WO2016035683A1

WO2016035683A1 - Pushcart

Info

Publication number: WO2016035683A1
Application number: PCT/JP2015/074333
Authority: WO
Inventors: 林毅至; 辻滋
Original assignee: 株式会社村田製作所
Priority date: 2014-09-02
Filing date: 2015-08-28
Publication date: 2016-03-10
Also published as: JP5935965B1; JPWO2016035683A1

Abstract

A conversion processing part (34) calculates the current angular velocity (ωh) of a main body section (11) on the basis of a pitch-direction rotation angle of wheels (12) detected by a wheel rotary encoder (25). The angular velocity (ωh) can be obtained from the ratio between turning radius (r) of the wheels and the turning radius (l) of the main body section. To tilt the main body section (11) rearward by θh, the wheels (12) have to be rotated forward by (r/l) × θ, so a relation expressed by rθt ≈ lθh is established. Differentiation of both sides of this mathematical expression yields ωh ≈ (r/l)ωt. The conversion processing part (34) can calculate the current pitch-direction angular velocity (ωh) of the main body section (11) from the pitch-direction rotation angle (θt) detected for the wheels (12) by the wheel rotary encoder (25). Consequently, a control unit (21) can detect the angular velocity (ωh) of the main body section (11) without using a gyro sensor or other sensor for detecting an angular velocity.

Description

Wheelbarrow

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

Conventionally, a two-wheeled vehicle that performs inverted pendulum control by driving and controlling wheels is known (see, for example, Patent Document 1).

The inverted motorcycle of Patent Document 1 includes a main body, two wheels, and drive means for driving the two wheels. Further, the inverted two-wheeled vehicle of Patent Document 1 includes an operation state detection unit that detects the posture of the main body and a sensor (for example, a gyro sensor) that detects a driving speed.

The inverted motorcycle of Patent Document 1 calculates a driving speed command by feedback control based on the posture information command and the current posture (operation state) detected by the posture detection device. Furthermore, the inverted two-wheeled vehicle of Patent Document 1 calculates torque to be applied to the driving means by feedback control based on the driving speed command and the current driving speed detected by the gyro sensor.

JP 2011-207277 A

The inverted motorcycle of Patent Document 1 requires a sensor for detecting the current driving speed (angular speed in the pitch direction). In Patent Document 1, a gyro sensor is described as an example of the sensor. However, the inverted two-wheeled vehicle of Patent Document 1 cannot satisfy the requirement for performing the inverted pendulum control without using the gyro sensor due to design reasons and the like.

For example, in order to perform inverted pendulum control in a handcart, the rotation angle in the pitch direction of the main body is limited within a predetermined range by providing a stopper for limiting the rotation of the main body before and after the pitch direction. It is preferable to do. Thereby, for example, even when the power is turned off, the main body does not tilt more than necessary in the pitch direction. In addition, even when the user puts weight on the grip provided on the main body, there is no fear of falling, and the user can be given a sense of security.

However, when the rotation angle of the main body is limited, the angular velocity detected by the gyro sensor may become zero, so that the inverted pendulum control may fail.

Therefore, an object of the present invention is to provide a handcart that realizes inverted pendulum control without using a sensor that detects angular velocity.

The handcart of the present invention includes a main body, a wheel rotatably supported by the main body, a driving unit that rotates the wheel in a pitch direction, a control unit that performs feedback control of the driving unit, and the main body. A body angle detector that detects a rotation angle of the wheel in the pitch direction, and a wheel angle detector that detects a rotation angle of the wheel in the pitch direction.

And the control unit calculates the angular velocity in the pitch direction of the main body based on the rotation angle in the pitch direction of the wheel detected by the wheel angle detection unit, and the calculated angular velocity in the pitch direction of the main body, The drive unit is controlled so that the rotation angle in the pitch direction of the main body unit becomes a target rotation angle based on the rotation angle in the pitch direction of the main body unit detected by the main body unit angle detection unit. To do.

