Integration of energetic cost into optimal control models of reaching

人们更喜欢以最小化能量的方式移动，但缺乏一种统一的方法来理解跨领域的首选运动。在运动中，我们知道人类运动系统更喜欢能量消耗最小的行走方式，当新的力量施加到身体上时，它可以改变人们喜欢的行走方式，与能量消耗最小化相一致。在人类的伸手过程中，该领域最近刚刚测量了每次伸手所消耗的能量。首选的方式达到，如路径的手旅行，手的速度和肌肉力量，现在被认为是反映能量成本和任务奖励之间的权衡，和变化时，新的力量施加到手上的首选达到也符合最小化能量成本。然而，一个生理和预测机制，解释能量成本的作用，在达到仍有待开发。 在接下来的5年里，我的研究计划旨在确定能量消耗如何影响人类运动系统控制伸手行为。在这项工作中，我将使用一个最佳人类接触的计算模型来预测三个不同领域的首选行为和能量消耗量。首先，我将确定能量成本模型如何预测正常到达的基本行为和成本（目标1）;其次，我将确定能量成本如何影响到达对外力的适应（目标2）;最后，我们将确定能量成本如何影响控制策略的制定（目标3）。电机控制中的术语"控制策略"具有特定的含义，在这种情况下，是指受控系统的状态与该状态的动作或施加的转矩和转矩之间的函数关系。我们使用标记和摄像系统或机器人外骨骼来测量手臂的运动，我们使用外骨骼施加力来改变运动的动力学。为了测试我们的预测模型，我们测量了人们偏好的运动变化以及他们消耗的能量，并将其与我们的模型进行比较，该模型预测了给定任务的位置，速度，扭矩，运动持续时间以及相关的代谢成本。然后，我们可以确定能量成本和任务目标如何影响运动系统的控制达到。 这项研究将为人类运动系统如何协调平滑、优美的运动提供一个基本的理解。这在加拿大工业中具有广泛的应用意义，例如：了解对衰老和受伤的自然适应;合理的康复方案，以尽量减少能源成本;辅助技术和学习和控制装置。我们的研究计划将为跨学科的学生提供丰富的培训环境，为加拿大工业和学术界的研究和技术做出贡献。

People prefer to move in ways that minimize energy, yet a unifying approach to understanding preferred movements across domains is lacking. In locomotion we know that the human motor system prefers ways of walking that have minimize energetic cost, and that it can change the way that people prefer to walk when novel forces are applied to the body, consistent with minimizing energetic cost. In human reaching, the field has just recently made measurements of the energy consumed per reach. Preferred ways of reaching-such as the path the hand travels, hand speeds, and muscle forces-are now thought to reflect a trade-off between energetic cost and task reward, and changes to preferred reaching when novel forces are applied to the hand are also consistent with minimizing energetic cost. However, a physiological and predictive mechanism that explains the role of energetic cost in reaching remains to be developed. Over the next 5 years of my research program I aim to determine how energetic cost affects how the human motor system controls reaching behaviour. In this work I will be using a computational model of optimal human reaching to predict both the preferred behavior, and quantity of energetic consumption, in three distinct areas. First I wil determine how the energetic cost model predicts fundamental behaviors and cost in normal reaching (Aim 1); next I determine how energetic cost affects the adaptation of reaches to external forces (Aim 2); and finally we will determine how energetic cost affects the development of control policies (Aim 3). The term `control policy' in motor control has a specific meaning, and in this case refers to a functional relationship between state of the controlled system, and the action or applied torques and torques for that satte. We measure the motion of the arms using either a marker and camera system, or a robotic exoskeleton, and we apply forces using that exoskeleton to change the dynamics of movement. To test our predictive model we measure changes in people's preferred motions, and the energy they consume, and compare that to our model, which predicts positions, velocities, torques, movement durations, and the associated metabolic cost, for a given task. We can then determine how both energetic cost and task objectives affect the motor system's control of reaching. The proposed research will provide a basic and foundational understanding of how the human motor system coordinates smooth, graceful motion. This has broad applied implications in Canadian industry, such as: understanding natural adaptations to ageing and injury; rationally based rehabilitation programs accounting for energetic cost minimization; assistive technologies and devices for learning and control. Our research program will provide a rich training environment for interdisciplinary students, well prepared to contribute to Canadian research and technology in industry and academia.