JP2017060351A - Travel control device, travel control method and travel control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control energy consumption of a drive section when performing travel control of a vehicle through independent control of a plurality of wheels by the drive section in response to a disturbance such as wind.SOLUTION: A control section 22 has a function to output control signals to control a main motor 17 and a sub-motor 18 on the basis of output signals from several types of sensors including a first to a third detection sensors 21A to 21C. The control section 22 also controls yaw motion of a vehicle 10, while the same is traveling, by appropriately controlling distribution of drive force of the sub-motor 18 between left and right rear wheels with reference to a storage section 23. Thus, the control section 22 can control the vehicle 10 in response to a travel state and vehicle body behavior thereof.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a travel control device, a travel control method, and a travel control program.

  Patent Document 1 discloses a wheel control device that reduces energy required for turning in a vehicle including a plurality of motors that can independently drive a plurality of wheels. The wheel control device sets the drive torque distribution of the plurality of motors based on the turning travel resistance acting on the plurality of wheels when the vehicle is turning. The turning resistance is a physical resistance received by a plurality of wheels when the driving torque is unevenly distributed to a plurality of wheels when the vehicle is turning, and the driving torque is distributed to a plurality of motors so as to suppress the turning resistance. To reduce the energy required for turning

JP, 2014-212614, A

  By the way, while the vehicle is traveling, the traveling state changes due to various disturbances. For example, disturbances such as crosswinds affect the running state of the vehicle. Therefore, in the vehicle, traveling control is performed to maintain the traveling direction and vehicle speed of the vehicle while suppressing the yaw rate generated by disturbance such as cross wind. However, when the travel control is performed, a sufficient examination has not been made as to how much a disturbance such as a cross wind affects the travel state of the vehicle. Therefore, there is room for improvement in performing vehicle travel control against disturbances such as crosswinds.

  The present invention has been made in consideration of the above-mentioned facts, and when driving control of a vehicle is performed by controlling each of a plurality of wheels independently by a driving unit in response to a disturbance such as wind, the consumption of the driving unit is It is an object of the present invention to provide a travel control device, a travel control method, and a travel control program that can suppress energy.

  In order to achieve the above object, a travel control device of the present invention includes a detection unit that detects disturbance and vehicle speed acting on a vehicle, and a drive unit that can independently drive each of a plurality of wheels provided in the vehicle. A storage unit that stores a distribution of driving forces of the plurality of wheels that reduce energy consumption of the driving unit with respect to disturbance and vehicle speed acting on the vehicle, and is detected by the detection unit while the vehicle is traveling. A controller that controls the drive unit such that each of the plurality of wheels is driven by the distribution of the driving force of the plurality of wheels stored in the storage unit with respect to disturbance and vehicle speed acting on the vehicle. I have.

  According to the present invention, the disturbance acting on the vehicle and the vehicle speed are detected by the detection unit. Each of the plurality of wheels provided in the vehicle can be driven independently by the drive unit. The storage unit stores a distribution of driving forces of a plurality of wheels that reduce energy consumption of the driving unit with respect to disturbances and vehicle speed acting on the vehicle. The control unit is configured to drive each of the plurality of wheels while driving the vehicle by distributing the driving force of the plurality of wheels stored in the storage unit with respect to the disturbance and the vehicle speed acting on the vehicle detected by the detection unit. Control the drive. Accordingly, when the vehicle travel control is performed by independently controlling each of the plurality of wheels by the drive unit according to the disturbance acting on the vehicle, the energy consumption of the drive unit can be suppressed.

  In the travel control device according to the present invention, the disturbance given to the vehicle may be wind force with respect to the vehicle.

  Further, in the travel control device according to the present invention, the storage unit stores the distribution of the driving force of the plurality of wheels corresponding to the yaw moment that minimizes the energy consumption of the driving unit with respect to the disturbance and the vehicle speed. be able to.

  Further, in the travel control device according to the present invention, the storage unit stores the distribution of the driving force of the plurality of wheels corresponding to the yaw moment that minimizes the energy consumption of the driving unit with respect to the disturbance and the vehicle speed. be able to.

  Further, in the travel control device according to the present invention, energy consumption of a plurality of motion performance nodes indicating the motion performance of the vehicle including the vehicle speed, and a drive unit capable of independently driving each of the plurality of wheels provided in the vehicle. Dependence between a plurality of energy consumption nodes shown and a plurality of dependent nodes related to at least one of the plurality of athletic performance nodes and at least one of the plurality of energy consumption nodes and indicating a disturbance applied to the vehicle A factor model setting unit that sets a factor model that expresses a relationship as a path that connects nodes, and a route from an athletic performance node to an energy consumption node that has a large dependency between nodes in the factor model set by the factor model setting unit Based on the obtained route and the route setting unit for setting the driving force distribution of the plurality of wheels with respect to the disturbance and the vehicle speed, the storage unit A storage control unit for performing storage control to 憶 may include a computing unit having a.

  Further, the travel control method according to the present invention detects a disturbance and a vehicle speed acting on the vehicle, and a disturbance acting on the vehicle with respect to the detected disturbance and vehicle speed detected during the traveling of the vehicle. And in the storage unit storing the distribution of the driving force of the plurality of wheels, the energy consumption of the driving unit capable of independently driving each of the plurality of wheels provided in the vehicle is reduced with respect to the vehicle speed. The drive unit is controlled such that each of the plurality of wheels is driven by the distribution of the driving force of the plurality of wheels with respect to the disturbance acting on the vehicle and the vehicle speed.

