WO2021046991A1

WO2021046991A1 - Method for detecting skidding by robot

Info

Publication number: WO2021046991A1
Application number: PCT/CN2019/115249
Authority: WO
Inventors: 崔江伟; 韩奎
Original assignee: 苏州科瓴精密机械科技有限公司
Priority date: 2019-09-10
Filing date: 2019-11-04
Publication date: 2021-03-18
Also published as: CN112549072A

Abstract

A method for detecting skidding by a robot, the robot comprising a working mechanism, a housing (10), a walking mechanism and a turntable that is rotatably provided on the housing (10). The method for detecting skidding comprises the following steps: a. providing a sensing assembly on the turntable; b. at the working boundary of the robot, providing n beacons (20) which are sensed by the sensing assembly; c. by using an m-th beacon (20) as reference, defining a calculated value of the steering angle of the robot as Δθ_m, and defining Δθ_m as the angle of rotation Δθ of the robot, wherein m refers to the m-th beacon (20), and 1≤m≤n; d. using a calculated angle value obtained by calculating by using the wheel speed of a walking wheel and the rotation time thereof as Δθ_speedΔ; and e. calculating the difference between the two calculated angle values, Δθ_aviation=Δθ-Δθ_speed; determining whether Δθ_aviation>θ_thresholdΔ is established; if the determination result is yes, the beacon (20) detects that skidding has occurred; and if the determination result is no, the beacon (20) does not detect that skidding has occurred, θ_threshold being a preset angle change difference. The described method for detecting skidding does not experience a cumulative error and has high real-time performance.

Description

Robot's slip detection method

Technical field

The invention relates to a method for detecting slippage of a robot, in particular to a method for detecting slippage of a lawn mower robot.

Background technique

Robot position and state determination is a very important part of robot guidance control. The robot usually completes the in-situ rotation through the differential speed of the left and right wheels. The rotation angle can be calculated by the wheel speed and the rotation time, and the rotation angle can also be calculated by the gyroscope. However, the rotation angle is calculated by the rotation speed. When the wheel is slipping, the accurate rotation angle cannot be obtained. However, there will be accumulated errors in the calculation by the gyroscope, which makes the calculated rotation angle not accurate enough. Therefore, the detection of slip is not accurate enough, and the hardware cost is increased.

Summary of the invention

The purpose of the present invention is to provide a method for detecting a robot's slippage, which has no accumulated error and high real-time performance.

In order to achieve one of the objectives of the above-mentioned invention, an embodiment of the present invention provides a method for detecting slippage of a robot. The robot includes a working mechanism, a housing, a walking mechanism provided in the housing and having walking wheels, and a rotatable device. On the turntable of the housing, the slip detection method includes the following steps:

a. Provide induction components on the turntable;

b. Provide n beacons for the sensing component to sense at the working boundary of the robot;

c. Define the calculated value of the steering angle of the robot with reference to the m-th beacon as Δθ _m , and define Δθ _m as the angle of rotation of the robot Δθ, where m refers to the m-th beacon, 1≤m ≤n;

d. The calculated value of the angle calculated by the wheel speed of the traveling wheel and its rotation time is Δθ _speed ;

e. Calculate the difference between the two angle calculation values Δθ _flight = Δθ-Δθ _speed ; judge whether Δθ _flight > θ _threshold is established, if the judgment result is yes, the beacon detects slippage, if the judgment result is no, then believe No slipping is detected on the mark, where θ _threshold is the preset angle change difference.

As a further improvement of an embodiment of the present invention, the slip detection method further includes a step b1 located between the steps b and c: traversing the angle of the beacon, and determining whether the traversal is completed, and if the determination result is no, then Go to step c.

As a further improvement of an embodiment of the present invention, if slip occurs in step e, count the detected slip Y=Y+1, and go to step b1, if no slip occurs in step e, go directly to Go to step b1.

As a further improvement of an embodiment of the present invention, in step b1, if the judgment result of whether the traversal is completed is yes, calculate the percentage of the number of detected slips to the total number of beacons that can be detected ε=Y/Y _all , and Judge whether ε>ε _threshold is established, if the judgment result is yes, confirm that the robot has slipped, if the judgment result is no, confirm that the robot has not slipped, where ε _threshold is the preset percentage value, and Y _all is detectable The total number of beacons.

