Vehicle monitoring strategy for detecting unintended acceleration during speed control

Abstract

Vehicle monitoring strategy for detecting unintended acceleration during speed control. The invention relates to a method of detecting unintended acceleration of a motor vehicle in a closed loop speed control mode by determining external forces on the vehicle via a controller and then using the measured vehicle speed and these external forces to calculate a desired acceleration. The method includes determining an actual acceleration of the vehicle including filtering a speed signal to a first actual acceleration value and / or using an inertial measurement unit (IMU) to measure a second actual acceleration value. During the speed control mode, the method includes calculating an acceleration change value from a difference between the desired acceleration and the actual acceleration and then using the acceleration change value to detect unintended acceleration during the speed control mode. A powertrain system for a motor vehicle (e.g., an electric vehicle) includes a controller and one or more torque producing devices coupled to road wheels of the vehicle.

Description

Background Technology

[0001] The vehicle powertrain includes an internal combustion engine and / or one or more rotating electric motors. Battery electric vehicles and hybrid electric vehicles specifically include one or more high-voltage electric propulsion motors, each with its output shaft connected, for example, via a corresponding drive axle, to one or more road wheels. When the propulsion motor is energized by a multi-cell battery pack, fuel cell stack, or other voltage source, output torque is delivered to the road wheels. During regenerative braking events, the electric propulsion motor, operating in its capacity as a generator, generates electricity, which is then used to recharge the components of the battery pack and / or power onboard electrical functions.

[0002] Some motor vehicle powertrain systems utilize closed-loop speed control to maintain a vehicle speed requested by the driver. Hybrid electric vehicles and battery electric vehicles may be able to execute low-speed driving modes (often called "one-pedal driving" or OPD), which allow the vehicle operator to maintain speed or bring the vehicle to a complete stop using one or more driver input devices. During speed control, releasing the accelerator pedal or brake, or activating the regen-on-demand paddle, results in a calibrated amount of regenerative resistance being applied by the propulsion motor(s) coupled to the wheels. This, in turn, has the effect of slowing the vehicle while simultaneously generating electrical energy. OPD and other closed-loop speed control modes help simplify driving tasks, especially in stop-and-go traffic. However, when used during such speed control modes, existing acceleration hazard monitoring solutions for detecting and responding to acceleration events exceeding expected thresholds may be less than optimal in terms of efficiency and false alarm modes. Summary of the Invention

[0003] This document discloses methods and accompanying systems for improving conventional acceleration-based hazard monitoring in motor vehicles, with the aim of reducing false fault conditions caused by erroneously detected unintended acceleration events. Although negative acceleration is often referred to as deceleration in the art, for the sake of simplicity, the terms "acceleration" and "acceleration event" as used herein broadly encompass both positive and negative acceleration based on speed in motor vehicles. While this teaching may be beneficial when used in open-loop torque control modes at certain higher speeds, it is particularly beneficial when implemented during closed-loop speed control modes, regardless of vehicle speed. Such speed control modes are illustrated herein, but are not limited to the aforementioned one-pedal driving control (OPD).

[0004] The acceleration-based control solutions described below with reference to the various accompanying figures specifically consider the external forces acting on the motor vehicle when determining the desired acceleration. As an illustration and not a limitation, the relevant external forces considered within the scope of this disclosure may include measured and / or calculated road loads, grade loads, vehicle mass, or other relevant external loads. For a given target speed or torque, such external forces require the application of additional drive torque from one or more onboard prime movers or torque generating devices. Without this teaching, vehicle performance may fail to convey onboard acceleration-based hazard indicators when the vehicle should be doing so, where avoidable false-failure results may lead to a "dead pedal" condition and / or the need to initiate a new key cycle.

[0005] As those skilled in the art will understand, motor vehicles equipped with OPD capability or other closed-loop speed control modes often rely on a propulsion controller to determine the commanded acceleration. The commanded acceleration is typically derived by dividing the commanded output torque determined by the propulsion controller by the static vehicle mass value. The desired acceleration can be calculated using a calibrated pedal diagram with the same nominal mass value. When an acceleration hazard is detected, the controller then compares the commanded acceleration value with the desired acceleration. This method aims to improve upon this approach by using actual acceleration values ​​instead of the aforementioned commanded acceleration, and also by taking into account the external forces acting on the motor vehicle when determining the desired acceleration as described above.

[0006] In a particular embodiment, a method for detecting unexpected acceleration of a motor vehicle during a closed-loop speed control mode (such as OPD) includes: calculating a desired acceleration via a controller using a speed profile of the motor vehicle. The method also includes determining the actual acceleration. This may require measuring the vehicle speed, deriving a speed profile from the measured speed, and differentiating the speed profile to determine the desired acceleration. During the closed-loop speed control mode, the controller calculates an acceleration change (delta) value in real time based on the difference between the desired acceleration and the actual acceleration. The controller then uses the acceleration change value to detect unexpected acceleration during the speed control mode.

[0007] Determining the actual acceleration of a motor vehicle may include one or both of the following: filtering the measured speed signal of the motor vehicle based on the measured vehicle speed and a derived speed profile to generate a first speed signal, then differentiating the first speed signal to generate a first actual acceleration value, and / or using an inertial measurement unit (IMU) or other suitable sensors(s) to measure a second actual acceleration value. Filtering the speed signal may include using a Kalman filter or alternatively a low-pass filter or another filter suitable for application in different embodiments to filter the output signal from the speed sensor. Differentiating the resulting speed signal yields the first actual acceleration value.

[0008] Calculating the desired acceleration within the scope of this disclosure may include determining external forces on a motor vehicle, including measuring and / or calculating road loads, gradient loads, mass loads, and / or braking loads in possible embodiments.

