KR101638242B1 - Method of Controlling Motor Driven Power Assisted Safe Stroller and Apparatus for the Same - Google Patents

Abstract

(Hereinafter, referred to as a stroller) such as a stroller, an elderly walker, an industrial wagon, or a cart for a mart, which is designed to assist the rotation of the wheel by the power generated by driving the motor by the battery power. do. A user's intention regarding the driving of the stroller is grasped from the 'force applied by the user to the stroller' measured using the force sensor, and the following angular velocity corresponding to the doctor is calculated. The actual angular velocity of the stroller is measured using a speed sensor. And calculates the angular velocity compensation value for the actual angular velocity to follow the tracking angular velocity. The inclination angle of the point where the baby carriage is located and the total mass of the baby carriage measured by the inclination sensor are used to calculate a torque compensation value for compensating the force that the baby carriage is pushed down from the inclined surface. The angular velocity compensation value and the torque compensation value are summed up to calculate a drive control signal for driving the motor section and provide it to the motor drive section. A control device for performing such control is also disclosed. According to this, since the motor assists the proper power according to the degree of inclination, the user can drive the stroller only by the force that the position of the stroller is always driven on the flat surface regardless of the level, the uphill, and the downhill. Even if you miss the handle of the stroller in the downhill, you can stop the stroller quickly and safely by recognizing the fact automatically, thus preventing a safety accident.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electric power assisted safety stroller,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stroller, an elderly walker, an industrial wagon, a cart for a mart, etc. (hereinafter, referred to as a representative example of a baby stroller) The present invention relates to an electric power assistance assisted safety baby carriage.

Baby strollers, which are indispensable for the external activities of families with infants and young children, are classified into passive and motorized types according to their driving methods. Although the passive type is advantageous in that it is cheap and easy to maintain, the pusher (hereinafter, referred to as the 'user') pushes the handle only by its own force. Therefore, It is very inconvenient to move up the slope, and if the handle is missed on the slope, it is difficult to cope with it, leading to an accident.

In recent years, the number of single-family homes has increased, and parents are increasingly purchasing high-priced strollers for their children. The industry is trying to focus on the safety and convenience of the stroller in keeping with this trend. have. For example, electric baby strollers using electric motors have been developed and sold. The electric baby stroller is only able to move the stroller at a fixed speed in a switch manner. Therefore, there is a problem that the stroller continues to move even when the stroller user forgets the handle of the stroller for any reason. If the road on which the stroller is to be moved is an uphill slope, adding a positive torque to the stroller wheels may reduce the user's effort. Conversely, on the downward slope, the user may use less force to prevent downward movement at high speeds by adding negative torque to the stroller wheels. The conventional electric baby stroller has no torque control function according to the inclination condition of the road, and thus there is a great opportunity to improve the safety and convenience of the baby stroller.

Korean Patent Registration No. 10-1408162 discloses a fully automatic stroller which is designed to prevent a downhill safety accident by stopping the stroller by activating the electromagnetic clutch brake installed on the stroller's wheel axis by sensing the distance between the protector and the stroller through the sensor mounted on the handle . However, this stroller also automatically recognizes the inclination condition of the road and does not automatically control the torque accordingly. Also, the stroller automatically recognizes the user's intention to operate the stroller and supports the stroller to operate the stroller conveniently and safely There is a limit that can not be met.

The present invention is intended to improve the limitations of the conventional electric baby stroller, and automatically grasps the user's intention regarding the inclination condition of the road and the operation of the baby carriage and reflects the user's intention to the motor drive, And an object of the present invention is to provide an electric power assisted safety baby carriage control method and control device for the same which are designed to provide both convenience of driving by force alone and safety of automatically stopping when a user misses the handle on a downhill slope.

According to an aspect of the present invention, there is provided a transfer device such as a stroller, an elderly walker, an industrial wagon, or a cart for a mart, which is designed to assist rotation of a wheel by a power generated by driving a motor by battery power In the method for controlling the baby carriage, a user's intention regarding the driving of the baby carriage is grasped from the 'force applied to the baby carriage by the user' measured using the force sensor, and the following angular velocity corresponding to the user is calculated ; Measuring an actual angular velocity of the baby carriage using a velocity sensor; Calculating an angular velocity compensation value for the actual angular velocity to follow the following angular velocity; Calculating a torque compensation value for compensating a force of the baby carriage pushed down from the slope by the inclination angle of the point where the baby carriage is positioned and the total mass of the baby carriage measured by the inclination sensor; And calculating the driving control signal for driving the motor unit by summing the angular velocity compensation value and the torque compensation value and providing the calculated driving control signal to the motor driving unit.

In the control method, the step of calculating the following angular velocity includes: measuring a force applied by a user to the baby carriage using a force sensor; Comparing the magnitude of the measured force signal with a reference value to determine whether the user intends to drive the stroller or to stop the stroller; And calculating a follow-up angular velocity according to the driving pseudo-reference model by applying a transfer function according to a driving pseudo-reference model in which the measured force is previously set, And calculating a follow-up angular velocity according to the pause pseudo-reference model by applying a transfer function according to a preset pseudo-assist reference model.

The control method calculates the torque compensation value by converting the force measurement value outputted by the force sensor into the actual total mass of the baby carriage with reference to a predetermined conversion table in a state in which the user lifts the rear wheel of the baby carriage away from the ground Step to be applied to the step.

In the control method, the torque compensation value is set such that, in order to enable the user to drive the stroller by applying a force equal to that of a flat surface even on an inclined surface, the gravitational force acting on the actual total mass of the stroller, regardless of the inclination angle of the inclined surface, It is preferable to set the size to prevent it from being pushed downward by the inclined surface.

In the control method, it is preferable that the angular velocity compensation value is calculated by performing proportional-plus-integral (PI) control on a difference value between the following angular velocity and the actual angular velocity.

