JP2008109833A - Electric cart - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric cart having a constitution where the cornering performance of which can be enhanced. <P>SOLUTION: The electric cart is equipped with a yaw moment calculating section 43 that calculates yaw moment YM from tire side forces Fya, Fyb of each of rear wheels 5a, 5b calculated by a tire side-force calculating section 39 and tire fore and aft forces Fxa, Fxb of each of rear wheels 5a, 5b calculated by a tire fore and aft force calculating section 41; a motor torque command value calculating section 45 that calculates a first motor torque command value TP1 of a fist electric motor 7 and a second motor torque command value TP2 of a second electric motor 11 so as to eliminate the difference between the calculated yaw moment YM and a target yaw moment GYM; and a motor control section 47, that controls the first motor 7 and the second motor 11, based on the calculated first motor torque command value TP1 and the second motor torque command value TP2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric cart such as an electric racing cart using an electric motor.

  In recent years, with the spread of motor sports, carts such as racing carts have been used by a wide range of age groups. In addition, a cart such as a racing cart is usually driven to rotate with the left and right rear wheels as drive wheels, and the left and right rear wheels are directly connected without a differential gear, and are integrated by a common engine or electric motor. It was rotationally driven.

In addition, there exist some which are shown to patent document 1 and patent document 2 as a prior art relevant to this invention.
JP-A-2005-231391 JP 2004-180800 A

  By the way, as described above, the left and right rear wheels of a cart such as a racing cart are directly connected without a differential gear, and are driven to rotate integrally by a common engine or electric motor. There are few things that do distribution control. In order to enable the driving force distribution control, it is necessary to provide a sensor for detecting the vehicle body speed, and the increase in cost due to this is inevitable. Therefore, when the engine torque of the engine or the motor torque of the electric motor is increased, the cart has a tendency to oversteer during cornering, which may cause spin. On the other hand, if the engine torque of the engine or the motor torque of the electric motor is reduced during cornering to try to avoid spin, the cart turning speed cannot be sufficiently secured. In short, the conventional cart has a problem that it is extremely difficult to improve cornering performance because it is difficult to perform advanced driving force distribution control due to various restrictions.

  Therefore, an object of the present invention is to provide an electric cart having a novel configuration that can sufficiently improve cornering performance.

  The first feature of the present invention (the feature of the invention described in claim 1) is detected in an electric cart that is driven to rotate independently by a first electric motor and a second electric motor with left and right rear wheels as drive wheels. Slip angle calculating means for calculating the slip angle of the rear wheel based on the steering angle and vehicle speed, and calculating the slip ratio of each rear wheel based on the vehicle speed and the detected wheel speed of each rear wheel. Slip rate calculating means, wheel load calculating means for calculating the wheel load of each rear wheel based on the detected lateral acceleration and detected longitudinal acceleration, the calculated slip angle of the rear wheel, and each calculated Tire lateral force calculating means for calculating the tire lateral force of each of the rear wheels by applying the wheel load of the rear wheel to tire lateral force data indicating a relationship between a tire lateral force, a slip angle, and a wheel load; Each of the rear wheels The tire front / rear force is calculated by applying the tire ratio and the calculated wheel load of each rear wheel to the tire longitudinal force data indicating the relationship between the tire longitudinal force, the slip ratio, and the wheel load. Force calculating means; and yaw moment calculating means for calculating a yaw moment around the center of gravity of the vehicle based on the calculated tire lateral force of each rear wheel and the calculated tire longitudinal force of each rear wheel. Motor torque command value calculating means for calculating the first motor torque command value of the first electric motor and the second motor torque command value of the second electric motor so as to eliminate the difference between the yaw moment and the target yaw moment. Motor control means for controlling the first electric motor and the second electric motor based on the first motor torque command value and the second motor torque command value. It is the gist of.

