

[0001] The invention relates to an adjusting device and a method for adjusting a steering angle of a vehicle. Background Art

[0002] Electromechanical steering systems (also known as EPS: Electric Power Steering) for vehicles are generally known in principle, wherein a program-controlled electric servomotor assists and superimposes the driver's steering movements by transmitting force to the steering gear.

[0003] Furthermore, electromechanical steering systems are known that have an adjusting device for reducing or suppressing interfering influences. Such adjusting devices have an integrated adjusting part for compensating for the transverse forces that occur.

[0004] Known control devices have an interface through which the control characteristics can be adapted, for example, according to the driving state or situation. This reduces oscillatory steering movements of electromechanical steering in autonomous or semi-autonomous driving and improves cooperative driving, where the driver and the steering servomotor simultaneously influence vehicle control. A disadvantage of the integrated control system is that deviations between the steering angle applied by the driver and the steering angle calculated by the steering angle control device can lead to increased counter-steering torque in the servomotor, which can be very annoying during cooperative driving. This can be prevented or at least mitigated by influencing the control characteristics via the control device interface.

[0005] The problem is that if the control system does not have such an interface or the design of the control system is unknown, the described measures for influencing the control behavior cannot be implemented, and thus undesirable control behavior cannot be compensated depending on the driving situation. For example, loaded integrated components in the steering angle control system can lead to undesirable vehicle behavior. Summary of the Invention

[0006] The object of the present invention is to provide an adjusting device which is able to influence the adjusting behavior of a steering angle control device even if no interface is present which provides for such influencing measures.

[0007] This object is achieved by a device having the features of independent claim 1. Preferred embodiments are the subject matter of the dependent claims. A method for steering angle control of a vehicle is the subject matter of the independent, coordinated claim 15.

[0008] According to a first aspect, the present invention relates to a control device for controlling the steering angle of a vehicle. The control device includes a first control unit whose control characteristic has at least one integral component. The first control unit is configured to receive a control difference between first steering angle information derived from desired steering angle information and the actual steering angle and to provide control information for an electric motor that actuates the steering system. The desired steering angle information may be provided, for example, by a driver assistance system that enables autonomous or semi-autonomous vehicle control.

[0009] Furthermore, a compensation control loop superimposed on the first controller unit is provided. The compensation control loop has a feedback path that receives motor control information, motor output torque, and / or information related to the motor output torque as input parameters and provides steering angle compensation information based on these input parameters. Based on the steering angle compensation information, the desired steering angle information is adjusted and adapted to thereby form the first steering angle information. In particular, a subtraction point is provided that receives the desired steering angle information and the steering angle compensation information and outputs the first steering angle information as a subtraction result. The control characteristics of the compensation control loop can be varied depending on at least one control parameter, wherein the control parameter is a driver influence parameter on the steering system and / or a measured parameter related to the driving situation. The driver influence parameter can be the torque applied by the driver to the vehicle steering wheel. The measured parameter related to the driving situation can be, for example, the curvature of the curve, i.e., the inverse of the curve radius, or the vehicle speed.

[0010] The technical advantage of the method according to the invention is that, by means of a superimposed compensation control loop, based on the available information, a control compensation can be achieved which improves the control behavior while, in particular, avoiding oscillations and reducing interfering influences of the integral control component.

[0011] According to one embodiment, the first controller unit is a PID controller or comprises a PID controller. The control characteristic of the PID controller has a control characteristic that is beneficial for steering angle control.

[0012] According to one embodiment, the first regulator unit is a closed regulator unit that lacks an external interface through which its regulating characteristics can be adjusted and adapted. In other words, the first regulator unit forms a so-called black box whose regulating characteristics cannot be adjusted and adapted from the outside, thereby preventing the regulation characteristics from being altered according to the situation. However, a compensating regulating loop superimposed on the first regulator unit as a subordinate regulating unit can compensate for the lack of such an interface via an external regulating loop.

[0013] According to one embodiment, a first regulator unit provides rated torque information as motor control information. The first regulator unit receives the adjustment difference between the first steering angle information and the actual steering angle as input information, converts the difference into rated torque information, and controls the motor based on the rated torque information. The motor includes a motor control device that converts the rated torque information into motor torque.

