JP2015024013A - Personal vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a personal vehicle which comprises means capable of detecting tangential velocity of the vehicle body at an inexpensive price.SOLUTION: An operation part possesses a pole-like member which is supported so as to be enabled to sway in the front, rear, left and right directions, and which inputs a target vehicle speed by the scale of a tilt in the front and back direction and inputs a target tangential velocity by the scale of a tilt in the right and left direction. Control to make the mean value of the turning angles αR, αL of casters 15R, 15L which are employed as front-wheels close to the swaying direction of the pole-like member is performed.

Description

  The present invention relates to a personal vehicle such as an electric wheelchair.

  A personal vehicle such as a wheelchair has a vehicle body having a seating portion on which a user is seated, and wheels that are drive wheels provided on the left and right of the user seated on the seating portion. The body of a personal vehicle is provided with an operation unit to which command values relating to the vehicle running speed and the turning angular velocity of the vehicle are input, and the vehicle traveling direction and speed are controlled by controlling the rotation speed of the left and right wheels. doing.

  By the way, when the personal vehicle travels straight while tilting to the left or right, such as in a direction crossing an inclined road surface (hereinafter referred to as cant travel), the roll axis (front-rear direction axis) of the vehicle body is used as the rotation axis. Depending on the roll angle to be performed, there is a risk that the straight traveling performance of the vehicle body is reduced. In other words, when the cant is running, the vehicle body slips on the road surface due to the inclination of the vehicle body (single flow) even though the user operates the operation unit so that the personal vehicle runs straight ahead. May occur, and the straight running performance of the personal vehicle may be impaired. Specifically, when the vehicle body tilts to the left and right, the center of gravity of the personal vehicle in the state where the user is seated is ahead of the rotation axis of the wheel, so that a turning moment in a direction in which the vehicle body can be bent is generated. If the car body is tilted, it will turn and slide down.

  The applicant of the present application discloses a personal vehicle in which the above problems are reduced in Patent Document 1. The personal vehicle control device disclosed in Patent Document 1 suppresses slipping of the vehicle body as long as the operation unit is operated straight ahead even when the roll angle of the personal vehicle is large when the personal vehicle cant travel. And a control unit that controls the personal vehicle so as to ensure straight running performance. The control unit performs feedback correction or the like so that the difference between the actual turning angular velocity of the vehicle body and the turning angular velocity command value determined by the user's operation is reduced. Therefore, it is necessary to accurately detect the turning angular velocity of the vehicle body in order to improve straight running performance during cant traveling.

  Further, in Patent Document 2, a front wheel turning restraining means is provided in a free caster for the front wheels, and during straight running (when the currents to the motors that drive the left and right wheels are the same), the turning of the front wheels is restrained during canting. It is restricted so that it does not fall down.

  For this reason, in Patent Document 2, it is necessary to start the turn after releasing the front wheel turning restraining means when turning left and right from straight running, so the reaction at the time of turning becomes slow and the user feels uncomfortable. In addition, since the currents of the left and right motors may be different even when the vehicle is traveling straight, if the currents are different when traveling straight, there is a possibility of unintended vehicle body movement. In addition, when the current supplied to the left and right motors is the same, the front wheel free caster turns are fixed to secure straight travel, so even if the current value is not the same due to road conditions, etc. It is difficult to prevent a decrease in straightness.

JP 2010-193939 A JP-A-3-218756

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is a problem to be solved to provide a personal vehicle having means capable of detecting the turning speed of the vehicle body at low cost for use in vehicle body control. And

The structural feature of the invention of (1) for solving the above-mentioned problems is a vehicle body having a seating portion on which a user is seated,
Left and right wheels provided on the left and right of the vehicle body;
A drive unit for driving the left and right wheels;
An operation unit for inputting a command value signal including a target turning angular velocity of the vehicle body;
A control unit that receives the command value signal and controls the drive unit based on the command value signal;
One or more casters that are positioned in at least one of the longitudinal directions of the vehicle body and that freely rotate and follow the movement of the vehicle body;
A caster sensor for detecting an actual caster turning angle in at least one of the casters;
Have
The controller is
A target turning angle calculation unit for calculating a target caster turning angle of the caster from the command value signal;
And a feedback control unit that controls the drive unit so that a difference between the target caster turning angle and the actual caster turning angle is small.

  In the personal vehicle of the present invention, the turning angular velocity of the vehicle body can be accurately detected by detecting the movement of the caster. Further, a sensor that detects the turning angle of the caster can be made cheaper than a sensor such as a gyro that detects the turning angular velocity of the vehicle body.

  The invention of the above (1) can be adopted by arbitrarily adding the structure of (2) described below.

(2) The operation unit is supported so as to be able to swing in the front-rear and left-right directions for inputting the target vehicle speed according to the magnitude of the inclination in the front-rear direction and for inputting the target turning angular velocity according to the magnitude of the inclination in the left-right direction. It has a bowl-shaped member,
The target turning angle calculation unit sets the target caster turning angle as the swinging direction of the bowl-shaped member.

  When adopting a configuration (a target vehicle speed in the front-rear direction and a target turning angular velocity in the left-right direction) that uses a saddle-shaped member that can swing back and forth and left and right as the operation unit, By adopting the tilted direction of the shaped member as the target turning angle of the caster as it is, the traveling direction intended by the user and the traveling direction of the vehicle body can be matched sensibly to the user, and the feeling of use is improved. .