Thus, the control unit can detect the angular velocity of the main body without using a sensor for detecting the angular velocity such as a gyro sensor by calculating the angular velocity of the main body from the rotation angle in the pitch direction of the wheels. Therefore, the handcart of the present invention can realize inverted pendulum control without using a sensor that detects the angular velocity of the main body.

More specifically, the angular velocity of the main body can be obtained by multiplying the wheel rotation angle by the ratio of the rotation radius of the wheel and the rotation radius of the main body to differentiate it. For example, if the rotation radius of the wheel is r, the rotation radius of the main body portion is l, and the rotation angle of the wheel is θt, when the wheel is rotated by (r / l) × θt, the target rotation angle θhr of the main body portion, The deviation angle from the current rotation angle θh of the main body is zero. Therefore, the relational expression rθt≈lθh is established, and when both sides of the relational expression are differentiated, the rotational angular velocity ωh of the main body can be obtained from the expression ωh≈ (r / l) ωt. However, this relational expression holds when the user U does not move the main body 11 or when the wheel 12 is not rotating.

Further, the target angular velocity ωhr can be obtained by multiplying the difference between the target rotation angle θhr of the main body and the current rotation angle θh of the main body by a predetermined response coefficient Kp (1 / s). The control unit calculates an angular acceleration αhr at which the deviation between the angular velocity ωh in the pitch direction of the main body and the target angular velocity ωhr becomes zero. Finally, the control unit multiplies the calculated angular acceleration by values such as the moment of inertia, the reduction ratio, and the efficiency, thereby calculating the torque that the driving unit applies to the wheels.

In this way, the control unit performs inverted pendulum control by feedback control of the drive unit.

The wheelbarrow is provided with speed limiting means for converting the target angular velocity into the traveling speed of the main body, limiting the converted traveling speed to a predetermined speed, and converting the limited traveling speed into the target angular speed again. The embodiment may be sufficient.

As described above, by limiting the target angular velocity as an input for feedback control, for example, even when the user strongly pushes the handcart, the traveling speed of the handcart can be prevented from exceeding the speed limit.

In addition, in the case of a mode including a brake operation reception unit that receives a brake operation on the wheel, the control unit reduces the target angular velocity as the operation amount of the brake operation increases, thereby limiting the speed according to the degree of grip of the brake. Can also be realized.

According to the present invention, the inverted pendulum control can be realized without using the sensor for detecting the angular velocity.

It is a side view of a wheelbarrow. FIG. 2A is a front view of the handcart, and FIG. 2B is a plan view of the handcart. It is a block diagram which shows the hardware constitutions of a handcart. FIG. 4A is a diagram for explaining the limitation on the pitch angle of the main body, and FIG. 4B is a diagram showing the relationship between the pitch angle of the main body and the rotation angle of the wheels. It is a control block diagram of a control part. It is a control block diagram of the control part which concerns on a modification. It is a block diagram which shows the hardware constitutions of the handcart 10A which concerns on a modification. It is a block diagram which shows the hardware constitutions of the handcart 10B which concerns on a modification. It is a flowchart which shows the restriction process of advancing speed.

FIG. 1 is a left side view of the wheelbarrow 10, FIG. 2A is a front view, and FIG. 2B is a plan view.

The handcart 10 includes a main body 11 having a shape that is relatively long in the vertical direction (Z direction in the drawing) and relatively short in the depth direction (Y direction in the drawing) and the left and right direction (X direction in the drawing). . A pair of wheels 12 is attached to an end in the left-right direction in the lower portion of the main body 11 in the vertically downward direction. In this embodiment, although the wheel 12 has shown the example which is 2 wheels, 1 wheel or 3 wheels or more may be sufficient.

The wheel 12 rotates around the rotation axis (axle) of the wheel 12 having a central axis. That is, it can rotate in the pitch direction. In this example, the wheel 12 does not rotate in the yaw direction and the roll direction. However, for example, the wheel 12 may be rotated in the yaw direction and change its direction with respect to the main body 11.