[0014] According to one embodiment, the input parameters of the feedback path of the compensation control loop are information about the setpoint torque of the first control unit, the current intensity of the current flowing through the electric motor generating the electric torque, or measured information proportional to this current intensity, such as the voltage drop or the electric torque across a resistor through which the motor current flows. These input parameters are also available in the closed control unit itself, since they are input information or output information of the first control unit, i.e., measured signals that can be detected at the input or output interface of the first control unit, or measured signals available at the steering motor.

[0015] According to one embodiment, the compensating control loop, in particular its feedback path, has a first control element that is designed as a threshold-dependent deadband. This allows for setting an input parameter threshold above and / or below which the compensating control loop becomes effective.

[0016] According to one embodiment, the first regulating element is designed to output an output variable having a value of 0 when an input variable of the first regulating element, in particular an input variable of a feedback path of the compensation regulating loop, falls below an input variable threshold value. As a result, the compensation regulating loop can be disabled when the input variable is low.

[0017] According to one embodiment, the threshold of the dead band, ie the input parameter threshold, can be varied depending on at least one control parameter. This allows the activation threshold of the adaptive compensation control loop to be adjusted depending on the driving situation or driving state.

[0018] According to one embodiment, the regulating device is configured to calculate the deadband threshold value based on at least one control parameter based on a first mathematical function. This allows adjustment of the influence of the control parameter on the deadband threshold value. The first mathematical function may, for example, be a monotonically increasing or decreasing function. If multiple control parameters are used, the first mathematical function may be configured to calculate the threshold value based on the multiple control parameters as input parameters.

[0019] According to one embodiment, the compensation control loop, in particular the feedback path of the compensation control loop, has a second control element designed as a low-pass filter or having low-pass characteristics. This makes it possible to filter out high-frequency components of the input variable of the feedback path, thereby avoiding oscillations and taking more account of low-frequency components, i.e., slowly varying components of the input variable originating from the integrated control element, in the compensation.

[0020] According to one embodiment, the second regulating element is a PT1 element or a higher-order PT element, or comprises such a PT1 element or a higher-order PT element.

[0021] According to one embodiment, the regulating characteristic of the second regulating element can be varied as a function of at least one control parameter. Thus, the regulating characteristic of the adaptive compensation regulating loop can be adjusted as a function of the driving situation or driving state.

[0022] According to one embodiment, the regulating device is configured to calculate a regulating characteristic of the second regulating element as a function of at least one control parameter based on a second mathematical function. This allows adjustment of the influence of the control parameter on the regulating characteristic of the second regulating element. For example, the second mathematical function may be a monotonically increasing or decreasing function. When multiple control parameters are used, the second mathematical function may be configured to calculate an output variable that influences the regulating characteristic of the second regulating element based on the multiple control parameters as input parameters.

[0023] According to one embodiment, the compensation control loop, in particular the feedback path of the compensation control loop, has a third control element designed as a limiter. This allows the influence of the compensation control loop, in particular the output signal of the feedback path of the compensation control loop, to be limited in order to avoid excessive feedback influences for safety reasons.

[0024] According to one embodiment, the limiter has a threshold value, starting from which the amplitude of the output signal is limited. The threshold value can be varied depending on at least one control parameter. Thus, the limiter threshold value can be adapted to the driving situation or condition.

[0025] According to one embodiment, the regulating device is configured to calculate a threshold value of the third regulating element based on at least one control parameter based on a third mathematical function. This allows adjustment of the influence of the control parameter on the limiter threshold value. The third mathematical function may, for example, be a monotonically increasing or decreasing function. If multiple control parameters are used, the third mathematical function may be configured to calculate the threshold value based on the multiple control parameters as input parameters.

