System and method for operating an electromechanical steering system of a vehicle

Abstract

The present invention relates to a system for operating an electromechanical steering system (2) of a vehicle, comprising a driver assistance system (3) designed to generate first steering control information (L1) and a control unit (4), the control unit having at least a first regulator unit (5), the control unit (4) having a first interface (S1) and at least one second interface (S2), the first interface being designed to receive driver torque information (M), the second interface being designed to receive at least one adaptation information (A1, A2) related to driving conditions and / or driving situations, the control unit (4) being designed to provide second steering control information (L2) related to the driver torque information (M) and the at least one adaptation information (A1, A2), the system (1) being designed to provide modified steering control information (L3) for the vehicle's steering system (2) based on the first steering control information (L1) and the second steering control information (L2), and to perform steering movements on the electromechanical steering system (2) based on the modified steering control information.

Description

Technical Field

[0001] This invention relates to systems and methods for operating electromechanical steering systems of vehicles. Background Technology

[0002] The electromechanical steering system of a vehicle (also known as EPS: electric power steering) is known in principle. Here, a programmable servo motor supports and amplifies the driver's steering movements by transmitting force to the steering mechanism.

[0003] Trajectory control driver assistance systems utilize detected environmental information to control the vehicle laterally and longitudinally along a planned trajectory. In most cases, the electromechanical steering system acts as the actuator for lateral vehicle control, obtaining appropriate handling information from the traction control device.

[0004] On the one hand, a system with a first interface scheme is known, in which the lateral dynamics of the vehicle are influenced by the additional superposition of the torque value and the torque of the control motor of the electromechanical steering system. On the other hand, a system with a second interface scheme is known, in which the lateral dynamics of the vehicle are controlled by a predetermined theoretical steering angle. In this case, a steering angle controller is implemented on the control device of the electromechanical steering system.

[0005] The primary design goal of driver assistance systems is to achieve high control quality in vehicle trajectory control. However, the driver's pursuit of high steering comfort during unauthorized control / unauthorized steering often conflicts with the goal of achieving high control quality. Here, "unauthorized control / unauthorized steering" refers to steering actions performed by the driver that deviate from the steering actions pre-defined by the driver assistance system.

[0006] Regardless of the interface scheme used, the known drawback of the implementation scheme is that when there is unauthorized control, the driver can only experience the magnitude, process and direction of the steering torque in a limited way or feel it is unnatural. This is because the steering torque is not matched with the corresponding driving situation and always conflicts with the driver's steering wheel movement, so the effect is indistinguishable.

[0007] In known implementations, even during overstepping control with minimal steering wheel deflection, the torque the driver must apply to the steering system (hereinafter referred to as driver torque) continuously increases until it reaches a level corresponding to a safety barrier / safety screen level, which is maintained due to the limitation on the motor torque of the servo motor in the electromechanical steering system. This increase in driver torque is because the driver's actions are interpreted in a control-technical sense as a disturbance torque acting directly on the angle control loop. Furthermore, the resulting change in vehicle direction is also interpreted as a disturbance variable in the trajectory tracking control loop. This type of driver disturbance can be compensated for by the dynamic effect of the total disturbance transfer function (TTF) of the lateral control. The higher the dynamic effect of the TTF, the faster the driver's reaction torque increases. Additionally, the higher the DC component of the TTF, the greater the driver's absolute reaction torque.

[0008] The drawback of the above effect is that, in extreme cases, such as during emergency steering maneuvers, the driver assistance system may resist the driver regardless of the driving situation. Since the driver must apply additional steering torque to take over the instructions of the driver assistance system that is currently following other control objectives, it hinders the driver's operation.

[0009] Generally speaking, in cooperative driving, that is, when the driver interacts with the driving assistance system, the above effects lead to a decrease in driving comfort, and thus a decrease in the acceptance of driving assistance functions. Summary of the Invention

[0010] Based on this, the objective of this invention is to propose an electromechanical steering system for controlling a vehicle, which enables cooperative driving behavior that is understandable and natural to the driver, without significantly affecting the effectiveness of driving functions.

[0011] This task is accomplished by a system having the features described in independent claim 1. The preferred embodiment is the subject of the dependent claim. The control method for the electromechanical steering system of a vehicle is the subject of co-claim 15.

[0012] According to a first aspect, the present invention relates to a system for operating an electromechanical steering system of a vehicle. The vehicle includes a driver assistance system designed to generate first steering control information. Furthermore, the system includes a control unit with at least a first regulator unit. The control unit includes a first interface designed to receive driver torque information. Additionally, the control unit includes at least one second interface designed to receive at least one adaptation information related to driving conditions and / or driving situations. Preferably, the first and second adaptation information are provided via the second interface. The at least one adaptation information is related to driving conditions or driving situations. The control unit is designed to provide second steering control information related to the driver torque information and the at least one adaptation information. Furthermore, the system is also designed to provide modified steering control information to the vehicle's steering system based on the first and second steering control information, and to perform steering actions on the electromechanical steering system based on the modified steering control information. Here, "performing steering actions based on the modified steering control information" means that the modified steering control information itself or variables derived from it, such as variables constituted by the transfer function of a safety barrier, are used to initiate the steering action of the electromechanical steering system.

[0013] The technical advantage of the system described in this invention lies in the fact that, during cooperative driving, the driver torque felt by the driver on the steering device can be adjusted according to the driving conditions or situations, thereby generating a driving behavior that feels natural to the driver. Preferably, only in extreme situations, such as during emergency steering maneuvers, a signal is given to the driver indicating that, based on the driving situation, it is best to follow the instructions of the driver assistance system, making it difficult for the driver assistance system to overstep its authority.

[0014] According to one embodiment, the first steering control information is the angle information, torque information, or information proportional to the torque of the servo motor of the electromechanical steering system. Therefore, the driver assistance system controls the electromechanical steering based on theoretical angle information or theoretical torque setpoints, and transforms these theoretical angle information or theoretical torque setpoints into modified steering control information based on the influence of the second steering control information on the driver. Thus, the system can be used with both angle-interface and torque-interface-interface solutions.