The two rod-shaped main body parts 11 connected to each wheel 12 are connected to the gripping part 15 at the upper part and are rotatable in the pitch direction around the axis of the wheel 12. However, the main body 11 does not need to have two rod shapes as in this example, and may be one rod-like member, a thin plate-like member, or the like. A box 16 containing a control board, a battery, and the like is disposed near the lower portion of the main body 11. The main body 11 is actually provided with a cover so that the internal substrate and the like cannot be seen in appearance.

The grip portion 15 has a cylindrical shape that is long in the left-right direction, is bent in the reverse direction (backward) with respect to the traveling direction near the left and right ends, and extends rearward. Thereby, the position where the user grips the grip portion 15 can be shifted backward, and the space at the user's feet can be widened.

A thin plate-like support portion 13 extending rearward is connected to the rotating shaft of the wheel 12. The support portion 13 is connected to the rotation axis of the wheel 12 so as to be rotatable in the pitch direction so as to extend in parallel with the road surface.

The supporting wheel 13 has an auxiliary wheel 14 connected to the lower surface in the direction opposite to the side connected to the rotating shaft of the wheel 12. Thereby, both the wheel 12 and the auxiliary wheel 14 come into contact with the road surface. The support portion 13 extends rearward from the wheel 12 with respect to the traveling direction. For this reason, the wheel 12 having a relatively large inner diameter is disposed forward with respect to the traveling direction, and it is easy to get over the step. The support portion 13 may extend in front of the wheel 12 with respect to the traveling direction, and the auxiliary wheel 14 may be disposed in front of the wheel 12. If the support portion 13 extends in front of the wheels 12, the space at the foot of the user U can be widened.

Note that a motor may be attached to a connection portion between the rotating shaft of the wheel 12 and the support portion 13, and the support portion 13 may be actively rotated in the pitch direction by driving the motor.

Further, in this example, two support portions 13 and two auxiliary wheels 14 are provided and connected to the rotation shafts of the left and right wheels 12, respectively, but one or three support portions 13 and auxiliary wheels 14 are provided. Two or more modes may be provided. However, as shown in FIG. 2, the space at the foot of the user U can be widened by connecting to the rotating shafts of the left and right wheels 12.

The grip 15 is provided with a user interface (I / F) 27 such as a power switch. The user U can push the handcart 10 in the traveling direction by grasping the grip portion 15. Alternatively, the user U places the forearm or the like on the gripping part 15 without pressing the gripping part 15 from above, and the forearm or the like is applied to the gripping part 15 by friction generated between the gripping part 15 and the forearm or the like. It is also possible to push the wheelbarrow 10 in the traveling direction while putting

Next, the hardware configuration and operation of the handcart 10 will be described. As shown in FIG. 3, the handcart 10 includes a control unit 21, a ROM 22, a RAM 23, a drive unit 24, a wheel rotary encoder 25, a main body rotary encoder 26, and a user I / F 27. The wheel rotary encoder 25 corresponds to a wheel angle detector of the present invention, and the main body rotary encoder 26 corresponds to a main body angle detector.

The control unit 21 is a functional unit that controls the wheelbarrow 10 in an integrated manner, and implements various operations by reading a program stored in the ROM 22 and developing the program in the RAM 23.

The driving unit 24 is a functional unit that drives a motor that rotates a rotating shaft attached to the wheel 12 to provide power to the wheel 12. The drive unit 24 drives the motor of the wheel 12 based on a torque command value described later output from the control unit 21 and rotates the wheel 12 in the pitch direction.

The wheel rotary encoder 25 detects the rotation angle of the wheel 12 in the pitch direction and outputs the detection result to the control unit 21.

The main body rotary encoder 26 detects a crossing angle, which is an angle formed by the main body 11 and the support 13, and outputs a detection result to the control unit 21. The control unit 21 calculates the rotation angle in the pitch direction of the main body 11 from the intersecting angle input from the main body rotary encoder 26. Hereinafter, the rotation angle in the pitch direction is referred to as a pitch angle.

