Energy optimization and locomotion control: task, strategy, and mechanisms

为什么一个人会像他们那样走路或跑步？确定实施特定控制策略的原因是我们研究计划的目标。根据新出现的证据，我们怀疑最小化能量消耗对运动策略的选择有重要影响。我们使用一系列操作来揭示能量成本对个体反应的作用，以绘制能量成本效应并确定最小化运动成本所涉及的机制。这些研究被组织成三个项目流，我的团队将在接下来的5年（甚至更长时间）内进行这些研究。正常的走路和跑步是解决用腿移动所面临的挑战的一种方法，但这些步态解决的实际问题并不一定是不言而喻的。我们的目标是确定可用的限制条件和机会。这填补了一个关键的空白，即感觉输入和运动输出协调以及肢体力学必须与个人或有机体运动的物理（动态）环境相结合。我们的重点是后一部分，确定腿部需要做什么才能产生有效的运动，以及为什么一个特定的解决方案比所有其他的都合适（以及有多少）。这是将中枢神经系统（CNS）动作置于功能环境中的关键因素，因此可以分析和解释运动控制决策过程。长期目标是通过考虑中枢神经系统可用的解决方案空间，并评估正常功能的个体/生物体如何从这一系列选项中进行选择来实现的。短期研究采用三个阶段的过程：(a)使用优化模型来确定可用的功能解决方案空间，(b)验证模型在相同情况下代表现实的经验（人类或动物）运动，然后(c)询问模型以确定确定优化解决方案的权衡。每个项目流打开一个新的方法来解决核心问题（理解步态策略选择）。该项目允许对步态环境进行控制操作，提供了直接比较模型预测（假设）与运动策略表达的经验量化的机会。将项目组织到相关的流程中，可以对项目进行划分，使项目适合HQP在本科和研究生阶段的参与。项目流1使用定制设计的计算机控制的振荡线束，对主干施加循环脉冲，从而能够分析人机交互。项目流2解决了四足步态问题，开发了基于原始动力学的模型，以了解动物形态如何影响运动。项目流3利用跑酷（城市体操）中采用的不同寻常的运动策略，定量地绘制一些标准动作的能量结果，这将允许对运动策略选择进行直接的实验评估。

Why does an individual walk or run as they do? Determining why specific control strategies are implemented is the goal of our research program. Based on emerging evidence, we suspect that minimizing energetic cost has an important effect on the movement strategy chosen. We use a range of manipulations to expose the role of energetic cost on individual response in order to map energetic cost effects and identify the mechanisms involved in minimizing locomotion cost. These studies are organized into three project streams that my group will work on over the next 5 years (and beyond). Normal walking and running are a solution to the challenges faced by moving on legs, but the actual problems solved by these gaits are not necessarily self-evident. It is our goal to identify the constraints and opportunities available. This fills a critical gap where sensory input and motor output coordination and within limb mechanics must integrate with the physical (dynamic) environment the individual or organism moves within. Our focus is on the latter component, determining what the leg needs to do in order to generate effective locomotion, and why a particular solution is appropriate over all others (and by how much so). This as a key factor putting central nervous system (CNS) action within a functional context, so the motor control decision process can be analyzed and interpreted. The long term goal is achieved by considering the solution space available to the CNS and evaluating how a normally functioning individual/organism selects from that array of options. Short term studies employ a three stage process: (a) use optimization models to identify the functional solution space available, (b) verify that the models represent realistic empirical (human or animal) movement in the same circumstance, then (c) interrogate the model to identify the trade-offs that determine the optimization solution. Each project stream opens a novel approach to the core problem (understanding gait strategy selection). The projects allow controlled manipulation of the gait environment, providing the opportunity to directly compare model predictions (hypothesis) with empirical quantification of motor strategy expression. Organization of projects into related streams allows division of projects that make the projects amenable to participation by HQP at both the undergraduate and graduate levels. Project stream 1 uses a custom designed computer controlled oscillating harness that applies a cyclic impulse to the trunk, enabling analysis of the machine-human interaction. Project stream 2 addresses the problem of quadrupedal gait, developing original dynamics based models to understand how animal form affects locomotion. Project stream 3 takes advantage of the unusual movement strategies employed in parkour (urban gymnastics) to quantitatively map energetic consequences of a number of standard maneuvers that will allow direct experimental evaluation of movement strategy choice.