  According to the first feature, the yaw moment calculating means includes the tire lateral force of each rear wheel calculated by the tire lateral force calculating means and the tire front and rear of each rear wheel calculated by the tire longitudinal force calculating means. The yaw moment around the center of gravity of the vehicle is calculated based on the force, and the motor torque command value calculation means calculates the first motor torque of the first electric motor so as to eliminate the difference between the calculated yaw moment and the target yaw moment. A command value and a second motor torque command value of the second electric motor are calculated, and the motor control means is configured to calculate the first electric motor based on the calculated first motor torque command value and the second motor torque command value. Since the second electric motor is controlled, the motor torque of the entire electric motor (the motor torque of the first electric motor and the second electric motor The first motor torque of the first electric motor and the second motor torque of the second electric motor can be varied according to a change in cornering status of the electric cart without reducing the sum of the motor torques. . Specifically, the motor torque of the second electric motor is sufficiently larger than the motor torque of the first electric motor during left cornering, and the motor torque of the first electric motor is increased to the second electric motor during right cornering. It can be made sufficiently larger than the motor torque of the motor.

  The gist of the second feature of the present invention (feature of the invention described in claim 2) is that, in addition to the first feature, the target yaw moment is freely set to oversteer, neutral steer, and understeer. .

  The third feature of the present invention (the feature of the invention described in claim 3) is that, in addition to the first feature or the second feature, the tire lateral force data includes the relationship between the tire lateral force, the slip angle, and the wheel load. The tire longitudinal force data is a tire longitudinal force map indicating the relationship between the tire longitudinal force, the slip ratio, and the wheel load.

  The fourth feature of the present invention (the feature of the invention described in claim 4) is that, in addition to the first feature or the second feature, the tire lateral force data includes the relationship between the tire lateral force, the slip angle, and the wheel load. The tire formula longitudinal force data is a magic formula relational formula indicating the relationship between the tire longitudinal force, the slip ratio, and the wheel load.

  In addition to the first feature, a fifth feature of the present invention (a feature of the invention described in claim 5) is a first torque detecting means for detecting the torque of the first electric motor, and a torque of the second electric motor. And a vehicle body speed calculation means for calculating a vehicle body speed from the torque detected by the first torque detection means, the torque detected by the second torque detection means, and the detected longitudinal acceleration. This is the gist.

  According to the invention according to any one of claims 1 to 5, the first motor torque of the first electric motor and the first motor torque can be reduced without reducing the motor torque of the entire electric motor. Since the second motor torque of the two electric motors can be varied in accordance with the change in the cornering state of the electric cart, stable cornering can be easily performed while sufficiently securing the turning speed of the electric cart. The cornering performance of the cart can be sufficiently increased.

  In particular, according to the invention described in any one of claims 2 to 5, since the target yaw moment is set to be neutral steer, the steering characteristic of the electric cart is set to neutral steer. Alternatively, it can be kept close to neutral steer, and the cornering performance of the electric cart can be greatly improved.

  An embodiment of the present invention will be described with reference to FIGS.

  Here, FIG. 1 is a control block diagram of the electric racing cart according to the embodiment of the present invention, FIG. 2 is a schematic plan view of the electric racing cart according to the embodiment of the present invention, and FIG. 3 is a CPU in the controller. 4 is a flowchart of a series of motor control processes according to FIG. 4, FIG. 4 is a diagram illustrating tire lateral force / tire longitudinal force of each rear wheel, and yaw moment around the vehicle center of gravity, and FIG. 5 (a) is a tire lateral force map. FIG. 5B is a diagram showing the tire longitudinal force.

  As shown in FIG. 2, an electric racing cart 1 according to an embodiment of the present invention is one of electric carts, and includes a vehicle body frame 3 as a base. In addition, left and right rear wheels 5 a and 5 b are rotatably provided at the rear portion of the vehicle body frame 3, and left and right front wheels 5 c and 5 d are rotatably provided at the front portion of the vehicle body frame 3. A first electric motor 7 is provided at the left rear portion of the body frame 3, and an output shaft of the first electric motor 7 is connected to a rotation mechanism of the left rear wheel 5a with a gear mechanism 9 or a chain mechanism (not shown). (Not shown). Similarly, a second electric motor 11 is provided at the right rear portion of the body frame 3, and the output shaft of the second electric motor 11 is connected to the rotation mechanism of the right rear wheel 5b with a gear mechanism 13 or a chain mechanism ( (Not shown). That is, the electric racing cart 1 is driven to rotate independently by the first electric motor 7 and the second electric motor 11 using the left and right rear wheels 5a and 5b as driving wheels.

  A steering wheel 15 that snakes the left and right front wheels 5c and 5d is provided at the front portion of the vehicle body frame 3. Although not shown, a seat on which a driver is seated is disposed at the center of the body frame 3, and an accelerator pedal and a brake pedal are provided at the front of the body frame 3, respectively.