(3) A structural feature for solving the above problems is a vehicle body having a seating portion on which a user is seated;
Left and right wheels provided on the left and right of the vehicle body;
A drive unit for driving the left and right wheels;
An operation unit for inputting a command value signal including a target turning angular velocity of the vehicle body;
A control unit that receives the command value signal and controls the drive unit based on the command value signal;
One or more casters that are positioned in at least one of the longitudinal directions of the vehicle body and that freely rotate and follow the movement of the vehicle body;
A caster sensor for detecting an actual caster turning angle in at least one of the casters;
A rotational speed sensor for detecting an actual rotational speed of the left and right wheels;
Have
The controller is
An actual turning angular velocity calculation unit that calculates an actual turning angular velocity of the vehicle body from the actual caster turning angle and the actual wheel rotation speed; and the drive unit that reduces a difference between the target turning angular velocity and the actual turning angular velocity. And a feedback control unit to control.

  In the personal vehicle of the present invention, the turning angular velocity of the vehicle body can be accurately detected from the motion of the caster and the speed of the personal vehicle calculated from the rotational speed of the wheels. Further, a sensor that detects the turning angle of the caster can be made cheaper than a sensor such as a gyro that detects the turning angular velocity of the vehicle body.

  The above inventions (1) to (3) can be adopted by arbitrarily adding the structure of (4) described below.

(4) There are two or more casters and caster sensors,
The controller is
When the difference between the two or more actual caster turning angles detected by the two or more caster sensors is larger than a predetermined value, the feedback control unit is not operated.

  The turning of the caster may be obstructed by involving an obstacle. In such a case, the turning angle of the caster shows a value unrelated to the turning angular velocity of the vehicle body. Therefore, two or more casters were provided, and the turning angle of these casters was measured. Even if there are multiple casters, their swivel angles should show similar values in principle, so verifying these measurements against each other verifies that there are no problems with the swivel of the casters. it can.

  In the inventions of (1) and (3), the turning angular velocity of the vehicle body can be accurately detected by detecting the movement of the casters. That is, since the caster turns following the movement of the vehicle body, the direction in which the vehicle body advances and the turning angular velocity can be known from the turning angle of the caster. Since the vehicle traveling direction and the turning angular velocity can be detected with high accuracy, the personal vehicle can be controlled smoothly.

  By adopting the configuration (2), the operation by the user and the actual movement of the personal vehicle can be easily matched, and the operation of the vehicle body can be brought closer to the direction intended by the user.

  By adopting the configuration of (4), highly reliable control can be realized even when a caster malfunction occurs.

It is a side view explaining typically the state where the personal vehicle of an embodiment is running straight on a flat ground. FIG. 2 is a side view schematically illustrating a state in which the personal vehicle illustrated in FIG. 1 is traveling in an upward direction on an inclined road surface. It is a block diagram explaining the structure of the control apparatus of the personal vehicle of embodiment. It is explanatory drawing explaining the form which filters the physical quantity based on an acceleration signal and a rate gyro signal, and calculates a road surface inclination angle. FIG. 2 is a rear view schematically illustrating a state where the personal vehicle shown in FIG. It is explanatory drawing explaining the form which filters the physical quantity based on an acceleration signal and a rate gyro signal, and calculates the roll angle of a road surface. It is the schematic which shows the structure of the front wheel with which the personal vehicle in embodiment is provided. It is a top view explaining typically the state where the personal vehicle of an embodiment is carrying out the right turn turning of a flat ground. FIG. 10 is a schematic diagram illustrating an operation state of an operation unit included in a personal vehicle according to a second embodiment. It is a block diagram which shows the control law which the control part with which the personal vehicle control apparatus of the modification 1 is provided.

(Embodiment 1)
In the present embodiment, the personal vehicle 1 (hereinafter simply referred to as the vehicle 1) corresponds to an electric wheelchair. FIG. 1 is a side view schematically illustrating a state in which the vehicle 1 of the embodiment is traveling straight on a flat ground. In FIG. 1, the front (arrow Fx direction) indicates the direction in which the face of the user who is normally seated on the vehicle 1 is facing, and the direction in which the vehicle 1 moves forward. The rear (arrow Rx direction) indicates the direction in which the face of the user who is normally seated on the vehicle 1 is facing away, and indicates the direction in which the vehicle 1 moves backward. FIG. 2 is a side view schematically illustrating a state in which the personal vehicle 1 shown in FIG. 1 is traveling in an upward direction on an inclined road surface 90. FIG. 5 schematically shows a state in which the road 90 on which the personal vehicle 1 shown in FIG. 1 is inclined is traveling in a direction (toward the back of the page) perpendicular to the inclination (downward direction). FIG.

  The vehicle 1 includes a vehicle body 11 having a seating portion 10 on which a user is seated, left and right wheels 12R and 12L that are rotatable drive wheels attached to the left and right of the vehicle body 11, and a drive source that rotationally drives the wheels 12. Left and right wheel motors 13R and 13L, an operation unit 14 for operating the wheel motors 13R and 13L, a rotatable front wheel 15 positioned in front of the wheel 12 and attached to the vehicle body 11, and the wheel 12 The support member 16 is attached to the vehicle body 11 so as to extend rearward, and the rotatable rear wheel 17 is attached to the distal end portion 16a of the support member 16. The seating portion 10 includes a seat portion 10a that supports the user's buttocks and a backrest portion 10b that supports the user's back.

