Working principle of the most popular simple tenni

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Working principle of simple ball serving machine

working principle of simple ball serving machine

the simple ball serving machine proposed in this paper is a comprehensive technical product integrating electronic, mechanical and computer technology. The basic principle of serving is to use the principle of single wheel friction, which is mainly composed of friction wheels and fixed raceways, and the gap between friction wheels and raceways is slightly smaller than the diameter of the ball; The friction wheel is driven by a DC motor

in the raceway, the ball is simultaneously squeezed by the rotating friction wheel and the friction force of the high-speed rotation of the friction wheel. When the ball leaves the raceway, it will obtain a certain initial speed, so as to launch the ball. This principle scheme is simple and practical, which can not only ensure the stability of the ball launch, but also control the frequency and speed of the ball launch, so that the Michelin company says that the learners can practice playing at will

3.1 analysis of ball motion types

assuming that the ball is a rigid body, the force generated by its compression is regarded as an external constant force when it runs in the raceway. In the raceway, the ball rolls downward along the raceway curve. The normal force Ⅳ L and friction of the ball are acted on by the gravity raceway surface, and the pressure Ⅳ 2 and friction of the roller acting on the ball. Due to the deformation caused by the extrusion of the contact surface between the ball and the raceway, the effective action point of the support deviates from the axis by a small distance. Because the simple ball serving machine can only launch the topspin ball, the force analysis of the ball model when it runs in the orbit

when the ball is pure rolling in the raceway, assuming that the force generated by its compression in the raceway is acted by the external constant force F, the ball's center of mass speed and rotation angle will change, resulting in static friction.

3.2 ball motion analysis

in fact, the ball's motion in the air is relatively complex, involving many factors. If all of them are considered, the problem will become complex. Therefore, when considering the law of ball motion, we should ignore the secondary factors and only consider the primary factors. Therefore, in the calculation, the movement of the ball in the air can be regarded as the movement in the truth,

45. Projection angle. At this time, the ejection height h is one fourth of the ejection distance D. In the field experiment, because the bounce height of the ball is high, the practitioner has a sense of discomfort in catching the ball, so it is changed to 30. Launch, although the range becomes shorter, but because the speed of the DC motor is fast enough, it can still meet the needs of the practitioners. After field experiment, 45. The service distance can reach 10 m, 30. The service distance can also be more than 8m, which can meet the requirements of serving half the court and meet the needs of practice

4 design of ball picking mechanism

the design scheme of ball picking mechanism is an innovative design based on the products and relevant patents of ball picking mechanisms at home and abroad and their advantages and disadvantages. Its basic principle is similar to the principle of serving, which is to use friction to pick up the ball

the ball is driven by the internal drum 1, rises to the top of the drum, and rolls obliquely downward into the ball receiving box to achieve the purpose of ball collection

through the design of the auxiliary ball gathering mechanism and considering the connection and assembly with the vehicle body as a whole, the driving wheel of the ball picking mechanism is directly integrated with the vehicle body, striving to use 3 to 5 years to reduce the overall size, and also using the forward power of the vehicle to drive the internal drum to rotate, so as to realize ball picking. In this way, while it is convenient to pick up the ball, it can save electric energy and concentrate the energy of the battery to launch the ball, so as to truly help the ball training

5 hardware circuit design of simple ball serve machine

the controller of simple ball serve machine adopts 8-bit singlechip 8. Nearly all aviation and aerospace flights adopt chemical drive 9s51121 as the core microprocessor, and the peripheral expansion circuit includes motor drive circuit and remote control circuit. Through software programming, the output signal is generated to control PWM and sent to the DC motor through the driving circuit. At the same time, the service speed, frequency, etc. are set. The remote control transmitting and receiving circuit is used to remotely control the intelligent ball service machine

because the control system needs to use analog signal to control PWM module, this paper uses single-chip microcomputer system to control the output of analog signal. The MCU system control board is mainly composed of the following chips: at89s5 1 chip, 74hc74 frequency divider, 74ls373 address latch, 64K program memory 27512, a/D conversion chip ADC0809, D/a conversion chip DAC0832, serial chip MAX232, etc

due to the different ball and water armours of the practitioners, the speed of hitting the ball is also different. In the aspect of software design, this paper designs several modes for this situation. The exercisers can use the remote controller in the to control the serve machine and choose the mode suitable for their own level

the main software functions to be realized in the design of the simple ball and serve machine control system: the system controls the output analog signal to control the PWM module, the program design and the start and stop frequency of the small motor

6 overall structure design

in order to facilitate the use of the trainers, this paper connects the serve machine and the ball picking machine through the car body, and uses the ball picking machine to pick up the scattered balls in the process of cycling. After the ball is poured into the serve machine, the remote controller can control the launch of the ball and practice the ball

people drive the rear wheel through the pedal of the car, drive the front wheel to rotate, transfer the rotating power to the drum of the ball picking machine, drive the ball to roll upward, collect the ball into the ball receiving box, and realize ball picking. The tee, relevant control circuit and power supply are fixed at the back of the car and driven by the car, which is convenient for unified management.. Through the field experiment, the ball cart designed in this paper can achieve the expected functions of picking up and serving the ball, and achieve a more satisfactory effect

7 conclusion

because some electronic parts and circuit boards are very sensitive to static electricity

the research content of this subject is to improve and innovate the existing ball serving machine and ball picking machine, and make corresponding theoretical analysis on their overall design, so as to make their structure as simple and easy to control as possible, provide convenience for ball lovers, and meet the needs of China's low-end market

through the above work, it is proved that the design of intelligent ball car is completely feasible. Of course, in order to improve the performance indicators of the serve mechanism and the pick-up mechanism, it needs to be further discussed and studied in the future

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