  A steering angle detection sensor 17 for detecting the steering angle δ is provided in the vicinity of the wheel shaft of the steering wheel 15, and a vehicle body speed detection sensor 19 for detecting the vehicle body speed V is provided at an appropriate position of the vehicle body frame 3. It has been. In addition, wheel speed detection sensors 21a and 21b for detecting wheel speeds Sa and Sb are provided in the vicinity of the rear wheels 5a and 5b, respectively. Furthermore, a lateral acceleration detection sensor 23 that detects lateral (left / right) acceleration and a longitudinal acceleration detection sensor 25 that detects longitudinal acceleration are provided at appropriate positions of the body frame 3.

  As shown in FIGS. 1 and 2, the vehicle body frame 3 is provided with a controller 27 for controlling the first electric motor 7 and the second electric motor 11, and the controller 27 includes a steering angle detection sensor. 17, body speed detection sensor 19, wheel speed detection sensors 21a and 21b, lateral acceleration detection sensor 23, and longitudinal acceleration detection sensor 25 are electrically connected. The controller 27 interprets a ROM (not shown) that stores a motor control program for controlling the first electric motor 7 and the second electric motor 11, and a motor control program stored in the ROM. CPU (not shown) to be executed and RaM (not shown) for providing a work area for the CPU. The ROM in the controller 27 has a function as the tire lateral force data storage unit 29 and a function as the tire longitudinal force data storage unit 31, and the CPU in the controller 27 functions as the slip angle calculation unit 33. , Function as slip ratio calculation unit 35, function as wheel load calculation unit 37, function as tire lateral force calculation unit 39, function as tire longitudinal force calculation unit 41, function as yaw moment calculation unit 43, motor torque It has a function as a command value calculation unit 45 and a function as a motor control unit 47. Details of each function are as follows.

  That is, the tire lateral force data storage unit 29 stores a tire lateral force map (see FIG. 5A) showing the relationship among the tire lateral force Fy, the slip angle θ, and the wheel load Fz as tire lateral force data. . A large number of actual tire lateral force maps are prepared for each wheel load Fz. The tire lateral force data storage unit 29 stores, as tire lateral force data, a relational expression of a magic formula indicating the relationship between the tire lateral force Fy, the slip angle θ, and the wheel load Fz instead of the tire lateral force map. It doesn't matter.

  The tire longitudinal force data storage unit 31 stores a tire longitudinal force map (see FIG. 5B) showing the relationship among the tire longitudinal force Fx, the slip ratio α, and the wheel load Fz as tire longitudinal force data. A large number of actual tire longitudinal force maps are prepared for each wheel load Fz. The tire longitudinal force data storage unit 31 may store a relational expression of a magic formula indicating the relationship between the tire longitudinal force Fx, the slip ratio α, and the wheel load Fz instead of the tire longitudinal force map.

The slip angle calculation unit 33 calculates the vehicle body speed V detected by the vehicle body speed detection sensor 19 and the steering angle δ detected by the steering angle detection sensor 17.
θ = f (δ, V) (1)
Is used to calculate the slip angle θ.

The slip ratio calculation unit 35 calculates the vehicle body speed V detected by the vehicle body speed detection sensor 19 and the wheel speeds Sa and Sb of the rear wheels 5a and 5b detected by the wheel speed detection sensors 21a and 21b.
α = (V−S) / S (2)
To calculate slip ratios αa and αb.

The wheel load calculator 37 calculates the lateral acceleration Gx detected by the lateral acceleration detection sensor 23 and the longitudinal acceleration Gy detected by the longitudinal acceleration detection sensor 25.
Fz = f (Gy, Gx) (3)
To calculate the wheel loads Fza and Fzb of the rear wheels 5a and 5b.

  The tire lateral force calculator 39 calculates the slip angle θ of the rear wheels 5a and 5b calculated by the slip angle calculator 33 and the wheel loads Fza and Fzb of the rear wheels 5a and 5b calculated by the wheel load calculator 37. Applying to the tire lateral force map stored in the tire lateral force data storage unit 29, the tire lateral forces Fya and Fyb (see FIG. 4) of the rear wheels 5a and 5b are calculated.