The support part 13 is connected to the rotating shaft of the wheel 12 so as to be parallel to the horizontal road surface. Therefore, the control unit 21 determines that the pitch angle is 0 degree when the intersection angle is 90 degrees, that is, the inclination angle with respect to the normal of the road surface of the main body 11 is 0 degree, and the traveling direction is increased when the intersection angle increases. On the other hand, the current pitch angle of the main body 11 is calculated assuming that the vehicle body is inclined forward and the vehicle is inclined backward with respect to the traveling direction when the intersection angle is small. For example, the pitch angle of the main body 11 is a positive value when tilted forward with respect to the traveling direction, and a negative value when tilted backward with respect to the traveling direction. "Degree" is calculated as the pitch angle. However, the support part 13 does not necessarily need to be parallel to a horizontal road surface. For example, when the wheelbarrow 10 is arranged on a horizontal road surface, if the angle between the road surface and the support portion 13 (the angle in the pitch direction) is known in advance, the difference between the angle formed in the pitch direction (the angle in the pitch direction) By calculating (change), the pitch angle of the main body 11 can be calculated.

Note that the pitch angle of the main body 11 is limited to a predetermined range (for example, ± 30 degrees) by a stopper or the like, as shown in FIG. Thereby, for example, even when the power is turned off, the main body 11 does not tilt more than necessary. Further, even when the user U puts weight on the gripping part 15, there is no fear of falling, and the user can be provided with a sense of security.

In addition, you may detect the pitch angle of the main-body part 11 not only with a rotary encoder but with a potentiometer.

Next, FIG. 5 is a control configuration diagram of the control unit 21. The control unit 21 functionally includes a target angular velocity calculation unit 31, a feedback (FB) control unit 32, a torque command value conversion unit 33, and a conversion processing unit 34.

The target angular velocity calculation unit 31 inputs the target pitch angle θhr (for example, θhr = 0) of the main body 11 and the current pitch angle θh of the main body 11. As described above, since the main body rotary encoder 26 detects the intersection angle, the target angular velocity calculation unit 31 calculates a value “intersection angle−90 degrees” obtained by subtracting 90 degrees from the input intersection angle. Input as pitch angle θh.

The target angular velocity calculation unit 31 calculates the target angular velocity ωhr based on the input target pitch angle θhr and the current pitch angle θh of the main body 11. The target angular velocity ωhr is calculated by the following formula 1 using a coefficient Kp representing control responsiveness.

ωhr = Kp (θhr−θh) Equation 1
The calculated target angular velocity ωhr is input to the FB control unit 32. The FB control unit 32 inputs the target angular velocity ωhr and the current angular velocity ωh of the main body 11. The current angular velocity ωh of the main body 11 is obtained by the conversion processing unit 34.

The conversion processing unit 34 calculates the current angular velocity ωh of the main body 11 based on the rotation angle in the pitch direction of the wheel 12 detected by the wheel rotary encoder 25. The angular velocity ωh can be obtained from the ratio between the rotation radius r of the wheel and the rotation radius l of the main body. As shown in FIG. 4B, the deflection angle between the target pitch angle θhr of the main body 11 and the current pitch angle θh of the main body 11 (if the target pitch angle θhr = 0, the deflection angle = θh. .) Becomes 0 when the wheel 12 is rotated by (r / l) × θt. That is, in order to tilt the main body 11 backward by θh, the wheel 12 is rotated forward by (r / l) × θt, and the following relational expression is established.

rθt≈lθh Equation 2
When both sides of Equation 2 are differentiated, Equation 2 is converted into Equation 3 below.

ωh≈ (r / l) ωt Equation 3
In this way, the conversion processing unit 34 can obtain the current angular velocity ωh in the pitch direction of the main body 11 from the rotation angle θt in the pitch direction of the wheel 12 detected by the wheel rotary encoder 25. Thereby, the control part 21 can detect angular velocity (omega) h of the main-body part 11 without using the sensor which detects angular velocity, such as a gyro sensor.