According to another aspect of the present invention, there is provided a stroller comprising: a plurality of wheels; a body frame coupled to the wheel; a stroller including a handle coupled to the body frame; (Hereinafter referred to as " stroller ") such as an industrial wagon or a cart for a mart, and is provided with a control unit for providing an electric power to the stroller, Force sensor; A tilt sensor installed on the baby carriage for measuring a tilt angle of a point where the baby carriage is located; A speed sensor installed in the stroller for measuring an actual angular speed equivalent to a speed of the stroller; A motor unit driven by an input motor drive signal to generate a rotational force to rotate at least a part of the plurality of wheels; A motor driving unit for generating a motor driving signal based on an input drive control signal and providing the generated motor driving signal to the motor unit; A battery used as an energy source necessary for driving the motor unit; And an actual angular velocity of the baby carriage which detects and feeds back the detected angular velocity of the baby carriage to follow the following angular velocity, And a torque compensation value for compensating a force of the baby carriage pushed down from the inclined surface by the inclination angle of the position of the baby carriage measured by the inclination sensor and the total mass of the baby carriage And a control unit for controlling the driving of the motor unit by providing the motor driving unit to the motor driving unit.

In the control device, the controller may determine that the baby stroller is to be stopped if the output signal of the force sensor is within a first range (hereinafter, referred to as a "stop doctor"), (Hereinafter, referred to as " drive doctor ") to drive the stroller, and if it is determined that the driver wants to stop the driver, the transfer function according to the reference model during stopping is applied to the output signal of the force sensor, It is preferable to perform the process of calculating the following angular velocity by applying a transfer function according to the reference model to the output signal of the force sensor when it is determined as a doctor.

In the control unit, it is preferable that the angular velocity compensation value is calculated by performing PI (Proportional Integral) control on the difference between the following angular velocity and the actual angular velocity.

In the control unit, the torque compensation value is determined by the gravity acting on the actual total mass of the stroller, regardless of the inclination angle of the inclined surface on which the stroller is located, so that the user can drive the stroller by applying force equal to the flat surface It is preferable that the size is set to a size that prevents the user from pushing down the slope.

It is preferable that the total mass of the baby carriage is an actual total mass of the baby carriage converted by referring to a predetermined conversion table by the force measurement value outputted by the force sensor while the user is raised so that only the rear wheel of the baby carriage is lifted away from the ground Do.

The motor unit and the wheel unit may be an in-wheel motor in which the motor unit is integrated into the hub of the wheel unit to directly drive the wheel unit. When the in-wheel motor is not employed, the control unit further includes a power transmission unit that transmits rotational force generated by the motor unit to at least a part of the wheels and assists rotation of the wheels.

In order to enable the driver to drive the stroller with the force equal to the flat surface when the user moves up, down, and down, the 'electric power assistant safety stroller' according to the present invention requires It compensates the power by the power of the motor. Regardless of whether the position where the stroller is located is a slope or a flat surface, the user can drive the stroller by applying only the driving force on the flat ground. Since it does not depend on the inclination condition of the traveling path, the driving force is less required to drive the stroller, so that the driving is easy and the moving range can be expanded.

The torque sensor of the stroller handle portion measures the torque generated when the user pushes the handle so as to determine whether the user intends to drive the stroller and to set a separate reference model in advance according to the user's intention, And controls the angular velocity to follow the following angular velocity according to the reference model. This control method can prevent safety accidents on slopes. In other words, the infant as a passenger has absolutely no resistance to outside situations. When the user unintentionally misses the handle of the stroller on the slope, the reference model for stopping the stroller is automatically applied so that the compensating torque generated by the motor acts as a brake to stop the stroller quickly and safely. It is possible to prevent safety accidents such as acceleration falling, collision, and conduction of the baby carriage on the inclined surface.

Since the problem of the existing baby carriage is compensated and the baby carriage is driven by a new system, the selection range of the baby carriage user is improved.

1 is a perspective view illustrating an electric power assistant safety baby carriage according to an embodiment of the present invention,
Fig. 2 shows a state in which the seat is removed from the stroller of Fig. 1 and viewed from behind,
FIG. 3 is a block diagram showing a control system for an electric power assistant safety baby carriage according to the present invention,
4 is a flowchart illustrating a method of controlling an electric power assisted safety baby carriage according to the present invention,
5 is a control flowchart showing the control logic performed by the control unit of Fig. 3,
6 is a free body diagram of a baby carriage for explaining torque compensation control when the baby carriage moves on an inclined plane,
7 is a graph for comparing the theoretical value and the actual value of the compensation torque according to the magnitude of the tilt angle on the slope.

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

A typical baby carriage includes a wheel portion including a front wheel and a rear wheel, a seat portion, a body frame portion supported by the wheel portion to support the seat portion, and a handle portion coupled to the body frame portion. The stroller 100 according to the preferred embodiment of the present invention has a configuration in which separate components for implementing the present invention described below are added based on the basic configuration of the stroller. Further, the structure of the basic structure is adaptively modified according to the functional and structural characteristics of the added components. 1 and 2 illustrate a state in which the seat portion 140 is installed and a state in which the stroller 100 is removed from a side and a rear side.

Specifically, the wheel part 110 is composed of two wheels that are axially coupled to at least one of the front wheel and the rear wheel. The baby carriage illustrated in the figure has a structure in which the rear wheel portion 112 has two wheels connected to each other via an axle 114. The rotational force generated by the motor 70 is transmitted to the axle 114 via a power transmitting means such as a gear portion 80, for example. In this case, the front wheel portion 116 is constituted by one or more wheels. The baby carriage 100 illustrated in the figure shows a case in which the front wheel portion 116 includes two wheels. Of course, the front part may also be configured to receive the rotational force of the motor by connecting two wheels with the axle like the rear wheel part.

