Electric vehicle single pedal control software safety mechanism
By introducing two layers of safety mechanisms into the electric vehicle single-pedal control system—torque amplitude and gradient limiting, as well as signal diagnosis and monitoring—the problem of unexpected acceleration or deceleration is solved, improving the system's safety and stability.
Patent Information
- Application Number
- CN202411071911.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-06
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2044-08-06
AI Technical Summary
The lack of safety mechanisms in the one-pedal control system of electric vehicles leads to safety hazards such as unexpected acceleration or deceleration.
A two-layer safety mechanism is adopted: a function execution layer and a function monitoring layer. The function execution layer limits torque amplitude and gradient, while the monitoring layer prevents abnormal values and takes safety measures such as torque limiting and power limiting through signal diagnosis and monitoring.
This reduces the risk of unintended acceleration or deceleration during single-pedal gliding energy recovery, improving the system's safety and stability.
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Figure CN119017949B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of automobile power assembly control technology, and in particular to a single-pedal control software safety mechanism for electric vehicles. BACKGROUND
[0002] Electric vehicles use electric motors for driving, and thus can make the electric motor work in the third quadrant, i.e., the power generation function. The excess kinetic energy during deceleration is used to generate electricity, thereby achieving kinetic energy recovery.
[0003] Kinetic energy recovery includes coasting energy recovery and braking energy recovery.
[0004] For coasting energy recovery, the commercial vehicle industry uses a fixed torque for coasting or different gears correspond to different coasting recovery torques.
[0005] Due to real-time changes in road driving conditions, a fixed coasting recovery torque may not meet the real-time deceleration requirements of the driver. Therefore, a single-pedal function is used to adjust the coasting recovery torque: the recovery torque is reduced when the accelerator pedal is depressed, the recovery torque is increased when the accelerator pedal is lifted, and the recovery torque is maximum when the accelerator pedal is not depressed. Since the single-pedal function uses the accelerator pedal signal to trigger but needs to output a negative torque, if there is no safety mechanism, unintended acceleration, unintended deceleration, and safety hazards may occur. SUMMARY
[0006] Based on the above problems, the present application provides a single-pedal control software safety mechanism for electric vehicles, which is implemented in two layers: a function execution layer and a function monitoring layer. The function execution layer mainly executes the torque amplitude limit, torque gradient limit function, and torque direction control of the VCU vehicle controller on the MCU. The function monitoring layer mainly executes the signal diagnosis of the VCU vehicle controller input signal and monitors the function execution layer. When abnormal values are detected in the function execution layer, safety measures such as torque and power limits are taken. The specific technical solutions are as follows.
[0007] A single-pedal control software safety mechanism for electric vehicles includes an L1 function execution layer and an L2 function monitoring layer arranged in a signal processing system of an electric vehicle. The signal processing system connects external signals of the electric vehicle and inputs the signals into the L1 function execution layer and the L2 function monitoring layer for fault analysis and processing. The L1 function execution layer includes:
[0008] Torque amplitude limit: prevents the VCU vehicle controller demand torque from exceeding the drive motor, power battery, or other controller limits; the demand torque after amplitude limitation is the minimum value of the coasting recovery gear torque limit and the demand coasting recovery torque:
[0009] Tl = min(Trl, Trd);
[0010] Wherein, Tl represents the demand torque after limiting the amplitude, Trl represents the torque limit of the coasting recovery gear, Trd is the demand coasting recovery torque, and min() is the minimum value function;
[0011] Torque gradient limit: prevent the demand torque gradient of the VCU vehicle controller from exceeding a reasonable range, and the demand torque after limiting the gradient is the minimum value between the difference between the current time input and the last time output and the gradient limit value added to the last time output torque:
[0012] Trgl=Trgl(k-1)+min((Tl-Trgl(k-1)),Tratel);
[0013] Wherein, Trgl represents the demand torque after limiting the gradient, Trgl(k-1) is the demand torque after limiting the gradient output at the last time, Tl represents the demand torque after limiting the amplitude, Tratel represents the torque gradient limit value, and min() is the minimum value function.
[0014] Specifically, the L2 function monitoring layer includes VCU vehicle controller input signal diagnosis and VCU vehicle controller function monitoring, and the VCU vehicle controller input signal diagnosis includes:
[0015] Signal amplitude check;
[0016] Signal reasonableness check;
[0017] Signal continuity check;
[0018] The VCU vehicle controller function monitoring includes:
[0019] VCU vehicle controller demand torque direction monitoring;
[0020] Speed acceleration monitoring;
[0021] Torque direction monitoring;
[0022] Torque offset value monitoring.