Then, the FB control unit 32 obtains the angular acceleration αhr so that the current angular velocity ωh of the main body 11 becomes the target angular velocity ωhr. That is, the FB control unit 32 calculates the angular acceleration αhr at which the deviation between the current angular velocity ωh of the main body 11 and the target angular velocity ωhr becomes zero.

In the present embodiment, the FB control unit 32 calculates the angular acceleration αhr by PI control as expressed by the following mathematical formula 4.

Kv in Equation 4 is a proportional gain, and Tv is an integration time. Note that the feedback control is not limited to PI control, and may be PID control to which differential control is added, for example, or only proportional control.

The angular acceleration αhr calculated by the FB control unit 32 is output to the torque command value conversion unit 33. The torque command value conversion unit 33 converts the input angular acceleration αhr into a torque command value tr. The torque command value tr can be obtained by the following Equation 5 from the moment of inertia J of the main body 11, the reduction ratio 1 / k of the reduction system related to the wheel 12 from the motor, and the efficiency η of the reduction system.

tr = J · η · k · αhr Equation 5
The torque command value conversion unit 33 inputs the calculated torque command value tr to the drive unit 24. The drive unit 24 applies torque based on the input torque command value tr to a motor (a motor that rotates a shaft attached to the wheel 12), drives the motor, and rotates the wheel 12.

Thus, the handcart 10 performs the inverted pendulum control, and controls the posture so that the pitch angle θh of the main body 11 is maintained at the target pitch angle θhr. For example, when the user U pushes the handcart 10 in the traveling direction and tilts the main body 11 in the traveling direction, the handcart 10 moves the wheel 12 to keep the pitch angle θh at the target pitch angle θhr (for example, 0 degree). Rotate forward. Thereby, the handcart 10 moves forward, and the handcart 10 also moves following the movement of the user U.

As described above, the handcart 10 in the present embodiment limits the pitch angle of the main body 11 within a predetermined range by a stopper or the like, and therefore performs feedback control using a sensor that detects an angular velocity such as a gyro sensor. There are cases where it cannot be performed (the detected angular velocity becomes zero). Further, the angular velocity of the main body 11 can be obtained by differentiating the pitch angle of the main body 11. However, when the change of the pitch angle is also limited, the differential value becomes extremely small and the calculated angular velocity. May become zero and feedback control may fail. However, the handcart 10 according to the present embodiment calculates the angular velocity in the pitch direction of the main body 11 based on the rotation angle in the pitch direction of the wheel 12 detected by the wheel rotary encoder 25, thereby the pitch angle of the main body 11. Even when the change of the above is restricted, the inverted pendulum control by the feedback control can be realized.

In the handcart 10 of the present embodiment, the target angular velocity calculation unit 31 calculates the target angular velocity ωhr using the coefficient Kp, and the torque command value conversion unit 33 converts the angular acceleration into a torque command value. All of these operations are simple multiplications, and the processing load is small. On the other hand, feedback control with a large processing load is performed only by the FB control unit 32. In the conventional control method, for example, feedback control is performed based on the target pitch angle and the current pitch angle to calculate the target angular velocity, and further, feedback control is performed based on the angular velocity detected by the gyro sensor to generate torque. Although the two-stage feedback control of calculating the command value was performed, the wheelbarrow 10 of the present embodiment does not need to perform such a two-stage feedback control, and thus can reduce the processing load. .

Next, FIG. 6 is a control configuration diagram of the control unit 21 A according to a modification of the control unit 21. The same components as those of the control unit 21 are denoted by the same reference numerals and description thereof is omitted. The control unit 21 A includes a speed limiting unit 35 in the subsequent stage of the target angular velocity calculation unit 31 and the previous stage of the FB control unit 32.

