WO2015098511A1

WO2015098511A1 - Pushcart

Info

Publication number: WO2015098511A1
Application number: PCT/JP2014/082622
Authority: WO
Inventors: 辻滋; 白土賢一; 久保昌幸; 羽根宜孝
Original assignee: 株式会社村田製作所
Priority date: 2013-12-25
Filing date: 2014-12-10
Publication date: 2015-07-02
Also published as: JPWO2015098511A1; JP5979321B2

Abstract

When a value of an inclination sensor (20) is less than -5°, a target angle determination unit (211) sets an angle whereat a main body unit (10) inclines forward (ex., θ1=2°). When the value of the inclination sensor (20) is less than -5°, a inclination estimation unit (214) sets a new dead zone of ±5° with the -5° value of the inclination sensor (20) at the time that the dead zone is exceeded as a reference. In the present example, however, an adjustment of an assist force is not carried out when the value of the inclination sensor (20) becomes even smaller, and thus, the dead zone is set from -∞ to 0°. Thus, the target inclination angle θ1 is fixed to a second angle (θ1=2°) while the value of the inclination sensor (20) is (0)° or less.

Description

Wheelbarrow

This invention relates to a wheelbarrow provided with wheels, and more particularly to a wheelbarrow that drives and controls wheels.

Conventionally, a handcart that assists walking by driving and controlling wheels and performing inverted pendulum control is known (for example, see Patent Document 1).

In such a wheelbarrow, it is important to adjust the assist force on the slope. For example, it is preferable that an inclination angle is detected by an inclination sensor, and in accordance with the detected inclination angle, an assist force is increased on an upward gradient, and a force to push back in a reverse direction is applied on a downward gradient.

FIG. 10A shows an example of a tilt sensor. The tilt sensor 20 is formed by processing a thin plate-like silicon wafer, and includes a spring 201, a movable portion 202, and a comb-shaped electrode portion 203.

As shown in FIG. 10B, when a tilt angle θ is input around the X axis of the tilt sensor 20 arranged horizontally, a force of Mg · sin θ acts on the movable portion 202 having the mass M. As a result, the spring 201 is displaced by ΔY in the Y direction. The inclination sensor 20 detects this displacement ΔY as a change in capacitance in the comb-shaped electrode portion 203. The tilt sensor 20 outputs this change in capacitance as a tilt angle. Thereby, the inclination sensor 20 detects an inclination angle.

International Publication No. 2012/114597

However, the tilt sensor as shown in FIG. 10 may erroneously detect acceleration or deceleration as a change in tilt angle because the capacitance of the comb-shaped electrode portion also changes depending on the acceleration in the traveling direction (Y direction). . In this case, there is a possibility that the assist force may be adjusted despite the fact that the actual ground inclination angle has not changed, and the assist force adjustment behavior may become unstable.

Therefore, an object of the present invention is to stabilize the adjustment behavior of the assist force in a handcart that performs inverted pendulum control and adjusts the assist force according to the inclination angle.

The wheelbarrow of the present invention is connected to a main body, a plurality of main wheels rotatably supported by the main body, and a rotation in the pitch direction with respect to a rotation axis of the main body or the plurality of main wheels. An angle change in the pitch direction of the main body unit, a control unit that controls the driving unit, a driving unit that rotates the plurality of main wheels, a driving unit that rotates the plurality of main wheels, and an auxiliary wheel coupled to the supporting unit. An angle change detection unit that detects the inclination of the support unit with respect to the horizontal direction.

The control unit sets a target angle of the main body unit based on the output of the tilt angle detection unit, and outputs the angle change detection unit so that the angle of the main body unit in the pitch direction becomes the target angle. Based on the above, the drive unit is controlled so that the angle change of the main body unit in the pitch direction becomes zero.

The control unit provides a dead zone that does not use the output change of the tilt angle detection unit for resetting the target angle, based on the output value of the tilt angle detection unit when the handcart is on a flat ground, When the output of the tilt angle detector exceeds the dead zone, the target angle is reset, and a new dead zone is reset based on the output value of the tilt angle detector when the dead zone is exceeded. It is characterized by.