  The left and right wheels 12R and 12L have a rim fixed to a rotating shaft by spokes or the like and an elastically deformable tire such as a tubular tire disposed on the rim. The rotation axis that connects the rotation centers 12a (see FIGS. 1 and 2) of the left and right wheels 12R and 12L is arranged directly below or near the center of gravity G in the front-rear direction of the vehicle 1. The front wheel 15 is a caster having a diameter smaller than the diameters of the left and right wheels 12R and 12L. The front wheels 15 are provided on the left and right, but in some cases, a single wheel may be provided near the center in the vehicle width direction. The front wheel 15 is supported on the vehicle body 11 such that the wheel 152 and the fork 151 for rotatably supporting the wheel 152 by the bearing 150 and the fork 151 can be turned freely about the axis S as a turning axis. The vehicle body 11 is disposed via a potentiometer 54. The axis S is oriented in the vertical direction (± Z direction in FIGS. 1 and 2). In addition to the potentiometer, a sensor capable of detecting the rotation angle such as a rotary encoder can be adopted.

  In the fork 151, the axis S, which is a pivot axis, and the axis of the bearing 150 that supports the wheel 152 are in a torsional relationship with a distance a shown in FIG. Therefore, the front wheels 15R and 15L turn by the movement of the vehicle body 11. Specifically, the fork 151 supported by the shaft S is pulled in the traveling direction of the vehicle body 11 by the shaft S, pulled in the direction opposite to the traveling direction by the bearing 150, and as a result, the direction FR extending from the bearing 150 to the shaft S. , FL will turn so that the front wheels 15R, 15L will coincide with the direction of movement of the part where the vehicle body 11 supports the front wheels 15R, 15L. Since the shaft S and the fork 151 are arranged so as to be relatively rotatable with respect to each other, the turning angle (actual caster turning angle) of the front wheels 15R and 15L is the speed of the vehicle body at the position where the front wheels 15R and 15L are provided (moving direction). ) Is well reflected. Therefore, if the turning angle of the front wheel 15 can be detected, the moving direction of the portion of the vehicle body 11 on which the front wheel 15 is supported can be calculated. Here, the smaller the value of the distance a, the more detailed the movement of the vehicle body can be followed, and the turning angular velocity is quickly reflected in the turning angle of the front wheel 15, and the larger the value of the distance a, the disturbance not related to the turning angular velocity. Therefore, the size of the interval a is set so that necessary performance can be obtained.

  Hereinafter, the outline of the relationship between the turning angle of the front wheel 15, the turning angular speed of the vehicle body, and the speeds of the wheels 12R and 12L will be described. As shown in FIG. 8, when the two front wheels 15R and 15L are arranged on the front extension line from the left and right wheels 12R and 12L, that is, the tread of the driving wheel having a length between the wheels 12R and 12L. Consider the case where the front wheel tread, which is the distance between T and the front wheels 15R, 15L, is the same. Then, since the tread of the front wheel is the same as the tread of the driving wheel, the speed of the right wheel 12R and the speed of the right front wheel 15R are the same, and the speed of the left wheel 12L and the speed of the left front wheel 15L are Be the same.

  It is assumed that the personal vehicle moves forward while turning right under these conditions. First, when the speed of the right wheel 12R is VR and the speed of the left wheel 12L is VL, VL> VR because the vehicle is turning right. The turning angular velocities of the vehicle body are both equal to ωgyaw (= (VR−VL) / T), and have a speed component in the turning direction at a speed corresponding to the distance from the rotation center of the vehicle body.

  Therefore, the turning angle αR of the right front wheel 15R is a direction obtained by combining VR and the turning speed derived from the turning angular speed at the positions of the front wheels 15R and 15L calculated from ωgyaw, and the turning angle αL of the left front wheel 15L is VL. And ωgyaw. Therefore, the turning angular velocity ωgyaw can be calculated from the turning angles αR, αL detected from the front wheels 15R, 15L and the speeds VR, VL of the left and right wheels 12R, 12L calculated from the rotational speeds of the left and right wheels 12R, 12L. The center of gravity of the personal vehicle is the position of the center of gravity (the position G where the center of gravity is projected at the height of the rotational axis of the wheels 12R, 12L in the ± Z direction of the personal vehicle (the vertical line from the center of gravity is the rotational axis of the wheels 12R, 12L) It can be approximated that there is a position that intersects a horizontal plane))). In that case, the inclination of the vehicle body is obtained by the size of the roll angle and the pitch angle, the turning center is estimated in consideration of the position of the center of gravity moving according to the inclination, and the position of the front wheels 15R, 15L is reflected by reflecting the position. The turning angular velocity at the position is calculated. For example, a method of calculating that the position of the center of gravity does not vary and a method of approximating the center C of the rotating shafts of the wheels 12R and 12L can be exemplified.

  Here, the turning angle of the front wheels 15R and 15L may be any reference, but in this specification, the direction of the front wheels 15R and 15L when traveling straight forward is 0 ° (that is, the wheel with respect to the axis S). The rotation angle of the caster is expressed in the range of 180 ° to −180 ° to the left and right with reference to that.

  Thus, when calculating the turning angular velocity, the turning angular velocity is calculated using both the turning angular velocity calculated from the turning angle αR of the right front wheel 15R and the turning angular velocity calculated from the turning angle αL of the left front wheel 15L. It is desirable. For example, an arithmetic average can be simply performed. Furthermore, when both values are compared and a difference of a certain level or more exists, it is estimated that the turning angle of at least one of the front wheels does not reflect the motion state of the vehicle body. For example, when there is a certain difference or more, it is possible not to use the value of the turning angular velocity calculated from the front wheels. Moreover, both speeds VR and VL are calculated from the rotational speeds of the left and right wheels 12R and 12L for driving, and the value obtained by calculating the turning angular velocity from these values is used as the turning angular speed, or the calculated value and the left and right wheels The turning angular velocity αR. Detected from the front wheels 15R, 15L. Compared with the value of αL, a closer value can be estimated and used as an accurate value.

