Swing-Leg Trajectory of Running Guinea Fowl Suggests Task-Level Priority of Force Regulation Rather than Disturbance Rejection

نویسندگان

  • Yvonne Blum
  • Hamid R. Vejdani
  • Aleksandra V. Birn-Jeffery
  • Christian M. Hubicki
  • Jonathan W. Hurst
  • Monica A. Daley
چکیده

To achieve robust and stable legged locomotion in uneven terrain, animals must effectively coordinate limb swing and stance phases, which involve distinct yet coupled dynamics. Recent theoretical studies have highlighted the critical influence of swing-leg trajectory on stability, disturbance rejection, leg loading and economy of walking and running. Yet, simulations suggest that not all these factors can be simultaneously optimized. A potential trade-off arises between the optimal swing-leg trajectory for disturbance rejection (to maintain steady gait) versus regulation of leg loading (for injury avoidance and economy). Here we investigate how running guinea fowl manage this potential trade-off by comparing experimental data to predictions of hypothesis-based simulations of running over a terrain drop perturbation. We use a simple model to predict swing-leg trajectory and running dynamics. In simulations, we generate optimized swing-leg trajectories based upon specific hypotheses for task-level control priorities. We optimized swing trajectories to achieve i) constant peak force, ii) constant axial impulse, or iii) perfect disturbance rejection (steady gait) in the stance following a terrain drop. We compare simulation predictions to experimental data on guinea fowl running over a visible step down. Swing and stance dynamics of running guinea fowl closely match simulations optimized to regulate leg loading (priorities i and ii), and do not match the simulations optimized for disturbance rejection (priority iii). The simulations reinforce previous findings that swing-leg trajectory targeting disturbance rejection demands large increases in stance leg force following a terrain drop. Guinea fowl negotiate a downward step using unsteady dynamics with forward acceleration, and recover to steady gait in subsequent steps. Our results suggest that guinea fowl use swing-leg trajectory consistent with priority for load regulation, and not for steadiness of gait. Swing-leg trajectory optimized for load regulation may facilitate economy and injury avoidance in uneven terrain.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

The effects of swing-leg retraction on running performance: analysis, simulation, and experiment

Using simple running models, researchers have argued that swing-leg retraction can improve running robot performance. In this paper, we investigate whether this holds for a more realistic simulation model validated against a physical running robot. We find that swing-leg retraction can improve stability and disturbance rejection. Alternatively, swing-leg retraction can simultaneously reduce tou...

متن کامل

Mechanical efficiency of limb swing during walking and running in guinea fowl (Numida meleagris).

Understanding the mechanical determinants of the energy cost of limb swing is crucial for refining our models of locomotor energetics, as well as improving treatments for those suffering from impaired limb-swing mechanics. In this study, we use guinea fowl (Numida meleagris) as a model to explore whether mechanical work at the joints explains limb-swing energy use by combining inverse dynamic m...

متن کامل

The role of intrinsic muscle mechanics in the neuromuscular control of stable running in the guinea fowl.

Here we investigate the interplay between intrinsic mechanical and neural factors in muscle contractile performance during running, which has been less studied than during walking. We report in vivo recordings of the gastrocnemius muscle of the guinea fowl (Numida meleagris), during the response and recovery from an unexpected drop in terrain. Previous studies on leg and joint mechanics followi...

متن کامل

Bio-inspired swing leg control for spring-mass robots running on ground with unexpected height disturbance.

We proposed three swing leg control policies for spring-mass running robots, inspired by experimental data from our recent collaborative work on ground running birds. Previous investigations suggest that animals may prioritize injury avoidance and/or efficiency as their objective function during running rather than maintaining limit-cycle stability. Therefore, in this study we targeted structur...

متن کامل

The energetic costs of trunk and distal-limb loading during walking and running in guinea fowl Numida meleagris: II. Muscle energy use as indicated by blood flow.

We examined the changes in muscle energy use in guinea fowl running at 1.5 m s-1 either unloaded, or carrying trunk loads equal to 23% of body mass, or loads on their distal legs equal to a total of 5% of body mass. We estimated muscle energy use by measuring blood flow to all of the leg muscles using injected microspheres. Total blood flow to the leg muscles increased by approximately 15% unde...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره 9  شماره 

صفحات  -

تاریخ انتشار 2014