  Further, in the travel control method according to the present invention, the energy consumption of a plurality of motion performance nodes indicating the motion performance of the vehicle including the vehicle speed and the drive unit capable of independently driving each of the plurality of wheels provided in the vehicle is obtained. Dependence between a plurality of energy consumption nodes shown and a plurality of dependent nodes related to at least one of the plurality of athletic performance nodes and at least one of the plurality of energy consumption nodes and indicating a disturbance applied to the vehicle Set a factor model that expresses the relationship as a route connecting nodes, and in the set factor model, set a route from a motor performance node with a large dependency relationship between nodes to an energy consumption node, and based on the obtained route, The distribution of the driving force of the plurality of wheels with respect to the disturbance and the vehicle speed can be obtained and stored in the storage unit.

  The travel control program according to the present invention detects a disturbance and a vehicle speed acting on the vehicle, and the disturbance acting on the vehicle with respect to the detected disturbance and vehicle speed detected during the traveling of the vehicle. And in the storage unit storing the distribution of the driving force of the plurality of wheels, the energy consumption of the driving unit capable of independently driving each of the plurality of wheels provided in the vehicle is reduced with respect to the vehicle speed. A computer is caused to execute a process including controlling the driving unit such that each of the plurality of wheels is driven by the distribution of the driving force of the plurality of wheels with respect to disturbance and vehicle speed acting on the vehicle.

  As described above, according to the present invention, when vehicle driving control is performed by independently controlling each of a plurality of wheels by a driving unit in accordance with a disturbance such as wind, energy consumption of the driving unit is suppressed. The effect that it can be obtained.

It is explanatory drawing which shows an example of the driving state of the vehicle which concerns on 1st Embodiment. It is an image figure which shows an example of a structure of the drive mechanism of a vehicle. It is an image figure of the yaw moment which generate | occur | produces when driving force is distributed to a right-and-left wheel. It is a block diagram which shows an example of a traveling control apparatus. It is a block diagram which shows an example of the computer which can implement | achieve a traveling control apparatus. It is a flowchart which shows an example of the flow of a process of a search process. It is an image figure which shows an example of an initial factor graph. It is an image figure which shows the factor graph after correction. It is explanatory drawing of the sensitivity of a node. It is a figure which searches a driving | running | working state and a control gain. It is explanatory drawing regarding the possibility of reduction of energy consumption. It is a flowchart which shows an example of the flow of a process of an allocation process. It is an image figure which shows an example of a structure of the drive mechanism of the vehicle which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)

  First, the traveling state of the vehicle 10 that is affected by a disturbance acting on the vehicle 10 traveling at the vehicle speed V will be described.

  FIG. 1 shows an example of disturbance acting on the vehicle 10 according to the present embodiment and the traveling state of the vehicle 10. The disturbance acting on the vehicle can be considered as a force vector in which physical energy acts on the vehicle from the outside. The force vector can be expressed by, for example, each component of direction and force. Here, wind force Fw is adopted as an example of disturbance acting on the vehicle 10. The wind force Fw can be represented, for example, by physical energy based on wind direction and wind speed components. In FIG. 2, an arrow x indicates a predetermined direction defined as a reference, and an arrow y indicates a direction intersecting with the predetermined direction defined as a reference. An arrow u indicates a direction along the traveling direction Df of the vehicle 10, and an arrow v indicates a direction intersecting the traveling direction Df. Further, the wind direction θw and the wind speed Vw are shown for the wind force Fw that is an example of the disturbance acting on the vehicle 10. Further, as an example of the traveling state of the vehicle 10, the steering angle δf, the vehicle speed V (Vu, Vv), and the yaw rate r are shown, and the slip angle β and the yaw angle βw are shown with respect to the center of gravity CL of the vehicle 10.

  As shown in FIG. 1, when the wind force Fw having the wind direction θw and the wind speed Vw acts as a disturbance on the vehicle 10 traveling at the vehicle speed V, the wind speed θw and the wind force Fw having the wind speed Vw are combined with the vehicle speed V to obtain the yaw angle βw. become. The traveling state of the vehicle 10 appears at the yaw rate r. Therefore, in the present embodiment, control of allocating the driving force to the left and right wheels is performed to suppress the yaw rate r generated by the disturbance caused by the wind force Fw such as a cross wind, and the energy consumption of the vehicle 10 is suppressed.

  FIG. 2 shows an example of the configuration of the drive mechanism of the vehicle 10 according to the present embodiment. The vehicle 10 shown in FIG. 1 uses a torque vectoring mechanism as an example of a mechanism capable of adjusting the distribution of the driving force acting on the wheels with respect to the left and right wheels. The vehicle 10 includes left and right front wheels 11 and 12 and left and right rear wheels 13 and 14 as wheels. The left and right front wheels 11 and 12 are supported by a vehicle body 10A serving as a spring on the vehicle 10 via a suspension mechanism (not shown). The directions of the left and right front wheels 11 and 12 are changed by the steering device 15. Further, the left and right rear wheels 13 and 14 are supported on the vehicle body 10A of the vehicle 10 via a suspension mechanism (not shown) each other or independently of each other.

  In addition, in order to simplify the following description, this embodiment demonstrates the case where the driving force which acts on the two wheels of the left and right rear wheels 13 and 14 is distributed to the left and right wheels. The vehicle 10 of the present embodiment employs a configuration in which the two left and right rear wheels 13 and 14 are driven by a main motor 17 and a sub motor 18 (that is, a rear wheel drive two-wheel motor vehicle). However, the disclosed technology is not limited to distributing the driving force acting on the wheels by the two left and right rear wheels 13 and 14 to the left and right wheels. For example, the driving force may be distributed between the left and right front wheels 11 and 12, or the driving force may be distributed among all four wheels. In FIG. 1, an arrow Df indicates the forward direction of the vehicle 10.

