A tennis ball serving robot and a tennis ball serving system

Abstract

The application provides a tennis ball serving robot and a tennis ball serving system. The tennis ball serving robot responds to a user-defined serving instruction, enters a user-defined serving mode based on the user-defined serving instruction, and serves according to received user-defined serving parameters in the user-defined serving mode. The application can improve the consistency and switching control of the tennis ball landing point, improve the serving routine, make the interaction more intuitive and simple, improve the capability and application scenarios of the tennis ball serving robot, and make the equipment maintenance safer and more convenient.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sports equipment, and particularly relates to a tennis serving robot and a tennis serving system. BACKGROUND

[0002] With the popularity and improvement of the technical level of tennis, the demand for tennis serving robots is increasing. Most of the existing extrusion type tennis serving robots adopt traditional mechatronics design, aiming to provide stable serving practice for users. However, a series of problems existing in such devices limit their support for training effect and user experience, which are specifically manifested in the following aspects: the preset serving mode is too single, the tennis landing point consistency is poor, the tennis speed adjustment function is lacking, the fault handling is inconvenient, and the effective interaction mechanism is lacking. SUMMARY

[0003] In order to at least partially overcome the problems existing in the related art, the present application provides a tennis serving robot and a tennis serving system.

[0004] According to a first aspect of the embodiments of the present application, the present application provides a tennis serving robot, which enters a custom serving mode based on a custom serving instruction of a user in response to the custom serving instruction of the user, and performs custom serving according to received custom serving parameters in the custom serving mode.

[0005] According to the tennis serving robot provided by the embodiments of the present application, the tennis serving robot includes a robot body, a ball collecting basket, a controller, a ball feeding module, a ball extruding module, a pitch module and a left-right module arranged on the robot body; the ball collecting basket is arranged above the ball feeding module; the ball feeding module, the ball extruding module, the pitch module and the left-right module are connected with the controller; the ball feeding module is used to obtain the collected tennis balls from the ball collecting basket and feed the tennis balls to the ball extruding module; the ball extruding module is used to extrude the tennis balls to realize serving; and the pitch module and the left-right module are used to adjust the up-down and left-right directions of the extruded tennis balls.

[0006] Further, the tennis serving robot further includes a hatch module connected with the controller, which is used to open or close the hatch in response to a user's hatch opening and closing instruction.

[0007] Further, the ball feeding module comprises a ball feeding motor and a photoelectric sensor, both of which are connected to the controller, the photoelectric sensor is arranged in the ball feeding channel and is used to detect the information of the tennis ball entering the ball feeding channel; the controller is used to receive the signal from the photoelectric sensor and control the action of the ball feeding motor based on the received signal; when the photoelectric sensor detects that the tennis ball enters the ball feeding channel, the controller stops the ball feeding motor in response to the signal sent by the photoelectric sensor until the tennis ball completely passes through the ball feeding channel and then restarts the ball feeding motor, thereby ensuring that only one tennis ball is fed out each time.

[0008] Further, the ball squeezing module comprises an upper wheel motor, a lower wheel motor, an upper wheel speed sensor and a lower wheel speed sensor, all of which are connected to the controller, the upper wheel speed sensor and the lower wheel speed sensor respectively detect the rotating speed of the upper wheel motor and the lower wheel motor and send the detected rotating speed to the controller, and the controller adjusts the rotating speed of the upper wheel motor and the lower wheel motor in real time according to the received rotating speed.

[0009] Further, the upper wheel speed v u and the lower wheel speed v d of the ball squeezing wheel are respectively:

[0010]

[0011] wherein k u , k d , k c , q u , q d and q c represent linear fitting coefficients, v n represents the speed of the tennis ball, w n represents the spin speed vector of the tennis ball, which is a parameter combined from the spin type and the spin speed w s .

[0012] Further, the pitching module comprises a pitching motor and a pitching angle sensor, both of which are connected to the controller, the pitching angle sensor is used to detect the pitching angle of the pitching motor and send it to the controller, and the controller performs closed-loop control on the pitching motor;

[0013] The left and right modules comprise left and right motors and left and right angle sensors, the left and right motors and the left and right angle sensors are connected with the controller, the left and right angle sensors are used for detecting the left and right angles of the left and right motors and sending the left and right angles to the controller, and the controller performs closed-loop control on the left and right motors.

[0014] The tennis serving robot provided by the embodiment of the application further comprises a user positioning device, the user positioning device communicates with the controller, the controller enters one or more of a self-defined serving mode, a back-to-position running mode, a follow-up combat mode and a smart running comparison mode in response to user position information detected by the user positioning device, the self-defined serving mode is configured to serve based on self-defined serving parameters of the user, the back-to-position running mode is configured to start serving when the user is determined to have run to a restoration point area based on information detected by the user positioning device, the follow-up combat mode is configured to determine single ball parameters of the next serving based on information detected by the user positioning device, and the smart running comparison mode is configured to compare running information detected by the user positioning device with expected running information templates.

[0015] Further, the user positioning device comprises a main base station, a secondary base station and a tag, the main base station is arranged on the robot body, the secondary base station is arranged on the net, and the tag is arranged on the user.

[0016] The tag and the main base station and the tag and the secondary base station both use electromagnetic wave time of flight to achieve distance measurement, and calculate the tag position based on triangulation to obtain the position information of the user.

[0017] Further, when the secondary base station is one, two solutions of the horizontal coordinate of the tag in the coordinates of the tennis court are:

[0018]

[0019] Two solutions of the vertical coordinate of the tag in the coordinates of the tennis court are:

[0020]

[0021] In the formula, parameters A, B and C are respectively:

[0022]

[0023] x0 and y0 represent the horizontal coordinate and the vertical coordinate of the main base station in the tennis court respectively, x1 and y1 represent the horizontal coordinate and the vertical coordinate of the secondary base station in the tennis court respectively, x t1 and x t2Let y represent the two solutions for the x-coordinate of the label in the coordinate system of the tennis court. t1 and y t2 Let t1 and t2 represent two solutions for the ordinate of the label in the coordinate system of the tennis court, respectively, where t1 and t2 are both intermediate variables.

[0024]

[0025] D0 represents the two-dimensional distance between the tag and the primary base station, and D1 represents the two-dimensional distance between the tag and the secondary base station.