  The tire longitudinal force calculation unit 41 includes the slip rates αa and αb of the rear wheels 5a and 5b calculated by the slip rate calculation unit 35 and the wheel loads Fza and Fb of the rear wheels 5a and 5b calculated by the wheel load calculation unit 37, respectively. Fzb is applied to the tire longitudinal force map stored in the tire longitudinal force data storage unit 31 to calculate the tire longitudinal forces Fxa and Fxb (see FIG. 4) of the rear wheels 5a and 5b.

The yaw moment calculating unit 43 includes the tire lateral forces Fya and Fyb of the rear wheels 5a and 5b calculated by the tire lateral force calculating unit 39 and the tire front and rear of the rear wheels 5a and 5b calculated by the tire longitudinal force calculating unit 41. Forces Fxa and Fxb
YM = −Lr (Fya + Fyb) −1/2 Wt (Fxa−Fxb) (4)
To calculate the yaw moment YM (see FIG. 4) around the vehicle center of gravity position GC. Here, in the formula (4), Wt is the tread of the electric racing cart 1, and Lr is the distance in the front-rear direction between the axle of the rear wheels 5a and 5b and the vehicle center-of-gravity position GC (see FIG. 4).

  The motor torque command value calculation unit 45 performs the first electric motor so as to eliminate the difference between the yaw moment YM calculated by the yaw moment calculation unit 43 and the target yaw moment GYM set so as to become neutral steer from the equation of motion of the vehicle. The first motor torque command value TP1 of the motor 7 and the second motor torque command value TP2 of the second electric motor 11 are calculated. More specifically, the motor torque command value calculation unit 45 includes the yaw moment YM around the vehicle center of gravity position GC, the first motor torque of the first electric motor 7, and the second motor torque of the second electric motor 11. The yaw moment YM calculated by the yaw moment calculator 43 is applied to the relational expression, and the first motor torque command value TP1 of the first electric motor 7 and the second motor torque command value TP2 of the second electric motor 11 are obtained. It is to calculate. The target yaw moment can be set to be oversteer or understeer as well as neutral steer.

  The motor control unit 47 controls the first electric motor 7 and the second electric motor 11 based on the first motor torque command value TP1 and the second motor torque command value TP2 calculated by the motor torque command value calculation unit 45. It is. More specifically, the motor control unit 47 controls the current value supplied to the first electric motor 7 and the current value supplied to the second electric motor 11.

  Next, a series of motor control processes by the CPU in the controller 27 will be described with reference to FIG. Note that a series of motor control processes by the CPU in the controller 27 is executed every predetermined cycle (for example, 4 msec).

  First, the CPU in the controller 27 executes input signal detection processing for various detection sensors (step 1). Specifically, the CPU in the controller 27 detects input signals from the steering angle detection sensor 17, the vehicle body speed detection sensor 19, the wheel speed detection sensors 21 a and 21 b, the lateral acceleration detection sensor 23, and the longitudinal acceleration detection sensor 25. .

  After the end of step 1, the CPU in the controller 27 executes a calculation process of the slip ratio, slip angle, and wheel load (step 2). Specifically, the CPU (slip angle calculation unit 33) in the controller 27 applies the detected steering angle δ and the detected vehicle body speed V to the equation (1) to calculate the slip angle θ, The CPU (slip rate calculation unit 35) in the controller 27 applies the detected vehicle body speed V and the detected wheel speeds Sa and Sb of the rear wheels 5a and 5b to the equation (2), thereby determining the slip rate αa, αb is calculated. In addition, the CPU (wheel load calculation unit 37) in the controller 27 applies the detected lateral acceleration Gx and the detected longitudinal acceleration Gy to the equation (3) to determine the wheel load Fza of each rear wheel 5a, 5b, Fzb is calculated.

  After the end of step 2, the CPU in the controller 27 executes a calculation process of tire lateral force and tire longitudinal force (step 3). Specifically, the CPU (tire lateral force calculation unit 39) in the controller 27 outputs the calculated slip angle θ of the rear wheels 5a and 5b and the calculated wheel loads Fza and Fzb of the rear wheels 5a and 5b to the side of the tire. The tire lateral forces Fya and Fyb of the rear wheels 5a and 5b are calculated by applying to the force map. Further, the CPU (tire front / rear force calculation unit 41) in the controller 27 uses the calculated slip rates αa, αb of the rear wheels 5a, 5b and the calculated wheel loads Fza, Fzb of the rear wheels 5a, 5b before and after the tires. Applying to the force map, the tire longitudinal force Fxa, Fxb of each rear wheel 5a, 5b is calculated.