[0015] According to one embodiment, the first adaptation information is a driver torque threshold. The control unit is configured to generate second steering control information when the magnitude / absolute value of the driver torque information exceeds the driver torque threshold. This second steering control information causes a correction to the first steering control information provided by the driver assistance system. Thus, the driver assistance system's regulations are only corrected by the driver exceeding their authority when the driver torque threshold is exceeded. Therefore, for example, unintentional slight steering movements by the driver will not affect the regulations of the driver assistance system.

[0016] According to one embodiment, the second adaptation information is overriding control stiffness information, which is a measure of the steering resistance that the driver must overcome on the steering device to overridden the steering behavior pre-defined by the driver assistance system. The overriding control stiffness information, for example, constitutes information about a variable spring constant, similar to a spring, through which the force that must be overcome to compress the spring can be adjusted. Here, the overriding control stiffness information demonstrates the difficulty for the driver to influence the pre-defined steering behavior of the driver assistance system. Therefore, by changing the overriding control stiffness information, the torque that the driver must exert on the steering device to achieve the prescribed steering movement of the electromechanical steering system can be adjusted according to the situation.

[0017] According to one embodiment, the control unit is designed to adapt the control behavior of a first regulator unit of the control unit based on overstepping control stiffness information. Preferably, at least one gain coefficient of the first regulator unit is adapted based on the overstepping control stiffness information. A function can be pre-defined that maps the metric required for the overstepping control stiffness to at least one gain coefficient. Preferably, there is an interdependence where a higher overstepping control stiffness translates to a lower control loop gain, and vice versa. Furthermore, to meet stability criteria, it is beneficial to adapt at least one cutoff frequency of the first regulator unit. For example, the cutoff frequency can be adapted based on the overstepping control stiffness information. A function can also be pre-defined that maps the metric of the required overstepping control stiffness to at least one cutoff frequency.

[0018] According to one embodiment, the control unit is designed to receive first and second adaptation information, wherein one of the two adaptation information has a fixed value, while the magnitude / absolute value of the other adaptation information is related to the driving condition or driving situation, or both the first and second adaptation information are related to the driving condition or driving situation. Therefore, the steering behavior of the driving assistance function can be designed according to the driving condition and driving situation, thereby achieving the most natural possible cooperative driving behavior.

[0019] According to one embodiment, the control unit is configured such that if the magnitude of the driver torque information is less than or equal to a driver torque threshold, the torque difference received by the first regulator unit is zero; and once the magnitude of the driver torque information exceeds the driver torque threshold, the value of the torque difference is the magnitude of the driver torque information minus the driver torque threshold. This ensures that the steering assist system's specifications are only affected by the driver when the driver applies a significant torque to the steering mechanism.

[0020] According to one embodiment, the first regulator unit has a monotonically decreasing magnitude characteristic curve above the cutoff frequency. This type of control behavior is beneficial for cooperative driving behavior because, for example, it can effectively avoid steering wheel vibration caused by negative feedback of the driver's torque in the control loop.

[0021] According to one embodiment, the first regulator unit has control behavior based on the PT1 controller. This type of controller is advantageously used for interactive control of the vehicle through the influence of the driver and driver assistance systems.

[0022] According to one embodiment, the control behavior of the first regulator unit is to modify the first steering control information using the second steering control information, thereby reducing the torque difference input to the first regulator unit as an input variable. The resulting system control behavior is such that the driving assistance function increasingly adapts to the driver's steering requirements, thus reducing the reaction torque exerted by the driving assistance system on the driver.

[0023] According to one embodiment, the first steering control information is angle information, yaw rate information, or curvature information. A second regulator unit is pre-configured, designed to convert the theoretical torque information of the steering angle controller of the servo motor used in the electromechanical steering system, or information proportional to the theoretical torque information, into steering angle information, yaw rate information, or curvature information as the second steering control information. Thus, the output information affected by the driver's torque information can be converted by the second regulator unit, allowing the second steering control information provided by the system to be used to directly correct the first steering control information, for example, through addition or subtraction arithmetic operations.

[0024] The second regulator unit is designed to receive theoretical torque information from the servo motor of the electromechanical steering system, weighted by an activation factor, which is provided by the first regulator unit. Preferably, the torque information is received from the control loop of the second regulator unit, and arithmetic operations are performed using the theoretical value. The torque information is provided, for example, by the steering angle controller of the electromechanical steering system. For example, the torque information is subtracted from the theoretical value, and the resulting control difference is multiplied by the activation factor. The result of the multiplication is then input to the second regulator unit. In cases of driver overreach, the magnitude of the servo motor torque is primarily a measure of the torque acting on the driver. Therefore, the second regulator unit attempts to reduce the control difference multiplied by the activation factor, thereby effectively reducing the impact of driver assistance functions on the driver. This reduction is determined by the magnitude of the activation factor.

[0025] According to one embodiment, the second regulator unit is designed to receive over-weighted control stiffness information and adapt the control behavior of the second regulator unit based on the over-weighted control stiffness information. Preferably, at least one gain coefficient of the second regulator unit is adapted according to the over-weighted control stiffness information. A function can be pre-set that maps a measure of the desired over-weighted control stiffness to at least one gain coefficient. Here, it is preferable that a higher over-weighted control stiffness translates to a lower control loop gain, and vice versa. Furthermore, to meet stability criteria, it is beneficial to adapt at least one cutoff frequency of the second regulator unit. For example, the cutoff frequency can be adapted based on the over-weighted control stiffness information. Here, a function can also be pre-set that maps a measure of the desired over-weighted control stiffness to at least one cutoff frequency.

[0026] According to one embodiment, the second regulator unit has a numerical characteristic curve that monotonically decreases above the cutoff frequency and / or exhibits control behavior according to the PT1 controller. This type of controller behavior, or this type of controller, is highly advantageously suited for interactive control of the vehicle under the influence of the driver and driver assistance systems.

[0027] According to another aspect, the present invention relates to a method for operating an electromechanical steering system for a vehicle, the vehicle including a driving assistance system and a control unit designed to generate first steering control information, the control unit having at least a first regulator unit, wherein the control unit receives driver torque information applied to the steering device by a driver, and receives at least one adaptation information related to driving conditions and / or driving situations, the control unit provides second steering control information related to the driver torque information and the at least one adaptation information, the system provides modified steering control information for the vehicle's steering system based on the first and second steering control information, and performs steering movements on the electromechanical steering system based on the modified steering control information.

