Control device for electric vehicles

Abstract

This control device for an electric vehicle comprises: a region-specific estimated road surface friction coefficient setting unit that estimates and sets a road surface friction coefficient for each region on the basis of travel environment information; a slip suppression control unit; and a reaction force instruction unit. The slip suppression control unit comprises: a slip vibration detection unit that detects slip vibration from motor vibration; and a motor estimated road surface friction coefficient setting unit that estimates and sets a road surface friction coefficient on the basis of the detected slip vibration. The reaction force instruction unit comprises: a variation calculation unit that calculates a variation of the road surface friction coefficient for each region; a reaction force instruction value setting unit that compares the variation of the road surface friction coefficient for each region and a first threshold value and, if the variation exceeds the first threshold value, sets a reaction force instruction value for generating a strong reaction force compared to when the variation is less than the first threshold value; and a reaction force instruction unit that outputs a command signal of the reaction force instruction value to a reaction force application unit if the road surface friction coefficient is less than or equal to a second threshold value.

Description

Technical Field

[0001] The present invention relates to a control device for an electric vehicle having a function of determining the presence or absence of slip.

Background Art

[0002] When the driving force applied to the tires of the drive wheels (referred to as "drive tires") of a vehicle in motion exceeds the grip force from the road surface acting on the drive tires (referred to as "road surface grip force"), slip occurs. As shown in FIG. 7, the driving force P of the drive tires (front wheels in the figure) in the vehicle M is P = T / r...(1) where T is torque and r is the effective radius of the drive tire.

[0003] Also, the road surface grip force F is F = μ·Wf...(2) where μ is the road surface friction coefficient and Wf is the vehicle body weight applied to the drive tires (front wheels). Incidentally, in FIG. 7, W is the total vehicle body weight and Wr is the vehicle body weight applied to the driven tires (rear wheels).

[0004] Therefore, as shown in FIG. 8, on a dry paved road, running control in a relationship where the driving force P does not exceed the road surface grip force F (P ≤ F) can be performed relatively easily. If the relationship of P ≤ F is always maintained, it is possible to continue running without generating slip.

[0005] On the other hand, on an unpaved road, the road surface grip force F of the tires decreases, so the relationship of P > F is likely to occur. Therefore, it is often difficult to run on an unpaved road without generating slip.

[0006] Even if the vehicle M is an electric vehicle represented by an electric vehicle (EV), a fuel cell vehicle (FCV), or a hybrid electric vehicle (HEV), slip can be prevented by running while always maintaining the relationship of P ≤ F.

[0007] The drive motors of electric vehicles often control their driving force using vector control. Vector control separates the current flowing through the motor into a torque component (torque current component) that generates torque and a magnetic flux component that generates magnetic flux in the rotor (magnetic flux current component), and controls each independently. Therefore, the driving force P of the drive tires can be estimated at high speed from the torque current component flowing through the motor.

[0008] On the other hand, when the drive tires slip, the motor torque fluctuates, and high-frequency vibrations (slip vibrations) occur in the motor's rotational speed. The road surface μ can be estimated from these slip vibrations. Furthermore, if slip vibrations are detected, it can be estimated that the grip force of the drive tires has decreased relatively. As is clear from equation (2) above, assuming the vehicle weight Wf is constant, the road surface grip force F of the tires is determined by the road surface μ.

[0009] For example, Japanese Patent Publication No. 2013-112192 discloses a technology in which, when a vehicle slip is detected from the difference between the rotational speed of the drive wheels and the rotational speed of the driven wheels, a reaction force control device applies a reaction force to the accelerator pedal to notify the driver that a slip has occurred.

[0010] However, as shown in Figure 8, the surface conditions of unpaved roads are not uniform, and there are various conditions in different areas, such as gravel roads, sandy areas, and muddy areas. The coefficient of friction also differs depending on the surface condition. Furthermore, there are also crossover roads where the coefficient of friction of the road surface in contact with the left and right drive wheels is different.