Thus, the control unit provides a dead zone (for example, about ± 5 °) that does not use the output change of the tilt angle detection unit, which is a tilt sensor, for resetting the target angle. When the output of the tilt angle detection unit exceeds the dead zone, the assisting force is adjusted by changing the torque applied to the plurality of main wheels by the drive unit by resetting the target angle. Here, if the actual inclination angle of the ground is a value close to the boundary of the dead zone (for example, 5 °), or if the inclination sensor erroneously detects the change in inclination angle due to acceleration or deceleration, the assist force is adjusted. It will be repeated frequently. Therefore, the control unit resets a new dead zone based on the output value of the tilt sensor at the time when the dead zone is exceeded (for example, 0 ° to 10 ° as a dead zone from 5 ° as a reference), thereby assisting force. The adjustment behavior can be stabilized.

The assist force can be adjusted by, for example, resetting the target angle so that the main body portion is tilted forward from the vertical direction, thereby obtaining a force that pulls the user. By resetting the target angle so that the portion is inclined, it is possible to obtain a force to push the user backward.

According to the present invention, the adjustment behavior of the assist force can be stabilized in the handcart that performs the inverted pendulum control and adjusts the assist force according to the inclination angle.

It is a side view of a wheelbarrow. It is a front view of a wheelbarrow. It is a block diagram which shows the structure of a handcart. It is a control block diagram which shows the structure of a control part. It is a figure which shows the relationship between the setting of a target inclination angle, and the inclination angle of the ground. 3 is a flowchart showing an operation of a control unit 21. It is a figure which shows the relationship between a dead zone and a target inclination angle. It is a figure which shows the relationship between a dead zone and the target inclination angle in the modification 1 and the modification 2. It is a control block diagram which shows the structure of a control part. It is a figure which shows the structure of an inclination sensor.

FIG. 1 is a left side view of a handcart 1 according to an embodiment of the present invention, and FIG. 2 is a front view. FIG. 3 is a block diagram showing a hardware configuration of the handcart 1.

The handcart 1 includes a main body 10 that is long in the vertical direction (Z direction in the figure) and short in the depth direction (Y direction in the figure) and in the left-right direction (X direction in the figure). A box 30 containing a control board, a battery, and the like is attached to the main body 10. The main body 10 is actually provided with a cover so that the internal substrate and the like cannot be seen in appearance.

A pair of main wheels 11 are attached to the left and right ends of the lower part of the main body 10 in the vertically downward direction. In this embodiment, although the main wheel 11 has shown the example which is 2 wheels, 1 wheel or 3 wheels or more may be sufficient.

The two rod-like main body parts 10 connected to each main wheel 11 are connected via a cylindrical gripping part 15 and are rotatable in the pitch direction around the axis of the main wheel 11. However, the main body 10 does not have to be two rods as in this example, and may be one rod-like member or a thin plate-like member.

A support part 112 and an auxiliary wheel 113 are installed on the rotating shaft (or main body part 10) of the main wheel 11 in front of the main wheel 11 (forward direction) with respect to the traveling direction. The support part 112 is a thin plate-like member. The support portion 112 is connected to the rotation axis (or the main body portion 10) of the main wheel 11 so as to be rotatable in the pitch direction so as to extend in parallel with the horizontal ground. Further, an auxiliary wheel 113 is connected to the support portion 112 on the lower surface in the direction opposite to the side connected to the main wheel 11. As a result, both the main wheel 11 and the auxiliary wheel 113 are in contact with the ground. In addition, the support part 112 may be an aspect that extends rearward from the main wheel 11 with respect to the traveling direction.

1 and 2, the auxiliary wheel 113 is in contact with the ground, but the support portion 112 and the auxiliary wheel 113 are not essential components in the present invention. By performing inverted pendulum control, the handcart 1 can be independent even when only the main wheel 11 is grounded.

A motor is attached to the connecting portion between the rotation shaft (or main body portion 10) of the main wheel 11 and the support portion 112, and the rotation shaft (or main body portion 10) of the main wheel 11 and the support portion 112 are driven by driving the motor. You may make it control the crossing angle which is an angle which forms.

The grip 15 is provided with a user interface (I / F) 28 such as a power switch. The user can hold the grip portion 15 or place a forearm or the like on the grip portion 15 and press the handcart 1 by friction between the grip portion and the forearm or the like.

Next, the hardware configuration and operation of the handcart 1 will be described. As shown in FIG. 3, the handcart 1 includes a tilt sensor 20, a control unit 21, a ROM 22, a RAM 23, a gyro sensor 24, a drive unit 25, a support unit rotary encoder 27, and a user I / F 28.

The control unit 21 is a functional unit that comprehensively controls the handcart 1 and reads out a program stored in the ROM 22 and develops the program in the RAM 23 to realize various operations.

