论文部分内容阅读
目的:分析运动员空中动作中转动惯量的变化特征。方法:根据跳水空中动作特点,建立人体多体系统模型,并开发相应的计算机仿真软件。对某运动员完成四个跳水动作(A:107B;B:407C;C:5136B;D:5235B)进行三维运动学分析和计算机仿真,获得人体总重心、外方位角及总转动惯量张量。最后计算对应于转体、翻腾和倾斜运动的三个中心主转动惯量I1、I2和I3。结果:总重心和外方位角的变化均符合真实运动情况。从四个动作的三个主转动惯量变化曲线看,I2和I3总比较接近,平均值约为I1的5倍。屈体或团身阶段时间约为0.2 s,而展开阶段约为0.1 s。动作A翻腾过程中I1变化较小,平均为2.12 kg·m2;翻腾阶段I2平均为3.46 kg·m2,翻腾结束时I2达最大,为12.48 kg·m2。动作B在翻腾过程中也是I1变化较小,平均为2.32 kg·m2;但I2在翻腾开始时最大,为13.62 kg·m2,翻腾阶段平均为3.30 kg·m2。动作C和D主转动惯量变化相似。动作C的转体阶段I1较小,平均为1.15 kg·m2,转体结束时可达到4.32 kg·m2;翻腾阶段I2最小,平均为3.65 kg·m2,结束时为12.95 kg·m2。结论:空中翻腾和转体过程中转动惯量呈快速、大范围变化,不同类型空中动作的惯性参量变化差异较大。本文建立了测量计算空中转动惯量变化的方法,为运动员分析空中姿态控制提供了新方法。
Objective: To analyze the changing characteristics of moment of inertia of air movement of athletes. Methods: According to the characteristics of diving aerial movement, the multi-body system model of human body was established and the corresponding computer simulation software was developed. Three-dimensional kinematics analysis and computer simulation are performed on an athlete to complete four diving movements (A: 107B; B: 407C; C: 5136B; D: 5235B) to obtain the body’s total center of gravity, outside azimuth and total moment of inertia tensor. Finally, the three center moments of inertia I1, I2 and I3 corresponding to swiveling, tumbling and tilting movements are calculated. Results: The changes of the total center of gravity and the external azimuths are in line with the actual movement. From the three movements of the four main moments of inertia curve, I2 and I3 are always closer, with an average of about 5 times I1. The pike or group stage time is about 0.2 s, while the deployment stage is about 0.1 s. In the process of action A, the change of I1 was small with an average of 2.12 kg · m2. The average I2 in the ascending stage was 3.46 kg · m2. The maximum I2 was 12.48 kg · m2 at the end of the ascending stage. In the process of bouncing, action B also showed a small change of I1 with an average of 2.32 kg · m2. However, I2 was the largest at the beginning of tumbling at 13.62 kg · m2 and the mean tumbling stage was 3.30 kg · m2. Movement C and D main moments of inertia change similarly. The rotation phase I1 of action C was smaller with an average of 1.15 kg · m2 and reached 4.32 kg · m2 at the end of the swivel phase. The minimum I2 was in the tumbling stage with an average of 3.65 kg · m2 and ended at 12.95 kg · m2. CONCLUSION: The moment of inertia during air tumbling and swerving changes rapidly and widely, and the inertial parameters vary greatly among different types of air movements. In this paper, a method of measuring the change of airborne moment of inertia is established, which provides a new method for the athlete to analyze the air attitude control.