  After the end of step 3, the CPU in the controller 27 executes yaw moment calculation processing (step 4). Specifically, the CPU (yaw moment calculator 43) in the controller 27 calculates the calculated tire lateral forces Fya and Fyb of the rear wheels 5a and 5b and the calculated tire longitudinal forces Fxa and of the rear wheels 5a and 5b. Fxb is applied to the equation (4) to calculate the yaw moment YM around the vehicle center of gravity position GC.

  After the end of step 4, the CPU in the controller 27 executes a motor torque command value calculation process (step 5). Specifically, the CPU (motor torque command value calculation unit 45) in the controller 27 performs the first electric motor so as to eliminate the difference between the calculated yaw moment YM and the target yaw moment GYM set to be neutral steer. The first motor torque command value TP1 of the motor 7 and the second motor torque command value TP2 of the second electric motor 11 are calculated.

  After the end of step 5, the CPU in the controller 27 executes a motor torque control process (step 6). Specifically, the CPU (motor control unit 47) in the controller 27 controls the first electric motor 7 and the second electric motor 11 based on the calculated first motor torque command value TP1 and second motor torque command value TP2. Control.

  In the embodiment described above, the example in which the vehicle body speed V is detected by the vehicle body speed detection sensor 19 has been described. However, the vehicle body speed can also be calculated from the torque and longitudinal acceleration of the motor related to driving. Hereinafter, an example in which the vehicle body speed is calculated from the torque of the first electric motor 7 directly connected to the left and right rear wheels of the electric cart 1, the torque of the second electric motor 11, and the longitudinal acceleration will be described.

  In the control block of the electric racing cart shown in FIG. 6, those having the same functions as those in the configuration shown in FIG. The control block shown in FIG. 6 includes a first motor torque detection sensor 53 that detects the torque of the first electric motor 7 and a second motor torque detection sensor 55 that detects the torque of the second electric motor 11. Includes a vehicle body speed calculation unit 57 that calculates the vehicle body speed V from the motor torque detected by the torque detection sensors and the longitudinal acceleration detected by the longitudinal acceleration detection sensor 25.

  Since the vehicle body speed can be calculated by the vehicle body speed calculation unit 57 in the controller 51, the vehicle body speed detection sensor 19 shown in FIG. 1 need not be provided in the present embodiment shown in FIG.

  Next, a series of motor control processes by the CPU in the controller 51 will be described with reference to FIG. Note that a series of motor control processes by the CPU in the controller 51 is executed every predetermined cycle (for example, 4 msec).

  The CPU in the controller 51 executes input signal detection processing for various detection sensors (step 11). Specifically, the CPU in the controller 51 detects input signals from the steering angle detection sensor 17, the vehicle body speed detection sensor 19, the wheel speed detection sensors 21 a and 21 b, the lateral acceleration detection sensor 23, and the longitudinal acceleration detection sensor 25. .

  After the end of step 11, the CPU (vehicle speed calculation unit 57) in the controller 51 includes a first motor torque detection sensor 53, a second motor torque detection sensor 55, and the motor torque detected by these torque detection sensors. The vehicle body speed is calculated from the longitudinal acceleration detected by the longitudinal acceleration detection sensor 25 (step 12).

  After the end of step 12, the CPU in the controller 27 executes a calculation process of the slip ratio, slip angle, and wheel load (step 13). The subsequent steps 13 to 17 are the same as the steps 2 to 6 shown in FIG. That is, the CPU (slip angle calculation unit 33) in the controller 27 applies the detected steering angle δ and the detected vehicle body speed V to the equation (1) to calculate the slip angle θ, and in the controller 27. The CPU (slip rate calculating unit 35) applies the vehicle body speed V calculated in step 12 and the detected wheel speeds Sa and Sb of the rear wheels 5a and 5b to the above equation (2), thereby determining the slip rate αa, αb is calculated. In addition, the CPU (wheel load calculation unit 37) in the controller 27 applies the detected lateral acceleration Gx and the detected longitudinal acceleration Gy to the equation (3) to determine the wheel load Fza of each rear wheel 5a, 5b, Fzb is calculated.