As a further improvement of an embodiment of the present invention, in step b1, if the judgment result of whether the traversal is completed is yes, the final calculation value Δθ of the steering angle is calculated from all detectable beacons, and the process proceeds to step d .

As a further improvement of an embodiment of the present invention, the slip detection method further provides a control module electrically connected to the sensing component; it is defined that during one turn of the robot, the turntable performs x rotation cycles in total, And the rotation speed of the turntable is constant, the sensing component detects that the m-th beacon is in the i-th rotation period of the turntable and records an angle signal. The azimuth angle of the angle signal processed by the control module is

And

Where i refers to the i-th turntable rotation period in the confirmation to obtain particular beacon signal, _m k means the k th of m beacons to give a valid signal, j refers to the j detected beacon sequence m, 1≤i≤x, 1≤k≤j, 1≤j≤x, the azimuth angle refers to the angle between the line from the rotation center of the robot to the first beacon and the heading (H0) of the robot.

As a further improvement of an embodiment of the present invention, it is defined that during the turning process of the robot, the sensing component can detect p beacons, where 1≤p≤n, then the steering angle of the robot is

As a further improvement of an embodiment of the present invention, it is defined that during the turning process of the robot, the n beacons are detected, and the turning angle of the robot is

As a further improvement of an embodiment of the present invention, the beacon n is set to 1, and during the turning process of the robot, the beacon is detected x times in total, defining the azimuth change at each detection The value is constant, and only the azimuth angle recorded by the beacon in the i-th rotation period of the turntable is detected as Δθ _1i1 , then the steering angle of the robot is

As a further improvement of an embodiment of the present invention, the sensing component includes a laser signal transmitter and a laser signal receiver, and the beacon is a reverse cursor.

As a further improvement of an embodiment of the present invention, the working mechanism is a cutting mechanism for mowing grass.

Compared with the prior art, the beneficial effect of the present invention is that the calculated value Δθ of the steering angle of the robot is calculated on the beacon, and then the calculated angle Δθ _{speed is calculated based on the wheel speed of the walking wheel and its rotation time.} , Calculate the difference Δθ _flight = Δθ-Δθ _speed ; and compare the difference Δθ _flight with the preset value θ _threshold to determine whether the robot is skidding. Therefore, the accumulated error in the detection process is avoided, and the real-time performance is high. In addition, the use of the turntable with sensing components on the existing robot further reduces the hardware cost.

Description of the drawings

Fig. 1 is a schematic diagram of a rotating state of a robot in an embodiment of the present invention;

2 is a flowchart of a method for detecting a robot's slippage in an embodiment of the present invention;

FIG. 3 is a recording table of the rotation angle of the robot in an embodiment of the present invention;

Fig. 4 is a flowchart of a method for detecting a robot's slippage in a fourth embodiment of the present invention.

detailed description

Hereinafter, the present invention will be described in detail with reference to the specific embodiments shown in the drawings. However, these embodiments do not limit the present invention, and the structural, method, or functional changes made by those skilled in the art according to these embodiments are all included in the protection scope of the present invention.

In each figure of the present application, for the convenience of illustration, some dimensions of the structure or part will be exaggerated relative to other structures or parts, therefore, it is only used to illustrate the basic structure of the subject of the present application.

In addition, terms such as "upper", "above", "below", "below" and the like used herein to indicate a relative position in space are for the purpose of facilitating explanation to describe a unit or feature as shown in the drawings relative to The relationship of another unit or feature. The terms of relative spatial position may be intended to include different orientations of the device in use or operation other than those shown in the figures. For example, if the device in the figure is turned over, the units described as being "below" or "below" other units or features will be "above" the other units or features. Therefore, the exemplary term "below" can encompass both the above and below orientations. The device can be oriented in other ways (rotated by 90 degrees or other orientations), and the space-related descriptors used herein are explained accordingly.

In this article, unless otherwise specified, m, n, x, i, j, and k are all positive integers.

