Tennis ball server and control method

Abstract

This invention discloses a tennis ball serving machine and its control method, belonging to the technical field of sports training equipment. The tennis ball serving machine includes: a main body, a motion device, and a support device. The support device includes a support wheel, an extendable support arm assembly, and a drive assembly; the drive assembly includes a DC motor and a first push rod, used to drive the support arm assembly to extend or retract. When the support arm assembly is extended, the support wheel contacts the ground, providing stable support for the moving ball serving machine. This invention also uses a current detection module to monitor the operating current of the DC motor in real time. When the support arm assembly moves to its limit position and abuts against a limit stop, causing the motor to stall and a sudden change in current, the control module determines the position is reached and controls the motor to stop. This invention has an ingenious structure, providing reliable lateral support during the movement of the ball serving machine and preventing tipping.

Description

Technical Field

[0001] This invention relates to the field of sports training equipment technology, and in particular to a ball-serving machine with a balance support frame. Background Technology

[0002] Existing tennis serve machines are typically placed in fixed locations for serve training and cannot move automatically, thus limiting the training range. Although a few movable tennis serve machines have appeared on the market, they are prone to tilting or even tipping over during movement due to changes in the center of gravity or centrifugal force during turning, resulting in poor stability. To solve this problem, some serve machines have attempted to add fixed support wheels, but fixed support wheels occupy a large amount of space when not in use and cannot be adjusted according to actual movement, affecting the compactness and maneuverability of the equipment. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a ball-launching machine with a balanced support frame, which has the characteristics of simple structure, stable movement, reliable control and stable support posture.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A tennis ball serving machine includes: a ball serving machine body, the ball serving machine body including a housing and a ball serving assembly; a motion device, the motion device being used to drive the ball serving machine body to move to a designated position; a support device, the support device including a support wheel, an extendable support arm assembly, and a drive assembly; the drive assembly including a DC motor and a first push rod driven by the DC motor, the first push rod being used to drive the support arm assembly to extend or retract; wherein, when the support arm assembly is extended, the support wheel contacts the ground, providing stable support for the ball serving machine body during movement.

[0006] Furthermore, the support arm assembly includes a second push rod and a third push rod, the second push rod and the third push rod being hinged to each other to form a linkage mechanism, so that the support wheel always maintains an oriented posture in contact with the ground during the unfolding and retraction of the support arm assembly.

[0007] Furthermore, there are two support devices, which are symmetrically arranged on both sides of the main body of the ball-launching machine.

[0008] Furthermore, the tennis ball serving machine also includes: a current detection module for detecting the operating current of the DC motor; and a control module electrically connected to the current detection module and the DC motor, wherein the control module is configured to control the DC motor to stop operating when the change in the operating current exceeds a preset threshold.

[0009] Furthermore, a limiting block is provided on the unfolding or retracting path of the support arm assembly; when the first push rod drives the support arm assembly to move to abut against the limiting block, the DC motor stalls, causing a sudden change in its operating current, which triggers the control module to control the DC motor to stop operating.

[0010] Furthermore, the control module is also configured to: after the DC motor stops operating due to the change in the operating current exceeding a preset threshold, when a control command is received again, control the DC motor to rotate in the opposite direction to drive the first push rod to move in the opposite direction to the current direction of movement.

[0011] Furthermore, the linkage mechanism formed by the second push rod and the third push rod is a pair of parallel quadrilateral linkage mechanisms; the support wheel is mounted on the bottom crossbar of the quadrilateral linkage mechanism; the end of the first push rod is connected to the drive arm of the quadrilateral linkage mechanism, and by pushing the drive arm, the quadrilateral linkage mechanism forms a stable triangular support structure when it is unfolded.

[0012] The present invention also provides a control method for the above-mentioned tennis ball serving machine, comprising the following steps: controlling the DC motor in the support device to rotate forward or in reverse to drive the first push rod to move along a first direction or a second direction, thereby driving the support arm assembly to unfold or retract; during the movement of the DC motor, detecting the operating current of the DC motor in real time; when the change in the operating current exceeds a preset threshold, controlling the DC motor to stop running, at which point the support device has completed the unfolding or retracting action and reached a predetermined position.

[0013] Furthermore, the change in the operating current exceeds the preset threshold because the first push rod drives the support arm assembly to move to the limit position and abuts against the limit block, causing the DC motor to stall and resulting in an increase in current.

[0014] Furthermore, after the DC motor stops operating, the procedure further includes the step of: when a control command is received again, controlling the DC motor to rotate in the opposite direction to drive the first push rod to move in the opposite direction to the current direction of movement, thereby preparing for the next unfolding or retracting action.

