KR20200053959A - A method of detecting a ground contact point of a robot comprising a plurality of wheels - Google Patents

Abstract

The present invention relates to a ground contact point detection apparatus for a robot having a plurality of wheels. In a method of measuring a ground contact point of the robot having the plurality of wheels, comprised are the following steps of: receiving distance data from a distance measuring sensor installed on one side of the body of the robot in which the wheels are in contact with the ground while the wheels are in contact with the ground, and thereby determining reference contact points of the initial wheels, respectively; collecting the distance data observed from each distance measuring sensor while the robot is moving; determining whether the wheel is floating on the ground from the collected distance data from the ground; and excluding the reference contact point of the wheel from zero moment point (ZMP) calculation if the wheel is off the ground.

Description

A method of detecting a ground contact point of a robot comprising a plurality of wheels}

The present invention relates to a method of detecting a ground contact point of a robot composed of a plurality of wheels, and more specifically, a ground of a robot composed of a plurality of wheels that detects a ground contact point for measuring the degree of stability due to shaking occurring when the robot is running. It relates to a contact point detection method.

In general, robots are mainly industrial robots that perform simple tasks repeatedly in the industrial field, but in recent years, they have become very close to humans due to innovations in key element technologies such as artificial intelligence, software, communication, sensors, and actuators. Products used in the environment are emerging.

In this situation, intelligent robots that coexist with humans that are predicted to increase rapidly in the future are basically electrical and mechanical operation mechanisms based on autonomous judgment based on sensors, and present a wide variety of risks in an environment that coexists with humans. It is highly likely that consumers will act as a negative factor in the spread and diffusion of robots.

In consideration of this, the ISO TC299 (Robotics), the technical committee of the International Organization for Standardization, defines the three types of robots (mobile helper robots, riding robots, and body assist robots) that are most closely used in human life as personal support robots. And published the international safety standard ISO 13482 (Safety Requirements for Personal Support Robots) in 2014.

However, the above standard only proposes guidelines for electrical / electronic / SW / HW safety, and does not suggest specific methods for developing safe robots.

Particularly, when a mobile helper or a boarding helper robot overcomes a stepped obstacle such as a groove or a threshold recessed in the driving environment, shaking occurs, and thus, a criterion for evaluating the safety of the robot is not proposed.

The safety standard for shaking in the related art proposes a safety standard through measurement of a physical amount applied to a virtual line connected to the wheel center of the robot and the wheel center, that is, a tip-over line in which an overturn can occur.

This physical quantity measures the ratio of the angle between the direction of force applied to each axis and the tip-over line or the presence of a ZMP (Zero Moment Point) in a polygon (SP: support polygon) composed of points where the wheels are in contact with the ground. The geometric stability measure method, the energy-based stability measure method based on the amount of energy accumulated in the tip-over axis, and the contact-force stability measure using the frictional force distribution on the ground are presented.

Among them, the second and third conventional methods are not suitable methods for indoor service robots using low-cost sensors because they require precise methods of measuring the angle and energy of each axis and the ground.

And SP is a closed curve composed of points that touch the outermost point among several contact points. In the previous paper, assuming that the contact point is known and does not change with time, the ZMP that changes when moving the armed robot is within the SP. If present, it provides a criterion for "the robot's movement is safe."

That is, since the constant SP is assumed for the demonstration of the motion safety indicator, consider the situation in which the SP is dynamically changed due to the phenomenon that some wheels float when a service robot moving in a real environment passes a step such as a gap or groove. There is no suggestion of a method for determining the contact point to do.

The present invention has been devised to solve the conventional problems, and the ground contact point of the robot having a plurality of wheels for obtaining the contact points necessary to measure the degree of motion safety issued due to the shaking during driving for a robot composed of several wheels It is to provide a detection device.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

According to a method of detecting a ground contact point of a robot having a plurality of wheels according to an embodiment of the present invention for achieving the above object, in a method of measuring a ground contact point of a robot having a plurality of wheels, wheels are in contact with the ground Receiving distance data from the distance measuring sensor installed on one side of the body of the robot in which the wheel is located, and determining the reference contact points of the initial wheels through the distance data; While the robot is moving, collecting distance data observed from each distance measuring sensor; Determining whether the wheel is floating on the ground from the collected distance data from the ground; And excluding the reference contact point of the corresponding wheel from index calculation when the wheel is lifted off the ground.