The tilt sensor 20 detects the tilt angle with respect to the horizontal direction and outputs it to the control unit 21. Specifically, as shown in FIG. 10A, the inclination sensor 20 is formed by processing a thin plate-like silicon wafer, and includes a spring 201, a movable portion 202, and a comb-shaped electrode portion 203. Then, as shown in FIG. 10B, when the inclination angle of θ is input around the X axis of the inclination sensor 20 arranged horizontally, the inclination sensor 20 receives Mg · A force of sin θ acts. As a result, the spring 201 is displaced by ΔY in the Y direction. The inclination sensor 20 detects this displacement ΔY as a change in capacitance by the comb-shaped electrode portion 203. The tilt sensor 20 outputs the change in capacitance to the control unit 21 as a tilt angle.

The gyro sensor 24 corresponds to the main body angle change detecting means of the present invention, detects the angular velocity of the main body portion 10 in the pitch direction, and outputs it to the control unit 21. The support unit rotary encoder 27 detects an intersection angle that is an angle formed by the main body unit 10 and the support unit 112, and outputs the detection result to the control unit 21. Moreover, the support part 112 does not necessarily have to extend parallel to the horizontal ground. The control unit 21 may measure the angle between the horizontal ground and the support unit 112 in advance and detect the crossing angle in consideration of the angle.

In addition, the handcart 1 includes an acceleration sensor that detects acceleration in each direction of the main body 10, a rotary encoder that detects the rotation angle of the main wheel 11, a rotary encoder that detects the rotation angle of the auxiliary wheel 113, and the like. May be further provided. Further, when the handcart 1 detects an acceleration or deceleration that is equal to or higher than a certain set value by using the rotary encoder of the main wheel 11, the wheelbarrow 1 may increase a threshold value of a dead zone described later. Conversely, when the handcart 1 detects that the acceleration or deceleration is equal to or lower than a certain set value, the dead zone threshold may be narrowed. Thereby, in the former case, erroneous detection is prevented, and in the latter case, it is possible to adjust the assist force substantially coincident with the change in the inclination.

FIG. 4 is a control configuration diagram of the control unit 21. The control unit 21 includes a target angle determination unit 211, a target angular velocity calculation unit 212, a torque command generation unit 213, and an inclination estimation unit 214.

The target angle determination unit 211 sets a target tilt angle θ1 that is a target of the tilt angle of the support unit 112 (tilt angle with respect to the ground). For example, as shown in FIG. 5A, as the target inclination angle θ1, a first angle (θ1 = −3 °) slightly behind 0 degrees with respect to the vertical direction is output.

The target angular velocity calculation unit 212 inputs a difference value between the first angle and the current inclination angle of the main body unit 10 and calculates the inclination angular velocity of the main body unit 10 such that the difference value becomes zero.

The current inclination angle of the main body 10 is calculated from, for example, the intersection angle between the main body 10 and the support 112 input from the support rotary encoder 27. The support portion 112 is connected to the shaft (or the main body portion 10) of the main wheel 11 so as to be parallel to the horizontal ground. Therefore, when the crossing angle is 90 degrees, the inclination angle of the main body 10 with respect to the ground is assumed to be 0 degree, and when the crossing angle is large, the inclination is backward with respect to the traveling direction, and the crossing angle is small. Assuming that the vehicle body is inclined forward with respect to the traveling direction, the current inclination angle of the main body 10 is estimated.

Note that the inclination angle can be obtained from the inclination sensor 20 attached to the main body 10 when the output value of the gyro sensor 24 is integrated or when the inclination sensor 20 is attached to the main body 10.

The torque command generation unit 213 inputs a difference value between the inclination angular velocity calculated by the target angular velocity calculation unit 212 and the current inclination angular velocity of the main body unit 10 input from the gyro sensor 24, and the difference value is 0. The applied torque is calculated as follows.

A control signal based on the applied torque calculated in this way is input to the drive unit 25. The drive unit 25 is a functional unit that drives a motor that rotates a shaft attached to the main wheel 11 to power the main wheel 11, and drives the motor of the main wheel 11 based on an input control signal. The main wheel 11 is rotated.

Thereby, the handcart 1 performs the inverted pendulum control, and controls the posture of the main body 10 to be kept constant. If the user performs an operation of pushing the handcart 1 forward with respect to the traveling direction, the inclination angle of the main body 10 is inclined forward with respect to the target inclination angle. In order to maintain the target inclination angle, a torque that rotates the main wheel 11 in the forward direction works. Thereby, the handcart 1 also moves following the movement of the user.