[0026] Furthermore, when there are two or more secondary base stations, the least squares method is used to solve the over-constrained distance equations to obtain the coordinates of the tag on the tennis court:

[0027]

[0028] In the formula, x t and y t Let M and P represent the x and y coordinates of the label on the tennis court, respectively. The cosine theorem coefficient matrix M and the cosine theorem constant matrix P are respectively:

[0029]

[0030] In the formula, (x i ,y i D represents the coordinates of the i-th secondary base station on the tennis court. i This represents the two-dimensional distance between the tag and the i-th secondary base station.

[0031] Furthermore, in the follow-up battle mode, the user positioning device uses a period T p Obtain user location information The data is then transmitted to the controller, which first determines the offset method and offset distance x of the user-configured follow-up battle mode. o Obtain the desired angles of the left and right modules, and the desired angles θ of the left and right modules under forehand offset. dy for in, Given the robot's position on the court, the desired angle θ between the left and right modules under backhand offset conditions. dy for

[0032] The robot body obtains the current actual angle θ of the left and right modules. ay and speed And combined with the remaining time T of the serve ly The motion angle θ of the left and right modules during this serve was calculated. ymin and θ ymax ;

[0033] Comparing the left and right module expected angle θ dy and the motion angle θ ymin and θ ymax , when θ dy < θ ymin , the target angle of the left and right module 15 of the serving robot is θ ymin ; when θ dy > θ ymax , the target angle of the left and right module of the serving robot is θ ymax ; when θ ymax ≥ θ dy ≥ θ ymin , the target angle of the left and right module of the serving robot is θ dy .

[0034] Further, in the intelligent comparison mode, the interval between two serving times of the serving robot is defined as an analysis cycle, and an expected starting area and a hitting area are defined for each serving time, and the serving time of the serving robot is defined as t The time when the user runs out of the expected starting area is t The time when the user enters the hitting area is t The time when the user hits the ball and enters the expected starting area of the next serving is t The time of the next serving is t Four evaluation times are obtained, including: the first waiting time t The starting time t The return time t And the second waiting time t

[0035] For the first waiting time t is less than t , it indicates that the user's preparation time for hitting the ball is insufficient; for the starting time t is less than t , it indicates that the user's running and hitting ability meets the standard, otherwise the running and hitting ability is insufficient; for the return time t is less than t , it indicates that the user's return running ability meets the standard, otherwise the return running ability is insufficient; for the second waiting time t is less than t , it indicates that the user's preparation time for the next hitting is insufficient.

[0036] According to a second aspect of the embodiments of the present application, the present application further provides a tennis serving system, which comprises the tennis serving robot and the smart racket as described above, the smart racket is in communication with the controller, the controller enters one or more of a self-defined serving mode, a back-to-base running mode, a follow-up match mode, a smart running comparison mode, a smart racket mode and a simulated match mode in response to the motion trajectory of the smart racket and the collision information between the tennis and the smart racket, wherein the self-defined serving mode is configured to serve based on the self-defined serving parameters of a user, the back-to-base running mode is configured to start serving when the user has run to the restoration point area based on the information detected by the user positioning device, determine the single ball parameters of the next serving based on the information detected by the user positioning device, the smart running comparison mode is configured to compare the running information detected by the user positioning device with the expected running information template, the smart racket mode is configured to start the tennis serving robot to serve when the user serves successfully based on the collision information between the smart racket and the tennis, and the simulated match mode is configured to adjust the single ball parameters and the combined parameters of the tennis serving in real time by using the information detected by the user positioning device and the collision information between the smart racket and the tennis.

[0037] According to the tennis serving system provided by the embodiments of the present application, the smart racket comprises a racket body, a rubber sleeve and a detection module, the detection module is fixed to the end of the handle of the racket body through the rubber sleeve, and an inertial measurement unit is arranged in the detection module, which is used to measure the motion trajectory of the racket body and the collision information between the tennis and the racket body.

[0038] According to the above specific embodiments of the present application, at least the following beneficial effects are achieved: the tennis serving robot provided by the present application can diversify the serving mode by setting the self-defined serving mode, meet the individual needs, and make the interaction more intuitive and simple; the consistency and switching control of the tennis landing point can be improved by the closed-loop control of the ball squeezing module, and the serving routine can be improved; the present application can improve the ability and application scenarios of the tennis serving robot by setting the robot body, the user positioning system and the smart racket, and setting the self-defined serving mode, the back-to-base running mode, the follow-up match mode, the smart running comparison mode, the smart racket mode and the simulated match mode in the robot body; the present application can make the equipment maintenance more safe and convenient by opening the hatch when a fault occurs.

[0039] It should be appreciated that the above general description and the following specific embodiments are only exemplary and explanatory, and cannot limit the scope of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0041] Figure 1 A schematic diagram of the overall structure of a tennis ball serving robot according to the present application;

[0042] Figure 2 A schematic diagram of the internal structure of a robot body in a tennis ball serving robot according to the present application;

[0043] Figure 3 A schematic diagram of the internal structure of a robot body in a tennis ball serving robot according to the present application;

[0044] Figure 4 A block diagram of the structure of a tennis ball serving robot according to the present application;

[0045] Figure 5 A flowchart of the process of opening a hatch in a tennis ball serving robot according to the present application;

[0046] Figure 6 A flowchart of the process of defining a serving mode in a tennis ball serving robot according to the present application;

[0047] Figure 7 A flowchart of the process of a return running mode in a tennis ball serving robot according to the present application;

[0048] Figure 8 A flowchart of the process of a follow-up match mode in a tennis ball serving robot according to the present application;

[0049] Figure 9 A flowchart of the process of a smart pace comparison mode in a tennis ball serving robot according to the present application;

[0050] Figure 10 A result block diagram of a tennis ball serving system according to the present application;

[0051] Figure 11 A flowchart of the process of an intelligent racket mode in a tennis ball serving robot according to the present application;

[0052] Figure 12 A flowchart of the process of a simulation match mode in a tennis ball serving robot according to the present application.

[0053] BRIEF DESCRIPTION OF DRAWINGS

[0054] 1. Robot body; 10. Ball collecting basket, 11. Controller;

[0055] 12. Ball feeding module; 121. Ball feeding motor; 122. Photoelectric sensor;

[0056] 13. Ball squeezing module; 131. Upper wheel motor; 132. Lower wheel motor; 133. Upper wheel speed sensor; 134. Lower wheel speed sensor;

[0057] 14. Pitching module; 141. Pitching motor; 142. Pitching angle sensor;

[0058] 15. Left-right module; 151. Left-right motor; 152. Left-right angle sensor;

[0059] 16. Hatch module; 161. Integrated electromagnet;

[0060] 2. User positioning device; 21. Main base station;

[0061] 3. Intelligent racket. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the drawings and detailed description will be used to clearly explain the spirit of the present application. Any person skilled in the art can make changes and modifications to the technology taught by the present application without departing from the spirit and scope of the present application.