The body frame 120 constitutes a body of the baby carriage 100. The body frame 120 is coupled to the wheel unit 110 and supports the seat unit 140. A rear frame 122 coupled to a wheel axis of the rear wheels 112 and a front frame 124 coupled to a wheel axis of the front wheels 116. [ The rear frame 122 and the front frame 124 can be made to directly support the seat portion 140. Alternatively, as illustrated in the drawings, the structure may further include a seat grasping frame 126 that is supported by being coupled to the rear frame 122 and the front frame 124 to support the seat portion 140. According to the illustrated example, the rear frame 122 and the front frame 124 each have a substantially inverted U shape, the front frame 124 is installed at an angle to the rear side, and the rear frame 122 is installed at an angle toward the front side , And the upper end portions come into contact with each other or come into contact with each other. The sheet holding frame 126 is also made substantially U-shaped so as to wrap around and cover the seat portion 140. The lower portion thereof is engaged with and supported by the upper portions of the rear and front frames 122 and 124, The left and right vertical portions are engaged to support the left and right sides of the seat portion 140 so as to be held.

The seat portion 140 includes a receiving portion 142 and a back portion 144 for allowing the infant to sit or lie thereon, both of which are coupled to be folded or unfolded at a desired angle. The seat portion 140 is coupled to and supported by the body frame portion 120. The seat portion 140 illustrated in the drawing is coupled to and supported by the seat grasping frame 126, and may be detached from the seat grasping frame 126, if necessary, as shown in Fig.

The handle 130 is coupled to the body frame 120 so as to transmit a user's force. The handle 130 illustrated in the figure includes a center handle that is pushed by the user and a predetermined length extending from both sides of the handle, and an end portion of the handle is extended to the left and right of the body frame portion 120, more specifically, And is substantially U-shaped including left and right extensions coupled to the vertical portion. The center knob is horizontally disposed near the user's chest and the left and right extended portions are disposed diagonally downward so that the user can easily apply force.

These basic components are usually provided by a passenger stroller which can be pushed and moved only by the force of the user. The stroller 100 according to the present invention includes a force sensor 20 for measuring the force applied when the user pushes or pulls the handle 130 to move the stroller 100 to such a basic component, A tilt sensor 30 for measuring the tilt of a point where the tilt sensor 100 is positioned and a speed sensor 40 for measuring the moving speed of the trolley 100.

The stroller 100 according to the present invention includes a motor unit 70 for generating a rotational power, a motor driving unit 60 for driving the motor unit 70, And a power transmission unit 80 for transmitting the rotational power generated by the motor unit 70 to the wheel unit 110 of the stroller 100. [ The baby carriage 100 is provided with the user force, the inclination angle, and the velocity value of the baby carriage 100 measured by the sensor unit, and compensates for the driving torque of the baby carriage by grasping the user's intention and the inclination of the position of the baby carriage 100, And a control unit 50 for performing overall control for preventing a safety accident.

The force sensor 20 measures the amount of deformation or voltage of the elastic deforming member when a deforming of the elastic deforming member occurs due to a force applied to the handle 130 or a voltage is applied or a method of measuring a force balance such as an electromagnetic force, And a method using a force measurement method known in the art can be used. For example, a torque sensor or a pressure sensor may be used as the force sensor 20 of the present invention as a kind of force sensor. For example, the torque sensor measures the torque when the user applies a force to the handle 130 of the stroller 100 and displays the measured torque value as a positive value when the torque is positive, And provides it to the control unit 50. [

The measured value of the force sensor 20 is used to determine whether the user intends to drive the stroller 100, that is, whether the stroller 100 is to be driven or stopped. It is preferable that the force sensor 20 be installed at a position where the driver's intention to drive the user's baby stroller can be grasped most accurately. The force applied by the user to the handle 130 for driving the baby carriage 110 is transmitted to the seat 140 through the left end of the handle 130 or the end of the right extension, Lt; / RTI > The coupling point is therefore a suitable point for installing the force sensor 20. Of course, since the force of the user is first applied to the center knob of the handle 130, it is also possible to install the force sensor 20 therein. The optimal installation position and installation type may vary depending on what kind of force sensor 130 is used. It may be suitably installed considering the characteristics of the force sensor 130 to be used. For example, when the torque sensor is used as the force sensor 20, as shown in the figure, the torque of the user due to the pushing force of the handle 130 is transmitted to the handle portion 130 It is most preferable to provide a torque sensor at the distal end portion thereof since it is easy and accurate to measure at the left extension portion or the distal extension portion of the right extension portion.

The measured value of the force sensor 20 is also used to grasp the actual total mass of the baby carriage 100 (the sum of the mass of the baby carriage 100 and the mass of infants and / or objects aboard it) More about this later). In order to control the driving of the motor part, in particular, in the control for preventing safety accident on the downhill road, knowing the actual total mass of the stroller 100 enables quick and accurate control.

The inclination sensor 30 is provided to measure the inclination angle of the point where the baby carriage 100 is positioned. The inclination sensor 30 is installed so that the inclination angle can be measured at 0 degree on a flat surface having an inclination angle of 0 degrees, It can be installed so that it can be measured. There are no other specific restrictions on the installation location. For example, it can be mounted on the bottom of a horizontal support for placing a controller 50 to be described later. 1-axis direction (traveling direction of the baby carriage 100) A tilt sensor is sufficient, and it is not necessary to use a tilt sensor capable of measuring the tilt in the multi-axis direction. The inclination sensor 30 provides the control unit 50 with an output signal having a positive (positive) value when the measured inclination angle is, for example, an uphill, and a negative (negative) value when the measured inclination angle is downhill.