[0009] This method may include temporarily reducing the output torque and / or output speed of the powertrain system until, or before, the powertrain system may be disabled. This remedial action may occur when the acceleration change exceeds a calibration threshold indicating unexpected acceleration or OPD capability.

[0010] The motor vehicle includes an electric propulsion motor and one or more driver input devices, typically an accelerator pedal, a brake pedal, and possibly on-demand regenerative paddles. The driver input devices respond to operator requests. In a possible use case, the speed control mode is the OPD mode described above, where, in this case, the speed of the electric traction motor is controlled below a threshold angular velocity only in response to operator requests provided via the driver input devices.

[0011] This document also discloses a powertrain system for a motor vehicle. Embodiments of the powertrain system include at least one torque generating device (e.g., an internal combustion engine and / or a rotary electric motor) and a controller. Each torque generating device is operatively coupled to a set of wheels of the motor vehicle. The controller is configured to detect unexpected acceleration (positive or negative in direction) of the motor vehicle during a closed-loop speed control mode. Execution of instructions by the controller causes the controller to perform the methods described above.

[0012] Additionally, aspects of this disclosure include an electric vehicle having the aforementioned controller, a plurality of driver input devices, wheels, and torque generating devices coupled to one or more of the wheels. The controller is configured to perform the method.

[0013] The present invention also provides the following technical solutions.

[0014] 1. A method for detecting unexpected acceleration of a motor vehicle during a closed-loop speed control mode, the motor vehicle having a powertrain system having at least one torque generating device, the method comprising:

[0015] The controller determines the measured speed of the motor vehicle and the external forces acting on the motor vehicle together.

[0016] The desired acceleration is calculated via the controller using the measured velocity and the external force.

[0017] Determining the actual acceleration of the motor vehicle includes filtering the velocity signal to a first actual acceleration value and / or using the inertial measurement unit (IMU) of the motor vehicle to measure a second actual acceleration value;

[0018] During the closed-loop speed control mode, the acceleration change value is calculated based on the difference between the desired acceleration and the actual acceleration; and

[0019] During the speed control mode, the unexpected acceleration is detected by using the acceleration change value via the controller.

[0020] 2. The method according to technical solution 1, wherein determining the external forces acting jointly on the motor vehicle includes measuring and / or calculating the gradient load and / or road load of the motor vehicle.

[0021] 3. The method according to technical solution 2, wherein determining the external forces acting jointly on the motor vehicle includes measuring and / or calculating the mass load and / or braking load of the motor vehicle.

[0022] 4. The method according to technical solution 1, wherein determining the actual acceleration of the motor vehicle includes: filtering the measured speed to obtain a first speed signal, differentiating the first speed signal to generate a first actual acceleration value, using the IMU to measure a second actual acceleration value, and calculating the actual acceleration as a weighted function of the first actual acceleration value and the second actual acceleration value.

[0023] 5. The method according to technical solution 4, wherein filtering the measured speed signal includes filtering the speed signal using a Kalman filter.

[0024] 6. The method according to technical solution 1, further comprising:

[0025] When the acceleration change exceeds the calibration threshold indicating the unexpected acceleration, the output torque and / or output speed of the powertrain system are temporarily reduced via the controller.

[0026] 7. The method according to technical solution 1, wherein the method further comprises:

[0027] The speed of the motor vehicle is measured using a rotary encoder and / or wheel speed sensor of the motor vehicle.

[0028] 8. The method according to technical solution 1, wherein the motor vehicle includes at least one driver input device, and wherein the speed control mode is a one-pedal driving mode, wherein the speed of the motor vehicle is controlled only in response to the state of the at least one driver input device.

[0029] 9. A powertrain system for a motor vehicle, the powertrain system comprising:

[0030] At least one torque generating device coupled to a set of wheels of the motor vehicle; and

[0031] A controller is configured to detect unexpected acceleration of the vehicle during closed-loop speed control mode via the execution of a command, wherein the execution of the command causes the controller to:

[0032] Identify the external forces acting together on the motor vehicle;

[0033] The desired acceleration of the motor vehicle is calculated using the external force and the measured speed of the motor vehicle.

[0034] Determining the actual acceleration of the motor vehicle includes filtering the velocity signal to a first actual acceleration value and / or using the inertial measurement unit (IMU) of the motor vehicle to measure a second actual acceleration value;

[0035] During the speed control mode, the acceleration change value is calculated based on the difference between the desired acceleration and the actual acceleration;

[0036] During the speed control mode, the acceleration change value is used to detect the unexpected acceleration; and

[0037] The dynamic state of the motor vehicle is controlled in response to the unexpected acceleration.

[0038] 10. The powertrain system according to technical solution 9, wherein the execution of the command causes the controller to determine the external forces acting jointly on the motor vehicle by using corresponding sensors to measure and / or calculate the gradient load and / or road load of the motor vehicle.

[0039] 11. The powertrain system according to technical solution 9, wherein the execution of the command causes the controller to determine the external forces acting jointly on the motor vehicle by determining the mass load and / or braking load of the motor vehicle.

[0040] 12. The powertrain system according to technical solution 9, wherein the motor vehicle includes the IMU, and wherein the execution of the command causes the controller to determine the actual acceleration of the motor vehicle by: filtering the speed signal to obtain a first speed signal, differentiating the first speed signal to obtain a first actual acceleration value, using the IMU to measure a second actual acceleration value, and calculating the actual acceleration as a weighted function of the first actual acceleration value and the second actual acceleration value.

[0041] 13. The powertrain system according to technical solution 12, wherein the execution of the command causes the controller to filter the speed signal of the motor vehicle through a Kalman filter to determine the first actual acceleration value.