[0026] According to another aspect, the present invention relates to a method for adjusting the steering angle of a vehicle by means of a regulating device. The regulating device includes a first regulating unit whose regulating characteristic has at least an integral component. The first regulating unit receives a regulating difference between first steering angle information derived from desired steering angle information and the actual steering angle, and provides drive information for an electric motor that actuates the steering device. In addition, a compensating regulating loop is provided superimposed on the first regulating unit, whose feedback path receives motor drive information, motor output torque, or information related to the motor output torque as input parameters and provides steering angle compensation information based on these input parameters. The desired steering angle information is adjusted and adapted based on the steering angle compensation information, thereby forming first steering angle information. The first steering angle information is obtained, in particular, by subtracting the steering angle compensation information from the desired steering angle information provided by a driver assistance system. The regulating characteristic of the compensating regulating loop is varied according to at least one control parameter, wherein the control parameter is a driver influence parameter on the steering device and / or a measured parameter that depends on the driving situation.

[0027] A "superimposed control loop" is a control loop that influences the control parameters of a subordinate controlled system, i.e., a control structure at a lower level in the architectural hierarchy. In particular, a superimposed control loop can use signals or information from a subordinate controlled system in order to influence its control characteristics.

[0028] In the meaning of the present invention, the terms “approximately”, “substantially” or “approximately” mean deviations from the respective exact value of + / - 10%, preferably + / - 5% and / or variations in which the deviations from the exact value are functionally insignificant.

[0029] Further configurations, advantages, and possible applications of the present invention are also apparent from the following description of exemplary embodiments and the accompanying drawings. All described and / or illustrated features, alone or in any combination, constitute the essential subject matter of the present invention, regardless of their summary in the claims or their subsequent description. The content of the claims is also part of the relevant description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be described in detail below with reference to the accompanying drawings of the embodiments, wherein:

[0031] Figure 1 The schematic diagram of the vehicle electromechanical steering system control loop is shown as an example;

[0032] Figure 2 is a schematic example of a control loop for an electromechanical steering system of a vehicle with a superimposed compensating control loop; and

[0033] Figure 3 is based on Figure 1 An example and schematic diagram of a control loop are shown, in which the first controller unit is designed as a PID controller. DETAILED DESCRIPTION

[0034] Figure 1 By way of example, a schematic block diagram of a control loop of a steering system EPS with an electromechanical drive is shown, in which a program-controlled electric motor assists the driver's steering movements or at least partially takes over its own steering movements in autonomous or semi-autonomous driving situations.

[0035] In the block diagram, the block with reference numeral 2 represents the steering angle adjuster, the block with reference numeral 3 represents the electric motor, and the block with reference numeral 5 represents the steering mechanism adjustment technology simulation. The steering mechanism and the electric motor 3 together form an electromechanical steering system - an electric power steering system (EPS).

[0036] The control loop obtains the desired steering angle, for example The desired steering angle is provided as input information, for example, by an electronic control unit, in particular a computer unit that controls autonomous or semi-autonomous driving functions.

[0037] Based on the actual steering angle Modify the rated angle The control loop subtraction point is followed by a first control unit 2 which, for example, provides a setpoint actuating torque T 额定 The first regulator unit 2 is as follows Figure 3 The first controller 2 has an integral part. This results in a PID controller. and the actual steering angle For example, when the driver at the steering wheel selects a steering angle that is different from the rated steering angle for a long period of time, the rated adjustment torque increases continuously. This occurs when the steering angle deviates from the setpoint. This results in an undesirable continuous increase in the steering force to maintain the desired steering angle. This is an unnatural driving behavior for the driver and therefore annoying.

[0038] The first control unit 2 is, for example, a closed or encapsulated control unit that has no interface for introducing external control signals that could influence the control behavior depending on the driving situation and / or the situation, in particular depending on driver commands. Therefore, the first control unit 2 does not have a direct option for compensating for disruptive control behavior caused by, for example, an integral component.

[0039] The first regulating unit 2 is coupled to an electric motor 3 on the output side. The electric motor is in particular a servo motor which can provide steering forces for mechanical steering of the vehicle. The electric motor 3 receives a setpoint actuating torque T from the first regulating unit 2, for example. 额定, which is converted by motor 3 into motor steering torque T EPS Here, the steering torque T EPS Is the actual torque transmitted from the motor 3 to the steering device. Steering torque T EPS It can be measured directly or determined indirectly by the current intensity of the current flowing through the electric motor 3, since the current intensity is related to the steering torque T generated by the electric motor. EPS There is a direct or nearly direct proportional relationship between them.