As shown in FIG. 1, the present invention discloses a robot. The robot includes a working mechanism (not shown), a housing 10 and a walking mechanism (not shown) provided in the housing 10. The robot also includes a turntable rotatably arranged on the housing 10 and an electronic sensing component arranged on the turntable. Generally, the housing 10 includes a chassis and an upper cover provided on the chassis to cover the working mechanism, wherein the walking mechanism is provided on the chassis, and the turntable is rotatably provided on the upper cover.

The traveling mechanism includes four traveling wheels, and the four traveling wheels are rotatably arranged on the chassis. And the four walking wheels are arranged symmetrically.

In this preferred embodiment, the robot is a lawn mowing robot, and specifically, the working mechanism is a cutting mechanism (not shown) for mowing grass. The cutting mechanism includes a cutting blade or cutting line. Of course, the robot can also be a sweeping robot or other types of robots. In addition, the working mechanism is arranged on the chassis or the upper cover.

The robot has a working boundary. The preferred embodiment also provides a method for measuring the rotation angle of the robot. In the working boundary of the robot, n beacons 20 for sensing components are provided; usually, n≥3; and electrical connection with the sensing components is provided. The control module; specifically, the sensing component includes a laser signal transmitter and a laser signal receiver, and the beacon 20 is a reverse cursor. The sensing component emits laser signals around the robot and receives the laser signals reflected by the beacon 20.

With further reference to Fig. 2, the present invention also provides a method for detecting a robot's slippage. The method for detecting slippage includes the following steps:

a. Provide induction components on the turntable;

b. Provide n beacons for the sensing components of the robot at the working boundary of the robot;

In step c, only one beacon, that is, the m-th beacon, can be used as a reference to calculate the steering angle of the robot, or multiple beacons can be used as a reference to calculate the steering angle of the robot. The beacon is a reference to calculate the steering angle of the robot.

In this preferred embodiment, the calculated value Δθ of the steering angle of the robot calculated by the beacon is calculated by the wheel speed of the walking wheel and its rotation time to obtain the calculated angle Δθ _speed , and the difference Δθ _flight = Δθ-Δθ _{speed is calculated} ; And by comparing the difference Δθ _navigation with the preset value θ _threshold , it is judged whether the robot is slipping. Therefore, the accumulated error in the detection process is avoided, and the real-time performance is high. In addition, the use of the turntable with sensing components on the existing robot further reduces the hardware cost.

The slip detection method also includes step b1 between steps b and c: traversing the angle of the beacon, and determining whether the traversal is completed, and if the determination result is no, proceed to step c. The traversal here refers to data acquisition of all detectable beacons, that is, to determine whether the data acquisition of all detectable beacons is completed, and to calculate the steering angle of the robot with each beacon as a reference. .

Further, if the result of the beacon detection in step e is that slippage occurs, the detected slippage is counted Y=Y+1, that is, each time a slippage is detected, the number of slippages is cumulatively increased by 1. And go to step b1. In step e, if the beacon detection result is that no slip has occurred, then go directly to step b1 to continue to determine whether there is an uncalculated steering angle corresponding to the beacon.

In step b1, if the judgment result of whether the traversal is completed is yes, calculate the percentage of the number of detected slips to the total number of detectable beacons ε=Y/Y _all , and judge whether ε>ε _threshold is established, if the result of the judgment is If yes, slip occurs, if the judgment result is no, no slip occurs, where ε _threshold is a preset percentage value, Y _all is the total number of detectable beacons, where 1≤Y _all ≤n.

Next, how to calculate the steering angle of the robot. During the working process of the robot, the robot needs to turn in place due to obstacle avoidance or work needs. The azimuth angle for a certain beacon 20 before the robot turns is θ ₁ , and the azimuth angle after completing the in-situ steering action is θ ₂ , then the steering angle of the robot Δθ = θ ₂ -θ ₁ , where Δθ is a positive value, then The robot rotates clockwise, as shown in Figure 1, the arrow D1 is the turning direction of the robot, the arrow D2 is the rotation direction of the turntable, H0 is the heading before the robot turns, and H1 is the heading after the robot turns; otherwise, the robot is reversed. The hour hand turns. The "azimuth angle for a certain beacon" mentioned here refers to the angle between the line from the rotation center of the robot to the beacon and the heading H0 of the robot. It is defined that during one turn of the robot, the turntable completes x rotation cycles, that is, the turntable drives the laser signal transmitter and laser signal receiver to rotate x times.