[0011] In the technology disclosed in Japanese Patent Publication No. 2013-112192, when a reaction force control device detects a slip, the reaction force applied to the accelerator pedal is set independently of the actual change in the road surface friction coefficient. Therefore, it is difficult to accurately inform the driver of the situation regarding the occurrence of a slip.

[0012] In view of the above circumstances, the present invention aims to provide a control device for an electric vehicle that can accurately notify the driver of the occurrence of a slip. [Disclosure of the Invention] [Means for solving the problem]

[0013] One aspect of the present invention includes a driving environment detection unit for detecting the driving environment in front of an electric vehicle, a vibration detection unit for detecting motor vibrations that occur in the rotational speed of a drive motor mounted on the electric vehicle, a reaction force application unit for applying a reaction force to an operating unit operated by the driver, and the driving environment detection unit for detecting ran The system comprises a region-specific estimated road surface friction coefficient setting unit that estimates and sets region-specific road surface friction coefficients based on environmental information, a slip suppression control unit, and a reaction force instruction unit, wherein the slip suppression control unit comprises a slip vibration detection unit that detects slip vibrations from the motor vibrations detected by the vibration detection unit, and a motor estimated road surface friction coefficient setting unit that, when the slip vibration detection unit detects slip vibrations, estimates and sets the road surface friction coefficient based on the slip vibrations, and the reaction force instruction unit estimates the road surface friction coefficient for each region detected by the region-specific estimated road surface friction coefficient setting unit The system includes a variation calculation unit that calculates the variation in coefficients, a reaction force instruction value setting unit that compares the variation in the road surface friction coefficient for each region calculated by the variation calculation unit with a first threshold value and sets a reaction force instruction value that generates a stronger reaction force when the variation exceeds the first threshold value compared to when the variation falls below the first threshold value, and a reaction force command unit that outputs a command signal for the reaction force instruction value set by the reaction force instruction value setting unit to the reaction force application unit when the road surface friction coefficient set by the motor estimated road surface friction coefficient setting unit is less than or equal to a second threshold value. [Brief explanation of the drawing]

[0014] [Figure 1] Schematic diagram of the drive control system installed in an electric vehicle. [Figure 2] Flowchart showing the routine for setting the initial value of the estimated road surface μ [Figure 3] Flowchart showing the routine for setting the road surface μ (μ) by camera for each region [Figure 4] Flowchart showing a slip suppression control routine [Figure 5A]Conceptual diagram of the basic road surface μ setting map based on road type [Figure 5B] Conceptual diagram of the weather correction coefficient setting map [Figure 5C] Conceptual diagram of the tire correction coefficient setting map [Figure 6] Conceptual diagram of the estimated road surface μ setting map based on road surface conditions [Figure 7] Explanatory diagram showing the relationship between the driving force of the driving tire and the road surface grip force [Figure 8] Explanatory diagram showing the relationship between the driving force applied to the driving tire and the road surface grip force when traveling on a paved road and an unpaved road

Best Mode for Carrying Out the Invention

[0015] Hereinafter, an embodiment of the present invention will be described based on the drawings. It should be noted that the drawings are schematic, and the relationships between the thicknesses and widths of each member, the ratios of the thicknesses of each member, etc. are different from the actual ones. Of course, there are also parts where the relationships and ratios of the dimensions are different between the drawings.

[0016] Reference numeral 1 in FIG. 1 is a drive control device. This drive control device 1 is mounted on the host vehicle M (see FIG. 7). The host vehicle M is an electric vehicle. Hereinafter, the host vehicle M will be described as the electric vehicle M.

[0017] The drive control device 1 has a vehicle integrated control unit 2. This vehicle integrated control unit 2 comprehensively performs various controls related to the drive of the electric vehicle M. A camera control unit 3 is connected to the input side of this vehicle integrated control unit 2. Although not shown, various sensors for acquiring information necessary for driving the electric vehicle M are connected to the vehicle integrated control unit 2.

[0018] Furthermore, a torque sensor 4 as a steering operation detection unit and a vibration sensor 14a as a vibration detection unit are connected to the input side of the vehicle integrated control unit 2. The torque sensor 4 detects the torque when the driver operates the steering 31c provided in the operation unit 31. The vibration sensor 14a detects the vibration [Hz] generated in the rotational speed of the drive motor 14 (hereinafter referred to as "motor vibration") described later.