  The rear wheel 17 is disposed in the left-right direction of the vehicle body 11 and is exemplified by an omni wheel that can move left and right, but is not limited thereto. In addition, the rear wheel 17 may be arrange | positioned in the center of the vehicle width direction, and the number of the rear wheels 17 is not specifically limited. In this embodiment, the turning angle of the front wheel is obtained and the turning angular velocity of the vehicle body is detected. However, by using a rotatable caster for the rear wheel, the turning angular velocity detecting means using the rear wheel is constituted. It is also possible. Which of the front wheels and the rear wheels is preferably used for detection of the turning angular velocity is preferably the front wheel or the rear wheel that is close to the state of being always in contact with the road surface.

  FIG. 3 is a block diagram illustrating a configuration of a personal vehicle control device (control device) included in the personal vehicle according to the embodiment. As shown in FIG. 3, the personal vehicle control device includes an operation unit 14, a sensor system, a control unit 2, and a wheel drive system.

  The operation unit 14 is provided in the vicinity of the seating unit 10 so that a user sitting on the seating unit 10 can easily operate. In addition, the position and aspect in which the operation unit 14 is provided are not particularly limited, and may be a remote control type operation unit that is separated from the vehicle body 11. The operation unit 14 is a part for inputting an original command value to the CPU 23 via the AD converter 21 in the control unit 2 and is formed of a so-called joystick. The operation unit 14 includes a speed command unit 141 that commands a vehicle travel speed and a turning angular speed command unit 142 that commands a turning angular speed. When the operation unit 14 is tilted forward, a forward command is output from the speed command unit 141. When the operation unit 14 is tilted backward, a reverse command is output from the speed command unit 141. Then, a method is adopted in which the straight traveling speed command value Vref increases according to the tilt angle of the operation unit 14 in the front-rear direction. When the operation unit 14 is tilted to the right, a command for turning the vehicle body 11 to the right is output from the turning angular velocity command unit 142. When the operation unit 14 is tilted to the left, a command for turning the vehicle body 11 to the left is output from the turning angular velocity command unit 142. A method is employed in which the absolute value of the turning angular velocity command value (target turning angular velocity) ωref increases in accordance with the right / left inclination angle of the operation unit 14. However, the operation unit 14 is not limited to a method using a joystick.

  As shown in FIG. 3, the sensor system includes a rate gyro (including a turning angular velocity detection unit that detects a turning angular velocity (pitch rate, roll rate) about the pitch axis and the roll axis) provided in the vehicle body 11, An accelerometer 52, a right wheel encoder 53R, and a left wheel encoder 53L are provided. Signals from the rate gyro 51 and the accelerometer 52 are input to the CPU 23 via the AD converter 21 in the control unit 2. Signals from the wheel encoders 53R and 53L are input to the CPU 23 via the counter 22 in the control unit 2, respectively.

  The above-described calculation of the turning angular velocity ωgyaw is calculated by the logic on the CPU 23 from various signals input from the sensor system. Specifically, the turning angles of the front wheels 15R and 15L inputted from the potentiometer (front wheel turning angle sensor) 54, the rotational speeds of the left and right wheels 12R and 12L inputted via the counter 22 from the left and right wheel encoders 53R and 53L, Is calculated by the above-described method (actual turning angular velocity calculation unit).

  A function of detecting the yaw rate from the difference in rotational speed between the left and right wheels 12R and 12L input from the wheel encoders 53R and 53L of the left and right wheels via the counter 22 may be provided. In other words, the yaw rate of the vehicle body 11 can be detected by acquiring the rotational speeds of the left and right wheels from the respective wheel encoders 53R and 53L, calculating the rotational speed difference, and taking the diameters of the respective wheels into consideration.

  According to the rate gyro 51, the angular velocity in the pitch direction and the angular velocity in the roll direction around the center of gravity G of the vehicle body 11 are detected. The pitch direction means the direction of rotational movement around the radial center 12a of the wheel 12 in the forward and backward direction of the vehicle 1 (arrow Fx and Rx directions in FIG. 2). The rotation axis connecting the rotation centers 12a of the left and right wheels 12R and 12L corresponds to the pitch axis that is the center of movement in the pitch direction.

  The accelerometer 52 detects acceleration in the forward / backward direction (x direction) of the vehicle body 11 of the vehicle 1, acceleration in the horizontal movement direction (y direction) of the vehicle body 11, and acceleration in the vertical direction (z direction) of the vehicle body 11. Can do. The output value of the accelerometer 52 is affected by the gravitational acceleration g when the vehicle 1 is inclined in the pitch direction. For this reason, the accelerometer 52 can detect the pitch angle θ1 (see FIG. 2) and the roll angle θ2 of the vehicle 1.

  As described above, the rate gyro 51 and the accelerometer 52 can function as sensors for determining the road surface inclination angle αx of the road surface 90 with respect to the horizontal line in FIG. 2, that is, the inclination angle θ1 of the vehicle body 11 in the pitch direction. Further, the rate gyro 51 and the accelerometer 52 can also function as sensors for determining the road surface inclination angle αy of the road surface 90 with respect to the horizontal line in FIG. 5, that is, the inclination angle θ2 of the vehicle body 11 in the roll direction.

  The detection form of the road surface inclination angle αx will be further described. FIG. 4 is an explanatory diagram for explaining a form in which the road surface inclination angle αx is calculated by filtering the physical quantity based on the acceleration signal and the rate gyro signal. The accelerometer 52 can be used as an inclinometer that detects the road surface inclination angle αx of the road surface 90. However, since the accelerometer 52 is affected by the acceleration of the vehicle body 11 moving forward and backward, it causes a measurement error of the road surface inclination angle αx. On the other hand, the road surface inclination angle αx is obtained by integrating the rate gyro signal obtained by the rate gyro 51 by the CPU 23, but the accumulated error of drift due to integration becomes a problem. The above description regarding the road surface inclination angle αx in the pitch direction can be similarly applied to the road surface inclination angle αy in the roll direction (among the description in FIG. 4, the x-axis direction is corrected to the y-axis direction and the pitch direction is corrected to the roll direction, respectively). This can be converted into a description of the road surface inclination angle αy in the roll direction.Hereinafter, “the road surface inclination angle αy in the roll direction” will also be described by explaining “the road surface inclination angle αx in the pitch direction”. .)