[0063] The illustrative embodiments of the present application and their descriptions are used to explain the present application, but are not as a limitation of the present application. In addition, the same or similar elements / components in the drawings and embodiments are used to represent the same or similar parts.

[0064] As for the "first", "second", and the like used herein, it is not particularly intended to refer to the order or sequence, nor to limit the present application. It is only for distinguishing elements or operations described using the same technical terms.

[0065] As for the "include", "comprise", "have", "contain", and the like used herein, they are all open terms, that is, they mean including but not limited to.

[0066] As for the "and / or" used herein, it includes any or all combinations of the described things.

[0067] As for the "multiple" herein, it includes "two" and "more than two"; as for the "multiple groups" herein, it includes "two groups" and "more than two groups".

[0068] Certain words used to describe the present application will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the present application.

[0069] The ball extruding motor of the existing extrusion type tennis ball serving robot generally adopts an open-loop control system. This means that without external feedback, the system cannot automatically adjust the working state according to the actual situation, resulting in a large deviation in the landing position of the tennis ball each time it is served, i.e., poor consistency of the landing point of the tennis ball, affecting the requirement for precision during training.

[0070] The speed of the internal drive motor of the existing extrusion type tennis ball serving robot remains constant during task execution, lacking a speed dynamic adjustment mechanism. As a result, it is difficult to simulate the varied serving styles in real game scenarios, such as the ability to quickly switch between different types of spin balls (e.g., from topspin to underspin), which is greatly limited.

[0071] The existing extrusion type tennis ball serving robot is usually only equipped with several fixed serving programs preset by the manufacturer, and the user has little room for selection, and the preset mode is too single. This patterned design is difficult to meet the personalized training needs, especially when it comes to specialized exercises for specific skills or strategies.

[0072] The existing extrusion type tennis ball serving robot also generally lacks a feedback system that allows the user to interact well with it, lacking an effective interaction mechanism. This makes it necessary for the operator to try several times to find the most suitable configuration when adjusting the settings to match the individual skill level, greatly reducing the training efficiency.

[0073] In addition, when encountering common problems such as ball jamming, the existing extrusion type tennis ball serving robot often requires the user to disassemble some components for cleaning or repair, which is a complex and time-consuming process, causing many inconveniences in daily use.

[0074] Although the existing extrusion type tennis ball serving robot can assist tennis enthusiasts and professional players to a certain extent in completing basic exercises, the above-mentioned defects seriously restrict the possibility of further improving the training effect. Therefore, developing a new generation of tennis ball serving robot with higher intelligent level and better user experience has become an urgent need for the development of the industry.

[0075] The tennis ball serving robot provided by the application responds to a user's custom serving instruction, enters a custom serving mode based on the user's custom serving instruction, and serves according to received custom serving parameters in the custom serving mode. The custom serving parameters include single ball parameters and combination parameters, the single ball parameters include one or more of serving speed, serving rotation type, serving rotation speed, arc, left-right orientation, single ball interval and single ball repetition number, and the combination parameters include one or more of group interval, single ball switching mode, automatic stop mode and parameters and countdown time.

[0076] As shown in Figures 1-3 The tennis ball serving robot provided by the application includes a robot body 1, a ball collecting basket 10 arranged on the robot body 1, a controller 11, a ball feeding module 12, a ball extruding module 13, a pitch module 14 and a left-right module 15. The ball collecting basket 10 is arranged above the ball feeding module 12, and the ball feeding module 12, the ball extruding module 13, the pitch module 14 and the left-right module 15 are all connected with the controller. The ball feeding module 12 is used to obtain the collected tennis balls from the ball collecting basket 10 and feed the tennis balls to the ball extruding module 13, the ball extruding module 13 is used to extrude the tennis balls to serve, and the pitch module 14 and the left-right module 15 are used to adjust the up-down and left-right directions of the extruded tennis balls.

[0077] In the embodiment, the ball collecting basket 10 adopts a cloth design supporting folding, which is convenient for storage. The upper sealing zipper can effectively prevent the tennis balls from falling off during the movement of the tennis ball serving robot, and has great practical value.

[0078] In the above embodiment, the tennis ball serving robot provided by the application further includes a hatch module 16 connected with the controller 11, which is used to open or close the hatch in response to the user's hatch opening and closing instruction.

[0079] In a specific embodiment, the ball feeding module 12 includes a ball feeding motor 121 and a photoelectric sensor 122, both of which are connected with the controller 11. The photoelectric sensor 122 is arranged in the ball feeding channel and is used to detect the information of the tennis ball entering the ball feeding channel. The information of the tennis ball entering the ball feeding channel includes the position and movement state of the tennis ball.

[0080] The controller 11 is used to receive the signal from the photoelectric sensor 122 and control the action of the ball feeding motor 121 based on the received signal. When the photoelectric sensor 122 detects that the tennis ball enters the ball feeding channel, the controller 11 stops the operation of the ball feeding motor 121 in response to the signal sent by the photoelectric sensor 122, and then restarts the ball feeding motor 121 after the tennis ball completely passes through the ball feeding channel, so as to ensure that only one tennis ball is fed out at a time.

[0081] In a specific embodiment, the ball extruding module 13 includes an upper wheel motor 131, a lower wheel motor 132, an upper wheel speed sensor 133 and a lower wheel speed sensor 134, all of which are connected to the controller 11. The upper wheel speed sensor 133 and the lower wheel speed sensor 134 respectively detect the rotation speeds of the upper wheel motor 131 and the lower wheel motor 132, and send the detected rotation speeds to the controller 11. The controller 11 adjusts the rotation speeds of the upper wheel motor 131 and the lower wheel motor 132 in real time according to the received rotation speeds, thereby completing the closed-loop control of the upper wheel motor 131 and the lower wheel motor 132 and improving the consistency of the ball serving.

[0082] In a specific embodiment, the pitch module 14 includes a pitch motor 141 and a pitch angle sensor 142, both of which are connected to the controller 11. The pitch angle sensor 142 detects the pitch angle of the pitch motor 141 and sends it to the controller 11, which controls the pitch motor 141 in a closed loop. The left-right module 15 includes a left-right motor 151 and a left-right angle sensor 152, both of which are connected to the controller 11. The left-right angle sensor 152 detects the left-right angle of the left-right motor 151 and sends it to the controller 11, which controls the left-right motor 151 in a closed loop.