  The left and right rear wheels 13, 14 are transmitted with torque (driving force) by the main motor 17 and the sub motor 18 via the mechanism 16. The control unit 22 is connected to a drive unit 19 including a main motor 17 and a sub motor 18, and controls the main motor 17 and the sub motor 18 to drive each of the left and right rear wheels 13, 14 in the drive direction (or braking direction). The driving force for controlling is controlled. The control unit 22 is connected to a detection unit 21 that detects the traveling state of the vehicle 10 and a storage unit 23, and the detection control unit 20 includes the detection unit 21, the control unit 22, and the storage unit 23. doing. In addition, the traveling control apparatus 20 includes a calculation unit 24, which will be described in detail later (see FIG. 4).

The main motor 17 is mainly used to give a driving force in the front-rear direction, and the sub motor 18 is used to make a driving force difference between the left and right rear wheels 13 and 14. The total driving force in the front-rear direction is determined by the torque of the main motor 17. The torque (driving force) by the left and right rear wheels 13, 14 is shown in the following equation.
Fl + Fr = (Tm / G · R)
Fl = {(Tm / 2−Ts / 2) / (G · R)}
Fr = {(Tm / 2 + Ts / 2) / (G · R)}
However, Tm [Nm] represents the torque (driving force) of the main motor 17, and Ts represents the torque (driving force) of the sub motor 18. G represents the gear ratio of the differential gear, R [m] represents the wheel radius, and Fl and Fr [N] represent the driving forces of the left and right wheels.

As shown in FIG. 3, the yaw moment Mz generated when the driving force acting on the two left and right rear wheels 13 and 14 is distributed to the left and right wheels can be expressed by the following equation (1).
Mz = Fr · dr−F1 · dl (1)
However, dl and dr represent the distance from the center of gravity CL of the vehicle to the location where the left and right driving force is generated.

・・・（２）

ここで、Ｋｐを比例ゲインとし、ＫＩを積分ゲインとする。これらのゲインを適切に設定すれば、横風等の外乱により発生するヨーレートｒを抑制しつつ、車両１０の消費エネルギを抑制することができる。なお、ヨーモーメントｒの制御は、ＰＩ制御器を用いることに限定されるものではない。 Therefore, by controlling the yaw moment Mz by feeding back the yaw rate r in the vehicle 10, the yaw rate r generated by a disturbance such as a cross wind can be suppressed. In the present embodiment, as an example of controlling the yaw moment r, a PI controller represented by the following equation that feeds back the yaw rate r is used.

... (2)

Here, Kp is a proportional gain and KI is an integral gain. If these gains are set appropriately, the energy consumption of the vehicle 10 can be suppressed while suppressing the yaw rate r generated by disturbance such as cross wind. Note that the control of the yaw moment r is not limited to using the PI controller.

  FIG. 4 shows an example of the travel control device 20 including the control unit 22 that can control the yaw moment r using the PI controller. The control unit 22 is connected to a drive unit 19, a detection unit 21 that detects the traveling state of the vehicle 10, and a storage unit 23. The drive unit 19, the detection unit 21, the control unit 22, and the storage unit 23 are connected to the control unit 22. The travel control device 20 is configured.

  The detection unit 21 includes a first detection sensor 21 </ b> A, a second detection sensor 21 </ b> B, and a third detection sensor 21 </ b> C, and output signals from various sensors including the first to third detection sensors 31 to 33 are control units 22. Is input. The first detection sensor 21 </ b> A is configured as a detection sensor for detecting an operation state operated by the driver for driving the vehicle 10. The second detection sensor 21 </ b> B is configured as a detection sensor for detecting a running state of the vehicle 10, particularly a motion state generated in the vehicle 10 during running. The third detection sensor 21C is configured as a detection sensor for detecting a disturbance acting on the vehicle 10 during traveling.

  Examples of the first detection sensor 21A include a steering angle sensor that detects a driver's operation amount (steering angle δf) with respect to a steering wheel (not shown) for steering a vehicle. As another example of the first detection sensor 21A, an accelerator sensor for detecting an operation amount (depression amount, angle, pressure, etc.) by a driver with respect to an accelerator pedal (not shown) is provided in an engine (not shown). A throttle sensor that detects the opening of the throttle that operates according to the operation of the accelerator pedal, a brake sensor that detects the amount of operation (depression, angle, pressure, etc.) by the driver with respect to the brake pedal (not shown), parking brake ( A parking brake sensor that detects an on / off state (not shown), an ignition sensor that detects an on / off state of an ignition (not shown), a power storage sensor that detects a charge state of a power storage device (not shown), and the like.

  As the second detection sensor 21B, for example, a vehicle speed sensor that detects the vehicle speed V of the vehicle 10, a yaw rate sensor that detects the yaw rate r generated in the vehicle 10, a yaw acceleration sensor that detects yaw acceleration, the main motor 17 and the sub motor 18 flow. Examples include a current sensor that detects current, a motor rotation speed sensor that detects rotation speeds of the main motor 17 and the sub motor 18. Other examples of the second detection sensor 21B include a sprung vertical acceleration sensor that detects vertical acceleration in the vertical direction of the vehicle body 10A (on the spring), and a horizontal acceleration sensor that detects horizontal acceleration generated in the vehicle body 10A. A pitch rate sensor that detects a pitch rate generated in the vehicle 10, a roll rate sensor that detects a roll rate generated in the vehicle 10, and the like.