The speed limiter 35 is a means for limiting the traveling speed of the main body 11 to a predetermined value or less. The speed limiter 35 converts the target angular velocity ωhr (rad / s) input from the target angular velocity calculator 31 into the traveling speed v (m / s) of the main body 11 using the following formula 6.

v = l · ωhr (6)
The speed limiter 35 limits the calculated traveling speed v to a predetermined value v ′ (for example, v ′ = 1.5 m / s) or less. Then, the speed limiter 35 reconverts the travel speed v ′ (m / s) after the limit into the target angular speed ω′hr (rad / s) using Equation 5. The converted target angular velocity ω′hr is input to the FB control unit 32. Therefore, the target angular velocity ω′hr is limited, the calculated torque command value αtr is limited, and the traveling speed of the main body 11 is limited. Thereby, even if the controller which performs feedback control is only the FB control part 32, the advancing speed of the main-body part 11 can be restrict | limited.

In this embodiment, since the rotation angle of the main body 11 is limited to a predetermined range, if a gyro sensor is used, the detected angular velocity of the main body 11 becomes 0, and the target angular velocity Even if ω′hr is limited, the calculated torque command value αhr may become large. However, since the control unit 21A obtains the angular velocity of the main body 11 based on the angular velocity of the wheel 12, the angular velocity ωh output from the conversion processing unit 34 does not become zero while the wheel 12 is rotating, The traveling speed of the part 11 does not increase significantly.

Next, FIG. 7 is a block diagram showing a hardware configuration of a handcart 10A according to a modification of the handcart 10. The components common to the wheelbarrow 10 are denoted by the same reference numerals and description thereof is omitted. The handcart 10 A includes a control unit 21 A instead of the control unit 21, and further includes a brake operation reception unit 45.

The brake operation reception unit 45 is, for example, a brake lever adjacent to the grip unit 15. The brake operation accepting unit 45 accepts a brake operation and its operation amount (brake operation amount b). The brake operation amount b is 0 when the user U does not operate the brake, and is 1 when the user U has the maximum brake operation. That is, the brake operation reception unit 45 detects the brake operation amount b (0 ≦ b ≦ 1) and outputs the detected brake operation amount b to the control unit 21A.

The speed limiting unit 35 of the control unit 21A inputs the brake operation amount b from the brake operation receiving unit 45, and the progress after the limitation according to the traveling speed v and the brake operation amount b with a function as shown in the following formula 7. The speed v ′ is calculated.

v ′ = f (b, v) (7)
The function f (b, v) is a function that linearly limits the traveling speed according to the brake operation amount of the brake operation receiving unit 45, for example, as shown in Equation 8 below.

f (b, v) = (1.0−b) · v Equation 8
Thereby, the traveling speed of the main body 11 decreases linearly as the brake operation amount of the brake operation receiving unit 45 increases.

Also, the function f (b, v) may be a function that limits the traveling speed so that the deceleration acceleration increases as the brake operation amount of the brake operation receiving unit 45 increases, for example, as shown in Equation 9 below. Is possible.

v ₀ is the traveling speed when the brake operation reception unit 45 receives the brake operation. a is the deceleration when the brake operation amount is maximum, v becomes a negative value in a range where v 'is not a negative value when ₀ is positive (during forward), v ₀ is negative (backward movement) Sometimes, it becomes a positive value in a range where v ′ does not become a positive value. The value of v ₀ is a value of zero in the case of zero. Therefore, in this example, f (b, v) is limited in terms of acceleration as the brake operation amount increases.

In addition, when the brake operation is received by the brake operation receiving unit 45, it is preferable to change the integration time Tv of the integral term in the FB control unit 32 in accordance with the brake operation amount. For example, when the user U continues to stop the wheel 12 by applying a large load to the gripping part 15, the value of the angular velocity ωh, which is the output value of the conversion processing part 34, becomes 0. The integral term indicated by becomes larger. Therefore, even if the user U performs a brake operation immediately after releasing the load on the gripping part 15, the traveling speed may not be immediately reduced. Therefore, if the integration time Tv of the integral term in the FB control unit 32 is reduced as the brake operation amount of the brake operation accepting unit 45 is increased, it proceeds quickly according to the brake operation even immediately after the wheels 12 are kept stopped. The speed will decrease.