[0028] In the context of this invention, the terms “approximately,” “substantially,” or “roughly” refer to an error of + / -10% from the respective precise values, preferably + / -5%, and / or an accuracy error that is functionally insignificant.

[0029] Other structural forms, advantages, and application possibilities of the invention also arise from the following description and accompanying drawings of embodiments. Here, all described and / or illustrated features constitute the basic subject matter of the invention independently or in arbitrary combinations, and are independent of their generalization or reference in the claims. The content of the claims is also an integral part of the related description. Attached Figure Description

[0030] The present invention will now be described in detail with reference to the accompanying drawings of the embodiments. Wherein:

[0031] Figure 1 This is a schematic example of a first embodiment of an electromechanical steering system for controlling a vehicle, wherein the control of the electromechanical steering is implemented by a driver assistance system using torque information;

[0032] Figure 2 This is a schematic example of a second embodiment of an electromechanical steering system for controlling a vehicle, wherein the control of the electromechanical steering is implemented by a driving assistance system using theoretical steering angle information. Detailed Implementation

[0033] Figure 1 The diagram shows a schematic block diagram of a first embodiment of system 1, which is used to control a steering system 2 with an electromechanical drive (EPS: electric power steering). In this type of steering system 2, a programmable servo motor supports the driver's steering actions, or at least partially performs its own steering actions during autonomous or semi-autonomous driving.

[0034] According to the first embodiment, the steering system 2 has a torque interface, that is, the steering system 2 is designed to receive torque information or information proportional to torque from the steering system 2 servo motor as input information, such as information about the current flowing through the steering system 2 servo motor.

[0035] System 1 includes a driving assistance system 3, which provides first steering control information L1 at its output interface. This driving assistance system may, for example, include an environment recognition unit 3.1, which constructs an environmental model within the vehicle area using sensor technology. Furthermore, the driving assistance system 3 may also include a trajectory planning unit 3.2. The trajectory planning unit 3.2 is at least indirectly linked to the environment recognition unit 3.1 and is designed to receive information from the environment recognition unit 3.1 and plan a driving trajectory based on this information.

[0036] Furthermore, the driving assistance system 3 preferably also includes a trajectory tracking control device 3.3. This trajectory tracking control device is at least indirectly linked to the trajectory planning unit 3.2 and is designed to calculate vehicle control information so that the vehicle moves along a calculated and selected driving trajectory. The output information of the trajectory tracking control device 3.3 is preferably a theoretical steering angle. It is used to drive on a selected driving trajectory.

[0037] Furthermore, the driving assistance system 3 preferably also includes a steering angle controller 3.4. This steering angle controller 3.4 is at least indirectly linked to the trajectory tracking control device 3.3 and receives control information from the trajectory tracking control device 3.3, particularly theoretical angles. The steering angle controller 3.4 is preferably designed to provide torque information of the servo motor of the steering system 2, or information proportional to the torque, such as information about the current flowing through the servo motor of the steering system 2, as specified as theoretical values. Furthermore, the steering angle controller 3.4 is also designed to suppress disturbances such as oscillating steering behavior. The steering angle controller 3.4 preferably provides first steering control information L1.

[0038] like Figure 1 As indicated by the vertical arrow, at least a portion of units 3.1 to 3.4 of the driving assistance system 3 can be connected to unit 7, which provides driving condition recognition or driving situation recognition. Unit 7 can be, for example, a functional component of the driving assistance system 3, either pre-installed in the control unit of the driving assistance system 3 or installed in a control unit independent of the driving assistance system 3. Furthermore, unit 7 may also include a device for observing the driver to detect and process driver behavior, gaze direction, and / or actions, thereby drawing conclusions about future driving instructions from the driver.

[0039] In addition, System 1 also has a control unit 4, which is designed to provide second steering control information L2. Here, System 1 uses the second steering control information L2 to correct the first steering control information L1, thereby achieving better cooperative driving with the resulting corrected third steering control information L3. This allows the driver to more freely cooperate in controlling the vehicle, even when driver assistance functions that cause lateral vehicle control are activated, depending on driving conditions and / or driving situations, thus reducing the impression that driving behavior is externally determined.

[0040] The control unit 4 has a first interface S1, which is designed to receive driver torque information M. Here, the driver torque information M is torque information indicating the torque applied by the driver to the vehicle steering system, or a variable proportional to the torque information.

[0041] The driver torque information M is preferably first generated as a value using the magnitude / absolute value unit 4.1. Thus, at the output of the magnitude unit 4.1, driver torque information |M|, independent of the driver's steering direction, is provided, regardless of its sign.

[0042] It should be noted that in the illustrated embodiment, a counting arrow system has been selected, wherein a positive driver torque is defined as having the same effect as the positive motor torque of the electromechanical steering system 2, or having the same effect as a positive steering angle that typically indicates a left turn.

[0043] Furthermore, the control unit 4 also includes a second interface S2, which provides first and second adaptation information A1, A2. The first and second adaptation information A1, A2 are preferably provided by unit 7. At least one of the adaptation information A1, A2 is a variable related to driving conditions and / or driving situations, meaning that the first and / or second adaptation information A1, A2 will change according to the driving conditions or driving situations identified by device 7. The first and second adaptation information A1, A2 are preferably adapted according to driving conditions and / or driving situations.

[0044] The first adaptation information A1 is preferably a driver torque threshold, i.e., a threshold used for torque information or for variables proportional to the torque information. The first adaptation information A1 is used in the control unit 4 to define a threshold that, when exceeded, allows the driver to influence the pre-defined steering behavior of the driving assistance system 3. Here, the sign-independent driver torque information |M| provided by the measurement unit 4.1 and the first adaptation information A1 are input to the subtraction module 4.2, which provides torque difference information ΔM at its output.

[0045] The torque difference information ΔM is sent as input to the first regulator unit 5. This first regulator unit receives second adaptation information A2 as another input. The controller unit 5 acts as a controller limiter, specifically by adapting the control behavior of the first regulator unit 5 to the second adaptation information A2, thereby adjusting the difficulty of the driver's overstepping control of the steering behavior pre-defined by the driver assistance system. In other words, the torque that the driver must apply to the steering wheel is pre-defined by the first regulator unit 5; exceeding this torque, the driver assistance system becomes increasingly compliant with the driver's different directional intentions. The degree of this compliance is defined by the adaptation information. Furthermore, the magnitude of the steering resistance felt by the driver when overstepping the steering regulations of the driver assistance system can be variably adjusted. Therefore, the second adaptation information A2 is also referred to below as "overstepping control stiffness."