  As the third detection sensor 21 </ b> C, for example, a wind sensor that detects the wind force Fw with respect to the vehicle 10 can be cited. Regarding the wind force Fw to be detected, examples of the sensor for detecting the component include a wind speed sensor for detecting the wind speed Vw and a wind direction sensor for detecting the wind direction. Other examples of the third detection sensor 21C include a stroke sensor that detects a stroke amount of a suspension mechanism (not shown), an unsprung vertical acceleration sensor that detects vertical acceleration in the vertical direction below the spring of the vehicle 10, and the like. Can be mentioned.

  The control unit 22 has a function of outputting control signals for controlling the main motor 17 and the sub motor 18 based on output signals from various sensors including the first to third detection sensors 21A to 21C. In addition, the control unit 22 controls the yaw motion while running the vehicle 10 by appropriately controlling the distribution of the driving force to the left and right rear wheels 13 and 14 by the sub motor 18 with reference to the storage unit 23. Thereby, the control unit 22 can grasp and control the traveling state of the vehicle 10 and the behavior of the vehicle body 10A.

  As shown in FIG. 4, the control unit 22 includes an acquisition unit 22A, a determination unit 22B, and an output unit 22C.

  Signals are input from the first detection sensor 21A, the second detection sensor 21B, and the third detection sensor 21C to the acquisition unit 22A. Then, the acquiring unit 22A acquires, for example, the steering angle δf of the steering wheel by the driver based on the input signal from the first detection sensor 21A. Further, the acquisition unit 22A acquires, for example, the vehicle speed V and the yaw rate r of the vehicle 10 based on the input signal from the second detection sensor 21B. Furthermore, the acquisition unit 22A acquires, for example, the magnitude of the influence of the wind force Fw on the vehicle 10 (wind direction θw and wind speed Vw) based on the input signal from the third detection sensor 21C. In this way, the acquisition unit 22A outputs the acquired various detection values to the determination unit 22B.

  The determination unit 22B refers to the wind power Fw (wind direction θw and wind speed Vw) and the vehicle speed V acting on the vehicle 10 with reference to the storage unit 23 using the various detection values from the acquisition unit 22A. The distribution of the driving force of the left and right rear wheels 13 and 14 that reduces the energy consumption is determined (details will be described later). Then, the determination unit 22B outputs a command value (motor command torque) representing the determined torque to the output unit 22C.

  The output unit 45 outputs a drive signal corresponding to the torque determined by the determination unit 22B to the drive unit 19. Accordingly, the drive unit 19 controls the drive power (drive current) supplied to the main motor 17 and the sub motor 18 to drive each of them. As a result, drive torque is generated in the left and right rear wheels 13 and 14. Further, by driving the sub motor 18, the driving force to the left and right rear wheels 13, 14 is appropriately distributed and a yaw moment is generated.

  By the way, the storage unit 23 has information used to determine the distribution of the driving force of the left and right rear wheels 13 and 14 that reduce the energy consumption of the driving unit 19 with respect to the wind force Fw and the vehicle speed V acting on the vehicle 10. Stored in advance. That is, the control unit 22 determines the motor command torque by changing to the optimal control gain according to the information on the running state (vehicle speed V and wind power Fw) obtained at each time that changes from moment to moment, Generate yaw moment. That is, the control gain of the control unit 22 is a function of the vehicle speed V and the wind power Fw (wind direction θw and wind speed Vw) as shown in the following equation.

      K (Vu, Vv, Vw, θw) (3)

  Therefore, a function of the vehicle speed V and the wind force Fw is obtained in advance, and the obtained function is stored in the storage unit 23. Alternatively, the obtained function is tabulated and stored in the storage unit 23. Processing for storing the functions of the vehicle speed V and the wind power Fw in the storage unit 23 is performed by the calculation unit 24. The calculation unit includes a factor selection unit 24A, a factor graph creation unit 24B, a route derivation unit 24C, and a control gain derivation unit 24D.

  The factor selection unit 24A selects a physical quantity that serves as an evaluation index for each of vehicle motion performance and energy consumption.

  The factor graph creation unit 24B uses the physical quantity related to the vehicle motion performance, the physical quantity related to the consumed energy, the physical quantity related to the vehicle motion performance, and the physical quantity dependent on the physical quantity related to the energy to determine each physical quantity ( Create an initial factor graph as a node. The factor graph is a representation of the physical coupling relationship (details will be described later, see FIGS. 7 and 8).

  The route deriving unit 24C obtains a node having the maximum sensitivity among the nodes having a direct dependency on the node indicating the physical quantity related to the energy consumption in the initial factor graph, and determines the node having the direct dependency on the obtained node. Find the node with the highest sensitivity. This process is performed until the node having the maximum sensitivity reaches the physical quantity related to the vehicle motion performance, and a route connecting the node indicating the physical quantity related to the vehicle motion performance and the node indicating the physical quantity related to the consumed energy with the maximum sensitivity is obtained.

  The control gain deriving unit 24D obtains a travel state (vehicle speed V and wind power Fw (wind direction θw and wind speed Vw)) and control gain that maximizes energy consumption along the route, and obtains the travel state (vehicle speed V and wind power). The relationship between Fw (wind direction θw and wind speed Vw)) and control gain is stored in the storage unit 23.

