CN109668577B - Automatic wheel radius calibration method and system for mobile robot - Google Patents
Automatic wheel radius calibration method and system for mobile robot Download PDFInfo
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- G05D1/02—Control of position or course in two dimensions
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- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
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- G05D1/02—Control of position or course in two dimensions
- G05D1/021—Control of position or course in two dimensions specially adapted to land vehicles
- G05D1/0276—Control of position or course in two dimensions specially adapted to land vehicles using signals provided by a source external to the vehicle
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Abstract
The invention provides a method and a system for automatically calibrating the radius of a wheel of a mobile robot, which comprises the following steps: step S100, obtaining a current first route according to the data of the distance sensor; obtaining a current second journey according to the current wheel radius and the data of the speed sensor; step S200, calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route; step S300, judging whether the difference between the current first route and the current second route is smaller than a preset iteration stop threshold or not; if not, taking the next time period as the current time period and taking the wheel radius of the next time period as the current wheel radius, and jumping to the step S100; and if the step S500 is yes, the wheel radius of the next time period is the target wheel radius, and the automatic calibration is finished. The invention can automatically calibrate the radius of the wheels of the robot, thereby not influencing the normal positioning and walking of the robot in the work task.
Description
Technical Field
The invention relates to the field of mobile robots, in particular to a wheel radius automatic calibration method and system for a mobile robot.
Background
The wheels of a mobile robot are typically calibrated manually, such as by measuring with a ruler. However, the wheels of the robot are worn over time, and the wheels needing to be inflated have air leakage, which can cause the radius of the wheels to change, thereby affecting the normal positioning and walking of the robot, and therefore, an automatic wheel radius calibration method is needed.
Disclosure of Invention
The invention aims to provide a wheel radius automatic calibration method and a wheel radius automatic calibration system for a mobile robot, which can automatically calibrate the wheel radius of the robot before or during the execution of a work task, so that the normal positioning and walking of the robot during the work task are not influenced.
The technical scheme provided by the invention is as follows:
a method for automatic wheel radius calibration for a mobile robot, comprising: step S100, obtaining the distance of the robot in the current time period according to the data of the distance sensor, and recording the distance as a current first distance; obtaining the distance of the robot in the current time period according to the current wheel radius and the data of the speed sensor, and recording as the current second distance; step S200, calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route; step S400, when the difference between the current first route and the current second route is not smaller than a preset iteration stop threshold, taking the next time period as the current time period, taking the wheel radius of the next time period as the current wheel radius, and jumping to step S100; step S500, when the difference between the current first route and the current second route is smaller than a preset iteration stop threshold, the wheel radius of the next time period is a target wheel radius, and the automatic calibration is finished.
In the technical scheme, the radius of the wheels of the robot is automatically calibrated, so that the normal positioning and walking of the robot in a work task are not influenced.
Further preferably, after the step S200, the method further includes: step S210, Gaussian filtering is carried out on the radius of the wheel in the next time period to obtain the radius of the wheel after filtering in the next time period; step S400 further includes, when the difference between the current first route and the current second route is not less than a preset iteration stop threshold, step S410, taking a next time period as the current time period, taking a filtered wheel radius of the next time period as the current wheel radius, and jumping to step S100; step S500 further includes, in step S510, when a difference between the current first route and the current second route is smaller than a preset iteration stop threshold, the filtered wheel radius of the next time period is a target wheel radius, and the automatic calibration is finished.
Further preferably, the gaussian filtering the wheel radius of the next time period to obtain the filtered wheel radius of the next time period includes: gaussian filtering is performed according to the following formula:
wherein R isf(n +1) is the radius of the wheel after filtering in the next time period, R (n +1-i) is the radius of the wheel which is pushed forward from the next time period by i time periods, G (0), G (1) and G (M-1) are M response values of the Gaussian filter, M is the length of the Gaussian filter, and G (1) is the length of the Gaussian filterNorm(0)、GNorm(1)、......GNorm(M-1) is the M normalized response values of the Gaussian filter.
In the technical scheme, the noise influence in the iteration process of the wheel radius is removed through Gaussian filtering, and the stability of the wheel radius output in the iteration process is improved, so that the accuracy of the target wheel radius is improved.
Further preferably, the step S200 calculates the wheel radius for the next time period according to the following formula:
wherein R (n +1) is the wheel radius of the next time period, R (n) is the current wheel radius, Dmap(n) is the current first journey, DodomAnd (n) is the current second distance, and step is the preset step.