[0046] Based on the second adaptation information A2, the control behavior of the first regulator unit 5 is modified. The regulator gain within the first regulator unit 5 is particularly affected by the second adaptation information A2. Here, one or more gain coefficients of the first regulator unit 5 are affected, thereby achieving the desired overweighted control stiffness.

[0047] For example, there is an interdependent relationship between the second adaptation information A2 and the control loop gain in the first regulator unit 5; that is, a higher second adaptation information A2 or over-authority control stiffness results in a lower regulator gain, and vice versa. In other words, the required lower over-authority control stiffness maps to a higher regulator gain in the first regulator unit 5, and vice versa. In the first extreme case, where the second adaptation information A2 is at its maximum or the over-authority control stiffness is at its maximum, the control loop gain is zero, meaning the control unit 4 is almost inactive, and the over-authority control stiffness is determined entirely or almost entirely by the disturbance suppression characteristics of the steering angle controller 3.4.

[0048] In the second extreme case, where the second adaptation information A2 is minimized or the overriding control stiffness is minimized, the regulator gain value is higher. The regulator gain is limited, for example, only by the cost of designing and implementing stabilization measures.

[0049] When the overriding control stiffness is low, the driver may perceive the assistance system as more compliant during cooperative driving, resulting in weaker suggestion functions. Especially when the overriding control stiffness is given in advance, due to the higher loop gain, it may be necessary to adapt the cutoff frequency of the first regulator unit 5 to comply with stability standards. The optimal adaptation of the filter cutoff frequency of the first regulator unit 5 is also based on the second adaptation information A2.

[0050] The control unit 4, especially the first regulator unit 5, preferably has a saturation function. The saturation function is selected, for example, by limiting the maximum value of the output information of the first regulator unit 5 or the maximum value of the second steering control information L2.

[0051] Therefore, the output information value of the first regulator unit 5 is limited by a saturation function to a predetermined threshold. The definition of these thresholds provides another degree of freedom for the design of unauthorized control behavior. The thresholds can be defined fixed values ​​or designed according to driving conditions. A low threshold allows for a further increase in the reaction torque on the driver from a certain degree of unauthorized control. This is because, with a relatively low threshold, the value of the first steering control information L1 exceeds the value of the second steering control information L2 from a certain degree of unauthorized control. Therefore, the modified steering control information L3, constituted by the additive module 8, increasingly represents the intention of the driver assistance system, which corrects for the driver as a disturbance in the control loop. This further increases the reaction torque on the driver. One application is that the driver torque is initially relatively small when the deviation from the requirements specified by the driver assistance system is small, but increases only when the deviation is large, thus conveying the permissible range of unauthorized control to the driver in a tactile manner.

[0052] The high threshold of the second steering control information L2 allows the first steering control information L1 to be rejected. Consequently, the modified steering control information L3 increasingly represents the driver's unauthorized control intentions, and the control objectives of the driver assistance system are increasingly suppressed. As a result, the steering torque required for steering maneuvers is less than that required without driver assistance functions. Emergency avoidance steering is one application of this approach, where the method not only reduces the reaction torque applied to the driver but also effectively provides support.

[0053] like Figure 1 As shown in the "Symbol" module, the output information provided by the first regulator unit 5 is multiplied by the sign of the driver's torque. The "Symbol" function determines the sign of the driver's torque information M, and by multiplying the output information of the first regulator unit 5 with the sign of the driver's torque information M, the second steering control information L2 is constructed. This enables the control unit 4 to provide steering control information L2 independently of the steering direction, which is designed to reduce driver torque.

[0054] The second steering control information L2 is transmitted to an adder module 8. There, the second steering control information L2 is added to the first steering control information L1, and a third steering control information L3 is provided. Clearly, in a reverse counting arrow system, the adder module 8 can be replaced by a subtraction module, thus producing a functionally identical system in the result.

[0055] The third steering control information L3 is input to a safety barrier SB, which provides fourth steering control information L4 on the output side. The safety barrier SB is a unit that monitors or actively limits control variables before physically considering absolute height (absolute magnitude) and gradient.

[0056] The safety barrier SB is configured, for example, to monitor whether the modified steering control information L3 meets safety objectives, and to correct it if necessary if it does not meet the safety objectives. Thus, for example, the absolute height and gradient of the modified steering control information L3 can be monitored, and it can be actively limited if necessary.

[0057] The fourth steering control information L4 constitutes the input variable of the electromechanical steering system 2. Based on the driver torque information M and the first and second adaptation information A1 and A2, the first regulator unit 5 generates the second steering control information L2, which modifies the first steering control information L1 generated by the driver assistance system 3, thereby applying the driver's influence to the vehicle steering system 2 in relation to the first and second adaptation information A1 and A2.

[0058] As indicated by the arrows pointing upwards from the driver assistance system 3 and the steering system 2 to unit 7, the information from functional units 3.1 to 3.4 of the driver assistance system 3 and the electromechanical steering system 2 is used to detect driving conditions or situations.

[0059] Figure 2 The diagram shown is a schematic block diagram of a second embodiment of the control system 1 of the steering system 2 with electromechanical drive device.

[0060] According to the second embodiment, the steering system 2 has an angle interface, that is, the steering system 2 is designed to receive angle information, especially theoretical angle information. As input information, the steering angle controller is preferably integrated into the steering system 2. The driver assistance system 3 provides theoretical angle information at the output interface. This serves as the first steering control information L1.

[0061] The driving assistance system includes, for example, an environment recognition unit 3.1, which constructs an environmental model of the vehicle area using sensing technology. Furthermore, the driving assistance system 3 may also include a trajectory planning unit 3.2. The trajectory planning unit 3.2 is at least indirectly connected to the environment recognition unit 3.1, and is used to receive information from the environment recognition unit 3.1 and plan a driving trajectory based on this information.

[0062] Furthermore, the driving assistance system 3 preferably also includes a trajectory tracking control device 3.3. It is at least indirectly connected to the trajectory planning unit 3.2 and is designed to calculate vehicle control information so that the vehicle moves along a calculated and selected driving trajectory. In the illustrated embodiment, the output information of the trajectory tracking control device 3.3 is theoretical angle information. The first steering control information L1 is in the form of driving on a selected driving trajectory.