The step of determining the reference contact points of the initial wheels may include: receiving first distance data (Intial_dis) with the ground for each wheel from the distance measuring sensor while the robot is placed on a flat surface; Storing the first distance data to the ground for each wheel received as an initial contact point; Receiving second distance data (Ground_dis) from the distance measuring sensor with respect to the ground of each wheel in a state in which a wheel not attached to the ground touches the ground on a flat surface; Determining whether the second distance data is greater than or equal to the first distance data; And in the determining step, if the second distance data is greater than or equal to the first distance data, determining a point obtained through the second distance data as a reference contact point of the wheel.

On the other hand, in the determining step, if the second distance data is smaller than the first distance data, determining a point obtained through the first distance data as a reference contact point of the wheel.

According to another embodiment of the present invention, the step of determining the reference contact points of the initial wheels may include: receiving distance data observed while moving from two or more distance measuring sensors on one wheel; If the observed distance data of the received wheel is greater than the distance data determined as the reference contact point of the wheel, it is determined that the wheel is in an abnormal state floating on the ground.

A ground contact point detection device for a robot having a plurality of wheels according to an embodiment of the present invention is a ground contact point measurement device for a robot having a plurality of wheels, which is installed on one side of the body of the robot on which the wheel is located, and the distance from the ground Distance measuring sensors for measuring and transmitting the measured distance data; A contact point setting unit for determining reference contact points of the initial wheels through distance data measured while the wheel is in contact with the ground; An abnormality determination unit that compares the distance data observed from the distance measuring sensor with the reference contact point to determine whether the wheel is floating on the ground; And a safety measurement unit excluding a reference contact point of the corresponding wheel from index calculation when the wheel is lifted off the ground.

The contact point setting unit receives the first `distance data (Intial_dis) of the ground for each wheel from the distance measuring sensor while the robot is placed on the flat surface, and the wheel not attached to the ground on the flat surface from the distance measuring sensor After receiving the second distance data (Ground_dis) with the ground of each wheel in a state in which the contact with the ground, the second distance data is determined by determining whether the second distance data is equal to or greater than the first distance data. If it is greater than or equal to the distance data, a point obtained through the second distance data is determined as a reference contact point of the wheel.

Meanwhile, when the second distance data is smaller than the first distance data, the contact point setting unit determines a point obtained through the first distance data as a reference contact point of the wheel.

According to another embodiment of the present invention, the contact point setting unit receives distance data observed while moving from two or more distance measuring sensors on one wheel, and the observed distance data of the received wheel is a reference contact point of the wheel. If it is larger than the distance data determined by, it is determined that the corresponding wheel is floating on the ground.

According to the present embodiment, the safety measurement unit excludes the wheel floating on the ground in real time, and thus has the effect of analyzing the motion stability of the robot while driving using a low-cost distance sensor.

1 is a view for explaining a configuration block of the ground contact point detection device of a robot having a plurality of wheels according to an embodiment of the present invention.
2 is a reference diagram for explaining an example of a ground contact point detection device of a robot having a plurality of wheels according to an embodiment of the present invention.
3 to 5 are reference diagrams for explaining the process of the contact point setting unit of FIG. 2 to set the contact point of each wheel.
6 to 9 are reference drawings for explaining the operation process of the ground contact point detection device of a robot having a plurality of wheels according to another embodiment of the present invention.
10 is a flow chart for explaining a method of detecting a ground contact point of a robot having a plurality of wheels according to an embodiment of the present invention.
11 is a flow chart for explaining the step (S200) of determining the reference contact points of the initial wheels of FIG. 10, respectively.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only the embodiments allow the disclosure of the present invention to be complete, and the ordinary knowledge in the technical field to which the present invention pertains. It is provided to fully inform the holder of the scope of the invention, and the invention is only defined by the scope of the claims. Meanwhile, the terms used in the present specification are for explaining the embodiments and are not intended to limit the present invention. In the present specification, the singular form also includes the plural form unless otherwise specified in the phrase. As used herein, "comprises" and / or "comprising" refers to the components, steps, operations and / or elements mentioned above, the presence of one or more other components, steps, operations and / or elements. Or do not exclude additions.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 is a view for explaining a configuration block of the ground contact point detection device of a robot having a plurality of wheels according to an embodiment of the present invention.