[0040] exist Figure 1 In FIG. 5 , reference numeral 5 represents a mechanical steering device as a schematic diagram of a control model. The control model of the mechanical steering device 5 can be simulated as an IT1 element, for example. It first includes a difference point, i.e., the steering torque T generated by the motor. EPS , disturbance variable d L and the internal feedback variable, here the steering angle The first derivative is obtained by multiplying by the friction force d.

[0041] Disturbance variable d L This can be any external disturbance variable (lane groove, lane inclination, cornering force, additional torque generated by the electric motor via the EPS steering assist function, etc.) and / or the steering torque applied by the driver to the steering wheel through steering movements.

[0042] The output variable of the control loop is the actual steering angle It is fed back to the difference point before the input of the first regulator unit 2 .

[0043] Compensation of the disturbance variable d by the integral part of the steering angle control device L This leads to the formation of the integral part. The following is the motor steering torque T based on the assumption of IT1 structure EPS :

[0044]

[0045] From formula 1, we can see that the disturbance variable d that forms the integral part L It is also reflected in the steering torque T generated by the motor EPS In other words, the steering torque T generated by the motor EPS The feedback is suitable for compensating the formation of the integral part in the first regulator unit 2.

[0046] Alternatively, instead of or in addition to the steering torque T generated by the electric motor EPS , you can also use the rated adjustment torque T 额定 As the variable to be fed back, the rated adjustment torque T 额定 It also contains information about the integral part to be formed. If at least temporarily no current motor generates a steering torque TEPS This is particularly helpful if you have information about

[0047] according to Figure 1 The regulatory loop combines Figure 3 This yields the following transfer function:

[0048]

[0049] Figure 2 Shown is a regulating device 1, wherein Figure 1 The control loop shown consists of a compensation control loop superimposed with a feedback path 4 in order to reduce or prevent disruptive influences on the steering angle control which cannot directly affect the first controller unit 2 even if there is no influencing capability.

[0050] In the embodiment shown, the steering torque T generated by the electric motor EPS is fed as an input variable to the feedback path 4 of the compensation control loop. As an alternative, the setpoint actuating torque T 额定 The feedback path of the compensation control loop provides steering angle compensation information as output variables. These output variables are fed to a subtraction point, where the steering angle compensation information is subtracted from the steering angle setpoint information. Get the first steering angle information Also called compensated steering angle target information. This is then used as input information for the control loop of the EPS steering system.

[0051] The feedback path 4 of the compensation control loop may contain one or more control elements that perform different control functions. It should be noted that more complex control structures may also be used, mapping the functions of multiple control elements into one physical controller.

[0052] In the embodiment shown, three adjusting elements 4.1, 4.2, 4.3 are provided. It should be noted that this is purely exemplary and that more or fewer adjusting elements may also be provided.

[0053] First control element 4.1 is designed, for example, to have a deadband, meaning it outputs a non-zero output signal only when its input signal exceeds or falls below a threshold. After exceeding the threshold, a linear relationship can exist between the input and output information. Thus, first control element 4.1 can define the starting threshold at which the compensation control loop should be activated.

[0054] The threshold value of the first regulating element 4 . 1 can be varied, in particular as a function of one or more control parameters s.

[0055] Here, at least one control parameter s can be transmitted directly as an input parameter to the first regulating element 4.1 or can be converted by a first mathematical function fl(s) into a control information related to the control parameter s, which is then transmitted to the first regulating element 4.1 for changing the threshold value.

[0056] The feedback path 4 of the compensating control loop can have a further second regulating element 4.2, which preferably receives the output information of the first regulating element 4.1 as input information. The second regulating element 4.2 has a transfer function G T which, for example, has a low-pass characteristic. The second regulating element 4.2 can be designed, for example, as a PTl element or a PT x element of a higher order (i.e. x e {2, 3, 4,..}). Basically, other regulating functions with a low-pass characteristic can also be envisaged. Due to the low-pass characteristic, the portion above the cut-off frequency is filtered out. Thus, the low-frequency portion, i.e. slow changes of the steering angle, have a greater influence, so that a cause for increasing the setpoint adjustment torque, which is derived by the integral portion, is fed back and a more natural steering behaviour is thus achieved. As an alternative, for example, a transfer function resulting from a standard design method, such as pole-zero compensation, state regulator or other transfer functions can also be used.