[0042] 14. The powertrain system according to technical solution 9, wherein the controller is configured to temporarily reduce the output torque and / or output speed of the powertrain system when the acceleration change value exceeds a calibration threshold indicating the unexpected acceleration.

[0043] 15. The powertrain system according to technical solution 9, further comprising:

[0044] A transmission, which has an output component;

[0045] A set of wheels;

[0046] A rotary encoder, positioned on or near the input component of the transmission; and

[0047] A wheel speed sensor is connected to at least one of the traveling wheels, wherein the measured speed is one or both of the following: the rotational speed of the output member, as measured by the rotary encoder; and the rotational speed of the at least one of the traveling wheels, as measured by the wheel speed sensor.

[0048] 16. The powertrain system according to technical solution 9, wherein the speed control mode is a one-pedal driving mode, wherein the controller is configured to control the speed of the motor vehicle only in response to actuation of a driver input device, and wherein the driver input device is an accelerator pedal, a brake pedal and / or an on-demand regenerative paddle shifter.

[0049] 17. An electric vehicle comprising:

[0050] Controller;

[0051] A driver input device, which includes one or more of an accelerator pedal, a brake pedal, and on-demand regeneration paddles;

[0052] Wheels; and

[0053] An electric propulsion motor, which is connected to one or more of the walking wheels;

[0054] The controller is configured to detect unexpected acceleration of the electric vehicle during one-pedal driving (OPD) mode, a closed-loop speed control mode, during which the controller adjusts the rotational speed of the electric propulsion motor to below a threshold speed only in response to actuation of the driver input device, and the controller is configured to:

[0055] Determine the common external forces acting on the electric vehicle;

[0056] The desired acceleration of the electric vehicle is calculated using the external force and the measured speed of the electric vehicle.

[0057] Determining the actual acceleration of the motor vehicle includes: filtering a speed signal to obtain a first speed signal and differentiating the first speed signal to generate a first actual acceleration value; and using the inertial measurement unit (IMU) of the electric vehicle to measure a second actual acceleration value.

[0058] During the speed control mode, the acceleration change value is calculated based on the difference between the desired acceleration and the actual acceleration;

[0059] During the closed-loop speed control mode, the acceleration change value is used to detect the unexpected acceleration; and

[0060] In response to the unexpected acceleration, control actions are performed on the electric propulsion motor, thereby changing the dynamic state of the electric vehicle.

[0061] 18. The electric vehicle according to technical solution 17, wherein the control action includes temporarily reducing the output torque and / or output speed of the electric propulsion motor as the dynamic state.

[0062] 19. The electric vehicle according to technical solution 17, wherein the controller is configured to:

[0063] The measured speed signal is filtered by a Kalman filter to determine the actual acceleration of the motor vehicle.

[0064] 20. The electric vehicle according to claim 17, wherein the controller is configured to determine each of the following as the external force: gradient load, road load, mass load and braking load of the electric vehicle.

[0065] The above summary does not represent every embodiment or aspect of this disclosure. The foregoing features and advantages, as well as other possible features and advantages, will readily become apparent from the following detailed description of embodiments and preferred modes for carrying out this disclosure, when taken in conjunction with the accompanying drawings and claims. Furthermore, this disclosure expressly includes combinations and sub-combinations of the elements and features presented above and below. Attached Figure Description

[0066] Figure 1 This is a schematic illustration of an exemplary motor vehicle having a powertrain system including a controller, wherein the controller is configured to detect unexpected positive or negative acceleration of the motor vehicle during a closed-loop speed control mode using the methods described herein.

[0067] Figure 2 This is a flowchart describing an exemplary embodiment of the method.

[0068] Figure 3 This is a schematic logic flowchart illustrating an embodiment of the control strategy. Detailed Implementation

[0069] This disclosure allows for many different forms of embodiments. Representative examples of this disclosure are shown in the accompanying drawings and are described in detail herein as non-limiting examples of the disclosed principles. For that purpose, elements and limitations described in the abstract, introduction, summary, and detailed description but not expressly set forth in the claims should not be incorporated into the claims individually or collectively by implication, inference, or otherwise.

[0070] For the purposes of this description, unless explicitly waived, the use of the singular includes the plural, and vice versa; the terms “and” and “or” should both be connected and separate; “any” and “all” should both mean “any and all”; and the words “including,” “contains,” “includes,” “has,” etc., should mean “including but not limited to.” Furthermore, words of approximate estimation (such as “about,” “almost,” “substantially,” “generally,” “approximately,” etc.) may be used herein in the sense of “for, close to, or almost…”, or “within 0-5% of…” or “within acceptable manufacturing tolerances”, or logical combinations thereof.

[0071] Referring to the accompanying drawings, similar reference numerals refer to similar parts. Figure 1A motor vehicle 10 is schematically depicted having a powertrain system 11 coupled to a set of wheels 14. The motor vehicle 10 is capable of operating in a closed-loop speed control mode, such as a single-pedal driving (OPD) mode or another closed-loop speed control mode that is typically, but not necessarily, executed below critically low vehicle speeds. As part of this disclosure, a controller (C) 35 is configured to monitor the motor vehicle 10 and its resident powertrain system 11 for sustained acceleration-based hazardous behavior during speed control modes in response to unexpected positive or negative acceleration (positive or negative, as described above), wherein the teachings may be extended to open-loop torque control modes occurring at higher vehicle speeds.