[0083] In a specific embodiment, the hatch module 16 includes an integrated electromagnet 161, which is connected to the controller 11. As shown in Figure 4 The controller 11 controls the ball feeding motor 121, the upper wheel motor 131, the lower wheel motor 132 and the left-right motor 151 to stop running according to the received hatch opening instruction, to ensure safety during maintenance. Then the controller 11 controls the integrated electromagnet 161 to actuate the hatch to open, to facilitate the user to clean the stuck ball or foreign matter. After the user completes the maintenance, the user can manually close the hatch and use the device normally. The whole operation process is safe and simple.

[0084] When the tennis ball serving robot appears to be stuck or needs to be cleaned for maintenance, the hatch module 16 provides great convenience. The user can complete the maintenance without disassembling the robot body 1, which is safe and practical.

[0085] In another embodiment, as shown in Figure 5As shown, the tennis serving robot provided by the application further comprises a user positioning device 2, which communicates with the controller 11, and the controller 11 enters one or more of the self-defined serving mode, the back-to-position running mode, the follow-up combat mode and the intelligent step comparison mode in response to the user position information detected by the user positioning device 2, wherein the self-defined serving mode is configured to serve based on the user's self-defined serving parameters, the back-to-position running mode is configured to start serving when the user has run to the restoration point area based on the information detected by the user positioning device 2, the follow-up combat mode is configured to determine the single ball parameters of the next serving based on the information detected by the user positioning device 2, and the intelligent step comparison mode is configured to compare the running information such as speed, time and trajectory detected by the user positioning device 2 with the expected running information template, so as to obtain the user's running ability, analysis results such as whether the running is up to standard, advantages and disadvantages, etc.

[0086] In a specific embodiment, the user positioning device 2 is realized based on the UWB positioning principle, and the user positioning device 2 comprises a main base station 21, a secondary base station and a tag, wherein the main base station 21 is arranged on the robot body 1, the secondary base station is arranged on the net, and the tag is arranged on the user, which can effectively reduce the deployment difficulty of the user positioning device 2. The user positioning device 2 completes the ranging of the tag and the main base station 21 and the ranging of the tag and the secondary base station by using the time of flight of electromagnetic waves, and then completes the calculation of the position of the tag based on the triangulation positioning.

[0087] The ranging principle of the tag and the main base station 21 and the ranging principle of the tag and the secondary base station are the double-sided and double-direction ranging four-message mode.

[0088] Taking the ranging of the tag and the main base station 21 as an example, the main base station 21 initiatively initiates the first ranging message, and the tag responds to the answer, so that the time from the sending time stamp of the main base station 21 to the receiving time stamp of the tag response is T r1 , the time from the receiving time stamp of the main base station 21 to the sending time stamp to the tag is T y1 ; after a certain time, the tag initiatively initiates the ranging message, and the main base station 21 responds to the answer, so that the time from the sending time stamp of the tag to the receiving time stamp of the main base station 21 response is T r2 , the time from the receiving time stamp of the main base station 21 to the sending time stamp to the tag is T y2 , and the time of flight T f is:

[0089]

[0090] The three-dimensional distance L0 between the tag and the main base station 21 is:

[0091] L0=V*T f .

[0092] In the formula, V represents the communication speed between the main base station 21 and the tag, and the three-dimensional distance L between the tag and the secondary base station i i The ranging calculation principle of the tag and the main base station 21 is the same as described above.

[0093] The user positioning device 2 supports the case of only one secondary base station and the case of more than one secondary base station. Considering that a tennis court is a plane, more attention is paid to the two-dimensional coordinates of the plane, so in either case, the three-dimensional straight-line distance needs to be projected into a two-dimensional straight-line distance first. Assuming that the height of the main base station 21 is H0, the height of the tag is H tag , the height of the secondary base station i is H i , the ranging between the tag and the main base station 21 is L0, and the ranging between the tag and the secondary base station i is L i , then the two-dimensional distance D0 between the tag and the main base station is The two-dimensional distance D i between the tag and the secondary base station i is:

[0094]

[0095] In the formula, i = 1…n, and n represents the number of secondary base stations in the user positioning device 2.

[0096] For the case of only one secondary base station, the intersection of the circle with the main base station 21 as the center and the two-dimensional distance D0 between the tag and the main base station 21 as the radius and the circle with the secondary base station as the center and the two-dimensional distance D1 between the tag and the secondary base station as the radius is the coordinate to be solved. When the two circles do not intersect, the positioning system fails to solve. When the two circles are tangent, the tangent point is the coordinate point to be solved. When the two circles intersect, the two intersection points may be the coordinate points to be solved. At this time, it is necessary to select in combination with the application scenario. For example, when the main base station 21 is installed on the robot body 1, and the secondary base station is installed on the right side of the net right above the double line, the coordinate point on the upper left of the robot body 1 is selected as the positioning coordinate of the user, because the movement range of the user playing the ball can only be located in the half court opposite the robot body 1. According to the above principle, the coordinate calculation method is as follows. Assuming that the coordinates of the main base station 21 on the tennis court are (x0, y0), the coordinates of the secondary base station on the tennis court are (x1, y1), and the coordinates of the tag to be solved on the tennis court are (x t , y t ), there are the following constraint equations:

[0097]

[0098] The one-variable quadratic equation group of x t obtained by arranging and eliminating is:

[0099]

[0100] In the formula, t1 and t2 are intermediate variables, which are respectively represented as:

[0101]

[0102] Solve the quadratic equation in one variable to obtain two solutions for the x-coordinate of the label. Further, two solutions for the label's ordinate were obtained. Taking advantage of the fact that the user's movement range when playing ball is limited to the half of the court opposite to the robot's main body, (x t1 y t1 ) and (x t2 y t2 Substitute (x, y) into the inequality x1-t1(y-y1)>x, and the values ​​that satisfy the inequality are the label coordinates we are looking for.

[0103] When there are more than two secondary base stations, the ranging between the tag and both the primary base station 21 and the secondary base stations is over-constrained. Therefore, the following least squares formula is used to solve the problem, and the coordinates of the tag on the tennis court are obtained as follows:

[0104]

[0105] In the formula, the coefficient matrix M and the constant matrix P of the law of cosines are respectively:

[0106]

[0107] In the formula, (x i ,y i D represents the coordinates of the i-th secondary base station on the tennis court. i This represents the two-dimensional distance between the tag and the i-th secondary base station.