Therefore, as shown in FIG. 4, the control unit 2 considers the gravitational acceleration g based on the acceleration accx in the x direction of the vehicle 1 obtained from the accelerometer 52 as one sensor, and sin ⁻¹ ( accx / g). Further, the value is filtered by a low-pass filter (cut-off frequency fc) to obtain a value θHL1x from which high-frequency noise is removed. Further, the control unit 2 obtains an integral value obtained by time-integrating the turning angular velocity ωgpit in the pitch direction that is an output value of the rate gyro 51 as the other sensor, and filters the integral value with a high-pass filter (cutoff frequency fc). Then, a value θHL2x from which noise in the low frequency range is removed is obtained.

  The control unit 2 adds the two values θHL1x and the value θHL2x to obtain the road surface inclination angle αx. As described above, the value θHL1x based on the output value of the accelerometer 52 is filtered by the low-pass filter. On the other hand, the value θHL2x based on the output value of the rate gyro 51 is filtered by a high-pass filter. In other words, the accelerometer 52 whose accuracy is not sufficient in the high frequency range and the rate gyro 51 whose accuracy is not sufficient in the low frequency range complement each other. Thereby, the detection accuracy of the road surface inclination angle αx can be increased from the low frequency range to the high frequency range. The cut-off frequency fc of the low-pass filter is preferably the same value as the cut-off frequency fc of the high-pass filter, but is not limited to this.

  The right wheel encoder 53R is a right wheel sensor that detects the rotation angle θR of the right wheel 12R, and also functions as a speed sensor of the vehicle 1 in combination with a left wheel encoder 53L described later. The left wheel encoder 53L is a left wheel sensor that detects the rotation angle θL of the left wheel 12L, and also functions as a speed sensor of the vehicle 1 together with the right wheel encoder 53R. When the CPU 23 differentiates the rotation angle θR of the right wheel 12R and the rotation angle θL of the left wheel 12L with respect to time, the rotation angular velocity θ dot R of the right wheel 12R and the rotation angular velocity θ dot L of the left wheel 12L are obtained. A dot means a differential value. That is, the right and left wheel encoders 53R and 53L also function as rotational angular velocity sensors that detect the rotational angular velocities θdot R and θdotL.

  The control unit 2 includes an AD converter 21 having an interface function, a counter 22, one or more CPUs 23, and a DA converter 24 having an interface function. The AD converter 21 performs AD conversion on the signals input from the operation unit 14, the rate gyro 51, the potentiometer 54, and the accelerometer 52, and passes them to the CPU 23. The counter 22 delivers the signals input from the right wheel encoder 53R and the left wheel encoder 53L to the CPU 23. The CPU 23 receives various signals from the AD converter 21 and the counter 22, performs various calculations described later, and obtains an actual command value necessary for traveling control of the vehicle 1. The DA converter 24 DA-converts the actual command value of the CPU 23 and outputs it to the vehicle drive system.

  The wheel drive system includes a right wheel motor 13R, a right wheel motor driver 131, a left wheel motor 13L, and a left wheel motor driver 132. Actual command values are input from the CPU 23 to the right and left wheel motor drivers 131 and 132 via the DA converter 24. The right wheel motor driver 131 controls the right wheel motor 13R, and the rotation drive of the right wheel 12R is controlled. The left wheel motor driver 132 controls the left wheel motor 13L, and the rotation drive of the left wheel 12L is controlled.

  When a user sitting on the seating unit 10 operates the operation unit 14, the straight traveling speed command value Vref and the turning angular speed command value ωref of the vehicle 1 are output to the control unit 2 in accordance with the operation of the operation unit 14. . In the control unit 2, the straight traveling speed command value Vref and the turning angular speed command value ωref are converted into the rotational angular speed command value θ dot R_ref of the right wheel 12R based on the following formula (1), for example, and the formula (2) Is converted into a rotational angular velocity command value θ dot L_ref of the left wheel 12L. In the equations (1) and (2), T represents the distance (tread) between the right wheel 12R and the left wheel 12L. R_r indicates the radius of the right wheel 12R. R_l indicates the radius of the left wheel 12L.

  According to the equations (1) and (2), the greater the straight speed command value Vref, and the smaller the radius R_r of the right wheel 12R and the radius R_l of the left wheel 12L, the rotation angular velocity command value θ of the right wheel 12R. The dot R_ref and the rotational angular velocity command value θ dot L_ref of the left wheel 12L increase. The right and left rotational angular velocity command values θ dot R_ref and θ dot L_ref are actual command values.

  Further, the control unit 2 obtains the drive torque TR of the right wheel 12R based on the following equation (3), and similarly obtains the drive torque TL of the left wheel 12L based on the following equation (4).

  In equations (3) and (4), KVR represents the rotational angular velocity feedback gain of the right wheel 12R, and KVL represents the rotational angular velocity feedback gain of the left wheel 12L. KPR represents the rotation angle feedback gain of the right wheel 12R, and KPL represents the rotation angle feedback gain of the left wheel 12L. θR indicates the rotation angle of the right wheel 12R, and θL indicates the rotation angle of the left wheel 12L. The θ dot R indicates the rotation angular velocity obtained by differentiating the rotation angle of the right wheel 12R with respect to time. The θ dot L indicates the rotational angular velocity obtained by differentiating the rotational angle of the left wheel 12L with respect to time. The obtained right and left driving torques TR and TL are actual command values.