[0072] Acceleration-based hazard monitoring performed according to this disclosure occurs in real time using method 100, as described below. Figure 2 A representative embodiment of the method is described below. The controller 35 may execute appropriate dynamic and / or logical state change control actions regarding the powertrain system 11 in response to monitoring results, such as when method 100 reveals that an acceleration threshold (e.g., 0.2-0.4g within 400-600 ms, or another threshold suitable for the application) has been exceeded. The associated control logic 50L suitable for implementing method 100 is programmed in the memory (M) of the controller 35 and executed using one or more processors (P) in a manner described below.

[0073] As part of its programming capabilities, Figure 1 The controller 35 shown can receive input signals from one or more driver input devices 13 (arrow CC) I ), of which these input signals (arrow CC) I This indicates an output speed request and / or torque request. For example, sensor 124A of accelerator pedal 24A and sensor 124B of brake pedal 24B can respectively generate corresponding acceleration request signals (arrow A). X ) and braking request signal (arrow B) X Alternatively, the on-demand regeneration dial 24P can generate an OTP request signal (arrow P). X Especially during OPD operation, for example, when rotating the motor (M) E 12. When the internal combustion engine 17 and / or another torque generating device 23 are used as part of the powertrain system 11, the operator may exclusively use the driver input device 13 to control the speed of the motor vehicle 10. For example, releasing the accelerator pedal 24A below a critical low speed may have the effect of slowing down and eventually stopping the motor vehicle 10.

[0074] Additional input signals to controller 35 within the scope of this disclosure (arrow CC) IThe acceleration values ​​(arrow A2) may be measured from an inertial measurement unit (IMU) 324, such as one or more accelerometers configured to measure longitudinal acceleration, and possibly lateral acceleration, pitch, yaw, and roll (if required). External load sensors (224) collectively measure and report indications of external forces (F) on the motor vehicle 10. EXT The value of ) is used to achieve the purpose of determining the desired acceleration as described herein. Exemplary measured and / or calculated forces on the motor vehicle 10 may include road loads, gradient loads, mass loads, and / or braking loads of the motor vehicle, wherein the latter may be notified by a braking request signal (arrow B). X ).

[0075] The controller 35 may also include a filter (F) configured to receive, for example, a measured speed signal (arrow N) indicating the ground speed of the motor vehicle 10 from one or more speed sensors 21S (e.g., a resolver or rotary encoder, wheel speed sensor, etc.). 10 See below for reference. Figure 2 and Figure 3 In detail, the filter F outputs a first actual acceleration value (A1), while the IMU 324 outputs a second actual acceleration value as the aforementioned acceleration value A2, wherein, when performing this method 100, the controller 35 uses these acceleration values ​​A1 and / or A2 in the disclosed manner.

[0076] exist Figure 1 In the exemplary configuration illustrated (where the motor vehicle 10 is embodied as a hybrid electric vehicle), the engine 17 has a plurality of engine cylinders 17C. Although for the sake of illustrative simplicity... Figure 1 The present invention depicts a single rotary motor 12, but those skilled in the art will appreciate that other battery-electric or hybrid-electric configurations of the powertrain system 11 can be readily envisioned within the scope of this disclosure, such as using more than one rotary motor 12, more than two powered wheels 14, previously using an engine 17, etc.

[0077] In a non-limiting hybrid electric embodiment of the motor vehicle 10, the motor output torque (arrow T) from the output shaft 19 of the motor 12 M ) and / or engine torque from engine 17 (arrow T) E The torque can be guided to the transmission (T) 20 via the transmission input member 21 as input torque (arrow T). I Then, the output torque from transmission 20 (arrow T) O The power is transmitted via output member 121 to one or more drive axles 22, and from there to one or more of the wheels 14. Engine 17 can be transmitted via input clutch C. I(For example, a friction clutch or hydraulic torque converter assembly) is selectively connected to and disconnected from the input member 21.

[0078] In a representative multiphase / alternating current (AC) embodiment, the rotating motor 12 includes a stator 12S arranged coaxially with the rotor 12R in a typical radial flux configuration, wherein this teaching can also be extended to an axial flux configuration. When the motor 12 is configured as an AC machine as shown, the powertrain system 11 may include an on-board power supply, which is depicted as a high-voltage traction battery pack (B... HV 15, for example, a multi-cell rechargeable lithium-ion battery pack. In other embodiments, a fuel cell system or another suitable power source may be used. While the term “high voltage” is relative to a typical 12-15 V auxiliary voltage level, and therefore may require voltage levels higher anywhere, the exemplary battery electrification propulsion applications of the type contemplated herein may require the battery pack 15 to have a voltage capability of 300-500 V or higher.

[0079] Instructions for implementing method 100 are stored in memory (M) and are executed by one or more processors (P) in response to input signals (arrow CC). I The controller 35 executes these instructions in real time. During instruction execution, the controller 35 outputs a signal (arrow CC). O The controller 35 may perform preemptive or responsive control actions to achieve specific control outcomes, such as shutting down the powertrain system 11, recording diagnostic codes, generating text messages, illuminating indicator lights within the vehicle 10, or performing various other possible control actions, in different embodiments. Although omitted for simplicity, the controller 35 may include one or more electronic control modules, units, processors, and their associated hardware components, and will be equipped with sufficient tangible and intangible variants of memory (M), application-specific integrated circuits (ASICs), system-on-a-chip (SoCs), input / output circuitry, high-speed clocks or oscillators, and other hardware and software as needed to provide the desired functionality.

