WO2021042389A1

WO2021042389A1 - Trajectory simplification method and device for industrial robot, and computer storage medium and industrial robot operating platform

Info

Publication number: WO2021042389A1
Application number: PCT/CN2019/104778
Authority: WO
Inventors: 丁万; 张泽昭
Original assignee: 罗伯特·博世有限公司; 丁万
Priority date: 2019-09-06
Filing date: 2019-09-06
Publication date: 2021-03-11
Also published as: DE112019007488T5; CN114375431A

Abstract

A trajectory simplification method and a trajectory simplification device (3000) for an industrial robot, and a computer storage medium and an industrial robot operating platform. The method comprises: generating a complete trajectory for an industrial robot according to a teaching process of the industrial robot; and simplifying the complete trajectory to obtain a feature point set, wherein the feature point set β(j) is contained in an original point set α(i), and with regard to an arbitrary point α(p), in the original point set, between α(i_j-1) corresponding to β(j-1) and α(i_j) corresponding to β(j), an approximate error between the arbitrary point α(p) and a straight line segment with β(j-1) and β(j) as endpoints is less than or equal to an error tolerance d, i_j-1 < p < i_j, and the approximate error is determined according to both a chord length between α(i_j-1) and α(p) and an arc length between α(i_j-1) and α(p). The computer storage medium comprises instructions, wherein the instructions execute the trajectory simplification method at runtime. The industrial robot operating platform comprises a trajectory simplification device (3000).

Description

Trajectory simplification method and equipment for industrial robot, computer storage medium and industrial robot operating platform

【Technical Field】

The invention relates to a trajectory simplification method and equipment for an industrial robot, a computer storage medium and an industrial robot operating platform.

【Background technique】

The teaching and operation of the robot is the integration point of the robot's motion and control. It is the main method to realize the communication between humans and robots. It is also one of the most difficult and key problems in the research and use of robot systems.

The robot's working ability is basically determined by its software system. What kind of teaching and operation the robot's software system can achieve determines the flexibility and intelligence of the robot's practical functions. For example, during the teaching process of an industrial robot for pick-and-place tasks, a complete collision-free trajectory is usually generated. The generated complete trajectory is manually taught by the operator by selecting the required key points on the path on the teach pendant. This operation method depends on the brand of the industrial robot and the programming experience of the operator. In order to study path and trajectory planning, the generated smooth collision-free trajectory (represented by points that have information such as position, velocity, and acceleration) needs to be transmitted to an industrial robot controller that is open and provides low-level control.

Unfortunately, the underlying control of mainstream industrial robot controllers is not open at present. Therefore, if too many points are sent to the robot controller and analyzed in the robot controller, it will cause inconsistencies in the speed and acceleration of the trajectory and peak changes.

Therefore, an improved trajectory simplification scheme is desired.

[Summary of the invention]

According to one aspect of the present invention, a trajectory simplification method for an industrial robot is proposed. The method includes: during a teaching process of the industrial robot, generating a complete trajectory for the industrial robot, the complete trajectory The trajectory includes an original point set α(i), i=1, 2,..., n, where n is the number of original points in the original point set; and the complete trajectory is simplified to obtain a feature point set β(j), j=1, 2,..., m, where m is the number of feature points in the feature point set, and the feature point set β(j) is included in the original point set α(i), m is less than or equal to n, where α(1)=β(1), α(n)=β(m), where, for 1<j<m, β(j)=α(i _j ), and where said original point set and β (j-1) an arbitrary point α (p) between the corresponding α (i _j-1) and a β (j) corresponding to α (i _j) in the β (j-1 ) And β(j) are the end points of the straight line segment, the approximate error is less than or equal to the error tolerance d, i _j-1 <p <i _j , and wherein the approximate error is based on α(i _j-1 ) and α The chord length between _{(p) and the arc length between α(i j-1} ) and α(p) are both determined.