The control module can record the position of the reverse cursor when the laser signal receiver receives the laser signal reflected by the anti-cursor, that is, the angle between the position of the anti-cursor and the heading of the robot; specifically, the control module detects the beacon 20 according to the turntable. , The turning angle of the turntable is the angle between the beacon's azimuth and the robot's heading. Here, the rotation angle of the turntable is defined as the angle from the initial position of the turntable to the position when the beacon 20 is detected. In this embodiment, the initial position of the turntable is the position when the laser transmitter faces the navigation direction of the robot. When the robot turns in place, the azimuth angle formed for a certain back cursor will change accordingly. Therefore, the steering angle of the robot can be obtained by calculating the azimuth angle for the specific back cursor.

3, taking the mth beacon 20 as a reference, for the mth (1≤m≤n) beacon 20, during a turn of the robot, the turntable completes a total of x rotation cycles, that is, it can detect at most The beacon 20 is detected x times, that is, the m-th beacon 20 can be detected at most x times. Therefore, theoretically, x azimuth angle change values can be obtained: Δθ _m1 , Δθ _m2 ,..., Δθ _mx . According to the above algorithm, the azimuth angle change value refers to the difference between the current azimuth angle and the previous azimuth angle. However, due to obstacles or other reasons, during the turning process of the robot, the beacon 20 may not be detected every time and the corresponding azimuth angle can be obtained. Since the rotation speed of the turntable and the rotation speed of the robot during one turn are basically constant, the sensing component detects that the m-th beacon 20 obtains the laser signal reflected by the beacon 20 during the i-th rotation period of the turntable. According to the laser signal, the azimuth angle is obtained after processing by the control module

Then the calculated value of the steering angle of the robot by the m-th beacon 20

1≤i≤x, _{1≤k m} ≤j≤x. Wherein m refers to m-

th beacon

20,1≤m≤n, i means the i-th turntable rotation period in the confirmation to obtain particular beacon signal, _m k means the k th of m give valid signals from a beacon 20 , J means that the m-th beacon 20 has been detected j times during a turn of the robot.

The following specific examples are described, and further referring to a specific embodiment listed in FIG. 2, in which,

Column i: It is confirmed that the turntable is in the i-th rotation period when the specific beacon signal is obtained;

k _m column: record the number of sequences confirming the receipt of the reflected signal from the m-th beacon;

Δθ _mx column: theoretical azimuth angle change value;

Column: The theoretical azimuth angle, in the table is obtained according to the following algorithm

In this embodiment, during one turn of the robot, the turntable drives the laser signal transmitter and the laser signal receiver to complete a total of 10 rotation cycles, that is, x=10. Taking the first beacon 20 as a reference, that is, m=1, the laser signal receiver confirms that the first beacon 20 is detected during the second, fifth, seventh, and eighth rotation period of the turntable, so the laser signal receiver The signal of the first beacon 20 is detected 4 times, that is, k=1 when i=2, k=2 when i=5, k=3 when i=7, and k=4 when i=8; Get

then

Therefore, taking the first beacon 20 as a reference, the estimated value of the steering angle of the robot is 100.007 degrees.

Taking the second beacon 20 as a reference, that is x=10 and m=2, the laser signal receiver detects the second beacon 20 during the 3rd, 4th, and 10th rotation period of the turntable, so the laser signal is received The device detects the signal of the second beacon 20 three times, that is, k=1 when i=3, k=2 when i=4, and k=3 when i=10;

then

Therefore, taking the second beacon 20 as a reference, the estimated value of the steering angle of the robot is 100.001 degrees.

Taking the third beacon 20 as a reference, that is, x=10, m=3, the laser signal receiver detects the third beacon 20 during the 1, 2, 5, 6, and 9 rotation cycles of the turntable. Therefore, the laser signal receiver has detected the signal of the third beacon 20 for 5 times, that is, when i=1, k=1, when i=2, k=2, when i=5, k=3, and when i=6, k =4, k=5 when i=9; and measured

then

Therefore, taking the third beacon 20 as a reference, the estimated value of the steering angle of the robot is 100.013 degrees.