[0080] Still referencing Figure 1The battery pack 15 is electrically connected to the power inverter module (PIM) 16 via a high-voltage DC voltage bus (VDC), whereby the PIM 16 is in turn electrically connected to the stator 12S via a high-voltage AC voltage bus (VAC). Although omitted for illustrative simplicity, the PIM 16 is internally constructed and externally controlled via the on / off state control of multiple dies of semiconductor switches, typically embodied as IGBTs or MOSFETs. Thus, the DC input voltage to the PIM 16 is inverted and controlled by high-speed pulse-width modulation or other suitable switching operations to ultimately deliver an AC output voltage and corresponding phase currents (Ia, Ib, Ic). In regenerative events such as braking, the PIM 16 can operate in the reverse manner, i.e., by converting the AC input voltage into a DC output voltage suitable for recharging the constituent battery cells of the battery pack 15.

[0081] Other components may be as follows Figure 1 The connections shown include, but are not limited to, the illustrated DC-DC converter / auxiliary power module (APM) 25, and connections at lower auxiliary voltages (V). AUX Lead-acid or other types of auxiliary batteries operating under (B) AUX 26. As mentioned above, the auxiliary voltage level is typically 12-15 V, and therefore, as is well known in the art, the APM 25 can be operated via internal switching and signal filtering to receive a relatively high DC voltage from the DC voltage bus (VDC) and convert the auxiliary voltage (V... AUX The output is sent to the auxiliary battery 26. Therefore, the motor 12 is only one of several devices that need to reliably and continuously supply electrical energy from the battery pack 15 during the continuous propulsion operation of the motor vehicle 10.

[0082] Now for reference Figure 2 Method 100 is configured to detect unexpected acceleration (positive or negative) of the motor vehicle 10 during a closed-loop speed control mode. The aforementioned one-pedal driving (OPD) operation represents this speed control mode. Method 100 can be used in embodiments of the motor vehicle 10 having a powertrain system 11, i.e., a motor vehicle having at least one torque generating device 13 (in this case, a rotary motor 12 and an engine 17), or the motor vehicle 10 can use either the motor(s) 12 or the engine 17 alone. Method 100 can be executed with the aid of control logic 50L, a representative embodiment of which is described in... Figure 3 It is shown in the figure and described below.

[0083] Starting from logic block B102, method 100 includes: via Figure 1 The controller 35 uses the derived velocity curve of the motor vehicle 10 to calculate the desired acceleration (“CALC A”).DES This speed curve can be used with the measured speed signal during the driving cycle (arrow N). 10 This can be generated, such as by recording the measured velocity as a velocity trajectory over time according to the calibrated sampling interval.

[0084] As part of method 100, logic block B102 also needs to measure or otherwise determine the external forces acting on the motor vehicle 10. Figure 1 F EXT The external forces may include road loads, gradient loads, mass loads, and / or braking loads of the motor vehicle 10. Measurements and / or calculations indicating such forces can be collected in real time during operation of the motor vehicle 10 and transmitted to the controller 35 using a controller area network or other suitable wired or wireless transmission conductor. The controller 35 then takes the external forces (F) into account. EXT The desired acceleration is calculated using the following method. Once the desired acceleration is determined, method 100 proceeds to logic block B104.

[0085] Logic block B104 (“DET A1, A2”) includes: a speed signal (N) of the motor vehicle 10 measured by filter F based on the speed curve described above in logic block B102. 10 The speed signal of the motor vehicle 10 (arrow N) is filtered to produce a first speed value, and then the derivative of the first speed value is calculated to produce a first actual acceleration value (A1). In another embodiment, the speed signal of the motor vehicle 10 (arrow N) is filtered to produce a first speed value, and then the derivative of the first speed value is calculated to produce a first actual acceleration value (A1). 10 Filtering can be performed using a Kalman filter or another suitable filter, such as, but not limited to, a low-pass filter. Logic block B104 may also include: using Figure 1 The IMU 324 shown, or another suitable sensor, is used to measure the second actual acceleration value (A2). While in some embodiments either the filter (F) or the IMU 324 may be used alone, using both together can provide a fidelity advantage, for example, by using a weighted average of these values. Method 100 then proceeds to logic block B106.

[0086] Figure 2 Logic block B106 (“CALC ΔA”) includes: during closed-loop speed control mode, using controller 35 to calculate the acceleration change value. As used herein, the acceleration change value is the difference between the desired acceleration determined at logic block B102 and a first actual acceleration value (A1) and / or a second actual acceleration value (A2). When the motor vehicle 10 includes an accelerator pedal 24A, for example, the closed-loop speed control mode may be the aforementioned OPD mode, wherein only in response to the accelerator pedal 24A or Figure 1The described driver input device 13 is actuated to closely control the rotational speed of the torque generating device(s) 13. Once the acceleration change value has been derived, method 100 proceeds to logic block B108.

[0087] At logic block B108, Figure 1 The controller 35 then uses the acceleration change value from logic block B106 to detect unexpected acceleration events during speed control mode. In a possible implementation, the controller 35 may compare the acceleration change value with a calibrated acceleration threshold (“…”). Exceeding this threshold will indicate unintended acceleration of the motor vehicle 10, which may trigger the control action described below. When an unintended acceleration event is detected, method 100 proceeds to logic block B110, and alternatively, if no unintended acceleration is detected, logic block B102 is repeated.

[0088] Figure 2 Logic block B110 includes: via Figure 1 The controller 35 performs a control action (“EXEC CA”) in response to a detected unexpected acceleration event. This control action may include altering the dynamic state of the vehicle 10 while allowing limited functionality of the powertrain system 11, including, where possible, reducing the output torque of the powertrain system 11. Figure 1 Arrow T O ) and / or the operating output speed of the motor vehicle 10, the latter being the measured vehicle speed (arrow N) 10 In a more aggressive dynamic state change control action, controller 35 may include temporarily and completely disabling the powertrain system 11 when the acceleration change value of logic block B106 exceeds a calibration threshold indicating unexpected acceleration (e.g., 0.1-0.3 g within approximately 300-600 ms, approximately 0.2 g within 500 ms, etc.). However, in cases where complete disabling of the powertrain system 11 is not achieved (e.g., when approaching but not exceeding the acceleration danger limit), as a remedial action suitable for the application, controller 35 may simply record a diagnostic code indicating approaching the acceleration-based danger limit, or controller 35 may transmit a text message to an operator and / or a remote server, illuminate indicator lights (not shown) within the vehicle 10, etc.