In the technical scheme, a specific implementation mode for calibrating the radius of the wheel is provided, and the method is simple and feasible.
It is further preferred that the wheel radius of the mobile robot is automatically calibrated before and/or during the performance of the work task.
Further preferably, the automatically calibrating the radius of the wheel of the mobile robot in performing the work task further includes: the wheel radius of the mobile robot is automatically calibrated at the beginning of the work task, and/or at intervals.
In the technical scheme, a plurality of modes are provided for a user to perform the automatic wheel radius calibration function under different conditions, for example, under the conditions that the mobile robot is not long in service time and the sealing performance of tires is good, the automatic wheel radius calibration before a cleaning task is executed is selected, the number of adaptive scenes is large, and the user selection is flexible.
Further preferably, the method further comprises the following steps: when the wheel radius of the mobile robot is automatically calibrated, the current wheel radius is displayed in real time through an interface, and a prompt is given through the interface in the calibration process and/or after the calibration is finished.
In the technical scheme, when the radius of the wheel is automatically calibrated, the prompt information is provided through the interface, so that a user can know the progress in time when operating the robot, or manual intervention is performed under special conditions, and the convenience of user operation is improved.
The present invention also provides an automatic wheel radius calibration system for a mobile robot, comprising: the calibration module is used for obtaining the distance of the robot in the current time period according to the data of the distance sensor and recording the distance as a current first distance; obtaining the distance of the robot in the current time period according to the current wheel radius and the data of the speed sensor, and recording as the current second distance; calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route; when the difference between the current first route and the current second route is not smaller than a preset iteration stop threshold, taking the next time period as the current time period, taking the wheel radius of the next time period as the current wheel radius, and reacquiring the current first route and the current second route; and when the difference between the current first route and the current second route is smaller than a preset iteration stop threshold, the wheel radius of the next time period is a target wheel radius, and the automatic calibration is finished.
In the technical scheme, the radius of the wheels of the robot is automatically calibrated, so that the normal positioning and walking of the robot in a work task are not influenced.
Further preferably, the calibration module further comprises: the filtering unit is used for carrying out Gaussian filtering on the radius of the wheel in the next time period to obtain the radius of the wheel after filtering in the next time period; the calibration module is further configured to, when a difference between the current first route and the current second route is not smaller than a preset iteration stop threshold, take a next time period as a current time period, take a filtered wheel radius of the next time period as a current wheel radius, and reacquire the current first route and the current second route; and when the difference between the current first route and the current second route is smaller than a preset iteration stop threshold, the filtered wheel radius of the next time period is the target wheel radius, and the automatic calibration is finished.
In the technical scheme, the noise influence in the iteration process of the wheel radius is removed through Gaussian filtering, and the stability of the wheel radius output in the iteration process is improved, so that the accuracy of the target wheel radius is improved.
Further preferably, the method further comprises the following steps: and the interface display module is used for displaying the current wheel radius in real time through the interface when the wheel radius of the mobile robot is automatically calibrated, and giving a prompt through the interface in the calibration process and/or after the calibration is finished.
In the technical scheme, when the radius of the wheel is automatically calibrated, the prompt information is provided through the interface, so that a user can know the progress in time when operating the robot, or manual intervention is performed under special conditions, and the convenience of user operation is improved.
The wheel radius automatic calibration method and the wheel radius automatic calibration system for the mobile robot provided by the invention have the following beneficial effects that: the invention can automatically calibrate the radius of the wheel of the robot before or during the execution of the work task, thereby not influencing the normal positioning and walking of the robot in the work task; when the radius of the wheel is automatically calibrated, prompt information is provided through an interface, so that a user can know the progress in time when operating the robot, and the convenience of the user in operation is improved.
Drawings
The above features, technical features, advantages and implementations of a method and system for automatic wheel radius calibration for a mobile robot will be further described in the following detailed description of preferred embodiments in a clearly understandable manner, in conjunction with the accompanying drawings.
FIG. 1 is a flow chart of one embodiment of a method of the present invention for automatic wheel radius calibration of a mobile robot;
FIG. 2 is a flow chart of another embodiment of a method of the present invention for automatic wheel radius calibration of a mobile robot;
FIG. 3 is a flow chart of another embodiment of a method of the present invention for automatic wheel radius calibration of a mobile robot;
FIG. 4 is a flow chart of another embodiment of a method of the present invention for automatic wheel radius calibration of a mobile robot;
FIG. 5 is a schematic diagram of an embodiment of an automatic wheel radius calibration system for a mobile robot according to the present invention;
FIG. 6 is a schematic diagram of another embodiment of the present invention for an automatic wheel radius calibration system for a mobile robot;
FIG. 7 is a schematic diagram of another embodiment of the present invention for an automatic wheel radius calibration system for a mobile robot;
fig. 8, 9, 10 and 11 are schematic interface displays of another embodiment of the automatic wheel radius calibration method for a mobile robot according to the present invention;
fig. 12 is a schematic diagram illustrating a change of a signal before and after gaussian filtering according to another embodiment of the present invention.