  According to equation (3), the greater the difference between the detected rotational angular velocity θ dot R of the right wheel 12R and the commanded rotational angular velocity command value θ dot R_ref of the right wheel 12R, the greater the driving torque TR of the right wheel 12R. Is big. Further, according to the equation (4), the drive torque of the left wheel 12L increases as the difference between the detected rotational angular velocity θ dot L of the left wheel 12L and the commanded rotational angular velocity command value θ dot L_ref of the left wheel 12L increases. TL is large.

  Based on the drive torque TR of the right wheel 12R and the drive torque TL of the left wheel 12L obtained in this way, control of forward and backward movement and turning of the vehicle 1 are realized by the control unit 2. If the drive torque TR of the right wheel 12R and the drive torque TL of the left wheel 12L are basically the same, the vehicle 1 goes straight. If the driving torque TR of the right wheel 12R is larger than the driving torque TL of the left wheel 12L, the vehicle 1 turns to the left. If the driving torque TL of the left wheel 12L is larger than the driving torque TR of the right wheel 12R, the vehicle 1 turns to the right.

  Note that the radius R_r and the radius R_l of the right wheel 12R and the left wheel 12L are basically considered to be generally the same length, and therefore the following equation (5) is established. Therefore, the calculation process may be simplified by substituting the expression (5) in the expressions (1) and (2).

  In the present embodiment, feedback control is performed so that the actual turning angular speed (turning angular speed ωgyaw) around the yaw axis of the vehicle body approaches the target turning angular speed (turning angular speed command value ωref) in order to improve straight traveling performance. For example, during the cant travel illustrated in FIG. 5, there is a turning angular velocity around the yaw axis of the vehicle body, so that a so-called single flow occurs. This prevents the vehicle 1 from sliding down for the purpose of eliminating such single flow. This is a control that improves straight running performance. Even if a single flow does not occur, the vehicle body may turn due to an unexpected event. In this case, it is desirable to recover the unexpected turn.

  Specific control contents regarding the turning angular velocity will be described below. FIG. 5 is a rear view schematically illustrating a state where the personal vehicle shown in FIG. As shown in FIG. 5, when the roll angle αy of the road surface 90 is large, a moment around the yaw axis may be generated when the vehicle 1 cant travels. In this case, even though the user sitting on the vehicle 1 inputs a straight traveling command in the direction crossing the road surface 90 (perpendicular to the plane of FIG. 5) with the operation unit 14 (joystick), the road surface There is a possibility that the vehicle 1 may slide down due to the influence of gravity toward the lower side of the slope of 90 (see the white broad arrow in FIG. 5; one-sided flow).

  First, based on the difference between the command value related to the turning angle input from the operation unit and the turning angular velocity with respect to the yaw axis and the original command value, the actual command value is obtained so that the difference becomes smaller, and further input from the operation unit An integral value is obtained by time-integrating the difference between the command value related to the turning angle and the turning angular velocity with respect to the yaw axis, and an actual command value is obtained based on the obtained integrated value and original command value so that the difference is reduced. .

  The control unit 2 calculates the turning angular velocity ωgyaw from the actual caster turning angle that is the turning angle of the front wheels 15R and 15L by the method described above. Next, the control unit 2 obtains the turning angular velocity command value ωref input from the operation unit 14. The control unit 2 further obtains a difference (ωref−ωgyaw) between the turning angular velocity command value ωref and the turning angular velocity ωgyaw. The greater the difference (ωref−ωgyaw), the greater the risk that the vehicle 1 that cant travel on the road surface 90 will fall off. This difference (ωref−ωgyaw) is used as a so-called proportional term for feedback control.

  That is, the control unit 2 can use the formula (6) instead of the above-described formula (1), and can use the formula (7) instead of the formula (2). Switching the formulas (1) and (2) to the formulas (6) and (7) may always be performed, or may be switched according to some condition (such as the roll angle). Hereinafter, formulas (6) and (7) will be described in detail.

  Based on the equation (6), the control unit 2 obtains the rotational angular velocity command value θ dot R_ref of the right wheel 12R according to the magnitude of the difference (ωref−ωgyaw). Further, the control unit 2 obtains the rotational angular velocity command value θ dot L_ref of the left wheel 12L according to the magnitude of the difference (ωref−ωgyaw) based on the equation (7). Such calculation of the actual command value is realized by calculation based on the straight command speed command value Vref and the turning angular speed command value ωref, which are original command values, and correction calculation by feedback control.

  More specifically, the right side of Equation (6) and Equation (7) is composed of three terms. The first term on the right side is the term obtained by dividing the straight speed command value Vref by the wheel radii R_r, R_l, and the second term is the right-to-left wheel distance T (tread) divided by twice the wheel radii R_r, R_l. And the product of the turning angular velocity command value ωref. That is, the first term and the second term are terms based on the original command value. The third term obtained by multiplying the difference (ωref−ωgyaw) by the turning angular velocity feedback gain Kω is a term relating to the first arithmetic rule, in other words, a term for feedback control using a proportional term.

  Only the first term is a plus sign in both equations (6) and (7). The second and third terms have the same absolute value, and have a positive sign in equation (6) and a negative sign in equation (7). Note that the third term of the equations (6) and (7) includes a term including a ratio (ωref / ωgyaw) between the turning angular velocity command value ωref and the turning angular velocity ωgyaow, instead of the difference (ωref−ωgyaw), and the difference ( It can also be replaced by a term that includes both (ωref−ωgyaw) and the ratio (ωref / ωgyaw).