[0019] Also, an inverter control unit 5 and a pressurizing actuator 8 as a reaction force applying unit are connected to the output side of the vehicle integrated control unit 2. Although not shown, the vehicle integrated control unit 2 is connected to various control units so as to be capable of two-way communication.

[0020] Each of the control units 2, 3, 5 is composed of a microcontroller including a CPU, a RAM, a ROM, a rewritable non-volatile memory (flash memory or EEPROM), and peripheral devices. The ROM stores programs and fixed data necessary for the CPU to execute each process. The RAM is provided as a work area for the CPU, and various data in the CPU are temporarily stored. The CPU is also called a MPU (Microprocessor) or a processor. Instead of the CPU, a GPU (Graphics Processing Unit) or a GSP (Graph Streaming Processor) may be used. Alternatively, the CPU, GPU, and GSP may be selectively combined and used.

[0021] An inverter 12 of the electric power train 11 is connected to the inverter control unit 5. The electric power train 11 includes an inverter 12, a high-voltage battery 13, and a drive motor 14. The inverter 12 is operated by a command signal from the inverter control unit 5. The inverter 12 converts the DC power (DC) of the high-voltage battery 13 into AC power (AC) according to the command signal from the inverter control unit 5 and supplies power to the drive motor 14. The inverter control unit 5 controls the driving force of the drive motor 14 by vector control.

[0022] The output shaft 21 of the drive motor 14 is connected to the drive shafts 22l and 22r of the left and right drive wheels Fl and Fr via a differential Df. The drive motor 14 uses power supplied from the inverter 12 to drive the drive wheels Fl and Fr, thereby propelling the electric vehicle M.

[0023] Reference numeral 31 denotes the operating unit. This operating unit 31 is operated by the driver and consists of an accelerator pedal 31a and a brake pedal 31b for setting the vehicle speed, and a steering wheel 31c for setting the direction of travel. Of these, a pressure actuator 8 is connected to the accelerator pedal 31a and the brake pedal 31b. This pressure actuator 8 applies a reaction force to the accelerator pedal 31a and the brake pedal 31b according to a command from the vehicle integrated control unit 2.

[0024] A camera unit 6, which serves as a driving environment detection unit, is installed at the front of the electric vehicle M. The camera unit 6 is equipped with a stereo camera consisting of a main camera 6a and a sub-camera 6b.

[0025] The camera control unit 3 processes images of the driving environment in front of the electric vehicle M, captured by both cameras 6a and 6b, to acquire information about the driving environment ahead. Furthermore, the non-volatile memory 3a in the camera control unit 3 stores information about the currently installed tires. This tire information is entered by the user or driver when the tires are installed. This tire information includes tire type, replacement timing, etc. Tire type includes whether it is a normal tire or a studless tire, and tire size.

[0026] Furthermore, this non-volatile memory 3a stores various maps. These maps include a basic road surface μ setting map (see Figure 5A), a weather correction coefficient setting map (see Figure 5B), and a tire correction coefficient setting map (see Figure 5C), which are read when setting the estimated μ initial value. In addition, the non-volatile memory 3a stores an estimated road surface μ setting map (see Figure 6).

[0027] As shown in Figure 5A, the basic road surface μ map stores pre-set basic road surface μ data for each type of road. Road types include paved roads (concrete roads, asphalt roads) and unpaved roads (gravel roads, dirt roads). The basic road surface μ for unpaved roads is set lower than that for paved roads.

[0028] As shown in Figure 5B, the weather correction coefficient setting map has correction coefficients set according to the weather (however, the correction coefficient ≤ 1). These correction coefficients are set to decrease in the order of sunny > cloudy > rainy > snowy.

[0029] As shown in Figure 5C, the tire correction coefficient setting map has correction coefficients set according to the tire type (however, the correction coefficient ≤ 1). The correction coefficient for normal tires is set higher than that for studless tires. Also, the higher the aspect ratio of the tire, the higher the correction coefficient value set.