Then, the inclination estimation unit 214 inputs the value of the inclination sensor 20, and determines whether or not the value of the inclination sensor 20 is within a predetermined range (dead zone). When the slope estimation unit 214 determines that the value of the tilt sensor 20 has exceeded the dead zone, the slope estimation unit 214 outputs the value of the tilt sensor 20 to the target angular velocity calculation unit 211 and notifies the target angle determination unit 211 that the dead zone has been exceeded. Notice. When the target angle determination unit 211 is notified that the dead zone has been exceeded, the target angle determination unit 211 resets the target inclination angle θ1. The target angle determination unit 211 may reset the target tilt angle when the value of the tilt sensor 20 exceeds the dead zone even for a moment, but the target tilt angle when the value exceeds the dead zone continuously for a predetermined time or more. It may be a mode of resetting. Furthermore, the handcart 1 is in a situation where, after resetting the target inclination angle, it becomes necessary to reset again, when traveling on a rough road, or when an operator is scolding. Since there is a possibility, emergency control such as stopping traveling may be performed.

FIG. 6 is a flowchart showing the operation of the control unit 21. As shown in FIG. 6, the inclination estimation unit 214 inputs the value of the inclination sensor 20 (s11), and determines whether or not the value of the inclination sensor 20 is within a predetermined range (dead zone) (s12). ).

FIG. 7 is a diagram showing the relationship between the dead zone and the target inclination angle. The horizontal axis of the graph shown in FIG. 7 is the value of the tilt sensor 20, and the vertical axis is the target tilt angle. In the initial state (flat ground), a dead zone of ± 5 ° is set with the inclination sensor value of 0 ° as a reference. That is, when the value of the tilt sensor 20 is between −5 ° and 5 °, the target tilt angle θ1 is fixed to the first angle (θ1 = −3 °), and the output change of the tilt sensor is controlled by the drive unit 25. Is not to be used. When the inclination estimation unit 214 determines that the value of the tilt sensor 20 has exceeded the dead zone (s12: Yes), the target angle determination unit 211 resets the target tilt angle θ1 (s13).

For example, as shown in FIG. 7, when the value of the tilt sensor 20 is less than −5 °, the target angle determination unit 211 sets the target tilt angle θ1 to an angle at which the main body unit 10 tilts forward from the first angle. It is reset to a certain second angle (for example, θ1 = 2 °). However, when the current inclination angle of the main body 10 is calculated from the intersection angle between the main body 10 and the support 112 input from the support rotary encoder 27, the target angle determination unit 211 considers the upward gradient. Then, a value (θ1 = 7 °) obtained by subtracting the value −5 ° of the tilt sensor 20 at the time when the dead zone is exceeded is output as the target tilt angle so that the main body 10 tilts 2 ° forward with respect to the vertical direction. .

Thereby, as shown in FIG. 5 (B), the main body portion 10 is tilted forward, so that the torque for rotating the main wheel 11 in the forward direction works more strongly. Thereby, the force which pulls a user can be acquired and it can climb a slope more comfortably.

For example, as illustrated in FIG. 7, when the value of the tilt sensor 20 is greater than 5 °, the target angle determination unit 211 tilts the main body 10 backward from the first angle as the target tilt angle θ1. A third angle that is an angle (for example, θ1 = −6 °) is output. However, when the current inclination angle of the main body 10 is calculated from the intersection angle between the main body 10 and the support 112 input from the support rotary encoder 27, the target angle determination unit 211 considers the downward gradient. Thus, a value (θ1 = −11 °) obtained by subtracting the value 5 ° of the tilt sensor 20 when the dead zone is exceeded is output as the target tilt angle so that the main body 10 tilts backward 6 ° with respect to the vertical direction. .

As a result, as shown in FIG. 5 (C), the main body portion 10 is tilted further rearward, so that torque that rotates the main wheel 11 rearward is exerted. As a result, the braking effect works and a force to push the user back can be obtained, and the user can go down the slope more safely.

Then, when the assist force is adjusted in this way, the gradient estimation unit 214 resets a new dead zone (s14). For example, as shown in FIG. 7, when the value of the inclination sensor 20 is less than −5 °, the inclination estimation unit 214 uses the value −5 ° of the inclination sensor 20 when the dead zone is exceeded as a reference. Set a new deadband of ± 5 °. However, in this example, when the value of the tilt sensor 20 is further reduced, the assist force is not adjusted, so the dead zone is set to −∞ to 0 °. Thus, while the value of the tilt sensor 20 is 0 ° or less, the target tilt angle θ1 is fixed at the second angle (θ1 = 2 °). When the value of the tilt sensor 20 is greater than 0 °, the first angle is reset as the target tilt angle θ1, and the dead zone of ± 5 ° is reset with respect to 0 °. .

