Menegaldo Luciano Luporini, Fleury Agenor de Toledo, Weber Hans Ingo
São Paulo State Institute for Technological Research, Control System Group/Mechanical and Electrical Engineering Division, and Department of Mechanical Engineering, Polytechnic School, University of São Paulo, Brazil.
J Biomech. 2003 Nov;36(11):1701-12. doi: 10.1016/s0021-9290(03)00170-2.
The present work describes the biomechanical modeling of human postural mechanics in the saggital plane and the use of optimal control to generate open-loop raising-up movements from a squatting position. The biomechanical model comprises 10 equivalent musculotendon actuators, based on a 40 muscles model, and three links (shank, thigh and HAT-Head, Arms and Trunk). Optimal control solutions are achieved through algorithms based on the Consistent Approximations Theory (Schwartz and Polak, 1996), where the continuous non-linear dynamics is represented in a discrete space by means of a Runge-Kutta integration and the control signals in a spline-coefficient functional space. This leads to non-linear programming problems solved by a sequential quadratic programming (SQP) method. Due to the highly non-linear and unstable nature of the posture dynamics, numerical convergence is difficult, and specific strategies must be implemented in order to allow convergence. Results for control (muscular excitations) and angular trajectories are shown using two final simulation times, as well as specific control strategies are discussed.
本研究描述了人体矢状面姿势力学的生物力学建模，以及使用最优控制从蹲姿生成开环起身动作。生物力学模型基于一个40肌肉模型，由10个等效肌肉肌腱驱动装置和三个环节（小腿、大腿以及头、臂和躯干）组成。最优控制解通过基于一致逼近理论的算法实现（施瓦茨和波拉克，1996年），其中连续非线性动力学通过龙格-库塔积分在离散空间中表示，控制信号在样条系数函数空间中表示。这导致通过序列二次规划（SQP）方法解决非线性规划问题。由于姿势动力学具有高度非线性和不稳定的性质，数值收敛困难，必须实施特定策略以实现收敛。使用两个最终模拟时间展示了控制（肌肉兴奋）和角轨迹的结果，并讨论了具体的控制策略。