[0089] Now for reference Figure 3 In a possible embodiment, control logic 50L for implementing method 100 is shown. Although schematically depicted as additional logic blocks B52-B74, those skilled in the art will understand that each component logic block can be implemented as a set of computer-readable instructions or code, associated input / output hardware, signal processing means, and Figure 1The aforementioned memory (M) and processor (P).

[0090] Figure 3 logic block B52 ("DET F") EXT ) is used to measure, calculate or otherwise detect the action of Figure 1 External forces on the motor vehicle 10, as described above, may include road loads, gradient loads, mass loads, and / or braking loads on the motor vehicle 10. Figure 1 As depicted, various external force sensors 224 can be used to measure some of these values ​​(e.g., the tilt angle of the road surface or motor vehicle 10 relative to it for calculating slope loads), while other values ​​(such as mass loads and road loads) can be calibrated, calculated, and / or reported to the controller 35. As is understood in the art, braking force can also be obtained from the brake request signal (arrow B). X The external force (arrow F) is derived from this. Once measured or otherwise determined in this way, the external force is... EXT It is then fed into logic block B54.

[0091] Logic block B53 is used to generate the desired torque (T) DES The torque target is determined by the propulsion control unit of a given motor vehicle, as will be understood by those skilled in the art. Therefore, the controller 35 described herein determines this value as part of its normal operating functions. This is used to determine the desired torque (T). DES The inputs include acceleration request signals and braking request signals. Figure 1 Arrow A X and B X ), measured vehicle speed (N) 10 ), the mass of the motor vehicle 10, etc. Expected torque (T) DES It is fed into logic block B54.

[0092] Controller 35 uses logic block B54 to generate the desired speed (N). DES The speed target is in the form of ) . The inputs to logic block B54 include: (a) the desired torque (T) from logic block B53 described above. DES (a) and (b) external forces (F) from logic block B52 EXT In an exemplary embodiment, the desired torque (T) can be used. DES ) and external force (F) EXT The desired speed (N) can be derived by using a lookup table or calculation. DES Then, these expected velocities (N) DES They are fed into logic blocks B56 and B60, as described below.

[0093] Logic block B56 receives the desired speed (N) as input from logic block B54. DES ), and thereafter generates a velocity-based desired acceleration (A DES-NB As is known in the art, the currently measured vehicle speed (N) 10 ) and desired speed (N) DES This knowledge allows controller 35 to determine how much acceleration is needed, again, "acceleration" has a positive or negative direction. This value is then fed into logic block B59.

[0094] At logic block B57, controller 35 receives the desired torque (T) from logic block B53. DES And generate the desired acceleration (A) based on torque. DES-TB The velocity-based expected acceleration (A) DES-NB The value is fed into logic block B59.

[0095] Logic block B58 is used to determine the vehicle control type, i.e., closed-loop speed control or open-loop torque control. The decision on which control type to use can be encoded as a simple speed-based decision, such as automatically or in response to an operator request when operating below a threshold speed (e.g., 10 kPH) or at higher speeds. The controller 35 then outputs control signals, such as bit flag 1 corresponding to torque control (T) or bit flag 0 corresponding to speed control (N), or vice versa, where such values ​​are communicated to logic blocks B59, B60, B70, and B72.

[0096] At logic block B59, controller 35 then takes the torque-based value (A) from logic block B57. DES-TB ) and acceleration-based values ​​from logic block B56 (A DES-NB Arbitration is performed between the desired acceleration values. This decision is made in response to the output from logic block B58, i.e., the open-loop torque control (type T) corresponds to using a torque-based value (A). DES-TB ), and closed-loop speed control (type N) corresponds to using speed-based values ​​(A). DES-NB Therefore, logic block B59 will expect acceleration (A). DES It is output to logic block B72 as one of two possible separately calculated values.

[0097] Still referencing Figure 3 In this embodiment, logic block B60 receives three inputs: the desired speed (N) from logic block B54. DES ), the expected torque (T) from logic block B53 DESThe output of logic block B58 indicates the specific vehicle control type (i.e., closed-loop speed control (N-type) or open-loop torque control (T-type)). Using logic block B60, controller 35 generates a command torque (T-type) based on either the closed-loop speed target or the open-loop torque target. CC ), of which the command torque (T) CC The command torque (T) is provided as input to logic block B70. In the battery-electric vehicle embodiment of motor vehicle 10, for example, the command torque (T) is provided as input. CC ) can be Figure 1 The command output torque of motor 12, or command torque (T) CC This may include multiple control signals for multiple different torque actuators, as will be understood by those skilled in the art.

[0098] Logic block B62 needs to use Figure 1 A filter (F) is used to generate vehicle acceleration values. In a particular embodiment, the filter (F) is or includes a Kalman filter. In other embodiments, the filter used at logic block B62 may include a low-pass filter or a filter capable of generating vehicle acceleration values ​​from the indicated measured vehicle speed (N). 10 This is another suitable filter for removing noise from the vehicle speed signal of the vehicle 10. Therefore, logic block B62 needs to filter and differentiate the speed signal of the vehicle 10 (e.g., according to the speed signal from the vehicle 10). Figure 1 The speed sensor 21S shown measures the vehicle speed (N). 10 The determined velocity curve is used to determine the first actual acceleration value (A1). The first actual acceleration value (A1) is fed as input to logic block B70.