The reference numbers illustrate:
100. the calibration module 200, the interface display module 110 and the filtering unit.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will be made with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.
For the sake of simplicity, only the parts relevant to the present invention are schematically shown in the drawings, and they do not represent the actual structure of the product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled. In this document, "one" means not only "only one" but also a case of "more than one".
In one embodiment of the present invention, as shown in fig. 1, a method for automatic wheel radius calibration of a mobile robot includes:
step S100, obtaining the distance of the robot in the current time period according to the data of the distance sensor, and recording the distance as a current first distance; obtaining the distance of the robot in the current time period according to the current wheel radius and the data of the speed sensor, and recording as the current second distance;
step S200, calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route;
step S300, judging whether the difference between the current first route and the current second route is smaller than a preset iteration stop threshold or not;
step S400, when the difference between the current first route and the current second route is not smaller than a preset iteration stop threshold, taking the next time period as the current time period, taking the wheel radius of the next time period as the current wheel radius, and jumping to step S100;
step S500, when the difference between the current first route and the current second route is smaller than a preset iteration stop threshold, the wheel radius of the next time period is a target wheel radius, and the automatic calibration is finished.
Specifically, a mobile robot, such as a cleaning robot, has a main sensor such as a distance sensor or a speed sensor mounted thereon. A range sensor, such as a lidar or ultrasonic sensor, calculates the distance of the robot from the target based on the time elapsed from the light pulse being emitted to the return being received. Speed sensors, such as encoders mounted on the wheels, can measure the angular velocity, linear velocity of the wheels. When the wheels move, the distance between the robot and the target changes, and the moving distance of the wheels can be calculated according to the change of data measured by the distance sensor, and the moving distance is called a first path. When the wheel moves, the speed sensor measures the rotation radian of the wheel in the moving time period, and the moving distance of the wheel can be estimated according to the rotation radian and the radius of the wheel, and the moving distance is called as a second path. Due to the uncertainty of the wheel radius, the second course is inaccurate and the first course is relatively accurate. The automatic calibration idea of this embodiment is to continuously iteratively modify the radius of the wheel to gradually approximate the second route to the first route.
The current wheel radius is initialized and may be set to the original tire size before unworn, and before flat. Obtaining a current first distance according to the data of the distance sensor; the current second leg is obtained based on the current wheel radius and the speed sensor data. And correcting the current wheel radius according to the deviation of the current second distance and the current first distance to obtain the wheel radius of the next time period. And if the difference between the current first route and the current second route is not smaller than the preset iteration stop threshold, taking the next time period as the current time period and the wheel radius of the next time period as the current wheel radius, and jumping to the step S100 to start the next iteration. And if the difference between the current first route and the current second route is smaller than the preset iteration stop threshold, finishing the calibration and taking the wheel radius of the next time period as the target wheel radius.
The method provided by the embodiment is suitable for single-wheel, double-wheel or multi-wheel robots, and each wheel can be automatically calibrated according to the method. After the wheel radius is automatically calibrated, the accuracy of the second leg calculated from the calibrated wheel radius is improved, as is the accuracy of the measured linear velocity, which is an improvement for job task applications that use the second leg, or linear velocity.
In another embodiment of the present invention, as shown in fig. 1, a method for automatic wheel radius calibration of a mobile robot includes:
step S100, obtaining the distance of the robot in the current time period according to the data of the distance sensor, and recording the distance as a current first distance; obtaining the distance of the robot in the current time period according to the current wheel radius and the data of the speed sensor, and recording as the current second distance;
step S200, calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route;
the wheel radius for the next time period is calculated according to the following formula:
wherein R (n +1) is the wheel radius of the next time period, R (n) is the current wheel radius, Dmap(n) is the current first journey, DodomAnd (n) is the current second distance, and step is the preset step.
Step S300, judging whether the difference between the current first route and the current second route is smaller than a preset iteration stop threshold or not;
step S400, when the difference between the current first route and the current second route is not smaller than a preset iteration stop threshold, taking the next time period as the current time period, taking the wheel radius of the next time period as the current wheel radius, and jumping to step S100;
step S500, when the difference between the current first route and the current second route is smaller than a preset iteration stop threshold, the wheel radius of the next time period is a target wheel radius, and the automatic calibration is finished.