As shown in FIG. 1, a ground contact point detecting device of a robot having a plurality of wheels according to an embodiment of the present invention is provided in a robot 10 having a plurality of wheels 11 and a plurality of distances It includes a measurement sensor 100, a contact point setting unit 200, an abnormality determination unit 300 and a safety measurement unit 400.

The distance measurement sensor 100 is respectively installed on one side of the body of the robot 10 where the wheel 11 is located, and transmits distance data measuring the distance to the ground to the contact point setting unit 200 and the abnormality determination unit 300 Plays a role. The distance measurement sensor 100 in this embodiment is preferably provided to measure the distance to the ground on one side of the robot 10 body where the wheel 11 is located.

In addition, the contact point setting unit 200 serves to determine the reference contact points of the initial wheels 11 through distance data measured while the wheel 11 is in contact with the ground.

In addition, the abnormality determining unit 300 serves to determine whether the wheel 11 is floating on the ground by comparing the distance data observed from the distance measuring sensor 100 with the reference contact point during movement.

In addition, when the wheel is lifted off the ground, the safety measurement unit 400 analyzes the motion stability of the robot after excluding the reference contact point of the wheel from ZMP (Zero Moment Point) calculation.

According to this embodiment, the safety measurement unit has the effect of analyzing the motion stability of the robot while driving using a low-cost distance sensor by excluding the wheel floating on the ground in real time.

Hereinafter, the operation process for the contact point setting unit of FIG. 1 will be described with reference to FIGS. 2 to 5, but it will be described as an example in which five wheels 11 are installed on the robot 10.

First, as shown in FIG. 2, the contact point setting unit 200 removes the ground for each wheel 11 from the distance measurement sensor in a state where the robot 10 of the five wheels 11 is placed on a flat surface. 1 Receives distance data (Intial_dis). At this time, the wheels of the robot 10 may be made of wheels 11-1 contacting the ground and wheels 11-2 away from the ground, as shown in FIGS. 3 and 4.

If the robot 10 is placed on a flat surface, and there is a wheel 11-2 that is not in contact with the floor, the contact point setting unit 200 is ground on the flat surface from the distance measuring sensor, as shown in FIG. While the wheel 11-2 not attached to the ground is brought into contact with the ground, the second distance data (Ground_dis) from the ground of each wheel is received.

On the other hand, if all the wheels are in contact with the ground, the first distance data is determined as the reference contact point of the wheel without performing the operation of receiving the second distance data in a state where the wheels not attached to the ground are brought into contact with the ground. .

Thereafter, the contact point setting unit 200 determines whether the second distance data is equal to or greater than the first distance data.

If the second distance data is greater than or equal to the first distance data, the contact point setting unit 200 determines a point obtained through the second distance data as a reference contact point of the wheel.

On the other hand, when the second distance data is smaller than the first distance data, the contact point setting unit 200 determines a point obtained through the second distance data as a reference contact point of the wheel.

According to another embodiment of the present invention, as shown in FIG. 6 or 7, unlike in one embodiment, at least two or more sensors 110 provided on the body of the robot 10 on which the wheel 11 is located It is provided.

Accordingly, the contact point setting unit 200 receives the distance data (o1, o2) observed while moving from two or more distance measuring sensors 110 on one wheel 11, and the received wheel 11 If the observed distance data (o1, o2) of is greater than the reference contact point (g1, g2) determined as the contact point of the wheel 11, it is determined that the corresponding wheel 11 is floating on the ground.

However, as shown in FIG. 8, the robot 10 is inclined, and the distance data o1 observed through the one-side distance measurement sensor 110 is smaller than the predetermined distance data g1, and the other-side distance measurement sensor 110 If the distance data (o2) measured through) is greater than the predetermined distance data (g2), it is determined that the wheel 11 is in contact with the ground.

And, as shown in Figure 9, the distance data (o1) measured through the distance measurement sensor 110 on one side and the distance data (o2) measured on the other distance measurement sensor 110 are both the predetermined reference contact point (g1) , g2), it is determined that the wheel 11 is not in contact with the ground.

10 is a flowchart illustrating a method for detecting a ground contact point of a robot having a plurality of wheels according to an embodiment of the present invention.