The feature point set is obtained by simplifying the original point set, and the simplification method uses whether the approximate error determined according to both the chord length and the arc length exceeds the error tolerance limit. This trajectory simplification method has a small amount of calculation and high accuracy.

Preferably, the above-mentioned trajectory simplification method may further include: sending a simplified trajectory including the feature point set β(j) to the controller of the industrial robot.

By removing unnecessary (redundant) path points from the original point set, the complete trajectory is simplified and a feature point set is obtained. In this way, too many points are sent to the industrial robot controller, so that the speed and stability of the final trajectory path (such as a curved path) are significantly improved, and there is no need to open the underlying control of the industrial robot controller. The simplified path represented by the feature point set can be directly analyzed and executed by the robot controller, avoiding opening the underlying control.

Preferably, in the above-mentioned trajectory simplification method, the complete trajectory includes a stopping point for performing a task and an intermediate point with the assigned movement type or command.

Preferably, in the above trajectory simplification method, both the complete trajectory and the simplified trajectory are obstacle avoidance path trajectories.

Preferably, in the above-mentioned trajectory simplification method, _{the chord length c(i j-1} _{, p) between α(i j-1} ) and α(p) is determined according to the following formula: c(i _j-1 , p) =||α(p)-α(i _j-1 )||.

Preferably, in the above-mentioned trajectory simplification method, _{the arc length s(i j-1} _{, p) between α(i j-1} ) and α(p) is determined according to the following formula:

Preferably, in the above-mentioned trajectory simplification method, the approximate error d(i _j-1 , p) is determined according to the following formula:

Preferably, in the above-mentioned trajectory simplification method, the error tolerance value d is a predetermined value, which represents the maximum allowable deviation of the simplified path.

Another aspect of the present invention provides a trajectory simplification device for an industrial robot, the device comprising: a generating device configured to generate a trajectory for the industrial robot during a teaching process of the industrial robot The complete trajectory of, the complete trajectory includes the original point set α(i), i=1, 2,..., n, where n is the number of original points in the original point set; and a simplified device, the simplified The device is configured to simplify the complete trajectory so as to obtain a feature point set β(j), j=1, 2, ..., m, where m is the number of feature points in the feature point set, and the feature points The set β(j) is contained in the original point set α(j), m is less than or equal to n, where α(1)=β(1), α(n)=β(m), where, for 1<j< m, β (j) = α (i j), and the (j-1) corresponding to α β (i _j-1) and a β (j) [alpha] corresponding to the original set point (i _j) The approximate error between the arbitrary point α(p) and the straight line segment with β(j-1) and β(j) as the endpoints is less than or equal to the error tolerance d, i _j-1 ＜p＜i _j , and wherein the approximation error (i _j-1) is determined between both the arc length α (p) in accordance with α (i _j-1) between the α (p) and a chord length α.

The simplification device in this trajectory simplification equipment obtains the feature point set by simplifying the original point set, and the simplification device uses the original point α corresponding to the determined feature point β(j-1) according to the interest point α(p) Whether the approximate error determined by the chord length and the arc length between (i _j-1 ) exceeds the error tolerance limit d is used to determine whether the interest point is necessary, and if necessary, the interest point is included in the feature point set. The trajectory simplified device has a small amount of calculation and high accuracy.

Preferably, the above-mentioned trajectory simplification device may further include: a sending device configured to send the simplified trajectory including the feature point set β(j) to the controller of the industrial robot.

By removing unnecessary (redundant) path points from the original point set, the complete trajectory is simplified and a feature point set is obtained. This prevents the sending device in the trajectory simplification device from sending too many points to the industrial robot controller, so that the speed and stability of the final trajectory path (such as a curved path) are significantly improved, and the industrial robot does not need to be opened. The underlying control of the controller. The simplified path represented by the feature point set can be directly analyzed and executed by the robot controller, avoiding opening the underlying control.

Preferably, in the above-mentioned trajectory simplifying device, the complete trajectory includes a stopping point for performing a task and an intermediate point having the assigned movement type or command.