Specifically, the present embodiment provides a specific iterative method for estimating the radius of the target wheel. In the iterative process, if the current second path is larger, which indicates that the radius of the corresponding wheel is larger, the radius of the wheel is adjusted to be smaller, and vice versa, the radius of the wheel is adjusted to be larger, and the larger the deviation is, the faster the adjustment speed is. As the number of iterations increases, when Dodom≈DmapThen the iteration tends to converge.
In another embodiment of the present invention, as shown in fig. 2, a method for automatic wheel radius calibration of a mobile robot includes:
step S100, obtaining the distance of the robot in the current time period according to the data of the distance sensor, and recording the distance as a current first distance; obtaining the distance of the robot in the current time period according to the current wheel radius and the data of the speed sensor, and recording as the current second distance;
step S200, calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route;
the wheel radius for the next time period is calculated according to the following formula:
wherein R (n +1) is the wheel radius of the next time period, R (n) is the current wheel radius, Dmap(n) is the current first journey, DodomAnd (n) is the current second distance, and step is the preset step.
Step S210, Gaussian filtering is carried out on the radius of the wheel in the next time period to obtain the radius of the wheel after filtering in the next time period;
gaussian filtering is performed according to the following formula:
wherein R isf(n +1) is the radius of the wheel after filtering in the next time period, R (n +1-i) is the radius of the wheel which is pushed forward from the next time period by i time periods, G (0), G (1) and G (M-1) are M response values of the Gaussian filter, M is the length of the Gaussian filter, and G (1) is the length of the Gaussian filterNorm(0)、GNorm(1)、......GNorm(M-1) is the M normalized response values of the Gaussian filter.
Step S300, judging whether the difference between the current first route and the current second route is smaller than a preset iteration stop threshold or not;
step S410, when the difference between the current first route and the current second route is not less than a preset iteration stop threshold, taking a next time period as a current time period, taking a filtered wheel radius of the next time period as a current wheel radius, and jumping to step S100;
step S510, when the difference between the current first route and the current second route is smaller than a preset iteration stop threshold, the filtered wheel radius of the next time period is a target wheel radius, and the automatic calibration is finished.
Specifically, in order to improve the stationarity of the iterative output wheel radius, gaussian filtering is performed on the wheel radius of the next time period, and the gaussian filtered wheel radius is applied to the estimation of the second route. Gaussian filtering is employed because the noise between nature, when co-determined by multiple factors, approximately follows a gaussian distribution.
Let the response function of the gaussian filter be:
discrete sampling is carried out on the filter, the sampling time interval is delta x, and then:
assuming that the length of the filter is M and the variance is sigma, obtaining M response values of the filter, namely G (0), G (1) and G (M-1); and then carrying out normalization processing to obtain M normalized response values of the filter.
The wheel radius of the next time segment is gaussian filtered to obtain the filtered wheel radius of the next time segment, and for example, the change of a signal before and after gaussian filtering is shown in fig. 12.
In another embodiment of the present invention, as shown in fig. 3, a method for automatic wheel radius calibration of a mobile robot includes:
step S600, automatically calibrating the radius of a wheel of the mobile robot before executing a work task; the calibration method adopts the automatic wheel radius calibration method in any one of the embodiments (shown in fig. 1, fig. 2 or fig. 3).
Step S700 is that when the radius of the wheel of the mobile robot is automatically calibrated, the current radius of the wheel is displayed in real time through an interface, and a prompt is given through the interface during the calibration process and/or after the calibration is finished.
In particular, the wheel radius auto-calibration function is a separate function that may be performed prior to performing a work task, including building a grid map of the work area, and/or cleaning tasks. For example, taking a double-wheel robot as an example, the radius of the wheel is automatically calibrated before the grid map is built, and a person pushes the trolley to walk in an environment with obvious characteristics until the radius of the wheel is calibrated; in the calibration process, the interface displays the current radius values of the left wheel and the right wheel in real time (as shown in fig. 8), and when the calibration is finished and the calibration is successful, the interface gives a prompt (as shown in fig. 9), and the user can optionally terminate the calibration; if the system considers the wheel radius calibration to fail after a period of calibration, the following information is suggested (as shown in FIG. 10): "wheel radius after calibration over a period of time, failed calibration! Please continue calibration or terminate calibration! ", the user may choose to continue with the calibration, and if the calibration is successful, the system will prompt the following (as shown in fig. 11): "after further calibration of the wheel radius, finish the calibration, please continue the calibration or terminate the calibration! ", the user may choose to terminate the calibration.
