Tennis training robot serving track control method

Abstract

A tennis training robot serving track control method belongs to the technical field of serving equipment. The problem that an existing pitching machine can not meet the requirements of a user for specific drop points and tracks when pitching according to a preset mode is solved. A corresponding yaw angle, an optimal launching speed and an optimal pitch angle are generated according to input given target drop point coordinates and given target net passing height, and corresponding control signals are generated according to the yaw angle, the optimal launching speed and the optimal pitch angle to control a yaw motor, a friction wheel motor and a pitch motor of the training machine. Therefore, the serving track is controlled at a given target drop point and a given target net passing height. The method is mainly used for ball serving track control of the tennis training machine.

Description

Technical Field

[0001] The invention belongs to the technical field of ball serving equipment. Background Art

[0002] Currently, traditional ball machines mainly control the landing point of the tennis ball by adjusting the pitch, yaw, and speed manually or according to preset points, but this method still has shortcomings. First, the manual adjustment process is cumbersome, requiring the operator to constantly try and error to roughly achieve the desired landing point, which greatly reduces training efficiency. Second, although it has certain automation functions, most of these functions are based on simple preset programs and cannot be flexibly adjusted according to the user's real-time input. For example, some ball machines can launch balls at different speeds and directions through preset programs, but these preset modes cannot meet the user's needs for specific landing points and trajectories. In addition, traditional ball machines have a poor user interaction experience, and the operation is complicated and not intuitive enough, which reduces the user's enthusiasm and user experience during training. Therefore, the above problems need to be solved urgently. Summary of the Invention

[0003] The present invention aims to solve the problem that the existing ball-serving machine cannot meet the user's requirements for specific landing points and trajectories by serving according to a preset mode. The present invention now provides a method for controlling the serving trajectory of a tennis training robot.

[0004] A tennis training robot serving trajectory control method comprises the following steps:

[0005] S1, according to the given target landing point coordinates , calculate the yaw angle The distance between the given target landing point and the tennis training robot , where the tennis training robot is the coordinate origin;

[0006] According to the given target net height , launch port height The distance between the tennis training robot and the net , get the pitch angle The initial value of

[0007] S2, at pitch angle Initialize the maximum speed V under the initial value of max and minimum speed V min , and combined with the maximum speed V max and minimum speed V min The distance between the corresponding landing point and the tennis training robot, and the maximum speed V max and minimum speed V min The height of the net under and The relationship between them is used to search for the optimal launch speed;

[0008] S3, at the optimal launch speed, according to and Optimizing the pitch angle using an iterative method , obtain the optimal pitch angle;

[0009] S4, according to the yaw angle , the optimal launch speed and the optimal pitch angle generate corresponding control signals to control the yaw motor, friction wheel motor and pitch motor of the tennis training robot respectively, so as to realize the control of the serving trajectory under a given target landing point and a given target net crossing height.

[0010] Preferably, the pitch angle The initial value is .

[0011] Preferably, in S2, at the pitch angle Initialize the maximum speed V under the initial value of max and minimum speed V min , and combined with the maximum speed V max and minimum speed V min The distance between the corresponding landing point and the tennis training robot, and the maximum speed V max and minimum speed V min The height of the net under and The relationship between them can be used to search for the optimal launch speed. The implementation methods include:

[0012] S21, at the pitch angle Initialize the maximum speed V under the initial value of max and minimum speed V min , and calculate the maximum speed V max The distance between the corresponding landing point and the tennis training robot and mesh height , minimum speed V min The distance L2 between the corresponding landing point and the tennis training robot and the height over the net , and make exist and between;

[0013] S22, take the maximum speed V max and minimum speed V min The intermediate value between the two is the intermediate speed V mid , and calculate the intermediate speed V mid The distance between the corresponding landing point and the tennis training robot and mesh height ;

[0014] S23, determine whether the Allowable error, and Allowable error, the result is yes, then the intermediate speed V mid The value of is output as the optimal transmission speed. If the result is no, execute step S24;

[0015] S24, determine whether , the result is yes, proving exist and At this time, the intermediate speed V mid The value of is assigned to the minimum speed V min , return to step S22, the result is no, exist and At this time, the intermediate speed V mid The value of is assigned to the maximum speed V max , return to step S22.

[0016] Preferably, in step S3, at the optimal transmission speed, according to and Optimizing the pitch angle using an iterative method , the optimal pitch angle can be achieved as follows:

[0017] S31. Get pitch angle The distance between the landing point and the tennis training robot corresponding to the optimal launch speed and mesh height ,

[0018] S32, determine whether the Allowable error, and Allowable error, the result is yes, the current pitch angle The value of is output as the optimal pitch angle, if the result is no, execute step S33; and All are intermediate variables;

[0019] S33, according to Get the angle correction , is the preset step size, let , return to step S31.