  Then, the calculated rotational angular velocity command values θ dot R_ref and θ dot L_ref are substituted into the equations (3) and (4), thereby obtaining the drive torque TR of the right wheel 12R and the drive torque TL of the left wheel 12L. It is done. Thereby, slipping of the vehicle 1 that cant travels on the road surface 90 is suppressed, and the straight traveling performance of the vehicle 1 is ensured.

  Here, based on Expression (6) and Expression (7), as the difference (ωref−ωgyaw) is larger, the rotational angular velocity command value θ dot R_ref of the right wheel 12R and the rotational angular velocity command value θ dot L_ref of the left wheel 12L are The difference between Further, the smaller the difference (ωref−ωgyaw), the smaller the difference between the rotational angular velocity command value θ dot R_ref of the right wheel 12R and the rotational angular velocity command value θ dot L_ref of the left wheel 12L. For this reason, it is preferable to reduce the difference (ωref−ωgyaw) (preferably to zero) during cant traveling. In the equations (6) and (7), the rotational angular velocity command value θ dot R_ref of the right wheel 12R and the rotational angular velocity command value θ dot L_ref of the left wheel 12L are directly derived. It goes without saying that the calculation can be performed via

(Embodiment 2)
The personal vehicle according to the present embodiment has the same basic configuration and operational effects as those of the personal vehicle according to the first embodiment. Below, it demonstrates focusing on a different structure.

  The personal vehicle of this embodiment employs an operation unit 14A in place of the operation unit 14 described above. The operation unit 14A includes the same device as the operation unit 14, and includes a hook-like member 143 that can swing in the front-rear and left-right directions and returns to the reference position B (the center in the front-rear direction and the left-right direction) when not operated (FIG. 9). ).

  The operation unit 14A is a part for inputting an original command value to the CPU 23 via the AD converter 21 in the control unit 2, and is formed of a so-called joystick. The operation unit 14A includes a front-rear direction tilt output unit 141A that outputs the magnitude of the front-rear direction tilt of the hook-shaped member 143, and a left-right direction tilt output unit 142A that outputs the magnitude of the left-right direction tilt of the lath-shaped member 143. And.

  When the hook-like member 143 is tilted forward or backward, the front-rear direction tilt output unit 141A outputs a front-rear direction tilt signal having a magnitude corresponding to the tilted angle (the forward direction is positive and the rear direction is negative). Further, when the hook-shaped member 143 is tilted to the right or left, a left-right direction tilt signal having a magnitude corresponding to the tilt angle is output from the left-right direction tilt output unit 142A (right direction is positive and left direction is negative). .

The controller 2 calculates a straight speed command value Vref from the front / rear direction tilt signal, and calculates an operation angle that is a direction in which the hook-shaped member 143 is tilted from the front / rear direction tilt signal and the left / right direction tilt signal (for example, (operation angle ) = Sin ⁻¹ [(left / right direction tilt signal) / {(front / rear direction tilt signal) ² + (left / right direction tilt signal) ² } ^0.5 ]).

  Hereinafter, a specific description will be given based on FIG. FIG. 9 is a schematic diagram for explaining the movement of the hook-like member 143 of the operation portion 14A, and is a view of the operation portion 14A as viewed from the direction of the extension line of the reference position of the hook-like member 143. The reference position B shown in FIG. 9 is a reference position when no operation is performed on the hook-shaped member 143 of the operation unit 14A. The operation unit 14A moves back and forth when the hook-like member 143 swings in the direction inclined by the operation angle θ from the forward direction to the right as shown in FIG. 9 (the magnitude of the swing is not reflected in FIG. 9). The magnitude of the swing in the forward direction (the above-mentioned linear speed command value Vref, which is a command value related to the speed in the front-rear direction of the personal vehicle), and how many times the hook-like member 143 is tilted from the forward direction to the left-right direction ( Operation angle θ: front wheel target turning angle θ: right direction is positive and left direction is negative).

  The control unit 2 performs control so that the arithmetic average (actual turning angle α) of the turning angles αR and αL obtained from the directions FR and FL in which the front wheels 15R and 15L are directed approaches the operation angle θ (target turning angle). Specifically, the corrected operation angle θα is increased when (operation angle θ) − (actual turning angle α) is positive, and is decreased when negative (negative).

  For example, as shown in FIG. 10, the operation angle θ is calculated from the operation signal from the operation unit 14A, and the turning angle α that is the actual angle of the front wheels is calculated from the front wheels 15R and 15L. That is, the corrected operation angle θα is calculated by correcting the value of the operation angle θ using the value obtained by subtracting the turning angle α from the calculated operation angle θ (difference β). Specifically, a value obtained by multiplying the difference β by the proportional constant Kk and a value obtained by multiplying the integral value βi of the difference β by the integration constant Kki are added to the operation angle θ to obtain a corrected operation angle θα. The values are limited so that the absolute value of the difference β and the integral value βi do not exceed a certain magnitude. As a result of the correction, the corrected operation angle θα is calculated such that the actual turning angle α approaches the operation angle θ.

  A turning angular velocity command value ωref is calculated from the obtained corrected operation angle θα. That is, the control unit 2 reversely calculates the front-rear direction inclination and the left-right direction inclination of the bowl-shaped member 143 on the contrary from the value of the corrected operation angle θα. The control unit 2 has a straight traveling speed command value Vref having a magnitude corresponding to the magnitude of the obtained forward / backward inclination and a turning angular speed having a magnitude corresponding to the obtained right / left inclination. A command value (target turning angular velocity) ωref is calculated. The control after obtaining the straight speed command value Vref and the target turning angular velocity ωref is the same as in the first embodiment. That is, the left and right wheels 12 are driven according to the control method described above using the straight traveling speed command value Vref and the target turning angular speed ωref. The straight speed command value Vref may be calculated directly from the front-rear direction tilt signal of the bowl-shaped member 143 input from the operation unit 14A. Since it is presumed that the front-rear direction inclination of the hook-like member 143 reflects the speed in the front-rear direction as it is, it may be better not to correct it and change it.