The speed sensor 40 is a means for measuring the moving speed of the baby carriage 100. Since the moving speed of the baby carriage 100 is a physical quantity equivalent to the angular velocity of the front wheels or the rear wheels 116 and 112 or the angular velocity o of the motor unit 70, this value can be measured. For example, the angular speed omega of the motor unit 70 can be measured by counting the number of revolutions of the motor unit 70. [ The speed sensor 40 is a speed sensor that is integrated with the motor unit 70 so as to measure the angular speed omega by counting the number of revolutions of the motor unit 70. [

The power transmission unit 80 is a means for transmitting the power generated by the motor unit 70 to the axle 114 to rotate the axle 114. [ For example, a gear assembly composed of gears coupled to the rotational axis of the motor unit 70 and gears coupled to the axle 114 of the wheel unit 110. Alternatively, it may be implemented using a belt and a pulley.

The motor driving unit 60 generates a driving signal required for driving the motor unit 70 and supplies the generated driving signal to the motor unit 70. This driving signal is generated by using the power source of the battery 90 in accordance with a control signal for motor driving provided by the control unit 50. [

The motor unit 70 generates rotational power by inputting a driving signal of the motor driving unit 60. It is preferable to implement a DC motor such as a brushless motor (BLDC motor) suitable for a DC power source to be used. The motor unit 70 is fixed at a position close to the axle 114 and is installed to be able to engage with the power transmission unit 80 to provide power to the axle 114. [

An in-wheel motor (also referred to as a wheel hub motor) may be employed. The in-wheel motor is a motor in which the electric motor is integrated into the hub of the wheel and the in-wheel motor directly drives the wheels. When at least a part of the motor part 70 and the wheel parts 112 and 116 of the baby carriage are replaced by an in-wheel motor 85, the power transmitting part 80 may be omitted. The in-wheel motor 85 may be applied only to the rear wheels or only to the front wheels, or both.

The control unit 50 is electrically connected to these sensors 20, 30 and 40 so that the respective measured values from the force sensor 20, the inclination sensor 30 and the velocity sensor 40 can be provided in the form of electric signals . The motor driving unit 60 is also electrically connected to the motor driving unit 60 so as to provide a control signal for driving the motor. When using the sensors 20, 30, and 40 that provide measured values as analog signals, the controller 50 includes an AD converter that converts the measured values to digital signals. The control unit 50 includes a DA converter for converting the motor drive control value into an analog signal because the motor drive control signal provided to the motor drive unit 60 is an analog signal. The control unit 50 basically receives a measurement value provided from a memory and sensors 20, 30, and 40 for storing necessary data and a program for executing the control method of the present invention to be described later, And calculates a control value related to the motor drive.

The stroller 100 has a battery 90 as a power source. The battery 90 is connected to the components requiring power supply, such as the sensor units 20, 30, 40, the control unit 50, the motor drive unit 60, and the like, Although not shown, a power switch may be further provided to allow the user to turn on or off the power supply of the battery 90 to these components as needed. The control method described below can be executed only when the power switch is turned on.

The battery 90, the motor driving unit 60, and the control unit 50 may be fixed at appropriate points since a sufficient space is provided in the lower portion of the body frame unit 120. For example, these can be fixed to a base plate (not shown), and the base plate can be fixed to the body frame portion 120. In order to improve the appearance, these components may be housed in a storage box (not shown), and the storage box may be fixed to the body frame portion 120. The stroller is generally designed to be folded in order to minimize the volume when the vehicle is moving. The stroller 100 according to the present invention may also be installed so as not to hinder the folding or unfolding of the stroller 100 when the battery 90, the motor driver 60, the controller 50 and the like are fixed to the body frame 120. [ . That is, the additional components according to the present invention may be installed in an existing or future folding or non-folding stroller.

Fig. 3 is a block diagram of a control system 10 for controlling the driving of the motor stroller 100. Fig. The control unit 50 reads out the measured values from the force sensor 20, the inclination sensor 30 and the velocity sensor 40 at each sampling cycle, that is, the force T applied by the user to the stroller 100, And the angular speed? ^* Of the motor unit 70 are provided in the form of electric signals, respectively. The controller 50 generates the motor drive control signal Cd by using the measured values provided by the sensor units 20, 30 and 40 to provide the motor drive unit 60 with the control logic described below. The motor drive unit 60 generates the motor drive signal Md based on the motor drive control signal Cd and provides it to the motor unit 70. [ The motor unit 70 is driven at the rotational speed indicated by the control unit 50 and the generated rotational force is transmitted to the axle 114 of the baby carriage 100 through the power transmitting unit 80. [ And the resultant force of the user and the auxiliary driving force added by the motor unit 70 drives the baby carriage 100. [ The angular speed? ^* Of the motor unit 70 is detected by the speed sensor 40 in real time and fed back to the control unit 50. [

The control method performed by this control system 10 is shown in the flow chart of Fig. A control method of the baby carriage 100 of the present invention will be described with reference to this flowchart.

First, the present invention applies a torque compensation control algorithm based on a user's intention. And is characterized by automatically grasping the intention of the user driving the stroller 100 and controlling the driving of the motor in accordance with the detected intention. There are two main types of users' opinions. One is a doctor who wants to drive a stroller, and the other is a doctor who wants to stop the stroller. Dynamically modeling the movement of the stroller, the stroller makes reference models for driving and stopping, respectively. If the user's intention is to drive the baby carriage, the control of the motor unit 70 is performed so that the actual baby carriage 100 follows the movement of the reference model at the time of driving. On the other hand, if the user's intention is to stop the baby carriage, the control of the motor is controlled so that the actual baby carriage 100 follows the movement of the reference model at the time of stopping. Hereinafter, this will be described in more detail.