Preferably, in the above-mentioned trajectory simplification device, both the complete trajectory and the simplified trajectory are obstacle avoidance path trajectories.

Preferably, in the above-mentioned trajectory simplification device, _{the chord length c(i j-1} _{, p) between α(i j-1} ) and α(p) is determined according to the following formula: c(i _j-1 , p) =||α(p)-α(i _j-1 )||.

Preferably, in the aforementioned trajectory simplifying device, _{the arc length s(i j-1} _{, p) between α(i j-1} ) and α(p) is determined according to the following formula:

Preferably, in the above-mentioned trajectory simplification device, the approximate error d(i _j-1 , p) is determined according to the following formula:

Preferably, in the above-mentioned trajectory simplification device, the error tolerance value d is a predetermined value, which represents the maximum allowable deviation of the simplified path.

Yet another aspect of the present invention provides a computer storage medium, which includes instructions that execute the aforementioned trajectory simplification method during runtime.

Another aspect of the present invention provides an industrial robot operating platform, which includes the trajectory simplifying device as described above.

【Explanation of the drawings】

With reference to the drawings, the disclosure of the present invention will become easier to understand. It is easily understood by those skilled in the art that these drawings are only for illustrative purposes, and are not intended to limit the scope of protection of the present invention. In the picture:

Fig. 1 shows a trajectory simplification method for industrial robots according to an embodiment of the present invention;

Figure 2 shows a trajectory simplification method for an industrial robot according to another embodiment of the present invention; and

Fig. 3 shows a trajectory simplification device for an industrial robot according to an embodiment of the present invention.

[Specific embodiment]

The following description describes specific embodiments of the present invention to teach those skilled in the art how to make and use the best mode of the present invention. In order to teach the principles of the invention, some conventional aspects have been simplified or omitted. Those skilled in the art should understand that variations derived from these embodiments will fall within the scope of the present invention. Those skilled in the art should understand that the following features can be joined in various ways to form many variations of the present invention. Therefore, the present invention is not limited to the following specific embodiments, but only by the claims and their equivalents.

When an industrial robot is used in combination with path planning, an intuitive way is to send a complete trajectory described by points (for example, a total of 1000 points). But most robots cannot smoothly process a complete trajectory composed of so many points (such as a curved path), because the length of the interval between adjacent points is too small and the robot must accurately reach each point, making the entire movement process unstable and improving Vibration occurs at TCP speed. In addition, online path planning needs to ensure continuous software communication and hardware circuit connection, so that the robot executes the planned path in each motion cycle.

One or more embodiments of the present invention solve one or more of the above-mentioned problems.

Referring to FIG. 1, FIG. 1 shows a trajectory simplification method 1000 for an industrial robot according to an embodiment of the present invention.

In step S110, during the teaching process of the industrial robot, a complete trajectory for the industrial robot is generated, the complete trajectory includes the original point set α(i), i=1, 2, ..., n, where n is The number of original points in the original point set;

In step S120, the complete trajectory is simplified to obtain a feature point set β(j), j=1, 2, ..., m, where m is the number of feature points in the feature point set.

The feature point set β(j) is included in the original point set α(i), that is, m is less than or equal to n. In the feature point set β(j), the first feature point and the last feature point correspond to the first and last points in the original point set respectively, that is, α(1)=β(1), α(n) = Β(m). For other points in the feature point set, β(j)=α(i _j ), 1<j<m. That is, β(j) corresponds to α(i _j ). Similarly, β(j-1) corresponds to α(i _j-1 ). The approximate error between any point α(p) between α(i _j-1 ) and α(i _j ) and the straight line segment with β(j-1) and β(j) as the endpoints is not greater than the error tolerance limit _{d, i j-1 <p} <i j, wherein according to said error between α (i _j-1) between the α (p) and a chord length α (i _j-1) and α (p) is approximately The arc length is determined by both.