In the embodiment, the automatic wheel radius calibration is carried out before the work task, so that the burden of the work task is not increased, and the calibrated wheel radius is adopted in the work task, so that the linear speed of the robot can be estimated more accurately, and the distance estimated according to the speed sensor is more accurate. The method is suitable for the condition that the robot is not used for a long time, the tire is not worn greatly, and the sealing performance of the tire is good.
In another embodiment of the present invention, as shown in fig. 4, a method for automatic wheel radius calibration of a mobile robot includes:
step S610, automatically calibrating the radius of the wheel of the mobile robot when a work task is just started and at intervals; the calibration method adopts the automatic wheel radius calibration method in any one of the previous embodiments (as shown in figure 1, figure 2 or figure 3);
step S700 is that when the radius of the wheel of the mobile robot is automatically calibrated, the current radius of the wheel is displayed in real time through an interface, and a prompt is given through the interface during the calibration process and/or after the calibration is finished.
In particular, the wheel radius of the mobile robot is automatically calibrated in performing work tasks, including building a grid map of the work area, and/or cleaning tasks. The work task is calibrated once at the beginning, and then is calibrated at regular intervals. When the tire has better sealing performance, the mode can meet the practical requirement.
The embodiment has various modifications, for example, the automatic calibration of the radius of the wheel is carried out in real time in the process of executing a work task, and when the sealing performance of the tire is poor, the automatic calibration can be changed along with the change of the radius of the wheel in real time; for another example, when the work task is started each time, the automatic calibration of the radius of the wheel is carried out simultaneously, after the calibration is finished, the calibration is stopped, when the sealing performance of the tire is good, and the change of the radius of the wheel in one day is small, the practical requirements can be met by adopting the mode to carry out calibration, the calibration workload of the robot can be reduced, and the work load of the robot can be reduced.
When the automatic wheel radius calibration is performed in a work task, in order to improve the intelligence of the robot in work, the less interaction with a user is desired to be performed during the task, so that only when the wheel radius changes abnormally and the calibration fails after a period of time, the work task should be suspended, for example, when sweeping, the user is prompted on an interface, and the information is as follows: "wheel radius does not match reality, automatic calibration fails, floor sweeping has been suspended! ".
In another embodiment of the present invention, as shown in fig. 5, an automatic wheel radius calibration system for a mobile robot includes:
the calibration module 100 is configured to obtain a distance of the robot in a current time period according to the distance sensor data, and record the distance as a current first distance; obtaining the distance of the robot in the current time period according to the current wheel radius and the data of the speed sensor, and recording as the current second distance; calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route; judging whether the difference between the current first route and the current second route is smaller than a preset iteration stop threshold or not; if not, the next time period is taken as the current time period, the radius of the filtered wheel in the next time period is taken as the radius of the current wheel, and the current first route and the current second route are obtained again; and if so, the wheel radius of the next time period is the target wheel radius, and the automatic calibration is finished.
Specifically, a mobile robot, such as a cleaning robot, has a main sensor such as a distance sensor or a speed sensor mounted thereon. A range sensor, such as a lidar or ultrasonic sensor, calculates the distance of the robot from the target based on the time elapsed from the light pulse being emitted to the return being received. Speed sensors, such as encoders mounted on the wheels, can measure the angular velocity, linear velocity of the wheels. When the wheels move, the distance between the robot and the target changes, and the moving distance of the wheels can be calculated according to the change of data measured by the distance sensor, and the moving distance is called a first path. When the wheel moves, the speed sensor measures the rotation radian of the wheel in the moving time period, and the moving distance of the wheel can be estimated according to the rotation radian and the radius of the wheel, and the moving distance is called as a second path. Due to the uncertainty of the wheel radius, the second course is inaccurate and the first course is relatively accurate. The automatic calibration idea of this embodiment is to continuously iteratively modify the radius of the wheel to gradually approximate the second route to the first route.
The current wheel radius is initialized and may be set to the original tire size before unworn, and before flat. Obtaining a current first distance according to the data of the distance sensor; the current second leg is obtained based on the current wheel radius and the speed sensor data. And correcting the current wheel radius according to the deviation of the current second distance and the current first distance to obtain the wheel radius of the next time period. And if the difference between the current first route and the current second route is not smaller than the preset iteration stop threshold, taking the next time period as the current time period and the wheel radius of the next time period as the current wheel radius, re-acquiring the current first route and the current second route, and starting the next iteration. And if the difference between the current first route and the current second route is smaller than the preset iteration stop threshold, finishing the calibration and taking the wheel radius of the next time period as the target wheel radius.
