Hill assist control method, device and system for electric vehicle

Abstract

Provided are a ramp assist control method, device and system for electric vehicles, the ramp assist control method is applied to a controller for controlling the output torque of the motor of the electric vehicle, the ramp assist control method comprises: obtaining a duration that satisfies the conditions that the speed of the electric vehicle is 0, the gear is the driving gear, the accelerator pedal is not pressed, the vehicle body tilt angle is greater than a first angle, and the brake pedal is not pressed; judging whether the duration is less than or equal to a first set time; and in the case where it is judged that the duration is equal to or less than the first set time, controlling the motor so that the motor continuously outputs a motor torque for offsetting the sliding torque of the electric vehicle, thereby causing the electric vehicle to pause on a ramp. The present invention uses a static torque sensor to directly measure the sliding torque of the vehicle, so that the motor torque and the sliding torque are offset to achieve temporary parking, with fast response speed, real-time accuracy and low cost.

Description

Technical Field

[0001] The present invention relates to hill assist control of an electric vehicle, and more particularly to a hill assist control method, device and system for an electric vehicle. Background Art

[0002] Traditional hill assist control systems (HAC) are based on the vehicle's ESP system (electronic stability program), which has a pressure stabilization system that allows the vehicle to stop for 1 to 2 seconds when the brake pedal is released (or "released") on a slope, and then the vehicle will glide.

[0003] However, the conventional hill assist control system has the following problems:

[0004] (i) It can only stop the vehicle on a slope for 1 to 2 seconds, and the stopping time is short;

[0005] (ii) It must rely on some structure of the ESP system and cannot work alone;

[0006] (iii) Its structure is complex and sealing is difficult;

[0007] (iv) Even with a hill assist control system, some vehicles will still slide for a short distance on the slope. The reason is that traditional vehicles use mechanical hydraulic valves, some of which require a short time to build up oil pressure. There will be slippage during the period from releasing the brake pedal to building up oil pressure. Summary of the invention

[0008] The present invention is made in view of the above-mentioned state of the prior art. An object of the present invention is to provide a hill assist control method, device and system for an electric vehicle, which allows the vehicle to stop on a slope without depressing the brake pedal.

[0009] A hill assist control method for an electric vehicle is provided, which is applied to a controller for controlling the output torque of a motor of the electric vehicle. The hill assist control method comprises:

[0010] Obtaining a duration that satisfies the conditions that the speed of the electric vehicle is 0, the gear position of the electric vehicle is the driving gear, the accelerator pedal of the electric vehicle is not pressed, the body inclination angle of the electric vehicle is greater than a first angle, and the brake pedal of the electric vehicle is not pressed;

[0011] Determining whether the duration is less than or equal to a first set time;

[0012] When it is determined that the duration is equal to or less than the first set time, the motor is controlled to continuously output a motor torque for offsetting a slip torque of the electric vehicle, thereby causing the electric vehicle to stop on the slope.

[0013] In at least one embodiment, the hill assist control method may also include: when it is determined that the duration is greater than the first set time, starting the electronic parking brake system of the electric vehicle to pause the electric vehicle on the slope, and controlling the motor to reduce the motor torque output by the motor to 0.

[0014] In at least one embodiment, the hill assist control method may further include:

[0015] When the electric vehicle is stopped on a slope by the electronic parking brake system, detecting whether the accelerator pedal is pressed;

[0016] If it is detected that the accelerator pedal is depressed, the electronic parking brake system is turned off, and the motor is controlled so that the motor torque output by the motor is equal to the driving torque obtained based on the accelerator pedal signal, so that the electric vehicle moves.

[0017] In at least one embodiment, the hill assist control method may further include:

[0018] In a case where the electric vehicle is stopped on a slope by the motor torque, detecting whether the accelerator pedal is pressed;

[0019] If it is detected that the accelerator pedal is depressed, the motor is controlled so that the motor torque output by the motor is equal to the driving torque obtained based on the accelerator pedal signal, so that the electric vehicle moves.

[0020] In at least one embodiment, the hill assist control method may further include: acquiring the vehicle body tilt angle from a tilt sensor for measuring the vehicle body tilt angle.

[0021] In at least one embodiment, the hill assist control method may further include: acquiring the slip torque from a static torque sensor mounted to a wheel axle of the electric vehicle.

[0022] In at least one embodiment, the first set time is less than or equal to 5 seconds.

