Energy Efficiency of Legged Robot Locomotion With Elastically-Suspended Loads Over a Range of Suspension Stiffnesses

2012 ◽  
Author(s):  
Jeffrey Ackerman ◽  
Xingye Da ◽  
Justin Seipel
Keyword(s):  
Energy Efficiency ◽  
Simple Model ◽  
Energy Cost ◽  
Legged Locomotion ◽  
Experimental Results ◽  
Legged Robot ◽  
Robot Locomotion ◽  
Cost Of Locomotion ◽  
Energy Cost Of Locomotion ◽  
Suspended Loads

Elastically suspending a load from humans and animals can increase the energy efficiency of legged locomotion and load carrying. Similarly, elastically-suspended loads have the potential to increase the energy efficiency of legged robot locomotion. External loads and the inherent mass of a legged robot, such as batteries, electronics, and fuel, can be elastically-suspended from the robot chassis with a passive compliant suspension system, reducing the energetic cost of locomotion. In prior work, we developed a simple model to examine the effect of elastically-suspended loads on the energy cost of locomotion from first principles. In this paper, we present experimental results showing the energy cost of locomotion for a simple hexapod robot over a range of suspension stiffness values. Elastically-suspended loads were shown to reduce the energy cost of locomotion by up to 20% versus a rigidly-attached load. We compare the experimental results to the theoretical results predicted by the simple model.

Energetic and Dynamic Analysis of Multifrequency Legged Robot Locomotion With an Elastically Suspended Load

2013 ◽  
Vol 9 (2) ◽  
Author(s):  
Xingye Da ◽  
Jeffrey Ackerman ◽  
Justin Seipel
Keyword(s):  
Natural Frequency ◽  
Average Power ◽  
Legged Locomotion ◽  
Suspended Load ◽  
Experimental Results ◽  
Energetic Cost ◽  
Legged Robot ◽  
Multiple Frequency ◽  
Robot Locomotion ◽  
Suspended Loads

Elastically suspended loads can reduce the energetic cost and peak forces of legged robot locomotion. However, legged locomotion frequently exhibits multiple frequency modes due to variable leg contact times, body pitch and roll, and transient locomotion dynamics. We used a simple hexapod robot to investigate the effect of multiple frequency components on the energetic cost, dynamics, and peak forces of legged robot locomotion using a high-speed motion tracking system and the fast Fourier transform (FFT). The trajectories of the robot body and the suspended load revealed that the robot was excited by both a body pitching frequency and the primary locomotion frequency. Both frequency modes affected the dynamics of the legged robot as the natural frequency of the elastic load suspension was varied. When the natural frequency of the load suspension was reduced below the primary locomotion and body pitching frequencies, the robot consumed less average power with an elastically suspended load versus a rigidly attached load. To generalize the experimental results more broadly, a modified double-mass coupled-oscillator model with experimental parameters was shown to qualitatively predict the energetic cost and dynamics of legged robot locomotion with an elastically suspended load. The experimental results and the theoretical model could help researchers better understand locomotion with elastically suspended loads and design load suspension systems that are optimized to reduce the energetic cost and peak forces of legged locomotion.

Energy Efficiency and Stability of a Nonlinear Coupled-Oscillator Model of Hopping With Elastically-Suspended Loads

2012 ◽  
Author(s):  
Jeffrey Ackerman ◽  
Justin Seipel
Keyword(s):  
Energy Efficiency ◽  
Energy Cost ◽  
High Speed ◽  
Legged Locomotion ◽  
System Stability ◽  
Coupled Oscillator ◽  
Load Carrying ◽  
Realistic Representation ◽  
Double Mass ◽  
Suspended Loads

Elastically suspending a load with a compliant suspension system can increase the energy efficiency of legged locomotion and load carrying in humans, animals, and robots. In prior work, we developed a simple linear model from first principles and showed that elastically-suspended loads reduce the energy cost and stability of locomotion. In this paper, we expand on this model by adding flight phases, transforming it into a nonlinear hybrid system that is a more realistic representation of human hopping and high-speed locomotion more generally. The addition of flight phases causes a counterintuitive shift in the behavior of the double-mass coupled-oscillator system. With the addition of flight phases, the tuning of the elastic load suspension becomes more critical in order to reduce the energy cost of human hopping. Elastically-suspended loads also increased the overall system stability compared to rigidly-attached loads when the system exhibits flight phases. Therefore, under certain conditions, a human hopping with an elastically-suspended load can exhibit increased energy efficiency and stability compared to a rigidly-attached load. This study will help improve our understanding of elastically-suspended loads and could enable the design of tuned suspension systems for load carrying.