[0020] Preferably, in S33, according to Get the angle correction The implementation methods include:

[0021] S331, obtain pitch angle The distance between the landing point and the tennis training robot corresponding to the optimal launch speed and mesh height ;

[0022] S332, calculation - About pitch angle The first derivative M of - About pitch angle The first derivative N;

[0023] S333, according to M, N, and , get the angle correction .

[0024] Preferably, /

[0025] Preferably, the pitch angle variable is calculated Next, the speed variable The corresponding landing point and net height are achieved as follows:

[0026] According to the speed variable , calculate the air resistance of tennis ;

[0027] Calculate the Magnus force based on the velocity variable V ;

[0028] according to and , calculate the acceleration of the velocity variable V in the x and y directions and ;

[0029] At pitch angle Next, according to the speed variable and acceleration and The fourth-order Runge-Kutta method is used to solve the landing point coordinates and net-crossing height corresponding to the velocity variable V;

[0030] in, or , .

[0031] Preferably, the pitch angle is calculated Calculate the acceleration of the velocity variable V in the x and y directions. and The implementation is:

[0032] ;

[0033] ;

[0034] ;

[0035] ;

[0036] in, is the air density, is the drag coefficient, is the cross-sectional area of ​​the tennis ball, | | is the modulo operation, is the Magnus coefficient, is the angular velocity of rotation, is the acceleration due to gravity, Tennis quality.

[0037] A computer-readable storage device stores a computer program, and when the computer program is executed, the serving trajectory control method of a tennis training robot is implemented.

[0038] A computer program product includes a computer program. When the computer program is executed by a processor, a method for controlling the serving trajectory of a tennis training robot is implemented.

[0039] Beneficial effects of this application:

[0040] The present invention provides a method for controlling the serving trajectory of a tennis training robot to realize the intelligent selection of the tennis training robot, and generates a corresponding yaw angle according to the input given target landing point coordinates and given target net height. , optimal launch speed, and optimal pitch angle. Based on these three parameters, the system generates corresponding control signals to control the trainer's yaw motor, friction wheel motor, and pitch motor, respectively. This allows the trainer to control the trajectory of the serve at a given target landing point and net height. By inputting landing point coordinates and net height to meet user needs, multi-mode training is possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a flowchart of a method for controlling the serving trajectory of a tennis training robot. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0044] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0045] Specific implementation method 1. Figure 1 The present embodiment describes a method for controlling the serving trajectory of a tennis training robot, which includes the following steps:

[0046] S1, according to the given target landing point coordinates , calculate the yaw angle The distance between the given target landing point and the tennis training robot , where the tennis training robot is the coordinate origin;

[0047] According to the given target net height , launch port height The distance between the tennis training robot and the net , get the pitch angle The initial value of; specifically, the pitch angle The initial value is ;

[0048] S2, at pitch angle Initialize the maximum speed V under the initial value of max and minimum speed V min , and combined with the maximum speed V max and minimum speed V min The distance between the corresponding landing point and the tennis training robot, and the maximum speed V max and minimum speed V min The height of the net under and The relationship between them is used to search for the optimal launch speed;

[0049] S3, at the optimal launch speed, according to and Optimizing the pitch angle using an iterative method , obtain the optimal pitch angle;

[0050] S4, according to the yaw angle , the optimal launch speed and the optimal pitch angle generate corresponding control signals to control the yaw motor, friction wheel motor and pitch motor of the tennis training robot respectively, so as to realize the control of the serving trajectory under a given target landing point and a given target net crossing height.

[0051] The present invention can control the trajectory of the serve by inputting a given target net height and a given target landing point coordinate, which reduces the user's adjustment time, improves the user's experience, and meets the user's needs for specific landing points and trajectories.

[0052] In specific applications, the coordinate system of the given target landing point coordinates takes the training machine as the coordinate origin, and the launch port of the tennis training robot is directed towards the y-axis direction, and the horizontal direction perpendicular to the y-axis direction is the x-axis direction.

[0053] In specific applications, intelligent control is adopted. Users input the given target net-crossing height and the given target landing point coordinates through an intermediate device, which greatly enhances the human-computer interaction experience and makes the training process easier and more enjoyable. The intermediate device can be a remote control.