Next, FIG. 8 is a block diagram showing a hardware configuration of a handcart 10B according to a modification of the handcart 10A. The components common to the wheelbarrow 10A are denoted by the same reference numerals, and the description thereof is omitted. The handcart 10 B further includes a contact detection sensor 46.

The contact detection sensor 46 is a sensor that is provided in the grip 15 and detects whether or not the user U is holding the grip 15 by detecting the contact of the user U. The detection result is input to the control unit 21A.

When the contact detection sensor 46 has not detected the contact of the user U, that is, when it is determined that the user U is not gripping the grip 15, the speed limiter 35 of the control unit 21 A determines the traveling speed v ′. Set to 0 and stop the handcart 10B. However, when the traveling speed v ′ is suddenly set to 0 and the target angular speed ω′hr is set to 0, the behavior of the main body 11 may become unstable. Therefore, it is preferable to reduce the traveling speed v ′ at a predetermined deceleration acceleration “a” as shown in Equation 10 below.

Here, v ₀ is the traveling speed when the contact detection sensor 46 stops detecting the contact of the user U. a is a predetermined deceleration, v ₀ positive 'becomes a negative value in the range where does not become a negative value, v ₀ is when a negative (reverse travel) v' v when the (forward-movement) is positive It becomes a positive value in the range that does not become a value. The value of v ₀ is a value of zero in the case of zero.

Thus, when the user U releases the grip portion 15, the wheelbarrow 10 is safely stopped.

In addition, the operation | movement which stops the handcart 10 by applying Formula 10 is, for example, when a failure of the own device is detected by the self-failure detection function, or when the user U performs an unreasonable operation (for example, pushing the handcart extremely When the object is detected by an obstacle detection sensor or the like.

Note that when the user U grips the grip 15 again after the hand U 10 has been released and the handcart 10 has stopped, there is a large deviation between the pitch angle of the main body 11 and the target pitch angle. In this case, a large torque command value tr is calculated by proportional control, and the main body 11 may suddenly rotate in the pitch direction. Therefore, when the contact detection sensor 46 detects the contact of the user U, the speed limiting unit 35 limits the traveling speed v ′ to be further reduced (for example, v ′ = 0.5 m / s). Then, when the current pitch angle θh of the main body 11 approaches the target pitch angle θhr (for example, within ± 2 degrees), the limit of the traveling speed v ′ is set to a normal value (for example, v ′ = 1. 5m / s) is performed. This operation can also be applied when the brake is released.

The above operations are summarized in the flowchart as shown in FIG. That is, the target angular velocity calculation unit 31 of the control unit 21A first calculates the target angular velocity ωhr (s11). Then, the speed limiting unit 35 converts the target angular speed ωhr (rad / s) into the traveling speed v (m / s) of the main body unit 11, and the traveling speed v is a predetermined value v ′ (for example, v ′ = 1). .5 m / s) or not (s12). When the traveling speed v exceeds a predetermined value, the speed limiter 35 limits the speed to a predetermined value v ′ (for example, v ′ = 1.5 m / s) or less (s13).

Next, the speed limiter 35 determines whether or not the contact detection sensor 46 detects the contact of the user U (s14). If it is determined that the user U is not gripping the grip 15, the speed limiter 35 reduces the travel speed v ′ at a predetermined deceleration acceleration a using Equation 10 (s 15). After that, the speed limiting unit 35 reconverts the traveling speed v ′ into the target angular speed ω′hr and outputs it to the FB control unit 32 (s21).

If the speed limiter 35 determines that the user U is holding the grip 15, whether or not the current pitch angle θh of the main body 11 is closer to the target pitch angle θhr (for example, within ± 2 degrees). Is determined (s16). The speed limiter 35 determines whether or not the pitch angle θh is close to the target pitch angle θhr (for example, within ± 2 degrees) even after the user U senses contact, and is in that state. If it is determined that there is not, the traveling speed v ′ is further reduced (for example, v ′ = 0.5 m / s) and limited (s17). However, in the state where the traveling speed v ′ is further limited, when the pitch angle θh is near the target pitch angle θhr, the restriction on the traveling speed is released.