The user's intention regarding the driving of the baby carriage can be grasped from the pushing force of the baby carriage knob 130 (step S10). When the torque sensor 20 is used as the force sensor 20 as shown in the figure, it can be grasped by using the value of the torque T generated at the handle 130. When the user applies a force to the handle 130, the torque sensor converts the torque applied to the handle 130 into a voltage signal (torque signal T) and provides the torque signal T to the controller 50 in step S12.

The torque sensor causes the magnitude of the measured torque to be converted into a voltage value within a range of, for example, -5 V to +5 V and output. In this case, the torque signal T is theoretically measured to be 0 [V] (reference value) when no force is applied to the knob portion 130, and when the force pushing the knob portion 130 is applied, The positive torque value within the range of 0 [V] <T? 5 [V] is measured, and when a force for pulling back the handle 130 is applied, -5 [V]? T A negative torque value within the range of < 0 [V] will be measured. In practice, noise due to various factors may be included in the torque signal. Therefore, when the value of the output voltage signal of the torque sensor is not exactly 0 [V] and is a value between -0.2 [V] and +0.2 [V] It is preferable that the handle 130 is regarded as not being subjected to a force. When the voltage value of the torque signal is substantially 0 [V], it can be regarded as a state in which the user does not perform a driving operation such as pushing or pulling the stroller 100, that is, in a stationary state and is not substantially 0 [V] The user can see that the user is driving the stroller 100, that is, the driving state.

Therefore, the control unit 50 determines whether the voltage value of the torque signal T provided by the force sensor 20, that is, the torque sensor is substantially 0 [V] (step S14). At this time, if the torque signal is an analog signal, the process of converting to a digital value is performed.

The control unit 50 sets the reference model in the stopped state and the reference model in the drive state in advance, and performs control relating to the drive of the motor unit 70 in accordance with the determination result in step S14. A control target of the control unit 50 is the angular velocity of the stroller 100, the actual speed and the equivalent value of the motor unit 70, the angular velocity (ω) are two standards model that is, stop state of the baby carriage reference model haedun pre-design of the (ω ^* And the angular speed? ^* Of the drive state reference model.

To this end, when the voltage value of the torque signal T provided by the torque sensor is not substantially 0 [V], the baby carriage following angular speed? ^* According to the driving state reference model is calculated (step S16). On the other hand, if the voltage value of the torque signal T is substantially 0 [V], the baby carriage following angular speed [omega] ^* according to the stopped reference model is calculated (step S18).

The controller 50 receives the actual angular speed? Of the motor unit 70 measured in real time by the speed sensor 40 in step S34 so that the controller 50 controls the motor unit 70 The angular velocity compensation value is calculated so that the actual angular velocity? Follows the calculated angular velocity? ^{* In} accordance with the two reference models (step S20). The specific calculation method of steps S18 and S20 will be described together with the description of FIG. 5 to be described later.

The present invention is also characterized in that it performs torque compensation control for preventing free fall on the inclined plane. Consider a situation in which the baby carriage 100 travels on an inclined plane (step S22). The control method according to the present invention compensates the torque according to the inclination angle of the point where the baby carriage 100 is located by the power of the motor unit 70. [ The actual total mass of the baby carriage 100 measured by the force sensor 20 and the inclination angle measured by the inclination sensor 30 in real time are used to calculate the magnitude of the torque to be compensated at the inclined portion. At this time, the required torque to be compensated for the wheel is calculated, and the DC motor compensates the torque. With the torque compensation, the user can move the stroller only with the same force as if driving the stroller 100 in the flat position regardless of the inclination of the position where the stroller 100 is located.

For this, the inclination sensor 30 measures the inclination angle of the point where the baby carriage 100 is located in real time, and provides the inclination signal converted into the corresponding voltage signal to the control unit 50 (step S24). For example, when the inclination sensor 30 that outputs an output voltage signal of 0.5 V to 4.5 V is used when the measurable inclination angle is -20 to +20, 2.5 is subtracted from the output voltage value of the inclination sensor 30, , It can be converted to an inclination angle of -20 ° to + 20 ° again. The voltage signal indicating the measured inclination angle is provided to the control unit 50. [

The control unit 50 receives an output voltage signal from the inclination sensor 30 and calculates a torque compensation amount to be compensated for the baby carriage 100 according to the inclination angle (step S28). 6 is a free body diagram of the baby carriage for explaining the torque compensation control. In the free body view of the baby carriage 100, gravity W = mg corresponding to the baby carriage mass m acts on the baby carriage 100 in the direction of the center of the globe. The magnitude of the component in the direction parallel to the slope of this force is mg · sin θ. Here, g is the gravitational acceleration, and? Is the inclination angle of the point (inclined plane) where the baby carriage 100 is located. When the frictional force between the inclined surface and the baby carriage wheels 112 and 116 is neglected, it can be seen that a force mg · sin θ is applied to the baby carriage 100 to roll down along the inclined surface. Therefore, when the user does not apply any force to the stroller 100, in order to prevent the stroller 100 from being pushed down from the slope, a force F equal to or greater than mg · sin θ is applied to the stroller 100 in the opposite direction Should be. That is,

......(1)

......(One)

A force F is compensated by using the inclination sensor 30 as a base.

The number of revolutions of the motor section 70 can be obtained from the following equation (when the power transmitting section 80 is constituted by gears having a reduction ratio of 1: 1)

......(2)

......(2)

Because of,

......(3)

(3)

The required torque T of the rear wheel 112 of the baby carriage 100 is obtained using the following equation.

Here, V represents the speed of the baby carriage, D represents the diameter of the rear wheel 112 of the baby carriage, and N represents the number of revolutions of the motor unit 70, respectively. (D is a unit of mm, N is RPM [rev / min], and the unit of velocity V is m / s, so use a constant such as the denominator to match the unit of RPM).