In the above solution, the starting point in the feature point set is set to be the same as the starting point in the original point. α(i _j-1 ) can represent the original point corresponding to the determined feature point β(j-1), by taking the points in the original point set after α(i _j-1 ) as the points of interest and determining Whether the approximate error exceeds the error tolerance limit. If the error tolerance is exceeded, the point of interest is deemed necessary and will be included in the feature point set. If the approximate error of the interest point is less than or equal to the error tolerance limit, the interest point is considered redundant and not included in the feature point set. And repeat the above process until all points except the starting point and the final point have calculated the approximate error. It is worth pointing out that the approximate error is based on _{the chord length between the previously determined feature point α(i j-1} ) and the current point of interest α(p) and the difference between α(i _j-1 ) and α(p). The arc length between the two is determined. By using the approximate error as the basis for removing unnecessary points, this trajectory simplified method has a small amount of calculation and high accuracy.

Referring to FIG. 2, FIG. 2 shows a trajectory simplification method 2000 for an industrial robot according to an embodiment of the present invention. Compared with FIG. 1, in addition to including steps S110 and S120, the trajectory simplification method 2000 of FIG. 2 also includes: step S210, sending a simplified trajectory including the set of feature points β(j) to the industrial robot Controller. In other words, the simplified trajectory (not the complete trajectory) is sent to the robot controller. In this way, too many points are sent to the industrial robot controller, so that the speed and stability of the final trajectory path (such as a curved path) are significantly improved, and there is no need to open the underlying control of the industrial robot controller.

In one embodiment, the industrial robot supports the TCP/IP communication function, so the simplified trajectory including the set of feature points can be sent to the controller of the industrial robot via TCP/IP communication. In addition, since the simplified trajectory has been sent to the robot controller, the external hardware can be removed after the controller stores the data. The simplified path represented by the feature point set can be directly analyzed and executed by the robot controller, avoiding opening the underlying control.

Combining the trajectory simplification method of FIG. 1 and FIG. 2, in one embodiment, the complete trajectory includes stopping points for executing tasks and intermediate points with assigned motion types or commands (such as SLIN/MoveL, etc.). In one embodiment, both the complete trajectory and the simplified trajectory are obstacle avoidance path trajectories.

In one embodiment, in the above-mentioned trajectory simplification method, _{the chord length α(i j-1} _{, p) between α(i j-1} ) and α(p) is determined according to the following formula: α(i _j-1 , P)=||α(p)-α(i _j-1 )||.

The chord length c(i _j-1 _{, p) represents the distance value between the original point α(i j-1} ) corresponding to the determined feature point β(j-1) and the interest point α(p).

In one embodiment, _{the arc length s(i j-1} _{, p) between α(i j-1} ) and α(p) is determined according to the following formula:

The arc length s(i _j-1 , p) means that from the original point α(i _j-1 ) corresponding to the determined feature point β(j-1) to the interest point α(p), the original point set The sum of the distances between two adjacent points.

In one embodiment, the approximate error d(i _j-1 , p) is determined according to the following formula:

According to the above formula, the approximation error is calculated sequentially at the corresponding point of the original α (i _j-1), the following points may be _{(i j-1) (j} -1) [alpha] is known for determining the origin point of the feature point beta], until The approximate error exceeds the predetermined error tolerance limit d. In one embodiment, the error tolerance value d represents the maximum allowable offset value of the simplified path.

Fig. 3 shows a trajectory simplification device 3000 for an industrial robot according to an embodiment of the present invention. Referring to FIG. 3, the trajectory simplifying device 3000 includes a generating device 310 and a simplifying device 320. Preferably, the trajectory simplification device 3000 may further include a sending device 330.

The generating device 310 is configured to generate a complete trajectory for the industrial robot during the teaching process of the industrial robot, the complete trajectory including a set of original points α(i), i=1, 2, ..., n, where n is the number of original points in the original point set. In one embodiment, the complete trajectory includes stopping points for performing tasks and intermediate points with assigned movement types or commands.