  The control in the calculation unit 24 is control for obtaining the correspondence between the control gain of the control unit 22 and the vehicle speed V and the wind power Fw. The factor selection unit 24A, the factor graph creation unit 24B, the route derivation unit 24C, and the control gain derivation unit Each of 24D can be realized by an algorithm executed by a computer. Control in the control unit 22 can also be realized by an algorithm executed by a computer.

  FIG. 5 shows an example of a computer that can implement the travel control device 20 as a computer 40. The computer 40 includes a CPU 42, a memory (RAM) 44, a nonvolatile storage unit (ROM) 46, and an input / output port (I / O) 56, which are connected to each other via a bus 58. The I / O 56 includes a vehicle speed sensor 60, a wind speed sensor 61, a yaw rate sensor 62, a yaw acceleration sensor 63, a steering angle sensor 64, a current sensor 65, and a motor rotation, which are examples of the first detection sensor 21A to the third detection sensor 21C. The speed sensor 66, the main motor 17, and the sub motor 18 are connected. The wind speed sensor 61 can detect the wind direction θw.

  The storage unit 46 can be realized by an HDD (Hard Disk Drive), a flash memory or the like. A storage unit 46 as a recording medium stores a control program 48 for causing the computer 40 to function as the travel control device 20 and a map 54. The control program 48 includes a search process 50 and a distribution process 52. The CPU 40 reads the control program 48 from the storage unit 46 and develops it in the memory 44, and executes the search process 50 or the distribution process 52. Thereby, the computer 40 which executed the control program 48 operates as the traveling control device 20 shown in FIG.

  That is, the control unit 22 is realized by the computer 40, and the computer 42 operates as the control unit 22 shown in FIG. 4 by executing the distribution process 52 included in the control program 48. Further, when the CPU 42 executes the search process 50 included in the control program 48, the computer 40 operates as the arithmetic unit 24 shown in FIG.

  Next, the operation of the travel control device 20 will be further described along with the processing in the computer 40.

  FIG. 6 shows an example of the flow of the maximum sensitivity search process of the computer 40 that functions as the calculation unit 24 when the search process 50 included in the control program 48 is executed by the CPU 40.

  In the maximum sensitivity search process, the relationship between the driving state (vehicle speed V and wind power Fw (wind direction θw and wind speed Vw)) and control gain is coupled with the energy consumption E of the drive motor, the dynamics of the vehicle, and the aerodynamic characteristics. A numerical simulation based on a so-called full vehicle model is performed or an experiment is performed. Here, when obtaining the sensitivity and each design parameter, a numerical simulation is performed or an experiment is performed.

In the present embodiment, the dynamics and aerodynamic characteristics of the vehicle can be simulated using the lateral force model Msw based on the wind force Fw (wind direction θw and wind speed Vw) and the yaw moment model Mw based on the wind force Fw shown in the following equation.
Msw = Msw (Vu, Vv, Vw, β, βw, dβw, θw, δf, r)
Mw = Mw (Vu, Vv, Vw, β, βw, dβw, θw, δf, r)

  Here, the design parameters are a traveling state (vehicle speed V, wind power Fw (wind direction θw and wind speed Vw)) and a control gain. Further, the evaluation index is the vehicle motion performance and the energy consumption E.

  First, in step 100, the CPU 40 selects a physical quantity that serves as an evaluation index for each of vehicle performance and energy consumption. This step 100 corresponds to the function of the factor selection unit 24A. In the next step 102, each physical quantity is saved using a physical quantity related to vehicle motion performance, a physical quantity related to energy consumption, and a physical quantity related to the vehicle motion performance and a physical quantity related to energy consumption. Node) to create an initial factor graph. The processing in step 102 corresponds to the function of the factor graph creating unit 24B.

  FIG. 7 shows an example of an initial factor graph. The example shown in FIG. 7 shows an example. In FIG. 7, Δ represents a difference, Pm represents energy consumption [J] of the main motor 17, and Ps represents energy consumption [J] of the sub motor 18. Cd represents a drag coefficient, Cy represents a yaw moment coefficient, and Cs represents a lateral force coefficient.

  The physical quantity related to the vehicle movement performance selected as the physical quantity serving as the evaluation index of the vehicle movement performance is set as a node that indicates the difference between the vehicle speed V (Vu, Vv) and the yaw rate r. A node group indicating the physical quantities related to the selected vehicle motion performance is defined as a vehicle motion subgraph. In addition, a physical quantity related to a physical quantity serving as an evaluation index of energy consumption is a node indicating a difference in energy consumption Pm of the main motor 17 and a difference in energy consumption Ps of the sub motor 18. A node group indicating the physical quantities related to these energy consumptions was defined as an energy consumption subgraph. A physical quantity that is dependent on a physical quantity related to vehicle motion performance and a physical quantity related to energy is defined as a node indicating a difference between the slip angle β, the steering angle δf, the yaw angle βw, and the yaw angular velocity dβw. In addition, a node indicating a difference between the drag coefficient Cd, the yaw moment coefficient Cy, and the lateral force coefficient Cs is used. A node group indicating a physical quantity having a dependency relationship with the physical quantity related to the vehicle motion performance and the energy consumption is defined as an aerodynamic characteristic subgraph. In addition, in order to show that there is dependency between nodes as nodes, a line segment connecting between nodes (nodes) having dependency is used as an edge.