The method provided by the embodiment is suitable for single-wheel, double-wheel or multi-wheel robots, and each wheel can be automatically calibrated according to the method. After the wheel radius is automatically calibrated, the accuracy of the second leg calculated from the calibrated wheel radius is improved, as is the accuracy of the measured linear velocity, which is an improvement for job task applications that use the second leg, or linear velocity.
In another embodiment of the present invention, as shown in fig. 5, an automatic wheel radius calibration system for a mobile robot includes:
the calibration module 100 is configured to obtain a distance of the robot in a current time period according to the distance sensor data, and record the distance as a current first distance; obtaining the distance of the robot in the current time period according to the current wheel radius and the data of the speed sensor, and recording as the current second distance; calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route; the wheel radius for the next time period is calculated according to the following formula:
wherein R (n +1) is the wheel radius of the next time period, R (n) is the current wheel radius, Dmap(n) is the current first journey, DodomAnd (n) is the current second distance, and step is the preset step.
The calibration module is further configured to determine whether a difference between the current first route and the current second route is smaller than a preset iteration stop threshold; if not, the next time period is taken as the current time period, the wheel radius of the next time period is taken as the current wheel radius, and the current first route and the current second route are obtained again; and if so, the wheel radius of the next time period is the target wheel radius, and the automatic calibration is finished.
Specifically, the present embodiment provides a specific iterative method for estimating the radius of the target wheel. In the iterative process, if the current second path is larger, which indicates that the radius of the corresponding wheel is larger, the radius of the wheel is adjusted to be smaller, and vice versa, the radius of the wheel is adjusted to be larger, and the larger the deviation is, the faster the adjustment speed is. As the number of iterations increases, when Dodom≈DmapThen the iteration tends to converge.
In another embodiment of the present invention, as shown in fig. 6, an automatic wheel radius calibration system for a mobile robot includes:
the calibration module 100 is configured to obtain a distance of the robot in a current time period according to the distance sensor data, and record the distance as a current first distance; obtaining the distance of the robot in the current time period according to the current wheel radius and the data of the speed sensor, and recording as the current second distance; calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route; the wheel radius for the next time period is calculated according to the following formula:
wherein R (n +1) is the wheel radius of the next time period, R (n) is the current wheel radius, Dmap(n) is the current first journey, DodomAnd (n) is the current second distance, and step is the preset step.
A filtering unit 110, configured to perform gaussian filtering on the radius of the wheel in the next time period to obtain a filtered radius of the wheel in the next time period; gaussian filtering is performed according to the following formula:
wherein R isf(n +1) is the radius of the wheel after filtering in the next time period, R (n +1-i) is the radius of the wheel which is pushed forward from the next time period by i time periods, G (0), G (1) and G (M-1) are M response values of the Gaussian filter, M is the length of the Gaussian filter, and G (1) is the length of the Gaussian filterNorm(0)、GNorm(1)、......GNorm(M-1) is the M normalized response values of the Gaussian filter.
The calibration module 100 is further configured to determine whether a difference between the current first route and the current second route is smaller than a preset iteration stop threshold; if not, the next time period is taken as the current time period, the radius of the filtered wheel in the next time period is taken as the radius of the current wheel, and the current first route and the current second route are obtained again; if so, the filtered wheel radius of the next time period is the target wheel radius, and the automatic calibration is finished;
specifically, in order to improve the stationarity of the iterative output wheel radius, gaussian filtering is performed on the wheel radius of the next time period, and the gaussian filtered wheel radius is applied to the estimation of the second route. Gaussian filtering is employed because the noise between nature, when co-determined by multiple factors, approximately follows a gaussian distribution.
Let the response function of the gaussian filter be:
discrete sampling is carried out on the filter, the sampling time interval is delta x, and then:
assuming that the length of the filter is M and the variance is sigma, obtaining M response values of the filter, namely G (0), G (1) and G (M-1); and then carrying out normalization processing to obtain M normalized response values of the filter.
The wheel radius of the next time segment is gaussian filtered to obtain the filtered wheel radius of the next time segment, and for example, the change of a signal before and after gaussian filtering is shown in fig. 12.