T = F x R (4)

Here, R is the radius of the rear wheel 112.

The control unit 50 calculates the compensation torque required by the motor unit 70 using these equations and supplies the calculated compensation torque to the motor drive unit 60. [ As a result, the torque generated by the motor unit 70 is compensated, and the driving of the motor unit 70 can be controlled as desired by the present invention.

According to such a torque compensation control, the stroller 100 is in a state where it is stopped because no force is applied to the flat surface. Further, even if the user accidentally misses the stroller handle 130 on the inclined surface, the stroller 100 does not slip down on the inclined surface and stops. This is because the user does not apply the force to the stroller 100 because the user misses the stroller 100 and the motor unit 70 applies the compensation torque to the stroller 100 to prevent the stroller 100 from descending.

To calculate the magnitude of the force mg · sin θ, you need to know the angle of inclination θ and the total mass of the stroller 100 (including all the masses of infants and other objects aboard the stroller) m. The inclination angle &amp;thetas; can be known from the detection value of the inclination sensor 30. [ The mass m may be fixed to a predetermined value (fixed value) in consideration of the average weight of the infant on board, but if the fixed value is larger than the actual total mass of the stroller 100, the magnitude of sin θ is not correct and an error occurs in the control. In order to minimize the error, the present invention uses a method of directly measuring the actual total mass of the stroller 100 by a simple operation of the user (step S26).

The total mass of the baby carriage 100 can be measured using the force sensor 20. Specifically, since the mass of the baby carriage 100 itself is a known value at the time of manufacture, the masses other than the baby carriage 100, such as infants and the like, should be accurately obtained. To do this, a test is performed to preliminarily make correlation data between the mass (or the total mass of the baby carriage) added to the baby carriage 100 and the measured value of the force sensor 20, and the correlation data Converted into a conversion table and stored in the control unit 50, and utilized for calculating the total mass of the baby carriage 100 in the future. The test for securing the correlation data is performed by loading a stapler (100) having a known mass (test object) on the seat part (140) and lifting the handle part (130) of the stroller The controller 50 calculates the magnitude of the force (e.g., torque) measured by the force sensor 20 in a state in which the rear wheel 112 is separated from the ground (in this case, the front wheel portion 116 touches the ground) The correlation data between the mass (or the total mass of the baby carriage) added to the baby carriage 100 and the measured value of the force sensor 20 is stored in advance as a conversion table. In this test, the above-mentioned correlation data is secured while increasing the mass of the test object by 1 kg from 1 kg to 30 kg (in this case, the theoretical maximum inclination of the total mass of the baby carriage 100 will be 0.5 kg).

In the state in which the correlation data between the mass added to the stroller 100 and the measured value of the force sensor 20 is prepared, the infant is actually brought to the stroller 100 (and / The actual total mass of the stroller 100 can be calculated by lifting the handle 130 of the stroller 100 in the same manner as the above test before starting the movement. That is, when the user lifts the baby carriage 100, the control unit 50 calculates the magnitude of the force (torque) measured by the force sensor 20 and refers to the conversion table relating to the built- The actual total mass m of the baby carriage 100 corresponding to the magnitude of the applied force (torque) can be calculated.

The control unit 50 calculates the total mass m of the baby carriage 100 in advance at the start of the driving operation and calculates the total mass m of the baby carriage 100 in accordance with the real time tilt angle? The torque compensation value to be generated by the torque converter 70 is calculated (step S28).

The controller 50 performs a predetermined control logic using the angular velocity compensation value calculated in step S20 and the torque compensation value calculated in step S28 as input values to generate a signal for controlling the drive of the motor unit 70 Signal) (step S30). 5 shows the control logic of the control unit 50 for this purpose.

The control unit 50 compensates the torque corresponding to the inclination by the power of the motor unit 70 when the user drives the stroller 100 on the inclined plane so as to drive the stroller 100 with the same force as when driving the stroller 100 on the flat surface And controls the baby stroller 100 to stop safely even if the user misses the handle 130 of the stroller 100 due to carelessness so as to prevent the occurrence of safety accidents due to rapid descent along the slant surface . Specifically, it is as follows.

The wheels 112 and 116 of the stroller are subjected to disturbance torques such as a force applied by a person, friction and the like. The speed sensor 40 measures the angular speed (the angular speed of the baby carriage 100) of the axle 114 connecting the rear wheels 112 and the motor unit 70 connected to the power transmission unit 80 by a gear. The control unit 50 calculates the torque to be compensated in the inclined plane by using the actual total mass of the inclination sensor 30 and the baby carriage 100 and supplies the calculated compensating torque to the motor unit 70 through the motor driving unit 60. [ To be compensated for. The control unit 50 controls the operation of the stroller 100 in which the sum of the compensated torque and the torque due to the force applied by the user to the stroller 100 acts on the rear wheel 112 to which the axle 114 of the stroller 100 is connected The actual angular speed? Is controlled so as to follow the angular speed? ^{* Of the} reference model. That is, the angular speed ω ^* of the virtual baby carriage reference model and the angular speed ω of the actual motor unit 70 obtained through the speed sensor 40 and the angular speed of the actual rear wheel of the baby carriage 112 are continuously compared, And use close-loop control.

For this purpose, a reference model for driving the stroller is set for each of the case where the user's intention to drive the stroller is 'stop' and the case where it is 'driving'. The two reference models can be represented by the following transfer functions H ₁ (s) and H ₂ (s) . These two transfer functions H ₁ (s) and H ₂ (s) are transfer functions of the entire stroller 100 in the case of stop and drive.