  Here, both the angle at which the operation unit 14A swings (operation angle θ) and the turning angle α of the front wheels 15R and 15L are combined with the speed of the personal vehicle as the front-rear direction and the turning angular speed around the yaw axis as the left-right direction. The obtained angle. Therefore, the user's intention is directly reflected in the movement (speed and turning angular velocity) of the vehicle body by performing control in the direction in which both are made coincident.

  In addition, when (operation angle θ) − (actual turning angle α) is positive, the rotational speed of the left wheel 12L is increased (the rotational speed of the right wheel 12R is decreased), and when it is negative This can also be realized by decreasing the rotation speed of the left wheel 12L (increasing the rotation speed of the right wheel 12R). Further, when (operation angle θ) − (actual turning angle α) is positive, the turning angular velocity command value ωref is increased (increasing the turning angular velocity to the right), and when negative, the turning angular velocity command This can also be realized by decreasing the value ωref (increasing the turning angular velocity in the left direction).

  For the turning angle α, the previous value is stored, and if there is a sudden fluctuation compared to the stored value, the occurrence of some malfunction is suspected, so the value of the turning angle α can be left as it is. The turning angular velocity obtained from the rotational speed of the wheels 12R and 12L can be replaced.

  In the present embodiment, feedback control (Equations (6) and (7)) based on the difference (ωref−ωgyaw) is performed. However, in the present modification, this feedback control may not be performed.

(Modification 1)
Instead of a device that can swing in the front-rear and left-right directions, the operation unit can be replaced with two devices that can swing independently in the front-rear direction and the left-right direction, or the size (angle) of the swing can be changed. Instead of the device that inputs the command value, a device that inputs the command value according to the magnitude of the movement distance that translates in the front-rear direction and the left-right direction can be employed.

(Other)
Note that the personal vehicle of the present invention is not limited to the above-described embodiments and modifications, and can be variously modified and improved by those skilled in the art without departing from the spirit of the present invention. Needless to say, it can be implemented.

DESCRIPTION OF SYMBOLS 1 ... Personal vehicle 10 ... Seating part 11 ... Car body 12 ... Wheel 12R ... Right wheel 12L ... Left wheel 14 ... Operation part 141 ... Speed command part 142 ... Turning angular speed command part 15R ... Right front wheel 15L ... Left front wheel 2 ... Control part 51 ... Rate gyro (shaft angle sensor) 52 ... Accelerometer (shaft angle sensor)
53R ... Right wheel encoder (wheel sensor)
53L ... Left wheel encoder (wheel sensor)
accx… x-direction acceleration R… average value of right and left wheel radius R_r… right wheel radius R_l… left wheel radius Vacc… vehicle speed based on accelerometer Ven… vehicle speed based on wheel sensor αy… roll angle θR … Rotation angle of right wheel θL… rotation angle of left wheel θi… integral value of difference in turning angular velocity ωref… turning angular velocity command value ωgyaw… turning angular velocity of vehicle body

Claims (4)

A vehicle body having a seating portion on which a user is seated;
Left and right wheels provided on the left and right of the vehicle body;
A drive unit for driving the left and right wheels;
An operation unit for inputting a command value signal including a target turning angular velocity of the vehicle body;
A control unit that receives the command value signal and controls the drive unit based on the command value signal;
One or more casters that are positioned in at least one of the longitudinal directions of the vehicle body and that freely rotate and follow the movement of the vehicle body;
A caster sensor for detecting an actual caster turning angle in at least one of the casters;
Have
The controller is
A target turning angle calculation unit for calculating a target caster turning angle of the caster from the command value signal;
A feedback control unit that controls the drive unit so that a difference between the target caster turning angle and the actual caster turning angle is small;
Personal vehicle. The operation unit inputs a target vehicle speed according to the magnitude of the inclination in the front-rear direction, and inputs the target turning angular velocity according to the magnitude of the inclination in the left-right direction. Have
The personal vehicle according to claim 1, wherein the target turning angle calculation unit sets the target caster turning angle as a swinging direction of the bowl-shaped member. A vehicle body having a seating portion on which a user is seated;
Left and right wheels provided on the left and right of the vehicle body;
A drive unit for driving the left and right wheels;
An operation unit for inputting a command value signal including a target turning angular velocity of the vehicle body;
A control unit that receives the command value signal and controls the drive unit based on the command value signal;
One or more casters that are positioned in at least one of the longitudinal directions of the vehicle body and that freely rotate and follow the movement of the vehicle body;
A caster sensor for detecting an actual caster turning angle in at least one of the casters;
A rotational speed sensor for detecting an actual rotational speed of the left and right wheels;
Have
The controller is
An actual turning angular velocity calculation unit for calculating an actual turning angular velocity of the vehicle body from the actual caster turning angle and the actual wheel rotation speed;
A feedback control unit that controls the drive unit so that a difference between the target turning angular velocity and the actual turning angular velocity is small;
Personal vehicle. There are two or more casters and caster sensors,
The controller is
The at least one of Claims 1-3 which does not operate the said feedback control part when the difference between the two or more said actual caster turning angles which the two or more said caster sensors detect is larger than predetermined value. Personal vehicle.

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