Zhang Peng, Baek Seung-Soo
School of Physical Education, Xinyang Normal University, Xinyang, China.
School of Physical Education, Sangmyung University, Seoul, Korea.
Front Bioeng Biotechnol. 2022 Apr 27;10:884318. doi: 10.3389/fbioe.2022.884318. eCollection 2022.
Based on the spectral representation method of random function and combined with memoryless nonlinear translation theory, this paper analyzes the transformation relationship between potential Gaussian random process and non-Gaussian random process, and successfully generates a stationary non-Gaussian random process that conforms to the target non-Gaussian random process. For the non-stationary non-Gaussian random process simulation, on the basis of the stationary Gaussian random process, the intensity non-stationary uniform modulation model is used to modulate it, and combined with the nonlinear translation theory, the non-stationary non-Gaussian random process conforming to the target non-Gaussian random process is obtained. Aiming at the single-leg bouncing model based on the flexible rotary hip joint, the stability of its bouncing motion under passive motion is studied, and the influence of the flexible hip rotary joint on the motion stability is analyzed by comparing the single-leg bouncing motion characteristics of the free rotary hip joint. Based on the inverse dynamic control of the air phase, the fixed point distribution of the single-leg bounce of the flexible rotary hip joint was improved, and the function of the flexible rotary hip joint in the energy conversion of the bouncing motion was studied by establishing the energy consumption evaluation function. The kinematic performance verification, dynamic performance verification, dynamic parameter identification verification, and modal experiment simulation analysis were carried out for the built experimental platform, and the comparison and analysis with its theoretical model were carried out. The results show that the theoretical motion trajectory of the test mobile platform is basically consistent with the actual motion trajectory in the X and Y directions, and there is a small error in the Z-axis direction, and the error is within an acceptable range, indicating that the experimental platform system can be used to simulate the human hip joint. There is a large error between the theoretical value of the driving torque calculated by the theoretical value of the dynamic parameters and the measured value, and the dynamic theoretical model cannot accurately predict the driving torque. The predicted value of the driving torque calculated by using the identification value of the dynamic parameters is in good agreement with the measured torque, and its confidence is increased by 10-16%, indicating that the dynamic parameter identification method in this paper has a high degree of confidence.
基于随机函数的谱表示方法，结合无记忆非线性变换理论，分析了潜在高斯随机过程与非高斯随机过程之间的变换关系，成功生成了符合目标非高斯随机过程的平稳非高斯随机过程。对于非平稳非高斯随机过程仿真，在平稳高斯随机过程的基础上，采用强度非平稳均匀调制模型对其进行调制，并结合非线性变换理论，得到了符合目标非高斯随机过程的非平稳非高斯随机过程。针对基于柔性旋转髋关节的单腿弹跳模型，研究了其在被动运动下弹跳运动的稳定性，并通过比较自由旋转髋关节的单腿弹跳运动特性，分析了柔性髋关节旋转对运动稳定性的影响。基于气相的逆动力学控制，改进了柔性旋转髋关节单腿弹跳的定点分布，并通过建立能量消耗评估函数，研究了柔性旋转髋关节在弹跳运动能量转换中的作用。对搭建的实验平台进行了运动学性能验证、动力学性能验证、动态参数辨识验证和模态实验仿真分析，并与理论模型进行了对比分析。结果表明，测试移动平台的理论运动轨迹在X、Y方向上与实际运动轨迹基本一致，Z轴方向存在较小误差，且误差在可接受范围内，表明该实验平台系统可用于模拟人体髋关节。由动力学参数理论值计算得到的驱动转矩理论值与测量值之间存在较大误差，动力学理论模型无法准确预测驱动转矩。采用动力学参数辨识值计算得到的驱动转矩预测值与测量转矩吻合良好，其置信度提高了10 - 16%，表明本文提出的动力学参数辨识方法具有较高的置信度。