  After the end of step 13, the CPU in the controller 27 executes a tire lateral force / tire longitudinal force calculation process (step 14). Specifically, the CPU (tire lateral force calculation unit 39) in the controller 27 outputs the calculated slip angle θ of the rear wheels 5a and 5b and the calculated wheel loads Fza and Fzb of the rear wheels 5a and 5b to the side of the tire. The tire lateral forces Fya and Fyb of the rear wheels 5a and 5b are calculated by applying to the force map. Further, the CPU (tire front / rear force calculation unit 41) in the controller 27 uses the calculated slip rates αa, αb of the rear wheels 5a, 5b and the calculated wheel loads Fza, Fzb of the rear wheels 5a, 5b before and after the tires. Applying to the force map, the tire longitudinal force Fxa, Fxb of each rear wheel 5a, 5b is calculated.

  After the end of step 14, the CPU in the controller 27 executes yaw moment calculation processing (step 15). Specifically, the CPU (yaw moment calculator 43) in the controller 27 calculates the calculated tire lateral forces Fya and Fyb of the rear wheels 5a and 5b and the calculated tire longitudinal forces Fxa and of the rear wheels 5a and 5b. Fxb is applied to the equation (4) to calculate the yaw moment YM around the vehicle center of gravity position GC.

  After the end of step 15, the CPU in the controller 27 executes a motor torque command value calculation process (step 16). Specifically, the CPU (motor torque command value calculation unit 45) in the controller 27 performs the first electric motor so as to eliminate the difference between the calculated yaw moment YM and the target yaw moment GYM set to be neutral steer. The first motor torque command value TP1 of the motor 7 and the second motor torque command value TP2 of the second electric motor 11 are calculated.

  After the end of step 16, the CPU in the controller 27 executes a motor torque control process (step 17). Specifically, the CPU (motor control unit 47) in the controller 27 controls the first electric motor 7 and the second electric motor 11 based on the calculated first motor torque command value TP1 and second motor torque command value TP2. Control.

  Then, the effect | action and effect of embodiment of this invention are demonstrated.

  The yaw moment calculating unit 43 includes the tire lateral forces Fya and Fyb of the rear wheels 5a and 5b calculated by the tire lateral force calculating unit 39 and the tire front and rear of the rear wheels 5a and 5b calculated by the tire longitudinal force calculating unit 41. The forces Fxa and Fxb are applied to the equation (4) to calculate the yaw moment YM, and the motor torque command value calculation unit 45 performs the first electric motor so as to eliminate the difference between the calculated yaw moment YM and the target yaw moment GYM. The first motor torque command value TP1 of the motor 7 and the second motor torque command value TP2 of the second electric motor 11 are calculated, and the motor control unit 47 calculates the calculated first motor torque command value TP1 and second motor torque command. Since the first electric motor 7 and the second electric motor 11 are controlled based on the value TP2, the motor torque of the entire electric motor (of the first electric motor 7). The motor torque of the first electric motor 7 and the second motor torque of the second electric motor 11 can be calculated in the cornering state of the electric racing cart 1 without reducing the motor torque and the motor torque of the second electric motor 11. It can be varied according to changes. Specifically, the motor torque of the second electric motor 11 is sufficiently larger than the motor torque of the first electric motor 7 during the left cornering, and the motor torque of the first electric motor 7 is set to the second electric motor during the right cornering. The motor torque of the motor 11 can be made sufficiently larger.

  As described with reference to FIGS. 6 and 7, the first motor torque detection sensor 53 that detects the torque of the first electric motor 7 and the second motor torque detection sensor that detects the torque of the second electric motor 11. 55, and the controller 51 includes a vehicle body speed calculation unit 57 that calculates the vehicle body speed from the motor torque detected by these torque detection sensors and the longitudinal acceleration detected by the longitudinal acceleration detection sensor 25. It is possible to perform advanced driving force distribution control without providing a vehicle body speed sensor or the like for detecting the above. Thereby, the cost increase by a vehicle body speed sensor etc. can be reduced.

  Therefore, according to the embodiment of the present invention, stable cornering can be easily performed while sufficiently securing the turning speed of the electric racing cart 1, and the cornering performance of the electric racing cart 1 can be sufficiently enhanced. . In particular, since the target yaw moment GYM is set to be neutral steer, the steering characteristics of the electric racing cart 1 can be maintained at a neutral steer or a state close to neutral steer, and the cornering performance of the electric racing cart 1 can be greatly improved. Can be improved.