[0099] Logic block B64 needs to generate vehicle acceleration based on accelerometer readings. For this purpose, logic block B64 can utilize... Figure 1 The IMU 324 shown here, i.e., its corresponding lateral and longitudinal acceleration measurements, as well as possible pitch, roll, and yaw values, are further refined in the calculation. Therefore, logic block B64 may need to use IMU 324 to measure a second actual acceleration value (A2) and then transmit the measurement result to controller 35.

[0100] At logic block B70, controller 35 then adjusts the commanded acceleration (A) between torque and speed. CC Arbitration is performed. That is, depending on the vehicle control type (T or N) determined at logic block B58, the command torque (T) from logic lock B60 is used for arbitration. CC ) is one of two different values. When operating in closed-loop speed control mode (e.g., single-pedal driving), logic block B70 will command acceleration (A) based on the closed-loop speed target applied at logic block B60.CC Output to logic block B72.

[0101] Command acceleration (A) from logic block B70 CC ) is the command torque (T) from logic block B60. CC The method 100 determines the actual acceleration value (A1, A2) and the actual acceleration value (A2). Value A1 or A2 can be used alone, or both values ​​A1 and A2 can be used together, for example, by averaging them with equal weights to provide a specific confidence level. Similarly, the vehicle 10 may not be equipped with an IMU 324, or the IMU 324 may be unavailable or in a fault mode at times; in such cases, the method 100 may use the second actual acceleration value (A2) alone.

[0102] At logic block B72, the desired acceleration (A) from logic block B59 is determined. DES ) and the actual acceleration (A) from logic block B70 CC )hour, Figure 1 The controller 35 analyzes vehicle performance against calibrated hazard indicators. As part of logic block B72, the controller 35 calculates the acceleration change value based on the difference between the following two (see...). Figure 2 Logic block B106: Expected acceleration (A) DES Whether it is based on torque or acceleration depends on the arbitration result at logic block B59; and the command acceleration (A) from logic block B70. CC It is also based on the torque or speed target from logic block B58, which depends on the vehicle control type (T or N).

[0103] Additionally, at logic block B72, controller 35 uses the acceleration change value to detect unexpected acceleration. For example, during speed control maneuvers such as one-pedal driving, controller 35 may compare the acceleration change value to a calibrated acceleration threshold, such as 0.2g-0.4g within 300-600 ms. While particularly useful at low speeds (where the operator and passengers of motor vehicle 10 may notice the threshold acceleration), this teaching can be advantageously used in an open-loop torque control mode at higher speeds, as will be understood by those skilled in the art. In response to the acceleration change value exceeding the threshold in this manner, controller 35 may output a fault signal (FLT) to logic block B74, where the fault signal (FLT) indicates unexpected acceleration.

[0104] exist Figure 3At logic block B74, controller 35 can selectively perform control action (CA) in response to a fault signal (FLT) from logic block B72. This control action may include, as described above, reducing acceleration via controller 35 when the acceleration change exceeds a calibration threshold indicating unexpected acceleration. Figure 1 The output torque of the motor vehicle 10 shown (arrow T) O This could involve adjusting the output speed or temporarily disabling the powertrain system 11, which would require a new key-on cycle. Other suitable remedial control actions can be conceived for situations where partial or complete disabling of the powertrain system 11 is not achieved, including but not limited to recording diagnostic codes and illuminating indicator lights. Such actions can also be used when the system is very close to, but does not exceed, a threshold.

[0105] When programmed and equipped to perform method 100 as described above Figure 1 The aforementioned controller 35 provides a control strategy for the desired and commanded accelerations of the motor vehicle 10. The desired acceleration is calculated by taking into account external forces on the motor vehicle 10, while the typical commanded acceleration is replaced herein by the actual acceleration. The actual acceleration can then be estimated from speed signal measurements and / or filtering or using a state model. Using the desired and actual accelerations determined in this way, the controller 35 is able to monitor continuous vehicle performance against calibrated acceleration-based hazard indicators, primarily but not necessarily in closed-loop speed control modes, such as single-pedal driving.

[0106] Therefore, the improved hazard detection accuracy achieved using method 100 aims to reduce situations where the controller 35 shuts down the motor vehicle 10 or otherwise takes overly aggressive preemptive actions under acceleration conditions that do not actually indicate unintended acceleration. These and other benefits will be readily apparent to those skilled in the art in light of the foregoing disclosure.

[0107] The detailed description and accompanying drawings support and describe this teaching, but the scope of this teaching is defined solely by the claims. While some of the best modes and other embodiments for carrying out this teaching have been described in detail, various alternative designs and embodiments exist for practicing the teaching as defined in the appended claims. Furthermore, this disclosure explicitly includes combinations and sub-combinations of the elements and features presented above and below.

Claims

1. A method for detecting unexpected acceleration of a motor vehicle during a closed-loop speed control mode, the motor vehicle having a powertrain system including at least one torque generating device, the method comprising: The controller determines the measured speed of the motor vehicle and the external forces acting on the motor vehicle together. The desired acceleration is calculated via the controller using the measured velocity and the external force. Determining the actual acceleration of the motor vehicle includes filtering the velocity signal to a first actual acceleration value and / or using the inertial measurement unit of the motor vehicle to measure a second actual acceleration value; During the closed-loop speed control mode, the acceleration change value is calculated based on the difference between the desired acceleration and the actual acceleration; as well as During the speed control mode, the unexpected acceleration is detected via the controller using the acceleration change value. When the acceleration change exceeds the calibration threshold indicating the unexpected acceleration, a control action is executed via the controller. The determination of the actual acceleration of the motor vehicle includes: filtering the measured speed to obtain a first speed signal; differentiating the first speed signal to generate a first actual acceleration value; using the inertial measurement unit to measure a second actual acceleration value; and calculating the actual acceleration as a weighted function of the first actual acceleration value and the second actual acceleration value. The determination of the external forces acting on the motor vehicle includes measuring and / or calculating the road load, gradient load, mass load, and / or braking load of the motor vehicle.