[0023] In at least one embodiment, the first angle is 5 degrees.

[0024] In at least one embodiment, the driving gear includes a forward gear and a reverse gear.

[0025] A hill assist control device for an electric vehicle is provided, comprising:

[0026] An acquisition module is used to acquire a duration satisfying that the speed of the electric vehicle is 0, the gear position of the electric vehicle is the driving gear, the accelerator pedal of the electric vehicle is not pressed, the body inclination angle of the electric vehicle is greater than a first angle, and the brake pedal of the electric vehicle is not pressed;

[0027] A judging module, used to judge whether the duration is less than or equal to a first set time;

[0028] The control module is used to control the motor so that the motor continuously outputs the motor torque for offsetting the slip torque of the electric vehicle, thereby causing the electric vehicle to pause on the slope when it is determined that the duration is equal to or less than the first set time.

[0029] In at least one embodiment, the electric vehicle is a hybrid electric vehicle, and the control device is a hybrid module control unit; or the electric vehicle is a pure electric vehicle, and the control device is a motor control unit.

[0030] A hill assist control system for an electric vehicle is provided, comprising:

[0031] A motor for driving the vehicle;

[0032] Inclination sensor for measuring the tilt angle of the vehicle body;

[0033] a controller capable of controlling at least the output torque of the motor; and

[0034] a static torque sensor mounted to a wheel axle of the vehicle for measuring the slip torque of the vehicle,

[0035] Wherein, within a first set time after the controller determines that the following conditions (i) to (v) are met, the controller controls the motor to continuously output the motor torque for offsetting the slip torque, so that the vehicle is suspended on the slope,

[0036] (i) Vehicle speed = 0;

[0037] (ii) the gear position is driving gear;

[0038] (iii) accelerator pedal signal = 0;

[0039] (iv) the tilt sensor signal > the first angle; and

[0040] (v) Brake pedal signal = 0.

[0041] A hill assist control method for an electric vehicle is provided, the vehicle comprising:

[0042] A motor for driving the vehicle;

[0043] Inclination sensor for measuring the tilt angle of the vehicle body;

[0044] a controller capable of controlling at least the output torque of the motor; and

[0045] a static torque sensor mounted to a wheel axle of the vehicle, which measures the slip torque of the vehicle,

[0046] The hill assist control method includes:

[0047] During a first set time after the controller determines that the following conditions (i) to (v) are satisfied, the controller controls the motor to continuously output the motor torque for offsetting the slip torque, thereby causing the vehicle to stop on the slope.

[0048] (i) Vehicle speed = 0;

[0049] (ii) the gear position is driving gear;

[0050] (iii) accelerator pedal signal = 0;

[0051] (iv) the tilt sensor signal > the first angle; and

[0052] (v) Brake pedal signal = 0.

[0053] The present invention adopts a static torque sensor to directly measure the sliding torque of the vehicle, so that the motor torque and the sliding torque are offset, and has fast response speed, real-time accuracy and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram showing an electric vehicle parked on a slope according to an embodiment of the present invention is shown.

[0055] Figure 2 A flowchart of a hill assist control method for an electric vehicle according to an embodiment of the present invention is shown.

[0056] Figure 3 A schematic diagram of a hill assist control system for an electric vehicle according to an embodiment of the present invention is shown.

[0057] Figure 4 A schematic diagram showing a hill assist control device for an electric vehicle according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0058] The exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present invention, and are not intended to exhaust all possible modes of the present invention, nor to limit the scope of the present invention.

[0059] Figure 1 FIG. 1 is a schematic diagram showing an electric vehicle 100 parked on a ramp according to an embodiment of the present invention. Figure 1 As shown, the electric vehicle 100 can be driven by, for example, an in-wheel motor / wheel hub motor. When the vehicle is parked on a slope, the in-wheel motor can be used to output a motor torque that is equal to the slip torque and opposite in direction to prevent the vehicle from sliding on the slope.

[0060] In order to obtain the above-mentioned slip torque, a static torque sensor 10 may be installed on, for example, a wheel axle. The static torque sensor 10 may use, for example, a built-in resistance strain device to convert the strain generated by the torsional moment into an electrical signal that is linearly related to the strain, thereby obtaining the slip torque of the vehicle. It should be understood that the wheel does not actually have to slip, and the above-mentioned slip torque may be calculated using microscopic deformation.