[0108] In one specific embodiment, based on the information detected by the upper wheel speed sensor 133, the lower wheel speed sensor 134, the pitch angle sensor 142, the left and right angle sensor 152, the photoelectric sensor 122, and the IMU, the serve mode can be customized in the controller 11.

[0109] like Figure 6 As shown, the parameters that need to be configured in the custom serve mode are single ball parameters and combination parameters. The single ball parameters include serve speed, serve spin type (topspin, backspin, and no spin), spin speed, trajectory, left and right orientation, single ball interval, and single ball repetition count. The combination parameters include inter-group interval, single ball switching mode (sequential, random, etc.), automatic stop mode and parameters (unlimited, timed, fixed number of times, and fixed group mode), and countdown time. Several single ball parameters and one combination parameter constitute a training routine.

[0110] This invention converts the serve speed, serve spin type, and serve spin speed magnitude into the upper and lower wheel rotation speeds of the squeeze wheel through the contact model between the squeeze wheel of the squeeze module 13 and the tennis ball. The specific implementation process is as follows:

[0111] Set the serve spin type and serve spin speed w s Combined into a single parameter w n When the serve spin type is topspin, w n =-w s w n When the value is less than 0, and the serve spin type is no spin, w n =0, when the serve spin type is backspin w n =w s w n Values ​​greater than 0.

[0112] Because the ball extrusion wheel uses closed-loop speed control, the tennis ball speed and rotation speed at different upward and downward extrusion speeds are obtained using a 1000fps high-speed camera, and the tennis ball speed v is obtained through linear fitting. n and rotation w n Compared with the speed v of the previous wheel u and the speed of the next wheel v d expression k u k d k c q u q d and q c These are the linear fitting coefficients.

[0113] The speed v of the previous wheel is obtained by elimination. u and the speed of the next wheel v d With tennis speed v n and rotation w n The relation is This resulted in the desired rotational speeds of the upper wheel motor 131 and the lower wheel motor 132 of the extrusion module 13.

[0114] The pitch module 12, the left-right module 15 and the pitch module 14 realize the motion control of the tennis serving robot. Meanwhile, based on the placement position of the tennis serving robot in the court, the left-right joint angle of the left-right module 15, the pitch joint angle of the pitch module 14 and the structural size of the robot body 1, the initial position of the tennis serving can be obtained by using the robot forward kinematics, the trajectory of the tennis before landing can be obtained by using the tennis analysis initial state (initial position, serving speed, serving rotation type and serving rotation speed) and the dynamics model of the tennis flying in the air, and the trajectory state (under the net and out of bounds, etc.), the landing point, the net height and the maximum height can be obtained based on the trajectory of the tennis.

[0115] The specific calculation process is as follows:

[0116] The world coordinate system Ow is established with the midpoint of the tennis court net as the center, the right side of the robot body 1 as the x direction and the forward direction as the y direction. The placement position of the robot body 1 in the court is P r (x r ,y r ), which is defined as the coordinate value of the rotation axis of the left-right module 15 projected on the world coordinate system, so as to obtain the conversion matrix of the robot body 1 base coordinate system and the world coordinate system.

[0117] According to the configuration design of the tennis serving robot, the conversion matrix of the left-right module 15 is where θ y is the angle of the left-right motion joint, and the conversion matrix of the pitch module 14 is where θ p is the angle of the pitch motion joint, and L1, L2 and L3 represent the structural bias dimensions of the tennis serving robot pitch joint and left-right joint, respectively.

[0118] The conversion matrix of the squeeze ball module 13 relative to the world coordinate system can be obtained by using the multiplication rule of the coordinate conversion matrix

[0119] Further, the initial position information of the tennis serving robot at the serving moment is obtained the initial speed information and the initial rotation information

[0120] By using the dynamics iterative model of the tennis flying in the air, all trajectory points of the tennis before colliding with the tennis court ground can be obtained based on the initial position, speed and rotation information of the tennis. The dynamics iterative model is described as follows:

[0121] The acceleration expression of the tennis flying in the air is:

[0122] Where k z k is the air drag coefficient. m The Magnus force coefficient, Let $\frac{ ... Let ||V| be the speed of the tennis ball in the k-th iteration. k ||For tennis speed Let wx, wy, and wz be the rotational velocities of the tennis ball in the x, y, and z directions, respectively, which remain approximately constant during flight, and g be the acceleration due to gravity.

[0123] Integrating the acceleration gives the speed of the tennis ball. and location Where dt is the iteration time step.

[0124] With flight trajectory points This allows you to determine the landing point of the tennis ball (z). k When x is less than 0 k and y k The values ​​are the landing point and the height over the net (y). k z is greater than 0 for the first time k The value is the height over the net, and the trajectory status (ball in, out, and in) is further obtained. The entire trajectory points before the landing point can be simulated by three-dimensional reconstruction to obtain a simulation animation. The simulation animation changes in real time as the serve parameters are adjusted.

[0125] The entire trajectory before the landing point can be displayed on the terminal, thus realizing the animated simulation display of customized serve parameter adjustments, which greatly facilitates the user's parameter adjustment and provides a WYSIWYG experience.

[0126] In a specific embodiment, such as Figure 7 As shown, the tennis serving robot can be set to a return-to-position running mode. In this mode, the robot body 1 determines whether the user has run to the return point area based on the information detected by the user positioning device 2 before starting the serve. Through the tennis techniques and tactics configured by the user, the robot can obtain serve information (single ball parameters and combination parameters) and the return point area (center coordinates of the return point area). The area width is wa, the area length is la, and the delay time is Tad. The user positioning device 2 obtains the user's location information in real time. When the user's location information enters the restoration point area for the first time, if the ball delivery module 12 of the robot body 1 is not delivering a ball, the ball delivery module 12 starts delivering a ball. If the ball delivery module 12 of the robot body 1 is already delivering a ball, the ball-delivering robot does not make any adjustments and continues the ball-delivering business logic. When the user's location is not entering the restoration point area for the first time, the method for determining whether the user has entered the restoration point area for the first time is described as follows:

[0127] Assume the user's coordinates are When x ac-wa / 2≤x h ≤x ac +wa / 2 and y ac -la / 2≤y h ≤y ac +la / 2 If the above conditions are met, it is determined that the user's position is in the home point area, otherwise it is determined that the user's position is outside the home point area. If the user's position is outside the home point area for N consecutive times, it is determined that the user's position is far from the home point area, to filter the false trigger caused by the fluctuation error of the positioning system. The first time the user enters the home point area is when the user's position is in the home point area at the current time, and the last time the user's position is outside the home point area is when the user's position is outside the home point area at the last time.