[0015] The beneficial effects of the present invention are as follows: by setting an extendable support device, stable support is provided when the ball machine moves, preventing tipping and swaying, and improving the ball serving accuracy; Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a ball-serving machine provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the internal structure of a ball-serving machine provided in an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the internal structure of a ball-serving machine provided in an embodiment of the present invention;

[0020] Figure 4 This is another internal structure diagram of the ball-serving machine provided in an embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of the internal support structure provided in an embodiment of the present invention;

[0022] Figure 6 A flowchart of a control method provided in an embodiment of the present invention.

[0023] In the diagram: 100-Ball machine; 110-Ball machine body; 120-Motion device; 130-Support device; 131-Support wheel; 132-Support base; 133-Second push rod; 134-Third push rod; 135-First push rod; 136-Fixed base; 137-DC motor; 140-Inner support; 141-Inner support body; 142-Stop block. Specific Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0025] Furthermore, the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0026] Please see Figure 1 The present invention provides a tennis ball serving machine 100, which mainly includes three core parts: the ball serving machine body 110, the motion device 120, and the support device 130.

[0027] The ball-serving machine body 110 includes a housing and a ball-serving assembly (not shown) housed within the housing. The ball-serving assembly is used to launch a tennis ball at a certain speed and spin. Its specific structure can be a friction wheel type, compressed air type, or mechanical swing arm type ball-serving mechanism known in the art, and the present invention does not specifically limit it.

[0028] The motion device 120 is installed at the bottom or on both sides of the ball machine body 110 and is used to drive the entire ball machine body 110 to move to a designated position. The motion device 120 may include a drive motor, a transmission mechanism, and wheels, enabling it to move and turn freely on the ground, thereby achieving flexible coverage of the tennis court.

[0029] The support device 130 is also mounted on the main body 110 of the ball-serving machine. Its main function is to provide additional stability support during the movement of the main body 110 of the ball-serving machine driven by the motion device 120, preventing the ball-serving machine from tipping over due to rapid start-stop or turning. The support device 130 includes a support wheel 131, an extendable support arm assembly, and a drive assembly.

[0030] Please refer to the following: Figure 2 The diagram illustrates an internal structure of a ball-serving machine. In this embodiment, the drive assembly of the support device 130 includes a DC motor 137 and a first push rod 135 driven by the DC motor 137. The first push rod 135 is used to drive the support arm assembly to extend or retract.

[0031] Specifically, the support arm assembly includes a second push rod 133 and a third push rod 134. The second push rod 133 and the third push rod 134 are hinged to each other and together form a linkage mechanism. One end of this linkage mechanism is connected to the ball machine body 110 via a fixed base 136, and the other end is connected to the support base 132. The support wheel 131 is mounted on the support base 132.

[0032] When the first push rod 135 extends under the drive of the DC motor 137, it pushes the linkage mechanism consisting of the second push rod 133 and the third push rod 134 to move, causing the entire support arm assembly to unfold away from the main body 110 of the ball machine. After the support arm assembly is unfolded into place, the support wheel 131 contacts the ground, thereby forming a stable support point on the side of the main body 110 of the ball machine, significantly increasing the support span of the whole machine and improving the anti-tipping ability during movement.

[0033] Conversely, when the first push rod 135 retracts, it will drive the linkage mechanism to move, causing the support arm assembly to retract towards the main body 110 of the ball machine, thereby reducing the overall width of the machine and making it easier to store or pass through narrow passages.

[0034] Please see Figure 2 In a preferred embodiment, the linkage mechanism formed by the second push rod 133 and the third push rod 134 is designed to ensure that the support wheel 131 always maintains an oriented posture in contact with the ground. That is, throughout the entire stroke of the support arm assembly's extension and retraction, regardless of the angle of the linkage mechanism, the axis of the support wheel 131 remains approximately horizontal, and the wheel surface always faces perpendicularly to the ground. This can be achieved by precisely designing the length ratio of the second push rod 133 and the third push rod 134, as well as the position of the hinge point, ensuring that the support wheel 131 can effectively roll and support in any extended position, rather than touching the ground with its rim, thus improving stability and smoothness of movement.

[0035] In one specific embodiment, the linkage mechanism formed by the second push rod 133 and the third push rod 134 is specifically a pair of parallel quadrilateral linkage mechanisms. The support wheel 131 is mounted on the bottom crossbar of the quadrilateral linkage mechanism; the end of the first push rod 135 is connected to the drive arm of the quadrilateral linkage mechanism. When the first push rod 135 pushes the drive arm, the entire quadrilateral linkage mechanism moves, and when fully extended, its geometry forms a stable triangular support structure. This structure fully utilizes the principle of triangle stability, giving the support arm assembly higher rigidity and resistance to deformation under load, further improving the reliability of the support.