2. The method according to claim 1, wherein, Filtering the measured velocity signal includes filtering the velocity signal using a Kalman filter.

3. The method according to claim 1, further comprising: When the acceleration change exceeds the calibration threshold indicating the unexpected acceleration, the output torque and / or output speed of the powertrain system are temporarily reduced via the controller.

4. The method according to claim 1, wherein the method further comprises: The speed of the motor vehicle is measured using a rotary encoder and / or wheel speed sensor of the motor vehicle.

5. The method according to claim 1, wherein, The motor vehicle includes at least one driver input device, and the speed control mode is a one-pedal driving mode, wherein the speed of the motor vehicle is controlled only in response to the state of the at least one driver input device.

6. A powertrain system for a motor vehicle, the powertrain system comprising: At least one torque generating device is connected to a set of wheels of the motor vehicle; as well as A controller is configured to detect unexpected acceleration of the vehicle during closed-loop speed control mode via the execution of a command, wherein the execution of the command causes the controller to: Identify the external forces acting together on the motor vehicle; The desired acceleration of the motor vehicle is calculated using the external force and the measured speed of the motor vehicle. Determining the actual acceleration of the motor vehicle includes filtering the velocity signal to a first actual acceleration value and / or using the inertial measurement unit of the motor vehicle to measure a second actual acceleration value; During the speed control mode, the acceleration change value is calculated based on the difference between the desired acceleration and the actual acceleration; During the speed control mode, the acceleration change value is used to detect the unexpected acceleration; and The dynamic state of the motor vehicle is controlled in response to the unexpected acceleration. The motor vehicle includes the inertial measurement unit, and the execution of the command causes the controller to determine the actual acceleration of the motor vehicle by: filtering the velocity signal to obtain a first velocity signal; differentiating the first velocity signal to obtain a first actual acceleration value; using the inertial measurement unit to measure a second actual acceleration value; and calculating the actual acceleration as a weighted function of the first actual acceleration value and the second actual acceleration value. The execution of the instruction causes the controller to determine the external forces acting on the motor vehicle by measuring and / or calculating the road load, gradient load, mass load, and / or braking load of the motor vehicle using corresponding sensors. The controller is configured to perform a control action when the acceleration change value exceeds a calibration threshold indicating the unexpected acceleration.

7. The powertrain system according to claim 6, wherein, The execution of the instruction causes the controller to filter the speed signal of the motor vehicle using a Kalman filter to determine the first actual acceleration value.

8. The powertrain system according to claim 6, wherein, The controller is configured to temporarily reduce the output torque and / or output speed of the powertrain system when the acceleration change value exceeds a calibration threshold indicating the unexpected acceleration.

9. The powertrain system according to claim 6, further comprising: A transmission, which has an output component; A set of wheels; A rotary encoder, which is positioned on the output component of the transmission; as well as A wheel speed sensor is connected to at least one of the walking wheels, wherein the measured speed is one or both of the following: the rotational speed of the output member measured by the rotary encoder; and the rotational speed of the at least one of the walking wheels measured by the wheel speed sensor.

10. The powertrain system according to claim 6, wherein, The speed control mode is a one-pedal driving mode, wherein the controller is configured to control the speed of the motor vehicle only in response to actuation of a driver input device, and wherein the driver input device is an accelerator pedal, a brake pedal, and / or an on-demand regenerative paddle.

11. An electric vehicle comprising: Controller; A driver input device, comprising one or more of an accelerator pedal, a brake pedal, and on-demand regeneration paddles; Wheels; as well as An electric propulsion motor, which is connected to one or more of the wheels; The controller is configured to detect unexpected acceleration of the electric vehicle during a one-pedal driving mode, which is a closed-loop speed control mode, during which the controller adjusts the rotational speed of the electric propulsion motor to below a threshold speed only in response to actuation of the driver input device, and the controller is configured to: Determine the common external forces acting on the electric vehicle; Identify each of the following as the external force: the gradient load, road load, mass load, and braking load of the electric vehicle; The desired acceleration of the electric vehicle is calculated using the external force and the measured speed of the electric vehicle. Determining the actual acceleration of the electric vehicle includes: filtering a speed signal to obtain a first speed signal and differentiating the first speed signal to generate a first actual acceleration value; measuring a second actual acceleration value using the inertial measurement unit of the electric vehicle; and calculating the actual acceleration as a weighted function of the first actual acceleration value and the second actual acceleration value. During the speed control mode, the acceleration change value is calculated based on the difference between the desired acceleration and the actual acceleration; During the closed-loop speed control mode, the acceleration change value is used to detect the unexpected acceleration; and In response to the unexpected acceleration, control actions are performed on the electric propulsion motor, thereby changing the dynamic state of the electric vehicle.

12. The electric vehicle according to claim 11, wherein, The control action includes temporarily reducing the output torque and / or output speed of the electric propulsion motor as the dynamic state.

13. The electric vehicle according to claim 11, wherein, The controller is configured to: The measured speed signal is filtered by a Kalman filter to determine the actual acceleration of the electric vehicle.

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