[0063] like Figure 2 As indicated by the vertical arrow, at least a portion of units 3.1 to 3.3 of the driving assistance system 3 can be connected to unit 7 to provide driving condition recognition or driving situation recognition. Unit 7 can be, for example, a functional component of the driving assistance system 3, which can be pre-installed in the control unit of the driving assistance system 3 or installed in a control unit independent of the driving assistance system 3. Furthermore, unit 7 may also include a device for observing the driver to detect and process driver behavior, gaze direction, and / or actions, thereby drawing conclusions about future driving instructions from the driver.

[0064] System 1 also has a control unit 4, which is designed to provide second steering control information L2. Here, System 1 uses the second steering control information L2 to correct the first steering control information L1, thereby achieving better cooperative driving with the corrected steering control information L3. In this way, depending on the driving conditions and / or driving situations, even when driving assistance functions affecting the lateral control of the vehicle are activated, the driver can more freely cooperate in controlling the vehicle, thereby reducing the impression that driving behavior is determined by external factors.

[0065] The control unit 4's interfaces S1 and S2, the measurement unit 4.1, and the first regulator unit 5 process and determine the information received from interfaces S1 and S2. Figure 1 The first embodiment shown is the same; therefore, please refer to the description above. These descriptions also apply to... Figure 2 Examples of implementations.

[0066] According to Figure 1 The main difference in the embodiments is that, according to Figure 2 In this embodiment, the second steering control information L2 is not directly provided by the first regulator unit 5, but rather the first regulator unit 5 provides the activation factor AF.

[0067] Furthermore, the control unit 4 also has a subtraction module 4.2. This subtraction module 4.2 provides, on the one hand, the theoretical value and the torque information DI of the electromechanical steering system 2, which in the illustrated embodiment is "0". The torque information DI is, for example, equivalent to the adjustment torque required by the steering angle controller of the electromechanical steering system 2, or equivalent to the required current flowing through the servo motor that is directly proportional to the adjustment torque. Therefore, the total torque derived from the actual motor current can be used after subtracting the torque or current required for other functions of the control unit of the electromechanical steering system 2.

[0068] In subtraction module 4.2, the torque information DI is subtracted from the theoretical value. This difference is corrected based on the activation factor AF. The output information of subtraction module 4.2 is multiplied by the activation factor AF, and the result is input to the second regulator unit 6. The activation factor is preferably a rational number between 0 and 1 (AF∈[0,1]). The activation factor is affected by the driver torque information M and the first and second adaptation information A1, A2. When the value is “0”, the driver will feel difficulty steering, that is, cooperative driving is strongly suppressed. Conversely, if the value is “1”, the steering system 2 will allow the driver to cooperate significantly, and the steering requirement weight of the driving assistance system 3 will be reduced.

[0069] The second regulator unit 6 receives the difference weighted by the activation factor AF. The second regulator unit 6 is designed, for example, as a torque control loop. The second regulator unit 6 is preferably designed as a PT1 (pulse sequence control) controller.

[0070] In a preferred embodiment, the second regulator unit 6 is connected to the first regulator unit 5, such that the first regulator unit 5 generates an activation factor AF at its output interface, the value of which is between 0 and 1. The control difference of the second regulator unit 6 can be scaled using this value. In the absence of driver interaction, the first regulator unit generates an activation factor of 0, thereby the torque information of the steering system 2, especially the torque information of the steering angle controller of the steering system 2, is not fed back. In the presence of driver interaction, the first control unit 5 generates an activation factor AF greater than 0 based on the first and second adaptation information A1, A2. Preferably, the contribution of the second adaptation information A2 (i.e., the overreach control stiffness) to the activation factor AF is such that a higher second adaptation information A2, i.e., a higher overreach control stiffness, results in a smaller activation factor AF at the output interface of the first regulator unit 5.

[0071] The contribution of the deviation between the driver torque information M and the first adaptation information A1 (i.e., the driver torque threshold) to the activation factor AF is designed such that the more the driver torque information M exceeds the first adaptation information A1, the larger the activation factor AF will be; that is, the larger the remaining driver torque, the larger the activation factor AF will be.

[0072] Preferably, the contribution of adaptation information to achieving the desired result can be weighted, especially by minimization.

[0073] Here, the use of weighting factors k1 and k2 provides flexibility in the design of the first regulator unit. The value range of the second adaptation information A2 is preferably between 0 and 1.

[0074] Use the following formula

[0075] ΔM=min(1,max(0,(|M|-A1)))

[0076] Wherein, ΔM is the torque difference (as input information of the first regulator unit 5), |M| is the magnitude / absolute value of the driver's torque information, A1 is the first adaptation information (driver torque threshold), and the torque difference ΔM is convolved with the impulse response g(t) of the first regulator unit 5 (convolution operator *).

[0077] The fit factor AF is obtained:

[0078] AF(t)=min(1,max(0,(min(k1·(ΔM(t)*g(t))),k2·(1-A(t))))))

[0079] like Figure 2As shown, the second adaptation information A2 can also be used to influence the control behavior of the second regulator unit 6. When the second adaptation information A2 decreases, it can, for example, be used to increase the regulator gain of the second regulator unit 6. Advantageously, according to the stability reserve, the parameters determining the frequency response of the second regulator unit 6 are also adapted simultaneously, for example, in the form of a pole shift and / or a zero shift.

[0080] According to Figure 2 In some embodiments, driver interaction can be adapted to the current driving situation using only the first adaptation information A1, only the second adaptation information A2, or a combination of both adaptation information A1 and A2. If only one of the two adaptation information A1 and A2 changes dynamically according to the driving condition or situation, the other corresponding adaptation information will be set to a fixed value. This value is selected such that, in itself, it enables the activation factor AF to be 1, thus allowing the driver to make the maximum possible dynamic intervention.

[0081] The second steering control information L2 provided by the second regulator unit 6 is transmitted to the adder module 9. There, the second steering control information L2 is added to the first steering control information L1 to provide the corrected steering control information L3.

[0082] The third steering control information L3 is preferably input to the safety barrier SB, which provides fourth steering control information L4 on the output side. The safety barrier SB is a unit that physically monitors or actively limits control variables by taking into account absolute height (absolute value) and gradient.