[0030] As shown in Figure 6, the estimated road surface μ setting map has estimated road surface μ values ​​set according to the road surface conditions. Based on the forward image captured by the camera unit 6, the image data of one frame is divided into regions for each road surface condition, for example, by image recognition using AI (artificial intelligence). This road surface condition information is acquired in real time for each region, including paved roads, unpaved roads (including roads under construction), metal joints at bridge joints, snow, fallen leaves, etc.

[0031] Furthermore, a navigation system 7 is connected to the camera control unit 3. This navigation system 7 has road map data. The navigation system 7 acquires vehicle position information (latitude, longitude, altitude) based on GNSS (Global Navigation Satellite System) satellites. The navigation system 7 then plots the acquired vehicle position on the road map data to estimate the current vehicle position and direction of travel on the road map. Therefore, this navigation system 7 is equipped with the function of a vehicle position detection unit according to the present invention.

[0032] Furthermore, the navigation system 7 acquires information about the surrounding environment of the vehicle based on road map data. This surrounding environment information includes static and dynamic information. Static information includes road surface information such as paved roads and unpaved roads. Dynamic information includes real-time weather information. Weather information includes weather conditions such as sunshine, rain, and snow, sunshine conditions, rainfall, snowfall, temperature, humidity, and atmospheric pressure. Note that weather information may also be acquired from weather information provided on a website. Therefore, the navigation system 7 is also equipped with the function of an environmental information acquisition unit according to the present invention.

[0033] Based on static and dynamic information about the vehicle's position input from the navigation system 7, the camera control unit 3 sets the estimated initial μ value of the road the electric vehicle M will travel on by referring to the map stored in the non-volatile memory 3a. Then, the camera control unit 3 corrects the region-specific basic road surface μ recognized based on the image captured by the camera unit 6 with the estimated initial μ value to set the region-specific camera-predicted road surface μc. The camera control unit 3 outputs the set region-specific camera-predicted road surface μc data to the vehicle integrated control unit 2.

[0034] The vehicle integrated control unit 2 detects slip vibrations from motor vibrations that occur in the rotational speed of the drive motor 14. When slip occurs in the drive wheels Fl.Fr, the motor torque fluctuates rapidly. This fluctuation in motor torque causes torsional resonance (rotational speed vibration) in the motor rotation shaft. In particular, when slip occurs, high-frequency vibrations (slip vibrations) are detected.

[0035] The vehicle integrated control unit 2 sets an estimated road surface μ based on this slip vibration. If this estimated road surface μ is below a predetermined threshold, it applies a reaction force to the accelerator pedal 31a and the brake pedal 31b. This reaction force notifies the driver of the occurrence of a slip and suppresses the occurrence of a slip by limiting the degree to which the accelerator pedal 31a and the brake pedal 31b are pressed.

[0036] The camera control unit 3 sets the estimated μ initial value according to the estimated road surface μ initial setting routine shown in Figure 2. The camera control unit 3 reads the vehicle's position information detected by the navigation system 7 (21). Next, the camera control unit 3 obtains the road type around the vehicle's position from the road map data (step S2). The road map data registers paved roads and unpaved roads as road types. Furthermore, paved roads are classified into concrete roads, asphalt roads, etc. Unpaved roads are classified into gravel roads, dirt roads, etc.

[0037] Subsequently, the camera control unit 3 refers to the basic road surface μ map (Figure 5A) based on the road type and sets the basic road surface μ corresponding to the acquired road type (step S3). The basic road surface μ map stores the road surface μ set for each road type, which has been determined in advance from experiments, etc.

[0038] Furthermore, current weather information for the vehicle's location is obtained from dynamic road map data or weather information provided on a website (Step S4). Then, based on this weather information, the weather correction coefficient is set by referring to the weather correction coefficient setting map (Figure 5B) (Step S5).

[0039] Furthermore, the camera control unit 3 sets the tire correction coefficient by referring to the tire correction coefficient setting map (Figure 5C) based on the tire information of the electric vehicle M that is pre-stored in the non-volatile memory 3a (step S6).