[0054] Furthermore, in S2, at the pitch angle Initialize the maximum speed V under the initial value of max and minimum speed V min , and combined with the maximum speed V max and minimum speed V min The distance between the corresponding landing point and the tennis training robot, and the maximum speed V max and minimum speed V min The height of the net under and The relationship between them can be used to search for the optimal launch speed. The implementation methods include:

[0055] S21, at the pitch angle Initialize the maximum speed V under the initial value of max and minimum speed V min , and calculate the maximum speed V max The distance between the corresponding landing point and the tennis training robot and mesh height , minimum speed V min The distance L2 between the corresponding landing point and the tennis training robot and the height over the net , and make exist and between;

[0056] S22, take the maximum speed V max and minimum speed V min The intermediate value between them is taken as the intermediate speed V mid , and calculate the intermediate speed V mid The distance between the corresponding landing point and the tennis training robot and mesh height ;

[0057] S23, determine whether the Allowable error, and Allowable error, the result is yes, then the intermediate speed V mid The value of is output as the optimal transmission speed. If the result is no, execute step S24;

[0058] S24, determine whether , the result is yes, proving exist and At this time, the intermediate speed V mid The value of is assigned to the minimum speed V min , return to step S22, the result is no, exist and At this time, the intermediate speed V mid The value of is assigned to the maximum speed V max , return to step S22.

[0059] In this preferred embodiment, a maximum speed and a minimum speed are set, and the corresponding landing points of these two speeds are calculated respectively, ensuring that the two corresponding landing points are on both sides of the target landing point. The intermediate value of the maximum and minimum speeds is taken to calculate the landing point corresponding to the intermediate speed. Given the maximum speed landing point, the minimum speed landing point, and the intermediate speed landing point, it is determined which two speeds the target landing point is between. The corresponding maximum or minimum speed is then updated using the intermediate speed until the landing point deviation and the mesh height deviation corresponding to the intermediate speed meet the allowable error. The intermediate speed is then used as the optimal launch speed to complete the search. This search method has the effect of quickly converging when calculating the optimal launch speed, reducing the amount of calculation.

[0060] Furthermore, in step S3, at the optimal transmission speed, according to and Optimizing the pitch angle using an iterative method , the optimal pitch angle can be achieved as follows:

[0061] S31. Get pitch angle The distance between the landing point and the tennis training robot corresponding to the optimal launch speed and mesh height ,

[0062] S32, determine whether the Allowable error, and Allowable error, the result is yes, the current pitch angle The value of is output as the optimal pitch angle, if the result is no, execute step S33; and All are intermediate variables;

[0063] S33, according to Get the angle correction , is the preset step size, let , return to step S31.

[0064] This preferred method for obtaining the optimal pitch angle has a fast convergence speed and high accuracy. The angle correction used in each round of pitch angle update is The advantage is that the optimization angle can be continuously updated according to the calculation results.

[0065] Specifically, in S33, according to Get the angle correction The implementation methods include:

[0066] S331, obtain pitch angle The distance between the landing point and the tennis training robot corresponding to the optimal launch speed and mesh height ;

[0067] S332, calculation - About pitch angle The first derivative M of - About pitch angle The first derivative N;

[0068] S333, according to M, N, and , get the angle correction .

[0069] Specific /

[0070] In this preferred embodiment, the angle correction value is obtained by A specific implementation method of , which has the advantage of approximating the nonlinear equation to a linear equation to solve, and can gradually approach the optimal pitch angle.

[0071] Furthermore, a general calculation method is given to calculate the speed variable The corresponding landing point and net height can realize the calculation of the corresponding landing point and net height under any set of pitch angles and speeds. As an example, the calculation of the pitch angle variable is given. Next, the speed variable The corresponding landing point and net height are achieved as follows:

[0072] According to the speed variable , calculate the air resistance of tennis ;

[0073] Calculate the Magnus force based on the velocity variable V ;

[0074] according to and , calculate the acceleration of the velocity variable V in the x and y directions and ; Specifically,

[0075] ;

[0076] ;

[0077] ;

[0078] ;

[0079] in, is the air density, is the drag coefficient, is the cross-sectional area of ​​the tennis ball, | | is the modulo operation, is the Magnus coefficient, is the angular velocity of rotation, is the acceleration due to gravity, Tennis quality.

[0080] At pitch angle Next, according to the speed variable and acceleration and The fourth-order Runge-Kutta method is used to solve the landing point coordinates and net-crossing height corresponding to the velocity variable V;

[0081] in, or , .

[0082] In this preferred embodiment, the acceleration in the x and y directions corresponding to the velocity variable V is obtained. and When calculating the acceleration in the x and y directions, factors existing in the real environment such as gravity, air resistance and Magnus force are taken into account, and the acceleration in the x and y directions is more accurate, providing an accurate data basis for the subsequent calculation of the landing point coordinates and the height over the net.

[0083] Specific embodiment 2: A computer-readable storage device stores a computer program, and when the computer program is executed, the serving trajectory control method of the tennis training robot is implemented.

[0084] Specific embodiment 3: A computer program product includes a computer program, which implements the serving trajectory control method of a tennis training robot when executed by a processor.

[0085] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be employed in conjunction with other described embodiments.