[0128] At this time, if the ball feeding module 12 of the robot body 1 is not feeding balls, the ball squeezing module 13, the pitching module 14 and the left-right module 15 start to prepare for serving, otherwise the serving robot does not adjust and continues the serving business logic. The tennis court is large, and in daily training, the user usually returns to a reasonable position on the court after a serving action to deal with the next serving, and the user needs to set the two serving time intervals suitable for himself, which cannot be changed in this process. The return running mode of the present application can adapt to the running ability of the user, and the serving robot starts to serve only when the user runs to the specified area. The faster the user runs, the shorter the serving interval, and the slower the user runs, the longer the serving interval, realizing the intelligent serving mode of adaptive serving frequency.

[0129] In a specific embodiment, the tennis serving robot can be set to a follow-up match mode, as shown in Figure 8 The user positioning device 2 obtains the position information of the user in real time, thereby obtaining the running ability of the user, and realizes the adaptive motion control of the serving robot by combining the driving ability of the serving robot and the tennis tactics configured by the user. In daily training, a large number of varied serves are needed to mobilize the user, and the follow-up match mode of the present application can realize serving following the position of the user on the court, realizing the intelligent serving mode of adaptive serving point, speed and rotation.

[0130] Taking baseline training as an example, the specific process is as follows:

[0131] The serving robot receives the serving parameters (single ball parameters and combined parameters) to perform normal fixed frequency serving, but the angle of the left-right module 15 in this mode is adjusted in real time based on the user positioning device 2. After starting, the user positioning device 2 obtains the position information of the user at a period Tp and transmits the data to the controller 11 through the serial port. The controller 11 first obtains the expected angle of the left-right module 15 through the offset mode (forehand offset, backhand offset and random offset) and offset distance x o configured by the user, and the expected angle of the left-right module 15 in the forehand offset case in, Given the placement of the robot body 1 on the court, the desired angles of the left and right modules 15 under backhand offset conditions. Random offset refers to the current serve's forehand or backhand offset, which randomly determines the desired angle of the left and right modules 15.

[0132] Subsequently, the serving robot obtains the actual angle θ of the current left and right modules by 15 degrees. ay and speed And combined with the remaining time T of the serve ly The achievable motion angle θ of the left and right modules 15 for this serve was calculated. ymin and θ ymax Next, compare the expected angle θ of the left and right modules 15. dy and the reachable motion angle θ ymin and θ ymax The relationship when θ dy <θ ymin The target angle of the left and right modules 15 of the serving robot is θ. ymin When θ dy >θ ymax The target angle of the left and right modules 15 of the serving robot is θ. ymax When θ ymax ≥θ dy ≥θ ymin The target angle of the left and right modules 15 of the serving robot is θ. dy This allows the ball to be served according to the user's position on the court, resulting in more intelligent changes in the landing point.

[0133] In one specific embodiment, the tennis serving robot can be set to a smart step comparison mode, such as... Figure 9 As shown, based on tennis techniques and tactics, the user's desired running information (speed, time, trajectory, etc.) is collected in advance through the user positioning device 2 as a template. The user then obtains actual running information through the user positioning device 2 and compares it with the template to obtain the user's running ability, whether the running meets the standard, strengths and weaknesses, and other analysis results. The specific method is described as follows:

[0134] Taking running time as an example, and using the interval between two serves by the serving robot as an analysis period, each serve is defined with an expected starting area (similar to a return run) and a hitting area (the landing point information is shown in the simulation animation). The serving time of the serving robot is defined as... The time it takes for the user to exit the expected startup area is The time when the user enters the hitting area is The expected starting zone for the user after hitting the ball is: The time for the next serve is Thus, four evaluation times can be obtained, a first waiting time Start-up time Return time and a second waiting time For a fixed training routine, each of the four evaluation times has an expected value, for the first waiting time Less than indicates that the user did not have enough time to prepare for the shot, for the start-up time Less than indicates that the user's running and hitting ability is up to standard, otherwise the running and hitting ability is insufficient, for the return time Less than indicates that the user's return running ability is up to standard, otherwise the return running ability is insufficient, for the second waiting time Less than indicates that the user did not have enough time to prepare for the next shot. In addition, state feedback and analysis can also be provided for not entering the expected start-up area and the hitting area, by comparison with the template parameters, to achieve feedback and evaluation of the training results.

[0135] Based on the tennis ball serving robot provided by the present application, as shown in Figure 10 The present application also provides a tennis ball serving system, which comprises a tennis ball serving robot, a user positioning device 2 and an intelligent racket 3. The tennis ball serving robot and the user positioning device 2 adopt wired serial communication, and the tennis ball serving robot and the intelligent racket 3 adopt wireless communication, which can be wireless Bluetooth communication. The user positioning device 2 is used to detect the position information of the user and send it to the tennis ball serving robot, and the intelligent racket 3 is used to measure the motion trail of the racket body and the collision information between the tennis ball and the racket body and send it to the tennis ball serving robot, and the tennis ball serving robot sets the serving mode, the return running mode, the follow-up combat mode, the intelligent walking comparison mode, the intelligent racket mode and the simulated combat mode according to the received information.

[0136] In a specific embodiment, the intelligent racket 3 comprises a racket body, a rubber sleeve and a detection module, wherein the end of the racket handle in the racket body is fixed with the detection module through the rubber sleeve, and the rubber sleeve can adapt to different thicknesses of the racket handle. The detection module is provided with an IMU (Inertial Measurement Unit), which is used to measure the motion trail of the racket body and the collision information between the tennis ball and the racket body.

[0137] In a specific embodiment, as shown in Figure 11As shown, the tennis serving robot can be set to an intelligent racket mode, in which the intelligent racket 3 obtains real-time three-dimensional acceleration and three-dimensional angular velocity of the racket, etc. Using these information, the hitting detection and hitting state (hitting time, hitting speed, racket posture and action category, etc.) detection can be realized. Combined with the incoming ball information (i.e. the serving information of the tennis serving robot), the user's return ball information can be obtained. Finally, through the tennis serving robot serving information, tennis tactics and user return ball information, the motion control of the tennis serving robot is realized. The specific implementation is described as follows:

[0138] The intelligent racket 3 is connected with the tennis serving robot through Bluetooth. The IMU data results processed and analyzed by the intelligent racket 3 are sent to the controller 11 through Bluetooth. The controller 11 determines the parameters of the next serving (such as single ball parameters and combined parameters, etc.) in combination with the current serving information, tennis tactics (user configuration or AI) and current user return ball information.