[0040] Subsequently, the camera control unit 3 sets the estimated initial value of road surface μ by multiplying the basic road surface μ by the average value of the weather correction coefficient and the tire correction coefficient, or the lower of the two values ​​(step S7), and then exits the routine. Note that the processing in step S7 corresponds to the estimated road surface friction coefficient initial value setting unit of the present invention. Furthermore, the camera control unit 3 sets the estimated road surface μc for each region based on the image captured by the camera unit 6. Specifically, this estimated road surface μc for each region is set according to the region-specific estimated road surface μc setting routine shown in Figure 3. Note that the processing in this routine corresponds to the region-specific estimated road surface friction coefficient setting unit of the present invention.

[0041] In this routine, the camera control unit 3 reads the camera image captured by the camera unit 6 and processed according to a predetermined image (step S11). Then, for each frame of this camera image, it divides the road into image regions based on feature quantities, for example using AI (artificial intelligence), and identifies the road surface conditions in each divided image region (step S12). As shown in Figure 8, the road surface conditions of unpaved roads are not uniform, and there are various conditions in parts, such as gravel roads, sandy areas, muddy areas, snow and fallen leaves. In particular, the road surface conditions of muddy areas, snow and fallen leaves change in real time. Furthermore, the road surface conditions may differ where the left and right drive wheels Fl and Fr make contact, such as on a crossover road. The camera control unit 3 divides the 1-frame image according to the road conditions.

[0042] Next, the camera control unit 3 sets the estimated road surface μ for each region by referring to the estimated road surface μ setting map shown in Figure 6, based on the road conditions for each region (step S13). Then, it reads the estimated road surface μ initial value set in the estimated road surface μ initial value setting routine (step S14).

[0043] Then, the camera control unit 3 corrects the estimated road surface μ set for each region with the initial estimated road surface μ value to set the region-specific camera estimated road surface μc (step S15), and exits the routine.

[0044] This region-specific camera-estimated road surface μc is read by the vehicle integrated control unit 2. If the vehicle integrated control unit detects the occurrence of slip, it performs slip suppression control by applying reaction forces to the accelerator pedal 31a and the brake pedal 31b.

[0045] This slip suppression control is specifically performed according to the slip suppression control routine shown in Figure 4. The processing in this routine corresponds to the slip suppression control unit of the present invention.

[0046] The vehicle integrated control unit 2 first reads the motor vibration [Hz] detected by the vibration sensor 14a (step S21). This vibration sensor 14a detects vibration [Hz] that occurs in the rotational speed of the drive motor 14. Then, based on the motor vibration [Hz] detected by the vibration sensor 14a, the vehicle integrated control unit 2 checks whether or not slip vibration is occurring in the drive motor 14 (step S22). If a sudden torque fluctuation occurs in the drive motor 14, vibration occurs in the rotational speed of the drive motor 14. If the drive wheels Fl and Fr slip, high-frequency motor vibration occurs in the rotational speed of the drive motor 14.

[0047] The vehicle integrated control unit 2 then determines that slip vibration is present (step S22: YES) if the motor vibration is above the set frequency. The vehicle integrated control unit 2 also determines that there is no slip vibration (step S22: NO) if the motor vibration is below the set frequency. If it determines that there is no slip vibration (step S22: NO), it exits the routine. Note that the processing in step S22 corresponds to the slip vibration detection unit of the present invention.

[0048] If the vehicle integrated control unit 2 determines that slip vibration is present (step S22: YES), it sets an estimated value of the road surface μ, which is the estimated road surface μ (hereinafter referred to as "motor estimated road surface μm") (step S23). Wheel spin (slip) of the drive wheels Fl and Fr occurs when the relationship P (driving force) > F (road surface grip force) is satisfied. The driving force P of the drive wheels Fl and Fr can be quickly determined from the torque current component of the drive motor 14. The vehicle integrated control unit 2 sets the motor estimated road surface μm based on the driving force P when slip of the drive wheels Fl and Fr is detected and the frequency [Hz] when slip vibration is detected. Note that the processing in step S23 corresponds to the motor estimated road surface friction coefficient setting unit of the present invention.