In another embodiment of the present invention, as shown in fig. 7, an automatic wheel radius calibration system for a mobile robot includes:
a calibration module 100 for automatically calibrating a wheel radius of the mobile robot before performing a work task; the calibration method adopts the automatic wheel radius calibration method in any one of the embodiments (shown in fig. 1, fig. 2 or fig. 3).
The interface display module 200 is configured to display a current wheel radius in real time through an interface when the wheel radius of the mobile robot is automatically calibrated, and give a prompt through the interface during and/or after the calibration is completed.
In particular, the wheel radius auto-calibration function is a separate function that may be performed prior to performing a work task, including building a grid map of the work area, and/or cleaning tasks. For example, taking a double-wheel robot as an example, the radius of the wheel is automatically calibrated before the grid map is built, and a person pushes the trolley to walk in an environment with obvious characteristics until the radius of the wheel is calibrated; in the calibration process, the interface displays the current radius values of the left wheel and the right wheel in real time (as shown in fig. 8), and when the calibration is finished and the calibration is successful, the interface gives a prompt (as shown in fig. 9), and the user can optionally terminate the calibration; if the system considers the wheel radius calibration to fail after a period of calibration, the following information is suggested (as shown in FIG. 10): "wheel radius after calibration over a period of time, failed calibration! Please continue calibration or terminate calibration! ", the user may choose to continue with the calibration, and if the calibration is successful, the system will prompt the following (as shown in fig. 11): "after further calibration of the wheel radius, finish the calibration, please continue the calibration or terminate the calibration! ", the user may choose to terminate the calibration.
In the embodiment, the automatic wheel radius calibration is carried out before the work task, so that the burden of the work task is not increased, and the calibrated wheel radius is adopted in the work task, so that the linear speed of the robot can be estimated more accurately, and the distance estimated according to the speed sensor is more accurate. The method is suitable for the condition that the robot is not used for a long time, the tire is not worn greatly, and the sealing performance of the tire is good.
In another embodiment of the present invention, as shown in fig. 7, an automatic wheel radius calibration system for a mobile robot includes:
a calibration module 100 for automatically calibrating the radius of the wheels of the mobile robot at the beginning of a work task and at intervals; the calibration method adopts the automatic wheel radius calibration method in any one of the previous embodiments (as shown in figure 1, figure 2 or figure 3);
the interface display module 200 is configured to display a current wheel radius in real time through an interface when the wheel radius of the mobile robot is automatically calibrated, and give a prompt through the interface during and/or after the calibration is completed.
In particular, the wheel radius of the mobile robot is automatically calibrated in performing work tasks, including building a grid map of the work area, and/or cleaning tasks. The work task is calibrated once at the beginning, and then is calibrated at regular intervals. When the tire has better sealing performance, the mode can meet the practical requirement.
The embodiment has various modifications, for example, the automatic calibration of the radius of the wheel is carried out in real time in the process of executing a work task, and when the sealing performance of the tire is poor, the automatic calibration can be changed along with the change of the radius of the wheel in real time; for another example, when the work task is started each time, the automatic calibration of the radius of the wheel is carried out simultaneously, after the calibration is finished, the calibration is stopped, when the sealing performance of the tire is good, and the change of the radius of the wheel in one day is small, the practical requirements can be met by adopting the mode to carry out calibration, the calibration workload of the robot can be reduced, and the work load of the robot can be reduced.
When the automatic wheel radius calibration is performed in a work task, in order to improve the intelligence of the robot in work, the less interaction with a user is desired to be performed during the task, so that only when the wheel radius changes abnormally and the calibration fails after a period of time, the work task should be suspended, for example, when sweeping, the user is prompted on an interface, and the information is as follows: "wheel radius does not match reality, automatic calibration fails, floor sweeping has been suspended! ".
It should be noted that the above embodiments can be freely combined as necessary. The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (7)
1. A method for automatic wheel radius calibration for a mobile robot, comprising:
step S100, obtaining the distance of the robot in the current time period according to the data of the distance sensor, and recording the distance as a current first distance; obtaining the distance of the robot in the current time period according to the current wheel radius and the data of the speed sensor, and recording as the current second distance;
step S200, calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route;
step S210 performs gaussian filtering on the wheel radius of the next time period according to the following formula to obtain a filtered wheel radius of the next time period:
wherein R isf(n +1) filtered rear wheel half for next time periodThe method comprises the following steps that R (n +1-i) is the radius of a wheel which is pushed forward from the next time period by i time periods, G (0), G (1) and GNorm(0)、GNorm(1)、......GNorm(M-1) M normalized response values for the gaussian filter;
step S410, when the difference between the current first route and the current second route is not less than a preset iteration stop threshold, taking a next time period as a current time period, taking a filtered wheel radius of the next time period as a current wheel radius, and jumping to step S100;
step S510, when the difference between the current first route and the current second route is smaller than a preset iteration stop threshold, the filtered wheel radius of the next time period is a target wheel radius, and the automatic calibration is finished.