  Next, in step 104 of FIG. 6, a node (node) having the maximum sensitivity among the nodes having a direct dependency relationship with the node indicating the physical quantity related to the energy consumption in the initial factor graph is derived and obtained. Further, the node having the maximum sensitivity among the clauses having a direct dependency relationship with is further derived. In the next step 106, the process of step 104 is executed until the node having the maximum sensitivity reaches the physical quantity related to the vehicle motion performance, and the node indicating the physical quantity related to the vehicle motion performance and the node indicating the physical quantity related to the energy consumption are displayed. Derive a route with maximum sensitivity. Steps 104 and 106 correspond to the function of the route deriving unit 24C.

  In the next step 108, the running state (vehicle speed V, wind force Fw) and control gain are derived based on the route derived in step 106. That is, the traveling state (vehicle speed V and wind power Fw (wind direction θw and wind speed Vw)) and the control gain that maximize the energy consumption are obtained by following the route.

  In the next step 110, numerical calculation is performed by changing only a small value in the vicinity of the traveling state (vehicle speed V, wind force Fw) obtained in step 108 and the control gain, and performance determination is performed in the next step 112. In other words, when the driving state (vehicle speed V, wind force Fw) and control gain are changed by a minute value, the energy consumption exceeding a predetermined threshold is reduced by analyzing the numerical calculation result. In step 112, an affirmative determination is made, and this processing routine ends. On the other hand, if a negative determination is made in step 112, in step 114, the factor graph is corrected on the factor graph to remove edges and nodes having a sensitivity equal to or lower than a predetermined threshold, and then the process returns to step 104. If the processing from step 104 to step 110 exceeds the predetermined number of trials and a negative determination is made in step 112, new edges and nodes are added to the factor graph based on the physical phenomenon that has not been considered in the previous processing. The process returns to step 104 after adding. The processing from step 108 to step 114 corresponds to the function of the control gain deriving unit 24D.

  After the processing routine shown in FIG. 6 is completed, a corrected optimal graph is derived from the initial factor graph shown in FIG. 7, and a running state (vehicle speed V, wind power Fw) and an optimal control gain in which a control effect tends to appear are obtained. Here, Kv represents a control gain for control for maintaining the forward vehicle speed, and Kr represents a control gain for control for suppressing the yaw rate r.

  FIG. 9 shows the sensitivity of a node indicating a physical quantity difference directly coupled to a node indicating a difference in energy consumption of each motor in FIG. Differences in energy consumption of each motor are described in the first column, physical quantity differences in the second column, and numerical calculation conditions as an example in the third to ninth columns. The top two energy consumption differences are indices relating to the main motor 17, and the others are indices for the sub motor 18. The magnitude of the consumed energy E is E2> E1 >> E3> E5> E4, and the consumed energy E1 and the consumed energy E3 have a difference of 10 times or more. Therefore, although the energy consumption difference of the sub motor 18 is affected by various physical quantities, it is 1/10 or less of the main motor 17 and it can be confirmed that the sensitivity is low. In particular, since the difference ΔVv in the vehicle speed Vv in the vehicle width direction and the difference ΔCs in the lateral force coefficient are very small, it is considered that even if the corresponding node is deleted, the influence is small.

  FIG. 8 shows a factor graph after correction in which correction is performed by deleting nodes and edges that seemed to have little influence. As described above, since the influence of the aerodynamic characteristic change is smaller than the influence of the vehicle speed change, it can be confirmed that the energy is most easily consumed to maintain the vehicle speed V. That is, as shown by the thick arrows in FIG. 8, the route from the difference Δr of the yaw rate r to the difference ΔVu of the vehicle speed Vu in the vehicle traveling direction and the difference ΔPm of the energy consumption of the main motor 17 is the maximum sensitivity route. Thus, the driving state (vehicle speed V, wind force Fw) and the control gain that maximize the energy consumption difference in this route are derived.

  Incidentally, in order to increase the influence of the difference Δr of the yaw rate r on the difference ΔVu of the vehicle speed Vu in the vehicle traveling direction, it is necessary to increase the yaw moment Mz generated in the vehicle by the wind force Fw. Increasing the yaw moment Mz sets the vehicle speed V and the wind power Fw (wind direction θw and wind speed Vw) as large as possible. For example, a traveling state in which a vehicle 10 traveling at 100 km / h is subjected to a crosswind of 10 m / s (for example, a transverse direction perpendicular to the vehicle) (Vu = 100 [km / h], Vw = 10 [m / s]) Let us consider the case of searching for a traveling state (vehicle speed V, wind power Fw) and a control gain that maximize the energy consumption difference.

  FIG. 10 shows search positions and directions searched for the three types of traveling states from case 1 to case 3.

  A point DT shown in FIG. 10 represents an initial value, and an area AR0 is an area where a reduction in energy consumption cannot be expected from the initial value, and an area AR1 is an area where a reduction in energy consumption can be expected from the initial value. For this reason, it is only necessary to search in the area AR1, and three types of directionality from case 1 to case 3 can be considered. FIG. 11 shows that consumption is reduced when only the control gain Kr for controlling the yaw rate is varied by a minute value to easily obtain the possibility of reducing energy consumption in each driving state. Indicates the amount of energy. As shown in FIG. 11, the energy consumption is remarkably reduced in case 2, and the energy consumption is reduced next in case 1. From this, it can be confirmed that the larger the vehicle speed V and the wind power Fw (wind direction θw and wind speed Vw), the better, and the wind power Fw is more sensitive to the unit speed increase than the vehicle speed V.

