This paper focuses on a dynamic sensory-motor control mechanism of reaching movements for a musculo-skeletal redundant arm model. The formulation of a musculo-skeletal redundant arm system, which takes into account non-linear muscle properties obtained by some physiological understandings, is introduced and numerical simulations are perfomed. The non-linear properties of muscle dynamics make it possible to modulate the viscosity of the joints, and the end point of the arm converges to the desired point with a simple task-space feedback when adequate internal forces are chosen, regardless of the redundancy of the joint. Numerical simulations were performed and the effectiveness of our control scheme is discussed through these results. The results suggest that the reaching movements can be achieved using only a simple task-space feedback scheme together with the internal force effect that comes from non-linear properties of skeletal muscles without any complex mathematical computation such as an inverse dynamics or optimal trajectory derivation. In addition, the dynamic damping ellipsoid for evaluating how the internal forces can be determined is introduced. The task-space feedback is extended to the ‘virtual spring-damper hypothesis’ based on the research by Arimoto et al. (2006) to reduce the muscle output forces and heterogeneity of convergence depending on the initial state and desired position. The research suggests a new direction for studies of brain-motor control mechanism of human movements.

中文翻译：

---

肌肉骨骼冗余手臂模型的伸手运动控制

本文着重于肌肉-骨骼冗余手臂模型达到动作的动态感觉运动控制机制。介绍了考虑到某些生理学知识获得的非线性肌肉特性的肌肉骨骼冗余手臂系统的公式，并进行了数值模拟。肌肉动力学的非线性特性使得有可能调节接头的粘度，并且所述臂收敛于同一个简单的任务空间反馈所需的点的结束点时被选择适当的内力，而不管冗余的关节。通过这些结果进行了数值模拟，并讨论了我们控制方案的有效性。结果表明，仅使用简单的任务空间反馈方案以及来自骨骼肌肉非线性特性的内力效应就可以实现伸展运动，而无需进行任何复杂的数学计算，例如逆动力学或最优轨迹推导。此外，引入了用于评估如何确定内力的动态阻尼椭圆体。根据Arimoto等人的研究，任务空间反馈被扩展到“虚拟弹簧阻尼器假说”。（2006）减少肌肉的输出力和收敛的异质性取决于初始状态和所需的位置。该研究为研究人类运动的脑运动控制机制提供了新的方向。