In addition, when the value of the inclination sensor 20 is greater than 5 °, the inclination estimation unit 214 sets a new dead zone of ± 5 ° with reference to the value 5 ° of the inclination sensor 20 when the value exceeds the dead zone. To do. However, in this example, when the value of the tilt sensor 20 is further increased, the dead zone is set to 0 ° to ∞ so that the assist force is not adjusted. Thus, while the value of the tilt sensor 20 is 0 ° or more, the target tilt angle θ1 is fixed at the third angle (θ1 = −6 °). When the value of the tilt sensor 20 is less than 0 °, the first angle is reset as the target tilt angle θ1, and the dead zone of ± 5 ° is reset with respect to 0 °. .

As a result, the control unit 21 detects that the actual inclination angle of the ground is a value close to the boundary of the dead zone (for example, 5 ° or −5 °), or the inclination sensor 20 erroneously detects the change of the inclination angle by acceleration or deceleration. The assist force adjustment behavior is not frequently repeated, and the assist force adjustment behavior can be stabilized.

Next, FIG. 8A is a diagram showing the relationship between the dead zone and the target inclination angle in the first modification. In the first modification, the value of the tilt sensor 20 is decreased and the assist force is adjusted strongly, and then the value of the tilt sensor 20 is further decreased, or the value of the tilt sensor 20 is increased and the assist force is weakly adjusted ( Alternatively, when the value of the tilt sensor 20 further increases after the assist force in the reverse direction is set), a new target tilt angle and dead zone are set again.

In the first modification, when the value of the inclination sensor 20 is less than −5 °, the inclination estimation unit 214 sets −5 ° to about −5 ° of the inclination sensor 20 when the dead zone is exceeded. A new dead zone is set between 0 °.

Then, when the value of the tilt sensor 20 becomes less than −8 °, the target angle determination unit 211 sets a fourth angle that is an angle at which the main body 10 tilts further forward than the second angle as the target tilt angle θ1. (For example, θ1 = 6 °) is set. However, when the current inclination angle of the main body 10 is calculated from the intersection angle between the main body 10 and the support 112 input from the support rotary encoder 27, the target angle determination unit 211 considers the upward gradient. Thus, a value (θ1 = 14 °) obtained by subtracting the value −8 ° of the tilt sensor 20 when the dead zone is exceeded is output so that the main body 10 tilts 6 ° forward with respect to the vertical direction.

Thereby, since the main body 10 is further tilted forward, the torque for rotating the main wheel 11 in the forward direction works more strongly, and the assist force is adjusted more strongly. In addition, the inclination estimation unit 214 sets a new dead zone on the basis of the value −8 ° of the tilt sensor 20 when the dead zone is exceeded. In this example, the new dead zone is -∞ to -5 °. As a result, when the value of the tilt sensor 20 becomes less than −8 °, the target tilt angle θ1 is reset to the fourth angle, and is fixed at the fourth angle until it exceeds −5 ° again. . When the value of the tilt sensor 20 exceeds −5 °, the target tilt angle θ1 is reset to the second angle, and a new dead zone of −8 ° to 0 ° is reset.

On the other hand, when the value of the inclination sensor 20 is greater than 5 °, the inclination estimation unit 214 newly sets a value between 0 ° and 8 ° with reference to the value 5 ° of the inclination sensor 20 when the dead zone is exceeded. Set a dead zone.

Then, when the value of the tilt sensor 20 becomes larger than 8 °, the target angle determination unit 211 sets the fifth angle (the angle at which the main body 10 tilts further backward than the third angle as the target tilt angle θ1). For example, θ1 = −9 °) is set. However, when the current inclination angle of the main body 10 is calculated from the intersection angle between the main body 10 and the support 112 input from the support rotary encoder 27, the target angle determination unit 211 considers the downward gradient. Thus, a value (θ1 = −17 °) obtained by subtracting the value 8 ° of the tilt sensor 20 when the dead zone is exceeded is output so that the main body 10 tilts backward by −9 ° with respect to the vertical direction. Thereby, since the main-body part 10 inclines further back, the torque which rotates the main wheel 11 back acts more strongly, the stronger brake effect works, and the force which pushes a user back can be acquired.

