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Implementation of a PLC-based Pitching System capable of Pitching a Breaking Ball

변화구 투구가 가능한 PLC기반의 피칭 시스템 구현

  • Kim, Min-Kyu (Department of Automation System, Korea Polytechnics)
  • 김민규 (한국폴리텍대학 자동화시스템과)
  • Received : 2018.09.03
  • Accepted : 2018.09.14
  • Published : 2018.11.30

Abstract

Recently, interest in baseball has been increasing as the level of international baseball games, the popularity of domestic leagues, and the number of players entering the MLB has increased. In this paper, we propose a pitching system that can be applied to both professional and amateur baseball. The pitching system consists of a control module using MSB764T PLC, a pitching mechanism including AC motors and a ball feed rail, an HMI using the CHA-070WR model, inverter, etc. To pitch the breaking balls, the two AC motors each use an inverter to independently control the speed. The implemented pitching system was experimented on, investigating ball speed and ball movement according to RPM using the BUSHNELL Velocity Speed Gun. Experimental results on ball speed are similar to the theoretical data and the measured data. From the experimental data, it is confirmed that the damping coefficient value for the pitching ball is about 0.98. In the case of the breaking ball, the larger the difference between the speeds on the sides of the ball and the faster the ball speed, the larger the bending degree.

Keywords

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Fig. 1. Concept of pitching machine to implement.

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Fig. 2. Schematic of control module including PLC, inverter, and relay.

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Fig. 3. Ladder program for PLC control.

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Fig. 4. Photograph of UI implemented in HMI.

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Fig. 5. Components of mechanism part (a) rotating wheel, (b) solenoid actuator.

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Fig. 6. Principle of magnus effect on pitching ball.

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Fig. 7. Experimental data of breaking ball (a) definition of movement, (b) movement of the ball.

Table 1. Comparison of theoretical and measured data on ball speed.

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