[Retracted] Research on Optimal Control Method of Tennis Racket String Diameter Based on Kalman Filter Algorithm

Table 6

Vibration frequency of racket swing in different string diameter groups.

NO	16L polyester thread	No. 18 polyester thread	NO	16L polyester thread	No. 18 polyester thread	NO	16L polyester thread	No. 18 polyester thread
1	40.13	40.66	17	39.87	40.56	33	40.83	39.94
2	40.52	39.71	18	40.58	39.87	34	40.70	40.00
3	39.96	39.95	19	40.77	40.26	35	40.25	39.90
4	40.13	40.24	20	39.97	39.72	36	40.05	39.71
5	40.19	40.36	21	40.15	39.63	37	40.40	39.95
6	40.39	40.00	22	40.54	39.77	38	40.26	40.41
7	40.55	39.89	23	40.49	39.98	39	39.93	39.76
8	40.78	40.07	24	40.40	40.07	40	39.99	40.42
9	40.15	40.11	25	40.54	40.10	41	39.91	40.67
10	40.23	39.73	26	40.05	39.88	42	40.69	40.09
11	40.70	39.81	27	39.95	39.61	43	40.24	40.24
12	40.26	40.11	28	40.60	40.01	44	40.37	39.80
13	40.59	40.01	29	40.30	40.53	45	40.26	39.80
14	40.54	40.11	30	39.97	40.02	46	40.26	40.58
15	40.21	40.35	31	40.69	40.11	47	40.84	39.99
16	40.46	40.09	32	40.29	40.26	48	40.10	39.95