[0036] For a preferred implementation, please refer to Figure 1 The support devices 130 are two in number, symmetrically arranged on both sides of the ball machine body 110. This symmetrical layout ensures that the ball machine experiences balanced forces on both sides during movement, providing stable lateral support whether moving forward, backward, or turning, effectively preventing lateral tilting.

[0037] To achieve automated control of the deployment and retraction of the support device and to accurately determine whether the action is in place, this invention introduces a closed-loop control scheme based on current detection.

[0038] Please see Figure 3 and combined Figure 4 The ball-launching machine 100 also includes a current detection module (not shown) and a control module (not shown). The current detection module is electrically connected to the DC motor 137 and is used to detect the operating current of the DC motor 137 in real time. The control module is electrically connected to both the current detection module and the DC motor 137.

[0039] Please see Figure 4 and Figure 5Inside the ball-serving machine body 110, specifically on the inner support 140, there is a limiting block 142. The inner support 140 includes an inner support body 141, and the limiting block 142 is fixedly mounted on the inner support body 141 and located on the movement path of the first push rod 135 or its driving component.

[0040] When the control module issues a command to control the DC motor 137 to rotate forward, driving the first push rod 135 to move along a first direction (e.g., the extension direction) to unfold the support arm assembly, the first push rod 135 will drive the related transmission components to move. When the support arm assembly is unfolded to the preset maximum position, the first push rod 135 or its linked components will abut against the limit stop 142. At this time, the mechanical movement is forcibly stopped, the DC motor 137 cannot continue to rotate, and a stall phenomenon occurs.

[0041] Due to stall, the current of DC motor 137 will increase sharply. The current detection module detects this sudden change in operating current (i.e., the current change exceeds a preset threshold) and transmits the signal to the control module in real time. After determining the current change, the control module immediately controls DC motor 137 to stop operating. At this time, the support arm assembly is exactly in the fully extended state, that is, it has reached the predetermined position.

[0042] Similarly, when the DC motor 137 is controlled to rotate in the opposite direction, driving the first push rod 135 to move in the second direction (e.g., the retraction direction) to retract the support arm assembly, the first push rod 135 will also abut against another limit block (not shown) when it retracts to the limit position, causing the DC motor 137 to stall and the current to change suddenly. The control module then controls the motor to stop, completing the retraction action.

[0043] This method of determining mechanical positioning by detecting changes in current eliminates the need for additional position detection components such as limit switches and photoelectric sensors, simplifying the structure, reducing costs, and offering high reliability.

[0044] As a further improvement to the above embodiments, the control module also includes stall detection and shutdown protection logic. During the movement of the first push rod 135 driven by the DC motor 137, when the support arm assembly moves to its extended or retracted limit position, the first push rod 135 or the corresponding part on the support arm assembly will abut against the limit stop 142. At this time, the DC motor 137 stalls, and the operating current changes abruptly. After the current detection module 136 detects that the current change exceeds a preset threshold, the control module 138 controls the DC motor 137 to stop operating, thereby achieving stop protection at the designated position and preventing damage to the motor and transmission mechanism due to continuous stalling.

[0045] In addition, the control module 138 also has reverse control logic. When the DC motor 137 stops operating due to the aforementioned sudden current change, the control module 138 records the current stop state; when it receives a control command again, the control module 138 controls the DC motor 137 to rotate in the opposite direction, so as to drive the first push rod 135 to move in the opposite direction to the current direction of movement, thereby preparing for the next unfolding or retracting action.

[0046] Please see Figure 6 The present invention also provides a control method for the tennis ball serving machine described in any of the above claims. This method embodies the core control logic of the present invention and specifically includes the following steps:

[0047] Step S1: Start the drive. Control the DC motor 137 in the support device 130 to rotate in the forward or reverse direction to drive the first push rod 135 to move in the first or second direction, thereby driving the support arm assembly to unfold or retract.

[0048] Step S2: Current detection. Throughout the entire movement of the DC motor 137, the operating current of the DC motor 137 is detected in real time through the current detection module.

[0049] Step S3: Position Determination and Stop. The real-time detected operating current is compared with a preset reference current. When the change in operating current (usually the instantaneous increase in current) exceeds a preset threshold, it is determined that the support arm assembly has moved to its limit position (i.e., fully extended or fully retracted). At this point, the DC motor 137 is immediately stopped. Thus, the support device has completed its extension or retraction action and reached the predetermined position.