Claims

1. A tennis training robot serving trajectory control method, characterized in that: The method comprises the following steps: S1, according to the given target landing point coordinates , calculate the yaw angle The distance between the given target landing point and the tennis training robot , where the tennis training robot is the coordinate origin; According to the given target net height , launch port height The distance between the tennis training robot and the net , get the pitch angle The initial value of S2, at pitch angle Initialize the maximum speed V under the initial value of max and minimum speed V min , and combined with the maximum speed V max and minimum speed V min The distance between the corresponding landing point and the tennis training robot, and the maximum speed V max and minimum speed V min The height of the net under and The relationship between them is used to search for the optimal launch speed; S3, at the optimal launch speed, according to and Optimizing the pitch angle using an iterative method , obtain the optimal pitch angle; S4, according to the yaw angle , the optimal launch speed and the optimal pitch angle generate corresponding control signals to control the yaw motor, friction wheel motor and pitch motor of the tennis training robot respectively, so as to realize the control of the serving trajectory under a given target landing point and a given target net crossing height.

2. The tennis training robot serving trajectory control method according to claim 1, characterized in that: Pitch angle The initial value is .

3. The tennis training robot serving trajectory control method according to claim 1, characterized in that: In S2, at the pitch angle Initialize the maximum speed V under the initial value of max and minimum speed V min , and combined with the maximum speed V max and minimum speed V min The distance between the corresponding landing point and the tennis training robot, and the maximum speed V max and minimum speed V min The height of the net under and The relationship between them can be used to search for the optimal launch speed. The implementation methods include: S21, at the pitch angle Initialize the maximum speed V under the initial value of max and minimum speed V min , and calculate the maximum speed V max The distance between the corresponding landing point and the tennis training robot and mesh height , minimum speed V min The distance L2 between the corresponding landing point and the tennis training robot and the height over the net , and make exist and between; S22, take the maximum speed V max and minimum speed V min The intermediate value between the two is the intermediate speed V mid , and calculate the intermediate speed V mid The distance between the corresponding landing point and the tennis training robot and mesh height ; S23, determine whether the Allowable error, and Allowable error, the result is yes, then the intermediate speed V mid The value of is output as the optimal transmission speed. If the result is no, execute step S24; S24, determine whether , the result is yes, proving exist and At this time, the intermediate speed V mid The value of is assigned to the minimum speed V min , return to step S22, the result is no, exist and At this time, the intermediate speed V mid The value of is assigned to the maximum speed V max , return to step S22.

4. The tennis training robot serving trajectory control method according to claim 1, characterized in that: In step S3, at the optimal transmission speed, according to and Optimizing the pitch angle using an iterative method , the optimal pitch angle can be achieved as follows: S31. Get pitch angle The distance between the landing point and the tennis training robot corresponding to the optimal launch speed and mesh height , S32, determine whether the Allowable error, and Allowable error, the result is yes, the current pitch angle The value of is output as the optimal pitch angle, if the result is no, execute step S33; and All are intermediate variables; S33, according to Get the angle correction , is the preset step size, let , return to step S31.

5. The tennis training robot serving trajectory control method according to claim 4, characterized in that: In S33, according to Get the angle correction The implementation methods include: S331, obtain pitch angle The distance between the landing point and the tennis training robot corresponding to the optimal launch speed and mesh height ; S332, calculation - About pitch angle The first derivative M of - About pitch angle The first derivative N; S333, according to M, N, and , get the angle correction .

6. The serving trajectory control method of a tennis training robot according to claim 5, characterized in that: / 。 7. The method for controlling the serving trajectory of a tennis training robot according to claim 1, 3, 4 or 5, wherein: Calculate the pitch angle variable Next, the speed variable The corresponding landing point and net height are achieved as follows: According to the speed variable , calculate the air resistance of tennis ; Calculate the Magnus force based on the velocity variable V ; according to and , calculate the acceleration of the velocity variable V in the x and y directions and ; At pitch angle Next, according to the speed variable and acceleration and The fourth-order Runge-Kutta method is used to solve the landing point coordinates and net-crossing height corresponding to the velocity variable V; in, or , .

8. The serving trajectory control method of a tennis training robot according to claim 7, characterized in that: Calculating pitch angle Calculate the acceleration of the velocity variable V in the x and y directions. and The implementation is: ； ； ； ； in, is the air density, is the drag coefficient, is the cross-sectional area of ​​the tennis ball, | | is the modulo operation, is the Magnus coefficient, is the angular velocity of rotation, is the acceleration due to gravity, Tennis quality.

9. A computer-readable storage device, characterized in that: The storage device stores a computer program, wherein the computer program, when executed, implements the serving trajectory control method of a tennis training robot according to any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the serving trajectory control method of a tennis training robot as claimed in claims 1 to 6 is implemented.

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