[0139] Serving connection is an important part of tennis training, which trains the user's ability to return the serve. The specific description is as follows: the user first serves, then the opponent returns the serve, and the user returns the ball again. The tennis serving robot of the present application can detect the user's serving information and respond to a serving simulation to return the serve in time, thereby achieving the effect of training the serving connection. The specific implementation is described as follows:

[0140] The intelligent racket 3 analyzes the IMU data to obtain the user's serving information (serving type, serving strength and serving time, etc.) and informs the controller 11 through Bluetooth communication. The controller 11 automatically adjusts the single ball parameters (serving speed, rotation type and speed) and combined parameters of the next serving according to the predetermined strategy (tennis tactics), so as to realize the simulation of returning the serve in actual combat.

[0141] In a specific embodiment, the tennis serving robot can be set to a simulated combat mode, and the flow chart is as follows: Figure 12As shown, the user positioning device 2 obtains the user running information and transmits the user running information to the controller 11 through serial communication, and the smart racket 3 transmits the user hitting information to the ball serving robot controller 11 through Bluetooth, and the ball serving robot controller 11 adjusts the single ball parameters and combined parameters of the ball serving in real time by using the two kinds of external information and the techniques and tactics of the tennis movement (the strategy configured by the user or AI), and further converts the single ball parameters and combined parameters of the ball serving into the up and down wheel speed control targets of the ball squeezing module 13, the target angles of the motors of the pitching module 14 and the left and right modules 15, and the start and stop time of the motor of the ball serving module 12, so that the target ball serving is realized, and the ball serving robot changes the ball serving more intelligently and in a closed loop than the traditional fixed rule ball serving. The system can effectively simulate the full link of the tennis movement to observe the user running position and characteristics and the hitting information to make the return strategy, and can realize the simulated combat intelligent tennis ball serving robot.

[0142] Specifically, the smart racket 3 detects the information and state of the tennis ball after the user hits the tennis ball, obtains the trajectory parameters of the incoming ball through animation simulation, adjusts the ball serving parameters of the ball serving robot, realizes the ball serving to cope with the incoming ball, and obtains the trajectory of the ball serving through animation simulation, combines the user running information obtained by the user positioning device 2, uses the encounter movement principle to obtain the trajectory state (intercept, pre-peak ball hitting and post-peak ball hitting), position, speed and rotation of the user at this time, and the information and state of the tennis ball after the user hits the tennis ball obtained by the smart racket 3, obtains the trajectory parameters of the incoming ball through animation simulation, adjusts the ball serving parameters of the ball serving robot, realizes the ball serving to cope with the incoming ball, and so on, which can realize the simulated combat.

[0143] The above embodiments of the present application can be implemented in various hardware, software coding or combination of both. For example, the embodiments of the present application can also be program codes for performing the above methods in a data signal processor. The present application can also relate to various functions performed by a computer processor, a digital signal processor, a microprocessor or a field programmable gate array. The above processor can be configured to perform specific tasks by executing machine-readable software code or firmware code that defines the specific methods disclosed in the present application. The software code or firmware code can be developed in different programming languages and different formats or forms. The software code can also be compiled for different target platforms. However, the software code executed by the processor according to the present application and other types of configuration code of different code styles, types and languages do not deviate from the spirit and scope of the present application.

[0144] The above description is only a specific implementation of the present application, and any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present application shall fall within the scope of the present application.

Claims

1. A tennis serving robot, characterized in that, In response to the user's custom serve command, the system enters the custom serve mode based on the user's custom serve command, and performs a custom serve according to the received custom serve parameters in the custom serve mode; The tennis serving robot includes a robot body and a controller and a ball delivery module mounted on the robot body. The ball delivery module includes a ball delivery motor and a photoelectric sensor. Both the ball delivery motor and the photoelectric sensor are connected to the controller. The photoelectric sensor is located in the ball delivery channel and is used to detect information that the tennis ball has entered the ball delivery channel. The controller is used to receive signals from the photoelectric sensor and control the operation of the ball delivery motor based on the received signals. When the photoelectric sensor detects that a tennis ball has entered the ball delivery channel, the controller responds to the signal emitted by the photoelectric sensor to stop the ball delivery motor from operating until the tennis ball has completely passed through the ball delivery channel before restarting the ball delivery motor, thereby ensuring that only one tennis ball is delivered at a time.

2. The tennis serving robot according to claim 1, characterized in that, It also includes a ball collection basket, a ball extrusion module, a pitch module, and a left-right module mounted on the robot body; wherein, the ball collection basket is positioned above the ball delivery module, and the ball delivery module, ball extrusion module, pitch module, and left-right module are all connected to the controller; the ball delivery module is used to retrieve collected tennis balls from the ball collection basket and deliver the tennis balls to the ball extrusion module, the ball extrusion module is used to extrude the tennis balls to achieve a serve, and the pitch module and left-right module are used to adjust the up-down and left-right directions of the tennis balls extruded by the ball extrusion module.

3. The tennis serving robot according to claim 2, characterized in that, It also includes a hatch module, which is connected to the controller and is used to respond to the user's hatch opening and closing commands to open or close the hatch.

4. The tennis serving robot according to claim 2, characterized in that, The ball extrusion module includes an upper wheel motor, a lower wheel motor, an upper wheel speed sensor, and a lower wheel speed sensor. All of the upper wheel motor, lower wheel motor, upper wheel speed sensor, and lower wheel speed sensor are connected to the controller. The upper wheel speed sensor and lower wheel speed sensor respectively detect the rotational speed of the upper wheel motor and the lower wheel motor, and send the detected rotational speed to the controller. The controller adjusts the rotational speed of the upper wheel motor and the lower wheel motor in real time according to the received rotational speed.

5. The tennis serving robot according to claim 4, characterized in that, The speed of the upper roller of the ball-squeezing roller is determined based on the serve speed, serve spin type, and serve spin magnitude. and the speed of the next wheel They are respectively: ， in, , , , , and They represent the linear fitting coefficients, Indicates the speed of a tennis ball. The serve spin velocity vector is determined by the type of serve spin and the magnitude of the serve spin velocity. The parameters are merged.