As illustrated in FIG. 10, the method for detecting the ground contact point of the robot having a plurality of wheels according to an embodiment of the present invention is preferably performed by the apparatus for measuring the ground contact point of the robot having a plurality of wheels.

First, in contact with the ground, the distance data from the distance measuring sensor 100 installed on one side of the body of the robot on which the wheel is located is received (S100).

Subsequently, reference contact points of the initial wheels are respectively determined (S200).

Thereafter, while the robot is moving, the distance data observed from each distance measurement sensor 100 is collected (S300).

Subsequently, it is determined whether the wheel is floating on the ground from the collected distance data from the ground (S400).

Thereafter, when the wheel is lifted off the ground, the reference point of contact of the wheel is excluded from ZMP (Zero Moment Point) calculation (S500).

Accordingly, the safety measurement unit 400 may analyze the motion stability of the robot by excluding the reference contact point of the corresponding wheel from the ZMP (Zero Moment Point) calculation when the wheel is off the ground. As described above, the safety measurement unit 400 has an effect of analyzing the motion stability of the robot during driving by using a low-cost distance sensor by excluding the wheel floating on the ground in real time.

Hereinafter, the step (S200) of determining the reference contact points of the initial wheels of FIG. 11 will be described in detail.

First, in a state where the robot is placed on a flat surface, first distance data (Intial_dis) with respect to the ground for each wheel is received from the distance measurement sensor (S210).

Subsequently, the first distance data to the ground for each wheel received is stored as an initial contact point (S220).

In addition, the second distance data (Ground_dis) of the wheels of the respective wheels is received from the distance measuring sensor in a state in which the wheels that are not attached to the ground touch the ground from the flat surface (S230).

Thereafter, it is determined whether the second distance data is equal to or greater than the first distance data (S240).

If, in the determination step S240, the second distance data is greater than or equal to the first distance data (YES), a point obtained through the second distance data is determined as a reference contact point of the wheel (S250).

On the other hand, in the determination step (S240), if the second distance data is smaller than the first distance data (NO), the point obtained through the first distance data is determined as a reference contact point of the wheel (S260).

According to another embodiment of the present invention, as shown in FIG. 6 or 7, unlike in one embodiment, at least two or more sensors 110 provided on the body of the robot 10 on which the wheel 11 is located It is provided.

Accordingly, the contact point setting unit 200 receives the distance data (o1, o2) observed while moving from two or more distance measuring sensors 110 on one wheel 11, and the received wheel 11 If the observed distance data (o1, o2) of is greater than the reference contact point (g1, g2) determined as the contact point of the wheel 11, it is determined that the corresponding wheel 11 is floating on the ground.

However, as shown in FIG. 8, the robot 10 is tilted so that the distance data o1 observed through the one-side distance measurement sensor 110 is smaller than the predetermined distance data g1, and the other-side distance measurement sensor 110 If the distance data (o2) measured through) is greater than the predetermined distance data (g2), it is determined that the wheel 11 is in contact with the ground.

And, as shown in Figure 9, the distance data (o1) measured through the distance measurement sensor 110 on one side and the distance data (o2) measured on the other distance measurement sensor 110 are both the predetermined reference contact point (g1) , g2), it is determined that the wheel 11 is not in contact with the ground.

The configuration of the present invention has been described in detail with reference to the accompanying drawings, but this is only an example, and those skilled in the art to which the present invention pertains have various modifications and changes within the scope of the technical spirit of the present invention. Of course this is possible. Therefore, the protection scope of the present invention should not be limited to the above-described embodiments and should be defined by the following claims.

10: robot 11: wheel
100: a plurality of distance measuring sensors 200: contact point setting unit
300: abnormality determination unit 400: safety measurement unit

Claims (1)

In the method of measuring the ground contact point of a robot having a plurality of wheels,
Receiving distance data from the distance measuring sensor installed on one side of the body of the robot in which the wheels are located while the wheels are in contact with the ground, and determining the reference contact points of the initial wheels through the distance data;
While the robot is moving, collecting distance data observed from each distance measuring sensor;
Determining whether the wheel is off the ground from the collected distance data from the ground; And
When the wheel is off the ground, the step of excluding the reference contact point of the wheel from the ZMP (Zero Moment Point) calculation; Ground contact point detection method of a robot having a plurality of wheels.

Images