[0023] Specifically, the signal amplitude check includes:
[0024] The amplitude of the MCU feedback drive torque is checked, and if the MCU feedback drive torque is not within the drive motor execution range, a drive torque out-of-limit value fault is prompted;
[0025] The amplitude of the MCU feedback motor speed is checked, and if the MCU feedback motor speed is not within the drive motor execution range, a motor speed out-of-limit value fault is prompted.
[0026] Specifically, the signal reasonableness check includes:
[0027] The direction of the driving torque feedback by the MCU is checked, and the driving gear is set to forward gear. If the kinetic energy recovery is triggered, the driving torque feedback by the MCU is negative, otherwise the driving torque feedback by the MCU is positive.
[0028] The direction of the motor speed feedback by the MCU is checked. When the driving gear is set to forward gear, if the speed feedback by the MCU is not positive, a forward gear speed direction rationality fault is prompted. When the driving gear is set to reverse gear, if the speed feedback by the MCU is not negative, a reverse gear speed direction rationality fault is prompted.
[0029] Specifically, the signal continuity check includes: if no input signal is collected for a plurality of consecutive sampling periods, a feedback signal continuity fault is fed back.
[0030] Specifically, the VCU vehicle controller demand torque direction monitoring includes:
[0031] When the recovery function is not triggered, the VCU vehicle controller demand torque direction is positive, otherwise a demand torque direction error fault is prompted.
[0032] When the recovery function is triggered, the VCU vehicle controller demand torque direction is negative, otherwise a demand torque direction error fault is prompted.
[0033] The demand torque direction error fault is defined as a three-level fault for processing, and the MCU feedback motor DC input power is limited to 0Kw.
[0034] Specifically, the speed acceleration monitoring includes:
[0035] When the recovery function is not triggered, the MCU feedback positive torque, the motor speed acceleration is positive, and the MCU feedback current value is positive.
[0036] When the recovery function is triggered, the MCU feedback negative torque, the motor speed acceleration is negative, and the MCU feedback current value is negative.
[0037] Specifically, the torque direction monitoring includes:
[0038] When the recovery function is not triggered, the MCU feedback torque direction is positive, and the VCU vehicle controller demand torque is in the same direction.
[0039] When the recovery function is triggered, the MCU feedback torque direction is negative, and the VCU vehicle controller demand torque is in the same direction, otherwise a torque direction error fault is prompted.
[0040] The torque direction error fault is defined as a three-level fault, and the fault processing measure is to limit the MCU DC input power to 0Kw.
[0041] Specifically, the torque offset value monitoring includes:
[0042] Demand torque is less than or equal to 100Nm or greater than -100Nm, the difference between VCU vehicle controller demand torque and MCU feedback torque is less than or equal to 3Nm;
[0043] Demand torque is greater than 100Nm or less than -100Nm, the ratio of VCU vehicle controller demand torque and MCU feedback torque is greater than 0.97 or less than 1.03, otherwise the torque deviation is too large fault is prompted.
[0044] Specifically, the torque deviation fault is divided into three levels, and the fault level determination standard and processing includes:
[0045] Primary fault: demand torque is less than 100Nm, torque deviation is greater than 3Nm and less than 10Nm; the processing mode is to limit the discharge power of the power battery corresponding to the 100Nm torque of the driving motor and the like, and adjust to 70% of the original power;
[0046] Secondary fault: demand torque is less than 100Nm, torque deviation is greater than 10Nm and less than 20Nm; or demand torque is greater than 100Nm, torque deviation is greater than 3% and less than 10%; the processing mode is to limit the discharge power of the power battery corresponding to the 100Nm torque of the driving motor and the like, and adjust to 50% of the original power;
[0047] Third fault: demand torque is less than 100Nm, torque deviation is greater than 20Nm; or demand torque is greater than 100Nm, torque deviation is greater than 10%; the processing mode is to limit the MCU direct current input power to 0Kw.
