Modelling and characterisation of a vibration sensor on string

• Main Author: Neo, Sean Xuan Wei
• Other Authors: Lye Sun Woh
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/78643
• Institution: Nanyang Technological University

The project aims to enhance current methods of locating point of impacts between the ball and the tennis racket. The enhancement includes the use of piezoelectric sensors which could potentially assist manufacturers in introducing new racket sensors and improve tennis players’ understanding of the game. Experiments are conducted to: understand string bed characteristics of the racket upon an impact; test the responsiveness of the piezoelectric sensors to detect impact force by balls on the racket at different impact points; measure the change in voltage output signals by sensors at different impact points; study the characteristics of the change in voltage output signals by sensors to determine the impact points. By using change in voltage readings, the results show that sensors are effective in detecting the time of impact as well as the number of hits between the ball and the racket. It is also evident that the significance of an impact is dependent on the proximity from the impact point. The nearer the impact points are to the sensors, the greater the change in tension experienced by the sensors attached to the strings, and thus a greater change in voltage value. This is pivotal for understanding the change in voltage trends observed and to identify impact points in the middle section of the racket. Due to the structure of the racket frame, the stiffness of strings nearer to its circumference also seemed to be higher. This accounts for the change in voltage trends seen when impact points are along the sides of the racket.