[0049] Subsequently, the vehicle integrated control unit 2 checks whether the driver is operating the steering wheel 31c (step S24). Whether the driver is operating the steering wheel 31c is determined, for example, based on the output value of the torque sensor 4; if the output value is above a predetermined value, it is determined that the steering wheel 31c is being operated.

[0050] Then, if the vehicle integrated control unit 2 determines that the driver is operating the steering wheel 31c (step S24: YES), it sets the reaction force generation threshold μst, which is the second threshold, to a high value μh (μst←μl: step S25). When the driver is operating the steering wheel 31c, setting the reaction force generation threshold μst to a high value μh allows a reaction force to be applied to the accelerator pedal 31a and the brake pedal 31b at an earlier timing. As a result, even if the driver's operation of the steering wheel 31c tends to increase the occurrence of slip, the occurrence of slip can be suppressed.

[0051] Furthermore, if the vehicle integrated control unit 2 determines that the driver is not operating the steering wheel 31c (step S24: NO), it sets the reaction force generation threshold μst to the normal value μn (μst←μn: step S26). Note that the processing in steps S24 to S26 corresponds to the second threshold setting unit of the present invention.

[0052] Subsequently, the vehicle integrated control unit 2 controls the motor speculation The road surface μm and the reaction force generation threshold μst are compared (step S27). Then, the motor speculation If it is determined that the road surface μm exceeds the reaction force generation threshold μst (NO), the routine is exited. Also, the vehicle integrated control unit 2 controls the motor speculation If it is determined that the road surface μm is less than or equal to the reaction force generation threshold μst (YES), the estimated road surface μc for each region is read (step S28).

[0053] Subsequently, the vehicle integrated control unit 2 calculates the variation σμ of the camera-estimated road surface μc for each region, which is set by dividing the image frame (step S29). Note that the processing in this step corresponds to the variation calculation unit of the present invention.

[0054] Then, the vehicle integrated control unit 2 compares the variation σμ of the camera-predicted road surface μc for each region with the variation determination threshold μth, which is the first threshold (step S30). This variation determination threshold μth determines whether the variation σμ of the camera-predicted road surface μc for each region is large or not, and is a fixed value set in advance based on experiments, etc.

[0055] If the vehicle integrated control unit 2 determines that the variation σμ is small (σμ < μth) (step S30: NO), it sets the reaction force instruction value Fc for the pressurizing actuator 8 to the normal reaction force instruction value Fn (Fc ← Fn: step S31). If the vehicle integrated control unit 2 determines that the variation σμ is large (σμ ≥ μth) (step S30: YES), it sets the reaction force instruction value Fc for the pressurizing actuator 8 to a stronger reaction force instruction value Fh than the normal reaction force instruction value Fn (Fc ← Fh: step S32). When it is predicted that the electric vehicle M will be traveling on a road surface with a large variation σμ (μc ≥ σμ), increasing the reaction force instruction value Fc for the pressurizing actuator 8 allows the driver to respond more safely when a slip occurs. Note that the processing in steps S30 to S32 corresponds to the reaction force instruction value setting unit of the present invention.

[0056] Subsequently, the vehicle integrated control unit 2 outputs a reaction force command signal to the pressurizing actuator 8, assigning a reaction force instruction value Fc (step S33), and exits the routine. Note that the processing in steps S28 to S33 corresponds to the reaction force instruction unit of the present invention. Also, the processing in step S33 corresponds to the reaction force command unit of the present invention.

[0057] The pressurizing actuator 8 applies a reaction force instruction value Fc to the accelerator pedal 31a and brake pedal 31b in accordance with the reaction force command signal from the vehicle integrated control unit 2. This reaction force instruction value Fc is a force that counteracts the pressure applied when the driver depresses the accelerator pedal 31a and brake pedal 31b. This reaction force may simply be a repulsive force applied to the accelerator pedal 31a and brake pedal 31b. Alternatively, this reaction force may generate vibrations in the accelerator pedal 31a and brake pedal 31b. Furthermore, this reaction force may apply both a repulsive force and vibrations to the accelerator pedal 31a and brake pedal 31b simultaneously or alternately.