[0048] The beneficial effects of the present application: the present application provides a single pedal control software safety mechanism for electric vehicles, the signal processing system connected to the external signals of the electric vehicle transmits the input signals into the L1 function execution layer and the L2 function monitoring layer arranged in the signal processing system of the electric vehicle, the L1 function execution layer and the L2 function monitoring layer analyze and process the signals, and reduce the risk of unintended acceleration or unintended deceleration in the single pedal coasting energy recovery process. BRIEF DESCRIPTION OF DRAWINGS
[0049] Figure 1 It is a whole architecture diagram of a single pedal control software safety mechanism for electric vehicles in the embodiment of the present application;
[0050] Figure 2 It is a functional schematic diagram of the L1 function execution layer in the embodiment of the present application;
[0051] Figure 3 It is a functional schematic diagram of the L2 function monitoring layer in the embodiment of the present application. DETAILED DESCRIPTION
[0052] In order to have a clearer understanding of the technical features, objectives and effects of the present application, the specific embodiments of the present application will now be described with reference to the accompanying drawings.
[0053] The present application proposes a single-pedal control safety mechanism for an electric vehicle. In the present embodiment, as shown in Figure 1 , the safety mechanism is implemented in two layers, an L1 function execution layer and an L2 function monitoring layer.
[0054] The specific functions of the L1 function execution layer are shown in Figure 2 , and include:
[0055] L1-S1 torque amplitude limitation, to prevent the demand torque of the VCU vehicle controller from exceeding the drive motor, power battery or other controller limits. The demand torque after amplitude limitation is the minimum value of the coasting recovery gear torque limit and the demand coasting recovery torque:
[0056] Tl=min(Trl,Trd)
[0057] Where Tl represents the demand torque after amplitude limitation, Trl represents the coasting recovery gear torque limit, Trd represents the demand coasting recovery torque, and min() is a minimum value function.
[0058] L1-S2 torque gradient limitation, to prevent the demand torque gradient of the VCU vehicle controller from exceeding a reasonable range;
[0059] In the present embodiment, the demand torque after gradient limitation is the minimum value between the difference between the current time input and the previous time output and the gradient limit value added to the previous time output torque.
[0060] Trgl=Trgl(k-1)+min((Tl-Trgl(k-1)),Tratel)
[0061] Where Trgl represents the demand torque after gradient limitation, Trgl(k-1) represents the demand torque after gradient limitation output at the previous time, Tl represents the demand torque after amplitude limitation, Tratel represents the torque gradient limit value, and min() is a minimum value function.
[0062] L1-S3, the coasting recovery demand torque is output to the torque structure.
[0063] In the present embodiment, the functions of the L2 function monitoring layer are shown in Figure 3 , and include the following levels:
[0064] L2-1 VCU vehicle controller input signal diagnosis:
[0065] L2-1-S1 signal amplitude check:
[0066] The amplitude of the MCU feedback torque is checked. The MCU feedback torque should be within the driving motor execution range. Otherwise, a driving torque out-of-limit value fault is reported.
[0067] The MCU feedback torque amplitude out-of-limit is defined as a first-level fault. The fault handling measure is to limit the MCU 70% DC input power.
[0068] The amplitude of the MCU feedback motor speed is checked. The MCU feedback motor speed should be within the driving motor execution range. Otherwise, a motor speed out-of-limit value fault is reported.
[0069] The MCU feedback motor speed amplitude out-of-limit is defined as a first-level fault. The fault handling measure is to limit the MCU 70% DC input power.
[0070] L2-1-S2 signal rationality check:
[0071] The direction of the MCU feedback driving torque is checked. If the driving gear is in forward gear and the kinetic energy recovery is triggered, the MCU feedback driving torque is negative. Otherwise, it is positive.
[0072] The MCU feedback driving torque direction error is defined as a third-level fault. The fault handling measure is to limit the MCU DC input power to 0Kw.
[0073] The direction of the MCU feedback motor speed is checked. If the driving gear is in forward gear, the MCU feedback speed should be positive. Otherwise, a forward gear speed direction rationality fault is reported. If the driving gear is in reverse gear, the MCU feedback speed should be negative. Otherwise, a reverse gear speed direction rationality fault is reported.
[0074] In this embodiment, the MCU feedback speed direction error is defined as a third-level fault. The fault handling measure is to limit the MCU DC input power to 0Kw.
[0075] L2-1-S3 signal continuity check:
[0076] No input signal is collected for more than 10 consecutive sampling periods, reporting a signal continuity fault.
[0077] In this embodiment, the signal continuity fault is defined as a first-level fault. The fault handling measure is to limit the MCU 70% DC input power.