[0057] The regulating characteristic of the second regulating element 4.2 is changeable, in particular preferably in dependence on one or more control parameters s.

[0058] Here, at least one control parameter s can be transmitted directly as an input parameter to the second regulating element 4.2 or can be converted by a second mathematical function f2(s) into a control information related to the control parameter s, which is then transmitted to the second regulating element 4.2 for changing the regulating characteristic.

[0059] The feedback path 4 of the compensating control loop can have a further third regulating element 4.3, which preferably receives the output information of the second regulating element 4.2 as input information. The third regulating element 4.3 can be designed, for example, as a limiter, also called saturation element. The limiter is preferably used for limiting the amplitude of the feedback information, in particular the output signal of the second regulating element 4.2, in order to avoid excessively high feedback values for safety reasons.

[0060] The third regulating element 4.3 preferably has a threshold value from which the amplitude limitation is carried out. This threshold value can be changed, preferably in dependence on one or more control parameters s.

[0061] Here, at least one control parameter s can be transmitted directly as an input parameter to the third regulating element 4.1 or can be converted by a third mathematical function f3(s) into a control information related to the control parameter s, which is then transmitted to the third regulating element 4.3 for changing the threshold value.

[0062] As the first to third mathematical functions f1(s) to f3(s), one or more monotonically increasing or decreasing functions can be used, which influence the influence of at least one control parameter s on the corresponding adjustment element 4.1 to 4.3. In addition to the monotonically increasing or decreasing functions described above, other types of functions, such as quadratic functions, can also be used.

[0063] In the case of using multiple different control parameters s, the mathematical functions f1(s) to f3(s) can also have multiple function parts, wherein each control parameter s is used as an input parameter of one function part, so that the overall result of each corresponding mathematical function f1(s) to f3(s) can be influenced by multiple control parameters.

[0064] One or more of the following information may be used as control parameter s:

[0065] The steering torque applied by the driver to the steering wheel. Thus, for example, as the driver's steering torque increases, the deadband width can be reduced in order to prevent the driver from being disturbingly controlled by the first regulating unit 2 .

[0066] - Steering angle speed, i.e. the speed of changing the steering angle, so as to reduce the threshold of the dead zone, i.e. the dead zone width, with increasing steering angle speed and optionally strengthen the transfer function G of the second regulating element 4.2 T , thus avoiding overshoot due to excessive loading of the I part.

[0067] - Curve curvature (i.e., the inverse of the curve radius of the curve being traveled), to avoid lowering the dead zone threshold as the curve curvature decreases, i.e., reducing the dead zone width, thereby avoiding oscillation.

[0068] The vehicle speed, so that the adjustment elements 4 . 1 to 4 . 3 can be adapted at least partially as a function of the speed.

[0069] While the present invention has been described above with reference to exemplary embodiments, it is noted that numerous modifications and variations are possible without departing from the scope of protection defined by the patent claims.