Also, the inclination estimation unit 214 sets a new dead zone with reference to the value 8 ° of the tilt sensor 20 when the dead zone is exceeded. In this example, the new dead zone is 5 ° to ∞. Thereby, when the value of the inclination sensor 20 exceeds 8 °, the target inclination angle θ1 is reset to the fifth angle, and is fixed at the fifth angle until it becomes less than 5 ° again. When the value of the tilt sensor 20 is less than 5 °, the target tilt angle θ1 is reset to the third angle, and a new dead zone of 0 ° to 8 ° is reset.

As described above, when the value of the tilt sensor 20 exceeds the dead zone, the control unit 21 does not need to set a dead zone having the same width (for example, ± 5 °) with reference to the value exceeding the dead zone, and adjusts appropriately. Is possible.

Next, FIG. 8B is a diagram showing the relationship between the dead zone and the target inclination angle in the second modification. In the second modification, when the value of the inclination sensor 20 is less than −8 °, the inclination estimation unit 214 sets −∞ to −3 ° as a new dead zone. As a result, when the value of the tilt sensor 20 is less than −8 °, the target tilt angle θ1 is reset to the fourth angle, and is fixed at the fourth angle until it exceeds −3 °. Assist power is maintained. When the value of the tilt sensor 20 exceeds −3 °, the target tilt angle θ1 is reset to the second angle, and a new dead zone of −8 ° to 0 ° is reset. Similarly, when the value of the inclination sensor 20 is greater than 8 °, the inclination estimation unit 214 sets 3 ° to ∞ as a new dead zone. Thereby, when the value of the inclination sensor 20 becomes larger than 8 °, the target inclination angle θ1 is reset to the fifth angle and is fixed at the fifth angle until it becomes less than 3 °, and the strong brake The effect is maintained. When the value of the tilt sensor 20 is less than 3 °, the target tilt angle θ1 is reset to the third angle, and a new dead zone of 0 ° to 8 ° is reset.

Thus, the boundary of each dead zone does not need to be the same value, and the value of the tilt sensor 20 for returning to the original target tilt angle may be set to a smaller value or a larger value.

Note that adjusting the assist force is not limited to changing the target inclination angle, and for example, as shown in FIG. 9A, an offset torque may be applied. In this case, the inclination estimation unit 214 determines an offset torque for compensating for the gravitational torque generated by the ground inclination angle according to the ground inclination angle estimated based on the value of the inclination sensor 20 as a gravity torque calculation unit 214A. Calculate with The offset torque is added to the torque calculated by the torque command generator 213 and applied to the drive unit 25. Further, as shown in FIG. 9B, offset torque may be further applied while changing the target inclination angle.

DESCRIPTION OF SYMBOLS 1 ... Wheelbarrow 10 ... Main-body part 11 ... Main wheel 15 ... Holding part 20 ... Inclination sensor 21 ... Control part 22 ... ROM
23 ... RAM
24 ... Gyro sensor 25 ... Driving unit 27 ... Rotary encoder 30 for supporting unit ... Box 112 ... Supporting unit 113 ... Auxiliary wheel 201 ... Spring 202 ... Movable unit 203 ... Comb electrode unit 211 ... Target angle determining unit 212 ... Target angular velocity calculating unit 213 ... Torque command generator 214 ... Slope estimation unit

Claims

The main body,
A plurality of main wheels rotatably supported by the main body;
A support portion coupled to be rotatable in a pitch direction with respect to a rotation axis of the main body portion or the plurality of main wheels;
An auxiliary wheel connected to the support,
A drive unit for rotating the plurality of main wheels;
A control unit for controlling the driving unit;
An angle change detector that detects an angle change in the pitch direction of the main body;
A handcart provided with an inclination angle detection unit for detecting an inclination of the support unit with respect to a horizontal direction,
The control unit sets a target angle of the main body unit based on an output of the tilt angle detection unit, the angle of the pitch direction of the main body unit becomes the target angle, and the angle change detection unit Based on the output, the drive unit is controlled so that the angle change in the pitch direction of the main body unit becomes zero,
Based on the output value of the inclination angle detection unit when the handcart is on a flat ground, a dead zone is provided in which the output change of the inclination angle detection unit is not used for resetting the target angle, and the output of the inclination angle detection unit When the vehicle exceeds the dead zone, the target angle is reset, and a new dead zone is reset based on the output value of the tilt angle detection unit when the dead zone is exceeded. .
The control unit sets the target angle based on the output of the tilt angle detection unit,
The handcart according to claim 1, wherein the target angle is reset when an output of the tilt angle detection unit exceeds the dead zone.