[0078] The VCU vehicle controller function monitoring specifically includes:
[0079] L2-2-1 VCU vehicle controller demand torque direction monitoring:
[0080] The recovery function is not triggered, and the VCU vehicle controller demand torque direction is positive.
[0081] Recuperation function triggered, VCU demand torque direction is negative.
[0082] L2-2-2 MCU current direction monitoring:
[0083] Recuperation function not triggered, MCU feedback positive torque, MCU feedback current value is positive, otherwise report MCU current direction error;
[0084] Recuperation function triggered, MCU feedback negative torque, MCU feedback current value is negative, otherwise report MCU current direction error;
[0085] In this embodiment, the speed acceleration direction fault is defined as a three-level fault, and the fault handling measure is to limit the MCU direct current input power to 0Kw.
[0086] L2-2-3 MCU feedback torque direction monitoring:
[0087] Recuperation function not triggered, MCU feedback torque direction is positive, same direction as VCU demand torque, otherwise report MCU feedback torque direction error fault;
[0088] Recuperation function triggered, MCU feedback torque direction is negative, same direction as VCU demand torque, otherwise report MCU feedback torque direction error fault.
[0089] In this embodiment, the MCU feedback torque direction error fault is defined as a three-level fault, and the fault handling measure is to limit the MCU direct current input power to 0Kw.
[0090] L2-2-4 torque deviation value monitoring:
[0091] VCU demand torque is less than or equal to 100Nm or greater than -100Nm, VCU demand torque-MCU feedback torque is less than or equal to 3Nm;
[0092] VCU demand torque is greater than 100Nm or less than -100Nm, VCU demand torque ÷ MCU feedback torque is greater than 0.97 or less than 1.03, otherwise report torque deviation too large fault.
[0093] In this embodiment, the torque deviation fault is divided into three levels.
[0094] First level fault, demand torque is less than 100Nm, torque deviation is greater than 3Nm and less than 10Nm;
[0095] Second level fault, demand torque is less than 100Nm, torque deviation is greater than 10Nm and less than 20Nm, or demand torque is greater than 100Nm, torque deviation is greater than 3% and less than 10%;
[0096] Third level fault, demand torque less than 100Nm, torque deviation greater than 20Nm or demand torque greater than 100Nm, torque deviation greater than 10%;
[0097] The torque deviation fault processing is specifically as follows:
[0098] First level fault processing, limit the drive motor to 70% of the power battery discharge power corresponding to the 100Nm torque zone;
[0099] Second level fault processing, limit the drive motor to 50% of the power battery discharge power corresponding to the 100Nm torque zone;
[0100] Third level fault processing, limit the MCU direct current input power to 0Kw.
[0101] The present application reduces the risk of unintended acceleration or unintended deceleration in the single-pedal coasting energy recovery process through a single-pedal control safety mechanism for an electric vehicle.
[0102] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.
Claims
1. A method for single-pedal control of an electric vehicle, the method comprising: The L1 function execution layer and the L2 function monitoring layer are arranged in a signal processing system of an electric vehicle, the signal processing system is connected with external signals of the electric vehicle and inputs the signals into the L1 function execution layer and the L2 function monitoring layer respectively for fault analysis and processing. The L1 function execution layer comprises: Torque amplitude limitation: preventing the demand torque of the VCU from exceeding the limitation of the drive motor, the power battery or other controllers; the demand torque after limitation is the minimum value between the torque limitation of the coasting recovery gear and the demand torque of the coasting recovery: Tl=min(Trl,Trd); Wherein, Tl represents the demand torque after limitation, Trl represents the torque limitation of the coasting recovery gear, Trd represents the demand torque of the coasting recovery, and min() represents the minimum value function; Torque gradient limitation: preventing the torque gradient of the VCU from exceeding a reasonable range; the demand torque after gradient limitation is the minimum value between the difference between the demand torque after limitation and the demand torque after gradient limitation output at the last time and the torque gradient limit value: Trgl=Trgl(k-1)+min((Tl-Trgl(k-1)),Tratel); Wherein, Trgl represents the demand torque after gradient limitation, Trgl(k-1) represents the demand torque after gradient limitation output at the last time, Tl represents the demand torque after limitation, Tratel represents the torque gradient limit value, and min() represents the minimum value function.