The simplification device 320 is configured to simplify the complete trajectory so as to obtain a feature point set β(j), j=1, 2, ..., m, where m is the number of feature points in the feature point set, and The point set β(j) is contained in the original point set α(i), m is less than or equal to n, where α(1)=β(1), α(n)=β(m), where, for 1<j <m, β (j) = α (i j), and set the original point and β (j-1) corresponding to α (i _j-1) and a β (j) corresponding to α (i _j The approximate error between any point α(p) between) and the straight line segment with β(j-1) and β(j) as endpoints is less than or equal to the error tolerance d, i _j-1 ＜p＜i _j and wherein the approximation error (i _j-1) is determined between both the arc length α (p) in accordance with α (i _j-1) between the α (p) and a chord length α. In one embodiment, both the complete trajectory and the simplified trajectory are obstacle avoidance path trajectories.

The simplification device 320 obtains a feature point set by simplifying the original point set. Specifically, the simplification device 320 utilizes both the chord length and the arc length between the interest point α(p) and the original point α(i _{j-1) corresponding to the determined feature point β(j-1).} Whether the determined approximation error exceeds the error tolerance limit d is used to determine whether the interest point is necessary, and if necessary, the interest point is included in the feature point set. With this simplification device 320, the calculation amount of the trajectory simplification device 3000 is small and the accuracy is high.

In one embodiment, the sending device 330 is configured to send the simplified trajectory including the feature point set β(j) to the controller of the industrial robot. As mentioned above, the simplification device 320 has simplified the original point set generated by the generating device 310 to remove redundant path points. The sending device 330 sends the simplified path (characteristic point set) to the industrial robot controller, which can avoid the inconsistency of the speed and acceleration of the trajectory and the peak change caused by sending too many points. Finally, the speed and stability of the simplified trajectory path (such as a curved path) are significantly improved, and there is no need to open the underlying control of the industrial robot controller. The simplified path represented by the feature point set can be directly analyzed and executed by the robot controller, avoiding opening the underlying control.

In one embodiment, the simplification device 320 calculates _{the chord length c(i j-1} _{, p) between α(i j-1} ) and α(p) in the following way: c(i _j-1 , p)= ||α(p)-α(i _j-1 )||.

In one embodiment, the simplification device 320 calculates _{the arc length s(i j-1} , p) _{between α(i j-1} ) and α(p) in the following manner:

In one embodiment, the simplification device 320 calculates the approximate error d(i _j-1 , p) in the following manner:

Those skilled in the art can easily understand that the trajectory simplification method provided by one or more embodiments of the present invention can be implemented by a computer program. For example, when a computer storage medium (such as a USB flash drive) storing the computer program is connected to the computer, the trajectory simplification method of the embodiment of the present invention can be executed by running the computer program.

In summary, various embodiments of the present invention provide a trajectory simplification solution. Although only some of the specific embodiments of the present invention have been described, those of ordinary skill in the art should understand that the present invention can be implemented in many other forms without departing from its spirit and scope, such as being implemented on an industrial robot operating platform. . Therefore, the examples and implementations shown are regarded as illustrative rather than restrictive. The present invention may cover various modifications without departing from the spirit and scope of the present invention as defined by the appended claims. And replace.

Claims

A trajectory simplification method for industrial robots, the method includes:

During the teaching process of the industrial robot, a complete trajectory for the industrial robot is generated, the complete trajectory includes a set of original points α(i), i=1, 2, ..., n, where n is The number of original points in the original point set; and

The complete trajectory is simplified to obtain a feature point set β(j), j=1, 2, ..., m, where m is the number of feature points in the feature point set, and the feature point set β( j) Included in the original point set α(i), m is less than or equal to n,