2. The method of claim 1, wherein the method comprises:
the step S200 calculates the radius of the wheel for the next time period according to the following formula:
wherein R (n +1) is the wheel radius of the next time period, R (n) is the current wheel radius, Dmap(n) is the current first journey, DodomAnd (n) is the current second distance, and step is the preset step.
3. The method of claim 1, wherein the method comprises:
the wheel radii of the mobile robot are automatically calibrated before and/or during the performance of the work task.
4. The method of claim 3, wherein the automatically calibrating the radius of the wheel of the mobile robot in performing the task further comprises:
the wheel radius of the mobile robot is automatically calibrated at the beginning of the work task, and/or at intervals.
5. The method of claim 1, further comprising:
when the wheel radius of the mobile robot is automatically calibrated, the current wheel radius is displayed in real time through an interface, and a prompt is given through the interface in the calibration process and/or after the calibration is finished.
6. An automatic wheel radius calibration system for a mobile robot, comprising:
the calibration module is used for obtaining the distance of the robot in the current time period according to the data of the distance sensor and recording the distance as a current first distance; obtaining the distance of the robot in the current time period according to the current wheel radius and the data of the speed sensor, and recording as the current second distance; calculating the radius of the wheel in the next time period according to the current radius of the wheel, the current first route and the current second route;
the calibration module further comprises:
the filtering unit is used for carrying out Gaussian filtering on the wheel radius of the next time period according to the following formula to obtain the filtered wheel radius of the next time period:
wherein R isf(n +1) is the radius of the wheel after filtering in the next time period, R (n +1-i) is the radius of the wheel which is pushed forward from the next time period by i time periods, G (0), G (1) and G (M-1) are M response values of the Gaussian filter, M is the length of the Gaussian filter, and G (1) is the length of the Gaussian filterNorm(0)、GNorm(1)、......GNorm(M-1) M normalized response values for the gaussian filter;
the calibration module is further configured to, when a difference between the current first route and the current second route is not smaller than a preset iteration stop threshold, take a next time period as a current time period, take a filtered wheel radius of the next time period as a current wheel radius, and reacquire the current first route and the current second route; and when the difference between the current first route and the current second route is smaller than a preset iteration stop threshold, the filtered wheel radius of the next time period is the target wheel radius, and the automatic calibration is finished.
7. The automatic wheel radius calibration system for a mobile robot of claim 6, further comprising:
and the interface display module is used for displaying the current wheel radius in real time through the interface when the wheel radius of the mobile robot is automatically calibrated, and giving a prompt through the interface in the calibration process and/or after the calibration is finished.
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| KR20160050739A (en) * | 2014-10-30 | 2016-05-11 | 현대모비스 주식회사 | Method and apparatus for radius revision of vehicle wheel |
| CN108334075A (en) * | 2018-01-08 | 2018-07-27 | 浙江立石机器人技术有限公司 | Robot tire absolute error scaling method, apparatus and system |
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| JP2007240167A (en) * | 2006-03-06 | 2007-09-20 | Maruhama:Kk | Vehicle-mounted travel distance measuring apparatus |
| CN104482937A (en) * | 2014-12-19 | 2015-04-01 | 中国人民解放军第二炮兵装备研究院第三研究所 | High-precision vehicle mileage measuring device and high-precision vehicle mileage measuring method |
| CN106054873A (en) * | 2016-05-19 | 2016-10-26 | 北京海尔广科数字技术有限公司 | Calibration method and device of mobile device driven by multiple motors |
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| CN108334075A (en) * | 2018-01-08 | 2018-07-27 | 浙江立石机器人技术有限公司 | Robot tire absolute error scaling method, apparatus and system |
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Effective date of registration: 20231116 Address after: Room 2401, Building 4, No. 209 Zhuyuan Road, Suzhou High tech Zone, Suzhou City, Jiangsu Province, 215000 Patentee after: Jiangsu Cheguan Environmental Sanitation Co.,Ltd. Address before: Room 212, 2nd Floor, Building 1, No. 599 Gaojing Road, Shanghai, 201702 Patentee before: SHANGHAI VIEW TECHNOLOGIES Co.,Ltd. |