2. The single-pedal control method for an electric vehicle according to claim 1, wherein The L2 function monitoring layer comprises VCU input signal diagnosis and VCU function monitoring, the VCU input signal diagnosis comprises: Signal amplitude check; Signal reasonability check; Signal continuity check; The VCU function monitoring comprises: VCU demand torque direction monitoring; Rotational speed acceleration monitoring; Torque direction monitoring; Torque offset value monitoring.
3. The single-pedal control method for an electric vehicle according to claim 2, wherein The signal amplitude check comprises: Amplitude check on the MCU feedback driving torque, if the MCU feedback driving torque is not within the driving motor execution range, a driving torque out-of-limit value fault is prompted; Amplitude check on the MCU feedback motor rotational speed, if the MCU feedback motor rotational speed is not within the driving motor execution range, a motor rotational speed out-of-limit value fault is prompted.
4. The single-pedal control method for an electric vehicle according to claim 2, wherein The signal reasonability check comprises: Direction check on the MCU feedback driving torque, if the driving gear is set to the forward gear and the kinetic energy recovery is triggered, the MCU feedback driving torque is negative, otherwise the MCU feedback driving torque is positive; Direction check on the MCU feedback motor rotational speed, if the MCU feedback rotational speed is not positive when the driving gear is set to the forward gear, a forward gear rotational speed direction reasonability fault is prompted; if the MCU feedback rotational speed is not negative when the driving gear is set to the reverse gear, a reverse gear rotational speed direction reasonability fault is prompted.
5. The single-pedal control method for an electric vehicle according to claim 2, wherein The signal continuity check comprises: if no input signal is collected for a plurality of continuous sampling periods, a feedback signal continuity fault is prompted.
6. The single-pedal control method for an electric vehicle according to claim 2, wherein The VCU demand torque direction monitoring comprises: When the recovery function is not triggered, the VCU vehicle controller demand torque direction is positive, otherwise the demand torque direction error fault is prompted; When the recovery function is triggered, the VCU vehicle controller demand torque direction is negative, otherwise the demand torque direction error fault is prompted; The demand torque direction error fault is defined as a three-level fault for processing, and the MCU feedback motor direct current input power is limited to 0Kw.
7. The single-pedal control method for an electric vehicle according to claim 2, wherein The rotational speed acceleration monitoring includes: When the recovery function is not triggered, the MCU feedback positive torque, the motor speed acceleration is positive, and the MCU feedback current value is positive; When the recovery function is triggered, the MCU feedback negative torque, the motor speed acceleration is negative, and the MCU feedback current value is negative.
8. The single-pedal control method for an electric vehicle according to claim 2, wherein The torque direction monitoring includes: When the recovery function is not triggered, the MCU feedback torque direction is positive, which is the same direction as the VCU vehicle controller demand torque, otherwise the torque direction error fault is prompted; When the recovery function is triggered, the MCU feedback torque direction is negative, which is the same direction as the VCU vehicle controller demand torque, otherwise the torque direction error fault is prompted; The torque direction error fault is defined as a three-level fault, and the fault processing measure is to limit the MCU direct current input power to 0Kw.
9. The single-pedal control method for an electric vehicle according to claim 8, wherein The torque deviation value monitoring includes: The demand torque is less than or equal to 100Nm, the difference between the VCU vehicle controller demand torque and the MCU feedback torque is less than or equal to 3Nm, otherwise the torque deviation is too large fault is prompted; The demand torque is greater than 100Nm, the ratio of the VCU vehicle controller demand torque to the MCU feedback torque is greater than 0.97 and less than 1.03, otherwise the torque deviation is too large fault is prompted.
10. The single-pedal control method for an electric vehicle according to claim 9, wherein The torque deviation fault is divided into three levels, and the fault level determination standard and processing includes: First-level fault: demand torque less than 100Nm, torque deviation greater than 3Nm and less than 10Nm; The processing method is: limit the drive motor and other torque area 100Nm torque corresponding to the power battery discharge power, adjust to 70% of the original power; Second-level fault: demand torque less than 100Nm, torque deviation greater than 10Nm and less than 20Nm; The processing method is: limit the drive motor and other torque area 100Nm torque corresponding to the power battery discharge power, adjust to 50% of the original power; Third-level fault: demand torque less than 100Nm, torque deviation greater than 20Nm; The processing method is: limit the MCU direct current input power to 0Kw.
Citation Information
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