[0083] The safety barrier SB is configured, for example, to monitor whether the modified steering control information L3 meets safety objectives, and to correct it if necessary if it does not. Thus, for example, the absolute height and gradient of the modified steering control information L3 can be monitored, and it can be actively limited as needed.

[0084] The fourth steering control information L4 constitutes the input variable of the electromechanical steering system 2. Based on the driver torque information M and the first and second adaptation information A1 and A2, the second regulator unit 6 generates the second steering control information L2, which modifies the first steering control information L1 generated by the driver assistance system 3, so that the driver's dynamic influence can be applied to the vehicle steering system 2 in relation to the first and second adaptation information A1 and A2.

[0085] The working principle of control unit 4 is as follows: control unit 4 receives the theoretical value of torque information DI from the angle controller of electromechanical steering system 2, and reduces the torque difference ΔM with the help of controller unit 6 based on the magnitude of torque difference ΔM and second adaptation information A2. To this end, second regulator unit 6 generates second steering control information L2 (steering angle deviation signal) and adds it to the first steering control information L1 provided by trajectory tracking control device 3.3. This constitutes a control loop that gradually reduces torque difference ΔM.

[0086] As indicated by the arrow pointing upwards from steering system 2 to unit 7, information from the electromechanical steering system 2 can also be used to detect driving conditions or situations.

[0087] As described above, unit 7 is designed to identify and assess driving situations or conditions. Here, unit 7 may also observe the driver, for example, via a camera device, and thereby deduce driver behavior. Specifically, the unit can provide information on whether the driver's steering is in the same direction as or opposite to the direction specified by the driving assistance system.

[0088] Unit 7 can, for example, respond to driving situations, driving conditions, or driver behavior as follows:

[0089] - If the driver turns in a dangerous area, the reaction torque of the driver assistance system 3 should be clearly felt and act in the direction of the safe lane area. The first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (overriding control stiffness) are set to higher values;

[0090] - If the driver turns toward a safe lane area, the driver should not be restrained during this maneuver. The values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (overriding control stiffness) are set to low values.

[0091] - If the driver signals to the driver assistance system 3, for example, via manual torque, that they wish to engage in cooperative driving, then cooperative driving can be achieved with very small steering torque, i.e., with low steering effort. For example, choosing an alternative route to the right instead of the left to cross an obstacle, or the driver wishing to achieve a constant lateral offset instead of precise lane centering, this is communicated to the driver assistance system 3 via appropriate steering. In this case, the values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (transition steering stiffness) are set to low.

[0092] If the driver assistance system 3 reaches the limits of the electromechanical steering system during a turn, and the driver desires lateral control to prevent the vehicle from deviating from the curve, this should not manifest as a large counter-steering torque on the steering wheel, but rather as assisted steering. During this assisted steering, the driver only needs to apply a portion of the steering force, which is the remaining force after deducting the maximum steering force limit of the electromechanical steering system. Since the values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (overriding control stiffness) are relatively large, the control unit 4 keeps the first steering control information L1 unchanged and forwards it to the electromechanical steering system 2 through the safety barrier SB, keeping it unchanged or almost unchanged (i.e., the second steering control information is zero or very small).

[0093] - If the driver performs an emergency steering maneuver (e.g., characterized by a high steering angular velocity) but has not yet triggered the emergency steering assist function (or this is not part of the assist function), the steering torque applied to the driver by the electromechanical steering system's steering angle controller should be very small to avoid hindering the driver's evasive maneuver. In this case, the values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (transition steering stiffness) are small.

[0094] - If the driver performs an emergency steering evasive maneuver (e.g., characterized by a high steering angular velocity) but has not yet triggered the emergency steering assist function (or this is not part of the assist function), the driver can additionally obtain active steering assist function, and the controller unit 5 has no restrictions or only imposes restrictions when the value of the output signal is high.

[0095] - When the emergency steering assist function is activated (i.e., when emergency evasive maneuvers are performed via the driver assistance system), as long as the driver's steering effort is less than the specified optimal evasive trajectory, the values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (overriding control stiffness) are set to high values. This optimal evasive trajectory is characterized by allowing the vehicle to safely pass obstacles, not placing high demands on wheel adhesion potential, and not causing vehicle instability.

[0096] - When the emergency steering assist function is activated, if the driver's dynamic steering exceeds the defined limit avoidance trajectory, the values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (overriding control stiffness) are set to high values. The limit avoidance trajectory is defined as a trajectory on which the vehicle is far from the obstacle, but at the same time, it is very likely to lose traction and cause instability.

[0097] - When the emergency steering assist function is activated, if the driver selects a trajectory between the optimal avoidance trajectory and the extreme avoidance trajectory through steering control, the values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (overreach control stiffness) will be set to low values. Here, the optimal avoidance trajectory and the extreme avoidance trajectory will be continuously redefined, and the driver's actions will be re-evaluated accordingly.

[0098] - In situations where lanes narrow, especially at construction sites where lane markings are sometimes of poor quality, the probability of driver intervention to make necessary corrections to the driving trajectory is often higher. To ensure that the driver can make corrections with less steering force, the values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (overriding control stiffness) are set to low values ​​when the lane width is narrow or when a construction site is identified.

[0099] Generally, when lane marking quality is poor, the probability of driver intervention to make necessary lane corrections increases. Here, to ensure the driver makes corrections with the smallest possible steering force, the values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (transition steering stiffness) are set to low values.

[0100] If the vehicle is likely to drift out of its lane due to driver inattention, the assistance system will intervene first to guide the vehicle back into a safe lane area. However, the driver can then take full control of the vehicle. Under conditions where the driver's chosen trajectory will not cause the expected vehicle instability, the felt steering torque should never be contrary to the driver's steering intention. In this case, the values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (overriding control stiffness) are set to low values.

[0101] - If the driver selects Sport driving mode (if the vehicle is equipped with this option), the steering system should provide more feedback. Therefore, it is recommended that the torque be higher when the driver performs a counter-steering maneuver. The values ​​of the first adaptation information A1 (driver torque threshold) and the second adaptation information A2 (overriding control stiffness) are set to high values.