  Therefore, when searching for the travel state (vehicle speed V, wind power Fw) and control gain, the area to be searched is narrowed down after determining the area AR0 where reduction of energy consumption cannot be expected and the area AR1 where reduction of energy consumption can be expected. As a result, the processing time until the maximum sensitivity point is reached can be shortened. In addition, if the energy consumption reduction level at a certain search point does not satisfy a predetermined reference value in the search process, the energy consumption reduction effect in the area AR0 is expected to be extremely small. Therefore, the energy consumption reduction level is a predetermined reference value. In the region that does not satisfy the condition, the optimization regarding the control gain Kr is not necessary, and the optimization regarding the control gain Kr may be performed within the range of the region AR1 in which the energy consumption reduction level is equal to or higher than a predetermined reference value. The efficiency of control gain adjustment according to the state (vehicle speed V, wind power Fw) is improved. If the sensitivity related to the aerodynamic characteristics is high, the control gain may be determined while considering the traveling state (vehicle speed V, wind force Fw) of the vehicle 10 in consideration of the aerodynamic characteristics.

  Next, the operation of the control unit 22 when the maximum sensitivity searching process is finished and the traveling state (vehicle speed V, wind power Fw) and the control gain of the vehicle 10 are stored in the storage unit 23 will be further described.

  FIG. 12 shows an example of the flow of distribution processing of the computer 40 that functions as the control unit 22 by executing the distribution process 52 included in the control program 48 by the CPU 40.

  First, in step 120, the CPU 40 acquires information such as sensor values based on input signals input from the first detection sensor 21A, the second detection sensor 21B, and the third detection sensor 21C. The process of step 120 corresponds to the function of the acquisition unit 22A.

  Next, in step 122, the CPU 40 refers to the storage unit 23 using the acquired various detection values, and sets a control gain for the wind force Fw (wind direction θw and wind speed Vw) and the vehicle speed V acting on the vehicle 10. By changing, the distribution of the driving force of the left and right rear wheels 13 and 14 where the energy consumption of the drive unit 19 is reduced is determined. In the next step 124, a command value (motor command torque) representing the determined torque is output. The process of step 122 corresponds to the function of the determination unit 22B, and the process of step 124 corresponds to the function of the output unit 22C.

  As described above, according to the present embodiment, the control of allocating the driving force to the left and right wheels is performed to suppress the yaw rate r generated by disturbance such as wind force, while suppressing the energy consumption of the vehicle 10. it can.

In addition, although this embodiment demonstrated the case where the wind force Fw was directly measured with a sensor, it is not limited to measuring a physical quantity directly with a sensor. That is, the wind force Fw (the wind direction θw and the wind speed Vw that are components thereof) can be estimated from the vehicle speed V, the yaw acceleration, and the steering angle δf without being detected by a sensor. Regarding the relationship between the vehicle yaw moment of inertia Iz, the yaw moment Mzw generated in the vehicle by the wind force Fw, the yaw moment Mzm generated in the vehicle 10 by the torque vectoring mechanism, the yaw moment Mzs generated in the vehicle 10 by steering and the yaw acceleration dr It is shown in equation (4).
Iz · dr = Mzw (Vu, Vv, Vw, θw, r) + Mzm + Mzs (Vu, Vv, r, δf)
... (4)

Using the expression (4), the information on the right side of the following expression (5) can be acquired, the yaw moment Mzw can be obtained, the yaw moment coefficient is known, and the vehicle speed V and the yaw rate r can be acquired. Therefore, the wind force Fw can be calculated backward.
Mzw (Vu, Vv, Vw, θw, r) = Iz · dr−Mzm−Mzs (Vu, Vv, r, δf)
... (5)
As a result, the control gain of the control unit 22 can be expressed as a function such as the following equation (6).
K (Vu, Vv, r, dr, δf) (6)

  In addition, although the case where each component of wind direction (theta) w and the wind speed Vw was used as the wind power Fw which is an example of a disturbance was demonstrated above, it is not limited to using both components. For example, the wind direction θw may be set to a predetermined wind direction θw0, and the wind force Fw may be approximately expressed using only the wind speed Vw that changes every moment. Alternatively, each component of the wind direction θw and the wind speed Vw may be classified into a predetermined number of stepwise physical quantities, and at least one of the physical quantities of the wind direction θw and the wind speed Vw may be made common within the classified fixed range. The wind direction θw is not limited to two dimensions, and may be three dimensions. The wind force Fw is not limited to the wind direction θw and the wind speed Vw. For example, a time component such as when the wind force Fw changes intermittently or when at least one of the wind direction θw and the wind speed Vw changes over time, etc. May be included.

(Second Embodiment)

  Next, a second embodiment will be described. In addition, since 2nd Embodiment is the structure similar to 1st Embodiment, it attaches | subjects the same code | symbol about the same structure, and abbreviate | omits description.

  FIG. 13 shows an example of the configuration of the drive mechanism of the vehicle 10 according to the present embodiment. The vehicle 10 shown in FIG. 13 uses an in-wheel motor mechanism as another example of a mechanism capable of adjusting the distribution of the driving force acting on the wheels with respect to the left and right wheels. In this embodiment, the main motor 17 and the sub motor 18 are provided with motors 30 and 32 inside the left and right rear wheels 13 and 14 corresponding to the motor.

  Since the in-wheel motor mechanism is directly attached to each wheel, the in-wheel motor mechanism can generate driving force independently on the left and right, and the total driving force in the front-rear direction is determined by the sum of the motor torques. Although the in-wheel motor mechanism is attached to the left and right rear wheels 13 and 14 in FIG. 13, the left and right front wheels 11 and 12 may be all four wheels.