[0061] Reference Figure 2 and Figure 3 The present invention provides a method and system for hill assist control of an electric vehicle. The hill assist control system 200 includes: a motor for driving the vehicle; a tilt sensor for measuring the tilt angle of the vehicle body; a controller capable of at least controlling the output torque of the motor; and a static torque sensor mounted on the wheel axle of the vehicle, which is used to measure the slip torque of the vehicle.

[0062] During a first set time after the controller determines that the following conditions (i) to (v) are met, the controller controls the motor to continuously output the motor torque for offsetting the slip torque, thereby causing the vehicle to stop on the slope.

[0063] (i) Vehicle speed = 0;

[0064] (ii) the gear position is driving gear;

[0065] (iii) accelerator pedal signal = 0;

[0066] (iv) the tilt sensor signal > the first angle; and

[0067] (v) Brake pedal signal = 0.

[0068] It should be understood that the electric vehicle of the present invention can be a hybrid electric vehicle and a pure electric vehicle, in particular an in-wheel drive / hub motor drive vehicle or a wheel side drive vehicle, as long as the electric vehicle has the motor.

[0069] The tilt sensor can be installed, for example, on the corresponding vehicle body below the trunk.

[0070] When the vehicle is a hybrid electric vehicle, the controller may be a hybrid module control unit (HCU). When the electric vehicle is a pure electric vehicle, the controller may be a motor control unit (MCU).

[0071] The static torque sensor can be mounted on the front or rear axle.

[0072] The motor torque used to offset the slip torque is a torque that is equal in magnitude and opposite in direction to the slip torque. The rotor can be fixed relative to the stator by energizing the stator coil of the motor, so that the rotor of the motor can output torque but does not rotate to keep the vehicle stationary.

[0073] To prevent the motor's rotor from outputting torque but not rotating for too long, which may cause the motor temperature to be too high and cause damage to the motor, the first set time is preferably less than or equal to 5 seconds. In particular, the first set time can be any time between 2 seconds and 5 seconds.

[0074] The vehicle speed can be measured by a vehicle speed sensor. The vehicle speed sensor can be installed at the wheel end, for example, and can calculate the vehicle speed according to the wheel speed.

[0075] The driving gears include a forward gear (D gear) and a reverse gear (R gear), and gear information may be provided by a gear sensor or a corresponding controller.

[0076] The accelerator pedal signal may be measured by an accelerator pedal position sensor, and an accelerator pedal signal = 0 indicates that the accelerator pedal is released, or in other words, the accelerator pedal is not pressed.

[0077] The first angle may be the maximum inclination angle of the road surface (ramp) when the vehicle can automatically come to a stop by wheel friction. The first angle may be different for different vehicles and can be easily measured in practice. For many vehicles, the vehicle can automatically come to a stop by wheel friction on a road surface with an inclination angle of less than 5 degrees. Therefore, the first angle is preferably about 5 degrees.

[0078] The brake pedal signal can be measured by a brake pedal position sensor. The brake pedal position sensor generally has only two signals 0 and 1, 0 represents that the brake pedal is not pressed (no brake), and 1 represents that the brake pedal is pressed (brake).

[0079] It should be understood that the above-mentioned vehicle speed sensor, accelerator pedal position sensor, and brake pedal position sensor are sensors that are present in almost all cars. In addition, most cars now have inclination sensors, and almost all off-road vehicles have them, which are used to measure different climbing angles to provide different power.

[0080] It can be considered that the hill assist control system 200 of the present invention or the vehicle using the hill assist control system 200 of the present invention further includes the above-mentioned vehicle speed sensor, gear position sensor, accelerator pedal position sensor, brake pedal position sensor and tilt sensor.

[0081] It should be understood that the signals of the above sensors can be directly read by the above controllers or obtained from other controllers. For example, in one example, some signals related to the motor can be directly read from the HCU or MCU, and the remaining signals can be transmitted from the VCU (vehicle control unit) to the HCU or MCU.

[0082] The static torque sensor may start to supply a feedback signal only when the hill assist operation is satisfied, that is, when the controller determines that the above conditions (i) to (v) are satisfied.

[0083] The hill assist control system 200 and method of the present invention call the signals of existing sensors, which has little structural change to the vehicle and low cost. Moreover, the hill assist control system 200 and method of the present invention do not need to use a pressure stabilization system, so the vehicle of the present invention can be without a pressure stabilization system.