  In addition, this invention is not restricted to description of the above-mentioned embodiment, In addition, it can implement in a various aspect. Further, the scope of rights encompassed by the present invention is not limited to these embodiments.

It is a control block diagram of the electric racing cart according to the embodiment of the present invention. 1 is a schematic plan view of an electric racing cart according to an embodiment of the present invention. It is a flowchart of a series of motor control processing by CPU in a controller. It is a figure explaining the tire lateral force of each rear wheel, the tire longitudinal force, and the yaw moment around the vehicle gravity center position. FIG. 5A shows a tire lateral force map, and FIG. 5B shows a tire longitudinal force. It is a control block diagram of the electric racing cart which concerns on another embodiment of this invention. It is a flowchart of a series of motor control processing by CPU in the controller of the electric racing cart which concerns on another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric racing cart 3 Body frame 5a, 5b Rear wheel 5c, 5d Front wheel 7 1st electric motor 11 2nd electric motor 17 Steering angle detection sensor 19 Vehicle body speed detection sensor 21a, 21b Wheel speed detection sensor 23 Lateral acceleration detection sensor 25 Front and rear Acceleration detection sensor 27 Controller 29 Tire lateral force data storage unit 31 Tire longitudinal force data storage unit 33 Slip angle calculation unit 35 Slip rate calculation unit 37 Wheel load calculation unit 39 Tire lateral force calculation unit 41 Tire longitudinal force calculation unit 43 Yaw moment calculation Unit 45 motor torque command value calculation unit 47 motor control unit 51 controller 53 first motor torque detection sensor 55 second motor torque detection sensor 57 vehicle body speed calculation unit

Claims (5)

In the electric cart that is driven to rotate independently by the first electric motor and the second electric motor using the left and right rear wheels as drive wheels,
Slip angle calculating means for calculating the slip angle of the rear wheel based on the detected steering angle and vehicle body speed;
Slip ratio calculating means for calculating a slip ratio of each rear wheel based on a vehicle body speed and a detected wheel speed of each rear wheel;
Wheel load calculating means for calculating the wheel load of each of the rear wheels based on the detected lateral acceleration and the detected longitudinal acceleration;
Applying the calculated slip angle of the rear wheel and the calculated wheel load of each rear wheel to tire lateral force data indicating the relationship between the tire lateral force, the slip angle, and the wheel load, the tire of each rear wheel Tire lateral force calculating means for calculating lateral force;
The calculated slip ratio of each rear wheel and the calculated wheel load of each rear wheel are applied to the tire longitudinal force data indicating the relationship between the tire longitudinal force, the slip ratio, and the wheel load. Tire longitudinal force calculating means for calculating tire longitudinal force;
A yaw moment calculating means for calculating a yaw moment around the center of gravity of the vehicle based on the calculated tire lateral force of each rear wheel and the calculated tire longitudinal force of each rear wheel;
Motor torque command value calculating means for calculating the first motor torque command value of the first electric motor and the second motor torque command value of the second electric motor so as to eliminate the difference between the calculated yaw moment and the target yaw moment;
Motor control means for controlling the first electric motor and the second electric motor based on the calculated first motor torque command value and the second motor torque command value;
An electric cart comprising:   The electric cart according to claim 1, wherein the target yaw moment is freely set to oversteer, neutral steer, or understeer.   Tire lateral force data is a tire lateral force map showing the relationship between tire lateral force, slip angle and wheel load, and tire longitudinal force data is a tire longitudinal force map showing the relationship between tire longitudinal force, slip ratio and wheel load. The electric cart according to claim 1 or 2, characterized in that   The tire lateral force data is a relational expression of the magic formula that indicates the relationship between the tire lateral force, the slip angle, and the wheel load. The tire longitudinal force data is the magic formula that indicates the relationship between the tire longitudinal force, the slip ratio, and the wheel load. The electric cart according to claim 1, wherein the electric cart is a relational expression. First torque detecting means for detecting the torque of the first electric motor;
Second torque detecting means for detecting the torque of the second electric motor;
The vehicle body speed calculating means for calculating a vehicle body speed from the torque detected by the first torque detecting means, the torque detected by the second torque detecting means, and the detected longitudinal acceleration. The electric cart according to 1.

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