[0102] The first adaptation information A1 (driver torque threshold) is preferably designed based on the internal control error variable of the lateral control, for example as follows:

[0103] - The greater the lateral distance between the vehicle and the theoretical trajectory, the higher the first adaptation information A1 will be;

[0104] - The greater the difference between the actual steering wheel angle and the theoretical steering wheel angle, the higher the first adaptation information A1 will be;

[0105] The greater the difference between the actual yaw rate and the theoretical yaw rate, the higher the first adaptation information A1 will be.

[0106] The second adaptation information A2 (overriding control stiffness) is preferably designed based on the internal control error variable of the lateral control, and the method is as follows:

[0107] - The greater the lateral distance between the vehicle and the theoretical trajectory, the higher the second adaptation information A2;

[0108] - The greater the difference between the actual steering wheel angle and the theoretical steering wheel angle, the higher the second adaptation information A2 will be;

[0109] The greater the difference between the actual yaw rate and the theoretical yaw rate, the higher the second adaptation information A2 will be.

[0110] Furthermore, if the driver deviates from the steering rules prescribed by the driver assistance system and chooses an alternative route that does not reduce driving safety, the smaller first and second adaptation information A1 and A2 are selected.

[0111] Conversely, if the driver and the driver assistance system share the same vehicle guidance target, or if the driver's alternative route choice results in or will result in lower driving safety, then higher levels of the first and second adaptation information A1 and A2 are preferred. Here, driving safety can be assessed by the expert system based on the predicted collision probability and the predicted wheel adhesion potential loss.

[0112] Like unit 7, control unit 4 can be located on the control unit of driving assistance system 3. Alternatively, control unit 4 can also be located on the control unit of electromechanical steering system 2. For this purpose, the interface between the control unit of driving assistance system 3 and the control unit of electromechanical steering system 2 is extended, for example, to transmit first and second adaptation information A1, A2.

[0113] In addition, System 1 may beneficially include one or more of the following functions:

[0114] If it is desired to switch between discrete values ​​of the first and second adaptation information A1 and A2, these values ​​must be smoothed / interpolated before the control unit 4 performs the relevant operation, if necessary, to avoid unwanted sudden movements of the steering wheel. The first and second adaptation information A1 and A2 preferably have continuous characteristics and are determined, for example, through fuzzy logic operations.

[0115] If there are conflicting requirements regarding the impact on the driver's torque, such as in a construction site area where a lower first adaptation information A1 should be selected in principle, but an emergency avoidance assist device with a higher first adaptation information A1 value is activated, this can be resolved, for example, through the arbitration unit in the driving condition recognition device.

[0116] This can also influence the driver's torque, replacing the aforementioned limiting control of control unit 4, and appropriately replanning the theoretical trajectory based on the driver's steering activity. Planning a trajectory, for example, precisely along the lane selected by the driver, will provide the driver with a reaction torque of 0 Nm (Newton-meters) if the initial state of the controller is ignored.

[0117] The planned trajectory located to the right or left of the current driving trajectory will provide a steering suggestion to turn right or left.

[0118] The drawback of this method is that during the new planning process, the initial state of the controller (e.g., the I component in the steering angle controller) must be selectively shut down; that is, it cannot simply remain at the planning level. Furthermore, achieving a seamless transition and thus obtaining a stable steering torque curve using this method is more challenging.

[0119] The new trajectory generated by the driver's steering reduces the driver's steering torque, which implicitly becomes part of the control loop. Therefore, additional precautions are necessary in trajectory planning to ensure stability, especially since the delay between triggering replanning and affecting the driver's torque is usually longer. To avoid hindering the driver's emergency steering maneuvers, the trajectory must be replanned every sampling step (e.g., every 10 milliseconds), starting from the driver's current memory of vehicle motion. This is computationally expensive and does not eliminate the damping characteristics of the angle controller. If the values ​​of the first or second adaptation information A1, A2 are selected as "0", the suppression effect of the angle controller is zero in the torque interface of the electromechanical steering system 2. In the steering angle interface of the electromechanical steering system 2, the adaptation factors A1, A2, ranging from zero to low residual torque, can effectively reduce the suppression of the angle controller significantly. Only through the combined effect of driver torque limitation and trajectory replanning can coordinated overall behavior be achieved.

[0120] The second adaptation information A2 (overriding control stiffness) may be implicitly affected for the following reasons, controlling the first adaptation information A1 (driver torque threshold) based on the steering wheel deflection. However, the cost of ensuring stability in this case is also greater.

[0121] The same method applies if the steering system 2 is specified with a yaw rate or curvature specification, rather than a steering angle. In this case, the control unit 4 will generate a correction variable for the theoretical yaw rate or theoretical curvature, rather than a steering angle deviation.

[0122] For the driver assistance system 2, which is based on the angle interface with the electromechanical steering system 2, the actual steering wheel angle can also be used in the first control unit 4 to more dynamically limit the driver's torque during overstepping control. To this end, in an intermediate step, when the driver's torque is higher than the first adaptation information A1, the theoretical steering angle and the actual steering angle are mixed proportionally until the theoretical steering angle finally corresponds to the actual steering angle when the driver's torque information M further increases. The control error of the steering angle controller of the electromechanical steering system 2 thus becomes zero, and the torque demand of the steering system 2 servo motor can no longer be increased. To unload the controller integral component in the steering angle controller of the electromechanical steering system 2, negative feedback of the torque demand is still required using the second regulator unit.

[0123] For a driver assistance system 2 based on an angle interface with an electromechanical steering system 2, a defined component can be subtracted from the theoretical torque information of the steering angle controller within the control unit 4, rather than considering the feedback of the entire theoretical torque information of the steering angle controller in a fixed-value control device. This component is then defined based on first and second adaptation information A1, A2. When the second adaptation information (steering stiffness) is high, or the driver torque information M is still low, this component is selected higher. If the driver torque information M increases, or if less second adaptation information A2 (overriding control stiffness) is required, this component is selected lower, and its final value is 0. This method may be necessary for the operation of the steering angle controller on a steering system 2 with high dynamic characteristics, otherwise the theoretical torque of the steering angle acting on the driver would decrease prematurely and the second adaptation information A2 (overriding control stiffness) would be perceived as too low. Alternatively, the component subtracting the theoretical torque of the steering angle can also be converted into a corresponding theoretical value for the second regulator unit.