[0070] Reference Signs List

[0071] 1 Adjustment device

[0072] 2 First regulator unit

[0073] 3 Motor

[0074] 4 Feedback path of the compensation regulation loop

[0075] 4.1 The first regulatory element

[0076] 4.2 Second regulatory element

[0077] 4.3 The third regulatory element

[0078] 5 Mechanical steering device

[0079] d Friction

[0080] d L disturbance variable

[0081] EPS steering

[0082] f1 first mathematical function

[0083] f2 second mathematical function

[0084] f3 third mathematical function

[0085] s control parameters

[0086] T EPS Motor steering torque

[0087] T 额定 Rated adjustment torque

[0088] Steering angle compensation information

[0089] Rated steering angle information

[0090] First steering angle information

[0091] Actual steering angle

Claims

1. A control device for adjusting a steering angle of a vehicle, comprising a first controller unit (2) whose control characteristic has at least one integral component, wherein: The first regulating unit (2) is designed to receive a control difference between first steering angle target information derived from the steering angle target information and the actual steering angle, and to provide actuation information for an electric motor (3) for controlling a steering device, wherein a compensation regulating loop is provided superimposed on the first regulating unit (2), wherein the compensation regulating loop has a feedback path (4), which receives actuation information of the electric motor (3), an output torque of the electric motor (3) and / or information related to the output torque of the electric motor (3) as input parameters, and provides steering angle compensation information based on these input parameters, wherein the steering angle target information is adjusted to the first steering angle information based on the steering angle compensation information, wherein the control characteristic of the compensation regulating loop can be changed according to at least one control parameter, wherein the control parameter is a driver's influence parameter on the steering device and / or a measured parameter related to the driving situation, and the input parameter of the feedback path (4) of the compensation regulating loop is the target torque information of the first regulating unit (2), the current intensity of the current flowing through the electric motor (3) or measured information proportional to the current intensity.

2. The adjustment device according to claim 1, characterized in that The first controller unit (2) has a PID controller or the first controller unit (2) is a PID controller.

3. The adjusting device according to claim 1 or 2, characterized in that: The first regulating unit (2) is an inherently closed regulating unit which has no external interface by means of which the regulating characteristics of the first regulating unit (2) can be adjusted.

4. The adjusting device according to claim 1 or 2, characterized in that: The feedback path (4) of the compensation control loop has a first control element (4.1) which is designed as a threshold-value-dependent dead band.

5. The adjustment device according to claim 4, characterized in that The threshold value of the dead band can be varied according to at least one control parameter.

6. The adjustment device according to claim 4, characterized in that The regulating device (1) is designed to calculate a threshold value of the dead band based on a first mathematical function as a function of at least one control parameter.

7. The adjusting device according to claim 1 or 2, characterized in that: The feedback path (4) of the compensation control loop has a second control element (4.2) designed as a low-pass filter.

8. The adjustment device according to claim 7, characterized in that The second regulating element (4.2) has a PT1 element or a higher-order PTx element.

9. The adjustment device according to claim 7, characterized in that The regulating characteristic of the second regulating element (4.2) can be varied as a function of at least one control parameter.

10. The adjustment device according to claim 9, characterized in that The regulating device (1) is designed to calculate a regulating characteristic of the second regulating element (4.2) based on a second mathematical function as a function of at least one control parameter.

11. The adjusting device according to claim 1 or 2, characterized in that: The feedback path (4) of the compensation control loop has a third control element (4.3) designed as a limiter.

12. The adjustment device according to claim 11, characterized in that The limiter has a threshold value, starting from which the amplitude of the output signal of the second control element is limited, and the threshold value can be varied as a function of at least one control parameter.

13. The adjustment device according to claim 12, characterized in that The regulating device (1) is designed to calculate a threshold value of a third regulating element (4.3) based on a third mathematical function as a function of at least one control parameter.

14. A method for regulating a steering angle of a vehicle by means of a regulating device (1), the regulating device comprising a first regulator unit (2) whose regulating characteristic has at least one integral component, wherein: A first regulating unit (2) receives a regulating difference between first steering angle information derived from the steering angle setpoint information and the actual steering angle, and provides actuation information for an electric motor (3) for controlling a steering device, wherein a compensation regulating loop having a feedback path (4) is provided, which is superimposed on the first regulating unit (2), wherein the feedback path receives actuation information of the electric motor (3), an output torque of the electric motor (3) and / or information dependent on the output torque of the electric motor as input parameters, and provides steering angle compensation information based on these input parameters, wherein the steering angle setpoint information is adjusted to the first steering angle information based on the steering angle compensation information, wherein the regulating characteristic of the compensation regulating loop is changed according to at least one control parameter, wherein the control parameter is a driver's influence parameter on the steering device and / or a measured parameter related to the driving situation, wherein the input parameter of the feedback path (4) of the compensation regulating loop is the setpoint torque information of the first regulating unit (2), the current intensity of the current flowing through the electric motor (3) or measured information proportional to the current intensity.

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