[0084] Compared with some existing solutions that calculate the vehicle's sliding torque by using road inclination / slope, vehicle weight and wheel diameter, the present invention uses a static torque sensor to directly measure the vehicle's sliding torque, which has a fast response speed, real-time and accurate measurement, and is less likely to cause vehicle sliding due to inaccurate calculation.

[0085] The vehicle or system may also include an electronic parking brake system (EPB). When the controller determines that the time for which the above conditions (i) to (v) are satisfied is greater than the first set time, the electronic parking brake system is activated and the motor torque is reduced to 0 within, for example, 2 seconds.

[0086] In the case where the vehicle is stopped on the slope by the motor torque, if the accelerator pedal signal>0 (ie, the accelerator pedal is pressed), the motor torque is made equal to the driving torque obtained based on the accelerator pedal signal, so that the vehicle moves.

[0087] The driving torque can be obtained by reading the accelerator pedal depth (accelerator pedal position sensor signal), and different accelerator pedal depths represent different torques.

[0088] When the vehicle is stopped on a slope by the electronic parking brake system, if the accelerator pedal signal is greater than 0, the electronic parking brake system is turned off and the motor torque is made equal to the driving torque obtained based on the accelerator pedal signal, so that the vehicle moves. Since the electronic parking brake system is electronically controlled, the (first) turning off the electronic parking brake system and making the motor torque equal to the driving torque can achieve seamless connection.

[0089] It should be understood that the present invention can be used in both uphill and downhill situations. For example, in the case of D gear uphill, if the brake pedal is not pressed, the vehicle may slip (move backward), and thus the motor can generate a motor torque that causes the vehicle to move forward (without actually moving the vehicle forward) to act on the axle, thereby offsetting the sliding torque of the vehicle. For example, in the case of D gear downhill, if the brake pedal is not pressed, the vehicle may slip (move forward), and thus the motor can generate a motor torque that causes the vehicle to move backward (without actually moving the vehicle backward) to act on the axle, thereby offsetting the sliding torque of the vehicle.

[0090] like Figure 2 As shown, the hill assist control method of an electric vehicle of the present invention can be applied to a controller for controlling the output torque of a motor of the electric vehicle, and the hill assist control method may include:

[0091] Obtaining a duration that satisfies the conditions that the speed of the electric vehicle is 0, the gear position of the electric vehicle is the driving gear, the accelerator pedal of the electric vehicle is not pressed, the body inclination angle of the electric vehicle is greater than a first angle, and the brake pedal of the electric vehicle is not pressed;

[0092] Determining whether the duration is less than or equal to a first set time;

[0093] When it is determined that the duration is equal to or less than the first set time, the motor is controlled to continuously output a motor torque for offsetting a slip torque of the electric vehicle, thereby causing the electric vehicle to stop on the slope.

[0094] The hill assist control method may further include: when it is determined that the duration is greater than the first set time, activating an electronic parking brake system of the electric vehicle to stop the electric vehicle on the slope, and controlling the motor to reduce the motor torque output by the motor to zero.

[0095] The hill assist control method may further include:

[0096] When the electric vehicle is stopped on a slope by the electronic parking brake system, detecting whether the accelerator pedal is pressed;

[0097] If it is detected that the accelerator pedal is depressed, the electronic parking brake system is turned off, and the motor is controlled so that the motor torque output by the motor is equal to the driving torque obtained based on the accelerator pedal signal, so that the electric vehicle moves.

[0098] The hill assist control method may further include:

[0099] In a case where the electric vehicle is stopped on a slope by the motor torque, detecting whether the accelerator pedal is pressed;

[0100] If it is detected that the accelerator pedal is depressed, the motor is controlled so that the motor torque output by the motor is equal to the driving torque obtained based on the accelerator pedal signal, so that the electric vehicle moves.

[0101] The hill assist control method may further include: acquiring the vehicle body tilt angle from a tilt angle sensor for measuring the vehicle body tilt angle.

[0102] The hill assist control method may further include acquiring the slip torque from a static torque sensor mounted to a wheel axle of the electric vehicle.