[0124] The invention has been described above with reference to embodiments. It should be noted that various modifications and variations may be made without departing from the scope of protection defined by the patent claims.

[0125] List of reference numerals

[0126] 1 System

[0127] 2. Steering System

[0128] 3. Driver Assistance Systems

[0129] 3.1 Environmental Recognition Unit

[0130] 3.2 Trajectory Planner Unit

[0131] 3.3 Trajectory Tracking Control Device

[0132] 3.4 Steering Angle Controller

[0133] 4 control units

[0134] 4.1 Measurement Unit

[0135] 4.2 Subtraction Module

[0136] 5 First regulator unit

[0137] 6 Second regulator unit

[0138] Unit 7

[0139] 8. Addition Module

[0140] 9. Addition Module

[0141] A1 First Adaptation Information

[0142] A2 Second Adaptation Information

[0143] AF activator

[0144] DI torque information

[0145] L1 First Steering Control Information

[0146] L2 Second Steering Control Information

[0147] L3 Third / Revised Steering Control Information

[0148] L4 Fourth Steering Control Information

[0149] M Driver torque information

[0150] ΔM torque difference

[0151] S1 First Interface

[0152] S2 Second Interface

[0153] SB safety barrier Theoretical steering angle information

Claims

1. A system for operating an electromechanical steering system (2) of a vehicle, the vehicle including a driver assistance system (3) designed to generate first steering control information (L1) and a control unit (4), the control unit having at least a first regulator unit (5), the control unit (4) having a first interface (S1) and at least one second interface (S2), the first interface being designed to receive driver torque information (M), the second interface being designed to receive at least one adaptation information (A1, A2) related to driving conditions and / or driving situations, the control unit (4) being designed to provide second steering control information (L2), the second steering control information being related to the driver torque information (M) and the at least one adaptation information (A1, A2). Related to this, the system (1) is designed to provide modified steering control information (L3) to the vehicle's steering system (2) based on first steering control information (L1) and second steering control information (L2), and to perform steering motion on the electromechanical steering system (2) based on the modified steering control information. At least one of the adaptation information is a variable related to driving conditions and / or driving situations. At least one of the adaptation information changes according to driving conditions and / or driving situations. The control behavior of the first regulator unit (5) is to modify the first steering control information (L1) using the second steering control information (L2) so that the torque difference (ΔM) input to the first regulator unit (5) as an input variable is reduced.

2. The system according to claim 1, characterized in that, The first steering control information (L1) is the torque information, angle information, or information proportional to the torque of the servo motor of the electromechanical steering system (2).

3. The system according to claim 1 or 2, characterized in that, The first adaptation information (A1) is the driver torque threshold, wherein the control unit (4) is designed to generate second steering control information (L2) when the value of the driver torque information (M) is higher than the driver torque threshold, which causes a correction to the first steering control information (L1) provided by the driving assistance system.

4. The system according to claim 1 or 2, characterized in that, The second adaptation information (A2) is the overriding control stiffness information, which is a measure of the steering resistance that the driver must overcome on the steering device in order to overridden the steering behavior pre-defined by the driving assistance system (3).

5. The system according to claim 4, characterized in that, The control unit (4) is designed to adapt the control behavior of the first regulator unit (5) of the control unit (4) based on the second adaptation information (A2).

6. The system according to claim 4, characterized in that, The control unit (4) is designed to receive first adaptation information (A1) and second adaptation information (A2). Of these two sets of adaptation information (A1, A2), one has a fixed value, while the value of the other set of adaptation information is related to the driving condition or driving situation, or The first adaptation information (A1) and the second adaptation information (A2) are related to driving conditions or driving situations.

7. The system according to claim 3, characterized in that, The control unit (4) is configured such that if the magnitude (M) of the driver torque information is less than or equal to the driver torque threshold, the torque difference (ΔM) received by the first regulator unit (5) is zero, and once the magnitude of the driver torque information exceeds the driver torque threshold, the torque difference has a value of the magnitude of the driver torque information minus the driver torque threshold.

8. The system according to claim 1 or 2, characterized in that, The first regulator unit (5) has a monotonically decreasing magnitude characteristic curve above the cutoff frequency.

9. The system according to claim 8, characterized in that, The first regulator unit (5) has control behavior according to the PT1 controller.

10. The system according to claim 1 or 2, characterized in that, In the case where the first steering control information (L1) is angle information, yaw rate information or curvature information, a second regulator unit (6) is pre-set. This second regulator unit is designed to convert the theoretical torque information of the steering angle controller of the servo motor used in the electromechanical steering system (2) or information that has a proportional relationship with the theoretical torque information into steering angle information, yaw rate information or curvature information as the second steering control information (L2).

11. The system according to claim 10, characterized in that, The second regulator unit (6) is designed to receive theoretical torque information of the steering angle controller for the servo motor of the electromechanical steering system (2) using an activation factor (AF), wherein the activation factor (AF) is provided by the first regulator unit (5).

12. The system according to claim 10, characterized in that, The second regulator unit (6) is designed to receive the second adaptation information (A2) and adapt the control behavior of the second regulator unit (6) based on the second adaptation information (A2).

13. The system according to claim 10, characterized in that, The second regulator unit (6) has a numerical characteristic curve that decreases monotonically above the cutoff frequency and / or according to the control behavior of the PT1 controller.

14. A method for operating an electromechanical steering system (2) of a vehicle, said vehicle including a driver assistance system (3) designed to generate first steering control information (L1) and a control unit (4), said control unit having at least a first regulator unit (5), wherein, The control unit (4) receives driver torque information (M) applied to the steering device by the driver and receives at least one adaptation information (A1, A2) related to the driving condition and / or driving situation. The control unit (4) provides second steering control information (L2) related to the driver torque information (M) and the at least one adaptation information (A1, A2). The system (1) provides modified steering control information (L3) to the vehicle's steering system (2) based on the first steering control information (L1) and the second steering control information (L2). Based on the modified steering control information, the system performs steering motion on the electromechanical steering system (2). At least one of the adaptation information is a variable related to the driving condition and / or driving situation. At least one of the adaptation information changes according to the driving condition and / or driving situation. The control behavior of the first regulator unit (5) is to modify the first steering control information (L1) using the second steering control information (L2) so that the torque difference (ΔM) input to the first regulator unit (5) as an input variable is reduced.

Images