In this preferred embodiment, since the m-th beacon 20 is used as a reference, it is defined that the m-th beacon 20 can be detected j times, and the angle change value detected each time is obtained, and then the corresponding value when the turntable rotates once is calculated The steering angle of the robot. And since the rotation speed of the turntable is constant, the angle of the robot's turning corresponding to the turntable's x times is obtained, that is, the angle of one rotation of the robot. In summary, the rotation angle calculated by the rotation angle measurement method provided by the robot provided by the present invention is more accurate.

Further, it is defined that during a turning process of the robot, the sensing component can detect p beacons 20, where 1≤p≤n, then the steering angle of the robot is

That is, the steering angle value calculated with reference to each beacon 20 is averaged to obtain the steering angle value of the robot. This makes the calculated rotation angle of the robot more accurate. Specifically, in this embodiment, a total of 3 beacons 20 of the first, second, and third are detected as an example, and the steering angle of the robot is

The second preferred embodiment provided by the present invention is a specific case of the first preferred embodiment. In this embodiment, p=n, x=1, i=1, and k=1. When the robot turns in place, the azimuth angle formed for the m-th beacon 20 will change accordingly. On the basis of maintaining the identification of the beacon 20, the angle change value Δθ _{m can be obtained for the beacon 20} . Specifically, in this embodiment, it is defined that in one in-situ turn of the robot, n beacons 20 can be detected once, that is, x=1, so an angle change value Δθ _m can be obtained for each beacon 20, Then the rotation angle of the robot is

The third preferred embodiment provided by the present invention is another specific case of the first preferred embodiment. In this preferred embodiment, in this embodiment, n=1, m=1, k=1, and j=1. And in a rotation of the robot, the turntable drives the beacon 20 to complete x rotation cycles, so the beacon 20 is still detected x times. If the rotation rate of the turntable is set to be constant, the rotation angle will change at equal intervals. It is uniform, that is, the value of the angle change in the same time is the same. When adopting a certain interval frequency to detect the change of the rotation angle during the rotation process, it is assumed that the beacon 20 can only be identified at a certain detection moment in the entire rotation process, that is to say, only the beacon 20 is detected and recorded during the i-th rotation period of the turntable. The azimuth angle is recorded as Δθ _1i1 . And because the azimuth angle change value is constant during each detection, the rotation angle of the robot is

The leftmost 1 in the subscript of Δθ _1i1 refers to a beacon 20, i means that the turntable is in the i-th rotation period when the specific beacon signal is confirmed, and the rightmost 1 refers to the obtained one-time valid signal.

For example, if the beacon 20 is detected 10 times during a turn of the robot, theoretically, 10 angle change values will be generated. However, only the first detection can determine that the signal angle change value comes from the beacon 20, and it is impossible to determine whether the signal angle change comes from the beacon 20 in the following nine times. Then the first recognizable angle change can be recorded as Δθ ₁₁₁ . And because it knows that it has undergone a total of x detections. From the previous setting, assuming that the angle change value during each subsequent detection is constant and the same as the first change value, the final robot's rotation angle can be estimated as,

As shown in Figure 4, it is the fourth embodiment provided by the present invention. In this embodiment, instead of accumulating the number of slips, the steering angles obtained by all detectable beacons are comprehensively calculated to finally obtain the robot’s The calculated value Δθ of the steering angle. In step b1, if the judgment result of whether the traversal is completed is yes, the final calculated value Δθ of the steering angle is calculated from all the detectable beacons, and the step d is also entered. _{It is to calculate the difference between the angle Δθ and the steering angle Δθ speed} calculated from the wheel speed and the turning time, and judge whether Δθ _navigation >θ _threshold is established. If the judgment result is yes, the beacon detects the occurrence of slipping. If the judgment result is no, the beacon does not detect the occurrence of slipping. Similarly, in step b1, if the judgment result of whether the traversal is completed is no, then go to step c, and continue to calculate the corresponding steering angle based on other detectable beacons. The calculation of the steering angle of the robot is the same as that of the first embodiment, and will not be described in detail here.