6. The tennis serving robot according to claim 2, characterized in that, The pitch module includes a pitch motor and a pitch angle sensor. Both the pitch motor and the pitch angle sensor are connected to the controller. The pitch angle sensor is used to detect the pitch angle of the pitch motor and send it to the controller, which then performs closed-loop control on the pitch motor. The left and right modules include left and right motors and left and right angle sensors. Both the left and right motors and the left and right angle sensors are connected to the controller. The left and right angle sensors are used to detect the left and right angles of the left and right motors and send them to the controller, which then performs closed-loop control on the left and right motors.

7. The tennis serving robot according to claim 1, characterized in that, It also includes a user positioning device that communicates with a controller. The controller, in response to user location information detected by the user positioning device, enters one or more of the following modes: a custom serve mode, a return-to-position running mode, a follow-up battle mode, and a smart step comparison mode. The custom serve mode is configured to perform a custom serve based on the user's custom serve parameters. The return-to-position running mode is configured to initiate a serve when the user has reached the reset point area based on information detected by the user positioning device. The follow-up battle mode is configured to determine the single-ball parameters for the next serve based on information detected by the user positioning device. The smart step comparison mode is configured to compare the running information detected by the user positioning device with a desired running information template. The single-ball parameters include one or more of the following: serve speed, serve spin type, serve spin speed magnitude, arc, left / right orientation, and single-ball interval.

8. The tennis serving robot according to claim 7, characterized in that, The user positioning device includes a main base station, a secondary base station, and a tag, wherein the main base station is installed on the robot body, the secondary base station is installed on the net, and the tag is installed on the user. The tag and the main base station, as well as the tag and the secondary base station, all use electromagnetic wave time-of-flight to achieve ranging, and calculate the tag position based on triangulation to obtain the user's location information.

9. The tennis serving robot according to claim 8, characterized in that, When the secondary base station is set to one, the two solutions for the x-coordinate of the tag in the coordinates of the tennis court are: ， The two solutions for the ordinate of the label in the coordinate system of the tennis court are: ， In the formula, the parameters They are respectively: ， In the formula, and These represent the x and y coordinates of the main base station on the tennis court, respectively. and Let x and y represent the x and y coordinates of the secondary base station on the tennis court, respectively. and Let represent the two solutions for the x-coordinate of the label in the coordinate system of the tennis court. and Let represent the two solutions for the ordinate of the label in the coordinate system of the tennis court. and Both represent intermediate variables. ， In the formula, This represents the two-dimensional distance between the tag and the main base station. This represents the two-dimensional distance between the tag and the secondary base station.

10. The tennis serving robot according to claim 8, characterized in that, When there are two or more secondary base stations, the least squares method is used to solve the over-constrained distance equations to obtain the coordinates of the tag on the tennis court: ， In the formula, and The x and y coordinates of the label on the tennis court are represented by the cosine theorem coefficient matrix. Sum of cosine constant matrix They are respectively: ， ， In the formula, Let represent the coordinates of the i-th secondary base station on the tennis court. This represents the two-dimensional distance between the tag and the i-th secondary base station.

11. The tennis serving robot according to claim 7, characterized in that, In the aforementioned follow-up battle mode, the user positioning device periodically... Obtain user location information The data is then transmitted to the controller, which first determines the offset method and offset distance of the user-configured follow-up battle mode. Obtain the desired angles of the left and right modules, and the desired angles of the left and right modules under forehand offset conditions. for ,in, Given the robot's position on the court, the desired angles of the left and right modules under backhand offset conditions. for ; The robot body obtains the current actual angle of the left and right modules. and speed And combine the remaining time of the serve The motion angles of the left and right modules for this serve were calculated. and ; Compare the expected angles of the left and right modules and motion angle and The relationship, when The target angles of the left and right modules of the serving robot are ;when The target angle of the left and right modules (15) of the serving robot is ;when The target angles of the left and right modules of the serving robot are .

12. The tennis serving robot according to claim 7, characterized in that, In the intelligent comparison mode, the interval between two serves by the serving robot is defined as an analysis cycle. Each serve is defined as having an expected starting area and a hitting area, and the serving time of the serving robot is defined as... The time it takes for the user to exit the expected startup area is The time when the user enters the hitting area is The expected starting zone for the user to enter the next service after hitting the ball is: The next serve will be served at the following time. Four evaluation times are obtained, including: the first waiting time. Startup time Return time Second waiting time ; For the first waiting time Less than This indicates that the user did not have enough time to prepare for the shot; regarding the start time Less than If the time is within a certain range, it indicates that the user's running and hitting ability meets the standard; otherwise, the running and hitting ability is insufficient. Regarding the return time... Less than If the return time is within a certain range, it indicates that the user's return-to-position running ability meets the standard; otherwise, the return-to-position running ability is insufficient. Regarding the second waiting time... Less than If the result is negative, it means the user does not have enough time to prepare for their next shot.

13. A tennis serving system, characterized in that, The system includes a tennis serving robot and a smart racket as described in any one of claims 7-12. The smart racket communicates with a controller, which, in response to the movement trajectory of the smart racket and the collision information between the tennis ball and the smart racket, enters one or more of the following modes: a custom serving mode, a return-to-position running mode, a follow-up battle mode, a smart step comparison mode, a smart racket mode, and a simulated battle mode. The custom serving mode is configured to perform a custom serve based on the user's custom serving parameters. The return-to-position running mode is configured to initiate the serve when the user has reached the reset point area based on information detected by the user positioning device, and to determine the single-ball parameters for the next serve based on the information detected by the user positioning device. The smart step comparison mode is configured to compare the running information detected by the user positioning device with a desired running information template. The smart racket mode is configured to initiate the tennis serving robot's serve when the user's serve is successful based on the collision information between the smart racket and the tennis ball. The simulated battle mode is configured to adjust the single-ball parameters and combination parameters of the tennis serve in real time using the information detected by the user positioning device and the collision information between the smart racket and the tennis ball.

14. The tennis serve system according to claim 13, characterized in that, The smart racket includes a racket body, a rubber sleeve, and a detection module. The detection module is fixed to the end of the handle in the racket body through the rubber sleeve. The detection module is equipped with an inertial measurement unit, which is used to measure the motion trajectory of the racket body and the collision information between the tennis ball and the racket body.

Images