Thereafter, the speed limiting unit 35 inputs the brake operation amount b from the brake operation receiving unit 45, and determines whether or not the brake operation is performed (s18). If it is determined that the brake operation is performed, the traveling speed v 'corresponding to the brake operation amount b is calculated by a function as shown in Formula 7 (s19). When the current pitch angle θh of the main body 11 is far from the target pitch angle θhr (for example, larger than ± 2 degrees) when the brake is released, the current pitch angle θh is close to the target pitch angle θhr. Limit the rate of progress until

Next, the speed limiting unit 35 detects a failure of the own device by the self-failure detection function, when the user U performs an unreasonable operation (for example, when pushing the wheelbarrow extremely strongly), or an obstacle. When an obstacle is detected by the detection sensor or the like, it is determined whether or not there is an abnormality such as (s20). If it is determined that there is an abnormality, the speed limiting unit 35 reduces the traveling speed v 'at a predetermined deceleration acceleration a using Equation 10 (s21).

Finally, the speed limiter 35 reconverts the traveling speed v ′ into the target angular speed ω′hr and outputs it to the FB controller 32 (s21).

The control unit 21A repeats the above processing to perform the travel speed limit processing.

DESCRIPTION OF

SYMBOLS

10, 10A, 10B ... Wheelbarrow 11 ... Main-body part 12 ... Wheel 13 ... Supporting part 14 ... Auxiliary wheel 15 ... Grasping part 16 ...

Box

21, 21A ... Control part 22 ... ROM
23 ... RAM
DESCRIPTION OF SYMBOLS 24 ... Drive part 25 ... Wheel rotary encoder 26 ... Main body rotary encoder 31 ... Target angular velocity calculation part 32 ... FB control part 33 ... Torque command value conversion part 34 ... Conversion processing part 35 ... Speed restriction part 45 ... Brake operation reception Unit 46 ... contact detection sensor

Claims

The main body,
A wheel rotatably supported by the main body,
A drive unit for rotating the wheels in the pitch direction;
A control unit that feedback-controls the driving unit;
A main body angle detector for detecting a rotation angle of the main body in the pitch direction;
A wheel angle detector for detecting a rotation angle of the wheel in the pitch direction;
A wheelbarrow with
The control unit calculates an angular velocity in the pitch direction of the main body based on a rotation angle in the pitch direction of the wheel detected by the wheel angle detection unit,
Based on the calculated angular velocity in the pitch direction of the main body and the rotation angle in the pitch direction of the main body detected by the main body angle detector, the rotation angle in the pitch direction of the main body becomes the target rotation angle. The wheelbarrow is characterized by controlling the drive unit as described above.
The control unit multiplies the rotation angle in the pitch direction of the wheel detected by the wheel angle detection unit by a ratio between the rotation radius of the wheel and the rotation radius of the main body, and differentiates the main body. The handcart according to claim 1, wherein an angular velocity in a pitch direction of the portion is calculated.
The control unit calculates a target angular velocity based on the target rotation angle and the rotation angle in the pitch direction of the main body detected by the main body angle detection unit,
The handcart of Claim 1 or Claim 2 which calculates the torque which the said drive part applies to the said wheel so that the calculated angular velocity of the pitch direction of the said main-body part may become the said target angular velocity.
The target angular velocity is converted into the traveling speed of the main body, the converted traveling speed is limited to a predetermined speed, and the speed limiting means for reconverting the limited traveling speed into the target angular speed,
4. The handcart according to claim 3, wherein the control unit calculates a torque that the drive unit applies to the wheel based on the target angular velocity after the speed limiting unit reconverts.
A brake operation reception unit for receiving a brake operation on the wheel;
The handcart according to claim 4, wherein the control unit sets a traveling speed limited by the speed limiting unit to be smaller as an operation amount of the brake operation received by the brake operation receiving unit increases.