It should be understood that although this specification is described in accordance with the implementation manners, not each implementation manner only includes an independent technical solution. This narration in the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

The series of detailed descriptions listed above are only specific descriptions of feasible implementations of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementations or implementations made without departing from the technical spirit of the present invention All changes shall be included in the protection scope of the present invention.

Claims

A method for detecting slippage of a robot, the robot including a working mechanism, a housing, a walking mechanism provided on the housing and having walking wheels, and a turntable rotatably provided on the housing, the method for detecting slippage includes The following steps:

a. Provide induction components on the turntable;

b. Provide n beacons for the sensing component to sense at the working boundary of the robot;

c. Define the calculated value of the steering angle of the robot with reference to the m-th beacon as Δθ m , and define Δθ m as the angle of rotation of the robot Δθ, where m refers to the m-th beacon, 1≤m ≤n;

d. The calculated value of the angle calculated by the wheel speed of the traveling wheel and its rotation time is Δθ speed ;

e. Calculate the difference between the two angle calculation values Δθ flight = Δθ-Δθ speed ; judge whether Δθ flight > θ threshold is established, if the judgment result is yes, the beacon detects slippage, if the judgment result is no, then believe No slipping is detected on the mark, where θ threshold is the preset angle change difference.
The robot slip detection method according to claim 1, characterized in that: the slip detection method further comprises a step b1 located between the steps b and c: traversing the angle of the beacon, and judging whether the traversal is completed, If the judgment result is no, go to step c.
The method for detecting the slip of a robot according to claim 2, characterized in that: if slip occurs in step e, the detected slip is counted Y=Y+1, and the process proceeds to step b1, if in step e If no slip occurs, then go directly to step b1.
The robot slip detection method according to claim 3, characterized in that: in step b1, if the judgment result of whether the traversal is completed is yes, then calculate the percentage of the number of detected slips to the total number of beacons that can be detected ε =Y/Y all , and judge whether ε>ε threshold is established, if the judgment result is yes, confirm that the robot has slipped, if the judgment result is no, confirm that the robot has not slipped, where ε threshold is a preset percentage value, Y all is the total number of beacons that can be detected.
The method for detecting robot slip according to claim 2, characterized in that: in step b1, if the judgment result of whether the traversal is completed is yes, then all the beacons that can be detected are used to calculate the final calculated value of the steering angle Δθ, and go to step d.
The method for detecting a robot's slippage according to claim 1, wherein the method for detecting slippage further provides a control module electrically connected to the sensing component; it is defined that during a turn of the robot, the turntable A total of x rotation cycles are performed, and the rotation speed of the turntable is constant, the sensing component detects that the m-th beacon is in the i-th rotation cycle of the turntable and records an angle signal, which is processed by the control module The azimuth is
And
Where i refers to the i-th turntable rotation period in the confirmation to obtain particular beacon signal, m k means the k th of m beacons to give a valid signal, j refers to the j detected beacon sequence m, 1≤i≤x, 1≤k≤j, 1≤j≤x, the azimuth angle refers to the angle between the line from the rotation center of the robot to the first beacon and the heading (H0) of the robot.
The method for detecting slippage of a robot according to claim 6, characterized in that: it is defined that during the turning process of the robot, the sensing component can detect p beacons, where 1≤p≤n, then the robot The steering angle is
The method for detecting a robot's slippage according to claim 6, characterized in that: it is defined that during the turning process of the robot, the n beacons are all detected, and the turning angle of the robot is
The method for detecting slippage of a robot according to claim 6, characterized in that: the beacon n is set to 1, and during the turning process of the robot, the beacon is detected x times in total, and each beacon is defined as The azimuth angle change value during the second detection is constant, and only the azimuth angle recorded by the beacon in the i-th rotation period of the turntable is detected as Δθ 1i1 , then the steering angle of the robot is
The method for detecting a robot's slippage according to any one of claims 1 to 9, wherein the sensing component includes a laser signal transmitter and a laser signal receiver, and the beacon is a reverse cursor.
The robot according to any one of claims 1 to 9, wherein the working mechanism is a cutting mechanism for mowing grass.