[0050] Preferably, the change in operating current exceeding a preset threshold is due to the first push rod 135 driving the support arm assembly to move to its limit position and abutting against the limit stop 142, causing the DC motor 137 to stall and resulting in an increase in current. This sudden change in current is obvious and easy to detect and judge.

[0051] Step S4: Reverse Reset (Preferred Step). After the DC motor 137 stops operating due to a sudden current change, upon receiving a control command again, the DC motor 137 is controlled to rotate in the reverse direction to drive the first push rod 135 to move in the opposite direction to the current direction of movement. This disengages the transmission component from the contact state with the limit block 142, preparing for the next unfolding or retracting action. This step effectively prevents the transmission mechanism from being under stress for extended periods, protecting the transmission mechanism and extending its service life.

[0052] The control method of this invention determines whether the support device has reached the deployment or retraction endpoint by detecting changes in the operating current of the DC motor. This eliminates the need for additional sensors or limit switches, greatly simplifying the equipment structure and control logic, and reducing manufacturing costs. Furthermore, it utilizes the significant current increase during DC motor stall to determine the endpoint, ensuring accurate and reliable judgment.

[0053] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0054] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A tennis ball serving machine, characterized in that, include: The ball-serving machine body includes a housing and a ball-serving assembly; A motion device, the motion device being used to drive the ball-serving machine body to move to a designated position; A support device, the support device including a support wheel, an extendable support arm assembly and a drive assembly; The drive assembly includes a DC motor and a first push rod driven by the DC motor, the first push rod being used to drive the support arm assembly to expand or retract. When the support arm assembly is deployed, the support wheel contacts the ground, providing stability support for the ball-launching machine body during movement.

2. The tennis ball serving machine according to claim 1, characterized in that, The support arm assembly includes a second push rod and a third push rod. The second push rod and the third push rod are hinged to each other and form a linkage mechanism so that the support wheel always maintains an oriented posture in contact with the ground during the unfolding and retraction of the support arm assembly.

3. The tennis ball serving machine according to claim 1 or 2, characterized in that, There are two support devices, which are symmetrically arranged on both sides of the ball-serving machine body.

4. The tennis ball serving machine according to claim 1, characterized in that, Also includes: A current detection module is used to detect the operating current of the DC motor; The control module is electrically connected to the current detection module and the DC motor respectively. The control module is configured to control the DC motor to stop operating when the change in the operating current exceeds a preset threshold.

5. The tennis ball serving machine according to claim 4, characterized in that, The support arm assembly is provided with a limiting block on its unfolding or retracting path; When the first push rod drives the support arm assembly to move to abut against the limit block, the DC motor stalls, causing a sudden change in its operating current, which triggers the control module to control the DC motor to stop operating.

6. The tennis ball serving machine according to claim 5, characterized in that, The control module is also configured to: after the DC motor stops operating due to the change in the operating current exceeding a preset threshold, when a control command is received again, control the DC motor to rotate in the opposite direction so as to drive the first push rod to move in the opposite direction to the current direction of movement.

7. The tennis ball serving machine according to claim 2, characterized in that, The linkage mechanism formed by the second push rod and the third push rod is a pair of parallel quadrilateral linkage mechanisms; the support wheel is mounted on the bottom crossbar of the quadrilateral linkage mechanism; The end of the first push rod is connected to the drive arm of the quadrilateral linkage mechanism. By pushing the drive arm, the quadrilateral linkage mechanism forms a stable triangular support structure when it is deployed.

8. A control method for a tennis ball-serving machine according to any one of claims 1 to 7, characterized in that, Includes the following steps: Control the DC motor in the support device to rotate in the forward or reverse direction to drive the first push rod to move in the first or second direction, thereby driving the support arm assembly to unfold or retract. During the operation of the DC motor, the operating current of the DC motor is detected in real time. When the change in the operating current exceeds a preset threshold, the DC motor is controlled to stop operating. At this time, the support device has completed the unfolding or retracting action and reached the predetermined position.

9. The control method according to claim 8, characterized in that, The change in operating current exceeds the preset threshold because the first push rod drives the support arm assembly to move to the limit position and abuts against the limit block, causing the DC motor to stall and resulting in an increase in current.

10. The control method according to claim 9, characterized in that, After the DC motor stops operating, the following steps are also included: When a control command is received again, the DC motor is controlled to rotate in the opposite direction to drive the first push rod to move in the opposite direction to the current direction of movement, thereby preparing for the next unfolding or retracting action.

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