......(5)Transfer function at stop:

(5)

......(6)Transfer function at driving:

(6)

Here, the moment of inertia a ₁ , a ₂ and the viscous friction b ₁ , b ₂ may be experimental values obtained through testing. This experimental value is obtained by inputting the torque to the stroller 100, outputting the stroller speed response at that time, and obtaining the transfer function of the actual stroller through system identification (System Identification). The virtual transfer function at the time of driving can be arbitrarily selected by the user while driving the actual baby carriage, and the virtual transfer function at the time of stopping can be set so that the user can safely decelerate and stop when the knob is missed.

When the force (torque) applied by the user to the baby carriage is 0, the transfer function at the time of stopping is applied. When it is not 0, the transfer function at the time of driving is applied. The tracking angular velocity calculation unit 52 of the control unit 50 receives the torque T (s) provided from the force sensor 20 and applies a transfer function H ₁ (s) or H ₂ (s) ^* ).

The control unit 50 performs feedback control so that the angular velocity of the baby carriage 100 follows the following angular velocity ω ^{* which} is obtained by passing the transfer function H ₁ (s) at the time of stopping and the transfer function H ₂ (s) at the time of driving. Specifically, the angular velocity error calculator 54 calculates a value obtained by subtracting the actual angular velocity? Of the baby carriage 100 detected by the angle sensor 40 from the calculated following angular velocity? ^* .

The calculated angular velocity difference is provided as an input value of the PI control unit 56, and gain control is performed. The gain control uses proportional control (P control) for increasing the response speed and integral control (I control) so that no error occurs when the baby carriage 100 stops. The gain control transfer function G (s), which is applied to the PI control,

......(7)

(7)

. Here, the proportional control coefficient K _p and the integral control coefficient K _i may be experimental values obtained through testing.

If the proportional control is applied, the response speed is fast, but the error of the steady state does not become zero. Therefore, when the user loses the stroller 100 on the slope, the stroller 1000 can not stop at the downhill, If the proportional integral control is performed, the steady state error becomes zero, and when the handle is released, the baby carriage is immediately turned on It stops well.

The tilt compensation unit 58 of the control unit 50 performs control for torque compensation based on the tilt angle of the slope with respect to the rotational angular velocity obtained through the PI control. As described above, a force of mg · sin θ is applied to the baby carriage 100 in the direction of descending along the inclined surface of the baby carriage 100. Due to this force, the user must push the baby carriage 100 more strongly when the baby car rises on the inclined surface, The baby carriage 100 should be held in the opposite direction. If the additional torque required to overcome the force mg · sin θ is compensated, the user can drive the stroller 100 as if pushing it on the flat surface, even when climbing up or down the slope. The inclination compensator 58 calculates an angular velocity corresponding to a torque mg · sin θ required for compensation, and adds the calculated angular velocity to the output angular velocity of the PI controller 56 to generate a drive control signal (step S30).

 Although the user can make the same amount of torque to compensate through the motor unit 70 when the user pushes the baby carriage 100 forward and backward with the same force, it is possible to make the user feel that the forward movement is faster and easier than the backward movement It is common. In consideration of this point, it is preferable that the control unit 50 compensates the torque by a larger ratio (for example, 1.2 to 2.5) in the case where the controller 50 pushes forward as compared with the case of pulling back. For example, when the above ratio is doubled and the negative torque value when pulling back is -2 [V], if the magnitude of the compensation torque is -10, the positive torque value at forward pushing is +2 [V ], The magnitude of the compensation torque is applied as +20 (= 10x2).

The angular velocity value thus obtained is an angular velocity that the control unit 50 provides to the motor driving unit 60 to drive and control the actual baby carriage 100. [ The motor driving unit 60 generates a motor driving signal using the angular velocity value to drive the motor unit 70 (step S32). The actual angular velocity? (I.e., the actual angular velocity of the motor unit 70)? Of the baby carriage 100 as a result is fed back to the angular velocity error calculator 54 through the velocity sensor 40 (step S34) closed loop control is performed so that the following angular velocity? ^* follows the following angular velocity? ^* .

According to such a control method, kinematics of the baby carriage is dynamically modeled to create a virtual model when the baby carriage is driven and stopped, and the driving of the motor is controlled so that the actual baby carriage follows the movement of the virtual model. It is possible to automatically detect whether the user has missed the handle 130 of the stroller 100 and whether the state has occurred on the inclined surface or the like. Since the motor unit 70 always compensates for the minimum compensation torque that can overcome the dropping torque applied to the baby carriage 100 due to the inclination of the inclined surface, the user unintentionally tilts the knob of the stroller 100, Even when the baby carriage 130 is missed, the baby carriage 100 can be stopped on the inclined plane. In addition, since the downward torque along the inclined surface is canceled by the power assist of the motor 70, the baby carriage 100 can exist as if it is in the flat state on the inclined plane. Therefore, the user can only drive the stroller 100 on the flat surface to drive the stroller 100 on the inclined surface.

The present inventors have found that when the baby carriage 100 is moved in the off state and on state of the control system 10 in order to check the stopping performance when the actual baby carriage 100 according to the present invention is missed, We compared the behavior of the sample at the position. It can be confirmed that when the control system 10 is turned off, the baby carriage 100 is rapidly lowered by its own weight and the baby carriage 100 stops quickly when the control system 10 is turned on.

The inclination angle read by the inclination sensor 30 and the total mass m of the stroller 100 are used to calculate a force mg · sin θ to be compensated. Based on the calculated force, the torque to be compensated for is output from the motor. Theoretically, a graph was obtained by dividing the torque to be compensated according to the inclination angle by the case where the total mass m was 30 kg, 35 kg, and 40 kg (see the graph of the theoretical value shown in the upper part of FIG. 7). In addition, the total mass m of the stroller was measured to be 30 kg, 35 kg and 40 kg, and the magnitude of the compensation torque according to the tilt angle was measured. The experimental results are shown in an actual value graph shown at the bottom of Fig. According to the experimental result, noise occurs due to the vibration of the stroller 100 when the flat surface, that is, the inclination angle? = 0 °, except that the torque compensation is calculated according to the total mass m of the stroller 100 And it was confirmed that it was done well. The above experiment shows a simple example that not only did you miss the handle, but also that the stroller would not move due to the weight caused by the slope, even when you did not hold the handle.