[0103] like Figure 4 As shown, the present invention provides a hill assist control device 300 for an electric vehicle, which includes:

[0104] An acquisition module is used to acquire a duration satisfying that the speed of the electric vehicle is 0, the gear position of the electric vehicle is the driving gear, the accelerator pedal of the electric vehicle is not pressed, the body inclination angle of the electric vehicle is greater than a first angle, and the brake pedal of the electric vehicle is not pressed;

[0105] A judging module, used to judge whether the duration is less than or equal to a first set time;

[0106] The control module is used to control the motor so that the motor continuously outputs the motor torque for offsetting the slip torque of the electric vehicle, thereby causing the electric vehicle to pause on the slope when it is determined that the duration is equal to or less than the first set time.

[0107] It should be understood that the above embodiments are only exemplary and are not intended to limit the present invention. Those skilled in the art may make various modifications and changes to the above embodiments under the guidance of the present invention without departing from the scope of the present invention.

Claims

1. A hill assist control method for an electric vehicle, applied to a controller for controlling the output torque of a motor of the electric vehicle, the hill assist control method comprising: Obtaining a duration that satisfies the conditions that the speed of the electric vehicle is 0, the gear position of the electric vehicle is the driving gear, the accelerator pedal of the electric vehicle is not pressed, the body inclination angle of the electric vehicle is greater than a first angle, and the brake pedal of the electric vehicle is not pressed; Determining whether the duration is less than or equal to a first set time; When it is determined that the duration is equal to or less than the first set time, the motor is controlled to continuously output a motor torque for offsetting a slip torque of the electric vehicle, thereby causing the electric vehicle to stop on the slope.

2. The hill assist control method according to claim 1, further comprising: When it is determined that the duration is greater than the first set time, an electronic parking brake system of the electric vehicle is activated to stop the electric vehicle on a slope, and the motor is controlled to reduce the motor torque output by the motor to zero.

3. The hill assist control method according to claim 2, further comprising: When the electric vehicle is stopped on a slope by the electronic parking brake system, detecting whether the accelerator pedal is pressed; If it is detected that the accelerator pedal is depressed, the electronic parking brake system is turned off, and the motor is controlled so that the motor torque output by the motor is equal to the driving torque obtained based on the accelerator pedal signal, so that the electric vehicle moves.

4. The hill assist control method according to claim 1, further comprising: In a case where the electric vehicle is stopped on a slope by the motor torque, detecting whether the accelerator pedal is pressed; If it is detected that the accelerator pedal is depressed, the motor is controlled so that the motor torque output by the motor is equal to the driving torque obtained based on the accelerator pedal signal, so that the electric vehicle moves.

5. The hill assist control method according to any one of claims 1 to 4, further comprising: The vehicle body inclination angle is acquired from an inclination sensor for measuring the vehicle body inclination angle.

6. The hill assist control method according to any one of claims 1 to 4, further comprising: The slip torque is acquired from a static torque sensor mounted to a wheel axle of the electric vehicle.

7. The hill assist control method according to any one of claims 1 to 4, further comprising: The first set time is less than or equal to 5 seconds.

8. The hill assist control method according to any one of claims 1 to 4, further comprising: The first angle is 5 degrees.

9. A hill assist control device for an electric vehicle, comprising: An acquisition module is used to acquire a duration satisfying that the speed of the electric vehicle is 0, the gear position of the electric vehicle is the driving gear, the accelerator pedal of the electric vehicle is not pressed, the body inclination angle of the electric vehicle is greater than a first angle, and the brake pedal of the electric vehicle is not pressed; A judging module, used to judge whether the duration is less than or equal to a first set time; The control module is used to control the motor so that the motor continuously outputs the motor torque for offsetting the slip torque of the electric vehicle, so that the electric vehicle is suspended on the slope when it is determined that the duration is equal to or less than the first set time.

10. A hill assist control system for an electric vehicle, comprising: A motor for driving the vehicle; Inclination sensor for measuring the tilt angle of the vehicle body; a controller capable of controlling at least the output torque of the motor; as well as a static torque sensor mounted to a wheel axle of the vehicle for measuring the slip torque of the vehicle, Wherein, within a first set time after the controller determines that the following conditions (i) to (v) are met, the controller controls the motor to continuously output the motor torque for offsetting the slip torque, so that the vehicle is suspended on the slope, (i) Vehicle speed = 0; (ii) the gear position is driving gear; (iii) accelerator pedal signal = 0; (iv) the tilt sensor signal > the first angle; and (v) Brake pedal signal = 0.

Images