The torque (driving force) by the left and right rear wheels 13, 14 according to this embodiment is shown in the following equation.
Fl = (Tl / R)
Fr = (Tr / R)
However, Tl [Nm] represents the torque (driving force) of the motor 30, and Tr represents the torque (driving force) of the motor 32.

・・・（７）
The present embodiment is an in-wheel motor mechanism that is different from the torque vectoring mechanism, but there is no difference in controlling the yaw moment Mz expressed by the equation (1). However, since the in-wheel motor mechanism is a left-right independent drive, coordinate conversion regarding the motor torque shown in the following equation is performed.

... (7)

That is, as in the case of the torque vectoring mechanism, Tm and Ts may be calculated based on the control law and converted to Tl and Tr using equation (7).
In the case of the torque vectoring mechanism, the energy consumption subgraph in the factor graph is composed of Pm and Ps. However, in the case of an in-wheel motor, it is replaced with Pl and Pr representing the energy consumption of the left and right wheel in-wheel motors. Become. The aerodynamic characteristic subgraph and the vehicle motion subgraph need not be changed.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments can be taken within the scope of the present invention. is there.

  In the above embodiment, the torque vectoring mechanism and the in-wheel motor mechanism have been described as an example of a mechanism capable of adjusting the distribution of the driving force acting on the wheels with respect to the left and right wheels. It is not limited to the in-wheel motor mechanism, and it is only necessary to have a mechanism capable of adjusting the distribution with respect to the left and right wheels.

  In the above-described embodiment, the process performed by executing the program stored in the storage unit has been described. However, the program process may be realized by hardware.

  Further, the processing in each of the above embodiments may be stored and distributed as a program in a storage medium such as an optical disk.

DESCRIPTION OF SYMBOLS 10 Vehicle 13, 14 Left and right rear wheel 15 Steering device 16 Mechanism part 17 Main motor 18 Sub motor 19 Drive part 20 Traveling control apparatus 21 Detection part 22 Control part 23 Storage part 24 Calculation part 30, 32 Motor 40 Computer

Claims (7)

A detection unit for detecting disturbance and vehicle speed acting on the vehicle;
A drive unit capable of independently driving each of a plurality of wheels provided in the vehicle;
A storage unit that stores the distribution of the driving force of the plurality of wheels, in which the energy consumed by the driving unit is reduced with respect to disturbance and vehicle speed acting on the vehicle;
While the vehicle is running, each of the plurality of wheels is driven by the distribution of the driving force of the plurality of wheels stored in the storage unit with respect to disturbance and vehicle speed acting on the vehicle detected by the detection unit. A control unit for controlling the drive unit,
A travel control device comprising: The disturbance applied to the vehicle is wind power to the vehicle.
The travel control device according to claim 1. The storage unit stores the distribution of the driving force of the plurality of wheels corresponding to the yaw moment that minimizes the energy consumption of the driving unit with respect to the disturbance and the vehicle speed.
The travel control apparatus according to claim 1 or 2. A plurality of motion performance nodes indicating vehicle performance including vehicle speed, a plurality of energy consumption nodes indicating energy consumption of a drive unit capable of independently driving each of a plurality of wheels provided in the vehicle, and the plurality of energy consumption nodes A factor representing a dependency relationship between at least one athletic performance node and at least one of the plurality of energy consumption nodes, and a plurality of dependent nodes indicating a disturbance given to the vehicle, by a path connecting the nodes. A factor model setting unit for setting a model;
In the factor model set by the factor model setting unit, a route setting unit that sets a route from the exercise performance node having a large dependency relationship between the nodes to the energy consumption node;
Based on the obtained route, a storage control unit that performs storage control for determining the distribution of the driving force of the plurality of wheels with respect to the disturbance and the vehicle speed and storing it in the storage unit;
The travel control device according to any one of claims 1 to 3, further comprising: an arithmetic unit including: Detect disturbances and vehicle speed acting on the vehicle,
While the vehicle is running, each of a plurality of wheels provided in the vehicle can be driven independently with respect to the detected disturbance and vehicle speed acting on the vehicle. The distribution of the driving force of the plurality of wheels with respect to the detected disturbance and the vehicle speed in the storage unit storing the distribution of the driving force of the plurality of wheels, which reduces the energy consumption of the driving unit. Controlling the drive so that each is driven,
A traveling control method including the above. A plurality of motion performance nodes indicating vehicle performance including vehicle speed, a plurality of energy consumption nodes indicating energy consumption of a drive unit capable of independently driving each of a plurality of wheels provided in the vehicle, and the plurality of energy consumption nodes A factor representing a dependency relationship between at least one athletic performance node and at least one of the plurality of energy consumption nodes, and a plurality of dependent nodes indicating a disturbance given to the vehicle, by a path connecting the nodes. Set up the model,
In the set factor model, set the path from the motor performance node having a large dependency between nodes to the energy consumption node,
Based on the obtained route, the distribution of the driving force of the plurality of wheels with respect to the disturbance and the vehicle speed is obtained and stored in the storage unit,
The driving | running | working control method of Claim 5 containing this. Detect disturbances and vehicle speed acting on the vehicle,
While the vehicle is running, each of a plurality of wheels provided in the vehicle can be driven independently with respect to the detected disturbance and vehicle speed acting on the vehicle. The distribution of the driving force of the plurality of wheels with respect to the detected disturbance and the vehicle speed in the storage unit storing the distribution of the driving force of the plurality of wheels, which reduces the energy consumption of the driving unit. Controlling the drive so that each is driven,
A traveling control program for causing a computer to execute processing including the above.

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