INDUSTRIAL APPLICABILITY The present invention can be easily fused not only with a baby carriage for infants and children, but also with a mobile body which can be moved by human force, such as a walker for the elderly, an industrial wagon, a cart for a mart and the like.

10: control system 20: force sensor
30: inclination sensor 40: speed sensor
50: control unit 60: motor driving unit
70: motor section 80: power transmission section
85: In-wheel motor 90: Battery
100: baby carriage 110:
120: body frame 130: handle 140: seat portion

Claims (12)

(Hereinafter referred to as a 'stroller') such as a stroller, an elderly walker, an industrial wagon, or a cart for a mart, which is designed to assist the rotation of the wheel by the power generated by driving the motor by battery power ,
Calculating a follow-up angular velocity suitable for the user by grasping the user's intention regarding the driving of the baby carriage from the 'force applied by the user to the baby carriage' measured using the force sensor;
Measuring an actual angular velocity of the baby carriage using a velocity sensor;
Calculating an angular velocity compensation value for the actual angular velocity to follow the following angular velocity;
Calculating a torque compensation value for compensating for a force that the stroller is pushed down from an inclined surface by the inclination angle of the point at which the stroller is positioned and the total mass of the stroller measured by the inclination sensor; And
Calculating a driving control signal for driving the motor unit by summing the angular velocity compensation value and the torque compensation value and providing the calculated driving control signal to the motor driving unit,
Wherein the step of calculating the following angular velocity includes: measuring a force applied by the user to the baby carriage using the force sensor; Comparing the magnitude of the measured force signal with a reference value to determine whether the user intends to drive the stroller or to stop the stroller; And calculating a follow-up angular velocity according to the driving pseudo-reference model by applying a transfer function according to a driving pseudo-reference model in which the measured force is previously set, And calculating a follow-up angular velocity according to the pseudo-pseudo-reference model by applying a transfer function according to a preset pseudo-pseudo-reference model,
In order to allow the user to drive the baby carriage by applying a force equal to that of a flat surface even on an inclined surface regardless of the inclination angle of the inclined surface on which the baby carriage is located, To prevent it from being pushed downward,
Wherein the angular velocity compensation value is calculated by performing proportional integral (PI) control on a difference value between the following angular velocity and the actual angular velocity. delete 2. The stroller according to claim 1, wherein the user reads the force measurement value outputted by the force sensor while lifting the rear wheel of the baby carriage away from the ground, converts the force measurement value into the actual total mass of the baby carriage with reference to a predetermined conversion table, To the step of calculating the electric power assisted safety baby carriage. delete delete (Hereinafter referred to as a &quot; stroller &quot;) such as a stroller, an elderly walker, an industrial wagon, or a cart for a mart, which includes a plurality of wheels, a body frame coupled to the wheels, (Hereinafter collectively referred to as &quot; control device &quot;),
A force sensor installed on the stroller for measuring a force applied by the user to the stroller;
A tilt sensor installed on the baby carriage for measuring a tilt angle of a point where the baby carriage is located;
A speed sensor installed in the stroller for measuring an actual angular speed equivalent to a speed of the stroller;
A motor unit driven by an input motor drive signal to generate a rotational force to rotate at least a part of the plurality of wheels;
A motor driving unit for generating a motor driving signal based on an input drive control signal and providing the generated motor driving signal to the motor unit;
A battery used as an energy source necessary for driving the motor unit; And
Wherein the controller is configured to calculate a following angular velocity suitable for the driver by grasping the user's intention regarding the driving of the baby carriage from the output signal of the force sensor and to make the actual angular velocity of the baby carriage, And a torque compensation value for compensating a force of the baby carriage pushed down from the inclined surface by the inclination angle of the position of the baby carriage measured by the inclination sensor and the total mass of the baby carriage, And a control unit for controlling the driving of the motor unit by providing the motor driving unit to the motor driving unit,
If the magnitude of the output signal of the force sensor is within the first range, the controller determines that the baby stroller is to be stopped (hereinafter referred to as a "stop doctor"), And a transfer function according to the reference model at the time of stopping is applied to the output signal of the force sensor when it is determined that the driver intends to stop the engine, The tracking angular velocity is calculated by applying a transfer function according to the reference model to the output signal of the sensor,
Wherein the angular velocity compensation value is calculated by performing proportional integral (PI) control on the difference value between the following angular velocity and the actual angular velocity,
In order to allow the user to drive the baby carriage by applying a force equal to that of a flat surface even on an inclined surface regardless of the inclination angle of the inclined surface on which the baby carriage is located, And the size of the electric power assisted safety baby carriage control device is determined so as to prevent the user from being pushed downward. delete delete delete 7. The stroller according to claim 6, wherein the total mass of the baby carriage is calculated by referring to a predetermined conversion table in the control unit, the force measurement value outputted by the force sensor in a state in which the user only lifts the rear wheel of the baby carriage away from the ground, Wherein the total mass of the stroller is the actual total mass of the stroller. 7. The control apparatus for an electric power assisted safety baby carriage according to claim 6, wherein the motor unit and the wheels are an in-wheel motor in which the motor unit is integrated into a hub of the wheels to drive the wheels directly. 7. The control apparatus for an electric power assisted safety baby carriage according to claim 6, further comprising a power transmitting unit for transmitting rotational force generated by the motor unit to at least a part of the wheels to assist rotation of the wheels.

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