Where α(1)=β(1), α(n)=β(m),

Wherein, for 1<j<m, β(j)=α(i j ), and for α(i j-1 ) and β(j-1) corresponding to β(j-1) in the original point set ) Any point α(p) between the corresponding α(i j ), the approximate error between the arbitrary point α(p) and the straight line segment with β(j-1) and β(j) as the endpoints is less than or equal to Error tolerance d, i j-1 ＜p＜i j , and

Wherein said approximation error (i j-1) is determined between both the arc length α (p) in accordance with α (i j-1) between the α (p) and a chord length α.
The trajectory simplification method according to claim 1, further comprising: sending the simplified trajectory including the feature point set β(j) to the controller of the industrial robot.
The trajectory simplification method according to claim 1 or 2, wherein the complete trajectory includes a stopping point for performing a task and an intermediate point having the assigned movement type or command.
The trajectory simplification method according to claim 1 or 2, wherein the complete trajectory and the simplified trajectory are both obstacle avoidance path trajectories.
The trajectory simplification method according to claim 1 or 2, wherein the chord length c(i j-1 , p) between α(i j-1 ) and α(p) is determined according to the following formula: c(i j -1 , p)=||α(p)-α(i j-1 )||.
The trajectory simplification method according to claim 1 or 2, wherein the arc length s(i j-1 , p) between α(i j-1 ) and α(p) is determined according to the following formula:
The trajectory simplification method according to claim 1 or 2, wherein the approximation error d(i j-1 , p) is determined according to the following formula:
3. The trajectory simplification method according to claim 1 or 2, wherein the error tolerance value d is a predetermined value, which represents the maximum allowable deviation of the simplified path.
A trajectory simplification device for industrial robots, the device comprising:

Generating device, the generating device is configured to generate a complete trajectory for the industrial robot during the teaching process of the industrial robot, the complete trajectory including the original point set α (i), i = 1, 2,. .., n, where n is the number of original points in the original point set; and

A simplification device configured to simplify the complete trajectory so as to obtain a feature point set β(j), j=1, 2, ..., m, where m is a feature point in the feature point set And the feature point set β(j) is included in the original point set α(i), m is less than or equal to n,

Where α(1)=β(1), α(n)=β(m),

Among them, for 1<j<m, β(j)=α(i j ), and for α(i j-1 ) and β(j) corresponding to β(j-1) in the original point set Any point α(p) between the corresponding α(i j ), the approximate error between the arbitrary point α(p) and the straight line segment with β(j-1) and β(j) as the endpoints is less than or equal to Error tolerance d, i j-1 ＜p＜i j , and

Wherein said approximation error (i j-1) is determined between both the arc length α (p) in accordance with α (i j-1) between the α (p) and a chord length α.
The trajectory simplifying device according to claim 9, further comprising: a sending device configured to send the simplified trajectory including the feature point set β(j) to the controller of the industrial robot.
The trajectory simplifying device according to claim 9 or 10, wherein the complete trajectory includes a stopping point for performing a task and an intermediate point with the assigned movement type or command.
The trajectory simplification device according to claim 9 or 10, wherein the complete trajectory and the simplified trajectory are both obstacle avoidance path trajectories.
The trajectory simplifying device according to claim 9 or 10, wherein the chord length c(i j-1 , p) between α(i j-1 ) and α(p) is determined according to the following formula: c(i j -1 , p)=||α(p)-α(i j-1 )||.
The trajectory simplification device according to claim 9 or 10, wherein the arc length s(i j-1 , p) between α(i j-1 ) and α(p) is determined according to the following formula:
The trajectory simplification device according to claim 9 or 10, wherein the approximation error d(i j-1 , p) is determined according to the following formula:
The trajectory simplifying device according to claim 9 or 10, wherein the error tolerance value d is a predetermined value, which represents the maximum allowable deviation of the simplified path.
A computer storage medium, which includes instructions that execute the trajectory simplification method according to any one of claims 1 to 8 during runtime.
An industrial robot operating platform, which comprises the trajectory simplifying device according to any one of claims 9 to 16.