[0058] Thus, according to this embodiment, slip is detected from the slip vibration of the drive motor 14, so that the occurrence of slip can be detected early and the driver can be accurately notified. Furthermore, when it is predicted that the electric vehicle M will be traveling on a road surface with large variation σμ (μc ≥ σμ), the vehicle integrated control unit 2 increases the reaction force instruction value Fc to the pressurizing actuator 8, so that the driver can respond more safely when a slip occurs.

[0059] Furthermore, when the vehicle integrated control unit 2 detects the driver's operation of the steering wheel 31c during a slip, it sets the reaction force generation threshold μst to a high value μh, allowing it to apply a reaction force to the accelerator pedal 31a and brake pedal 31b at an earlier timing. This makes it possible to suppress the occurrence of slip even if the driver's operation of the steering wheel 31c tends to exacerbate the slip.

[0060] Furthermore, the electric vehicle M may be a four-wheel drive vehicle. Also, the estimated road surface μ initial setting routine shown in Figure 2 may be executed by the vehicle integrated control unit 2. In addition, the slip suppression control may not only apply reaction force to the accelerator pedal 31a and brake pedal 31b, but may also notify the occurrence of slip with sound or images on the monitor.

Claims

1. A driving environment detection unit that detects the driving environment in front of the electric vehicle, A vibration detection unit for detecting motor vibrations that occur in the rotational speed of the drive motor mounted on the electric vehicle, A reaction force applying unit that applies a reaction force to the control unit operated by the driver, A region-specific estimated road surface friction coefficient setting unit estimates and sets region-specific road surface friction coefficients based on the driving environment information detected by the aforementioned driving environment detection unit, Slip suppression control unit, Reaction force indicator and Equipped with, The slip suppression control unit, A slip vibration detection unit detects slip vibrations from the motor vibrations detected by the vibration detection unit, When the slip vibration detection unit detects the slip vibration, the motor estimated road surface friction coefficient setting unit estimates and sets the road surface friction coefficient based on the slip vibration. Equipped with, The reaction force indicator unit is A variation calculation unit calculates the variation in the road surface friction coefficient for each region detected by the region-specific estimated road surface friction coefficient setting unit, A reaction force instruction value setting unit compares the variation of the road surface friction coefficient for each region calculated by the variation calculation unit with a first threshold value, and sets a reaction force instruction value that generates a stronger reaction force when the variation exceeds the first threshold value compared to when the variation falls below the first threshold value. If the road surface friction coefficient set by the motor estimated road surface friction coefficient setting unit is less than or equal to the second threshold, the reaction force command unit outputs a command signal for the reaction force instruction value set by the reaction force instruction value setting unit to the reaction force application unit. A control device for electric vehicles, characterized by comprising the following:

2. It further includes a steering operation detection unit that detects steering operations performed by the driver, The reaction force indicator unit is The system further includes a second threshold setting unit that, when the steering operation detection unit detects steering operation, sets the second threshold to a higher value than when no steering operation is detected. The control device for an electric vehicle according to claim 1.

3. A vehicle position detection unit that detects the current position of the electric vehicle, An environmental information acquisition unit acquires information about the surrounding environment of the electric vehicle based on the current position of the electric vehicle detected by the self-position detection unit, An estimated road friction coefficient initial value setting unit sets an initial value of the estimated road friction coefficient based on the surrounding environmental information acquired by the environmental information acquisition unit. Furthermore, The aforementioned region-specific estimated road surface friction coefficient setting unit corrects the estimated region-specific road surface friction coefficient with the initial value of the estimated road surface friction coefficient set by the estimated road surface friction coefficient initial value setting unit to set a new region-specific road surface friction coefficient. The control device for an electric vehicle according to claim 1.

4. The aforementioned surrounding environment information is at least one of road map information and weather information. The control device for an electric vehicle according to claim 3.

5. The aforementioned operating unit is at least one of the accelerator pedal and the brake pedal. The control device for an electric vehicle according to claim 1.

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