Energetic cost of locomotion in the tammar wallaby

1992 ◽  
Vol 262 (5) ◽  
pp. R771-R778 ◽  
Author(s):  
R. V. Baudinette ◽  
G. K. Snyder ◽  
P. B. Frappell
Keyword(s):  
Oxygen Consumption ◽  
Blood Lactate ◽  
Body Mass ◽  
Energy Cost ◽  
Physiological Adaptation ◽  
Energetic Cost ◽  
Cost Of Locomotion ◽  
Lactate Levels ◽  
Energy Cost Of Locomotion ◽  
Blood Lactate Levels

Rates of oxygen consumption and blood lactate levels were measured in tammar wallabies (Macropus eugenii) trained to hop on a treadmill. In addition, the work required to overcome wind resistance during forward locomotion was measured in a wind tunnel. Up to approximately 2.0 m/s, rates of oxygen consumption increased linearly with speed and were not significantly different from rates of oxygen consumption for a quadruped of similar body mass. Between 2.0 and 9.4 m/s, rates of oxygen consumption were independent of hopping speed, and between 3.9 and 7.9 m/s, the range over which samples were obtained, blood lactate levels were low (0.83 +/- 0.13 mmol.min-1.kg-1) and did not increase with hopping speed. The work necessary to overcome drag increased exponentially with speed but increased the energy cost of locomotion by only 10% at the average speed attained by our fast hoppers. Thus, during hopping, the energy cost of locomotion is effectively independent of speed. At rates of travel observed in the field, the estimated energy cost of transport in large macropods is less than one-third the cost for a quadruped of equivalent body mass. The energetic savings associated with this unique form of locomotion may have been an important physiological adaptation, enabling large macropods to efficiently cover the distances necessary to forage in the semiarid landscapes of Australia.

Strength Training for Middle- and Long-Distance Performance: A Meta-Analysis

2018 ◽  
Vol 13 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Nicolas Berryman ◽  
Iñigo Mujika ◽  
Denis Arvisais ◽  
Marie Roubeix ◽  
Carl Binet ◽  
...  
Keyword(s):  
Strength Training ◽  
Energy Cost ◽  
Meta Analysis ◽  
Maximal Power ◽  
Long Distance ◽  
Beneficial Effects ◽  
Maximal Force ◽  
Subgroup Analyses ◽  
Cost Of Locomotion ◽  
Energy Cost Of Locomotion

Purpose: To assess the net effects of strength training on middle- and long-distance performance through a meta-analysis of the available literature. Methods: Three databases were searched, from which 28 of 554 potential studies met all inclusion criteria. Standardized mean differences (SMDs) were calculated and weighted by the inverse of variance to calculate an overall effect and its 95% confidence interval (CI). Subgroup analyses were conducted to determine whether the strength-training intensity, duration, and frequency and population performance level, age, sex, and sport were outcomes that might influence the magnitude of the effect. Results: The implementation of a strength-training mesocycle in running, cycling, cross-country skiing, and swimming was associated with moderate improvements in middle- and long-distance performance (net SMD [95%CI] = 0.52 [0.33–0.70]). These results were associated with improvements in the energy cost of locomotion (0.65 [0.32–0.98]), maximal force (0.99 [0.80–1.18]), and maximal power (0.50 [0.34–0.67]). Maximal-force training led to greater improvements than other intensities. Subgroup analyses also revealed that beneficial effects on performance were consistent irrespective of the athletes’ level. Conclusion: Taken together, these results provide a framework that supports the implementation of strength training in addition to traditional sport-specific training to improve middle- and long-distance performance, mainly through improvements in the energy cost of locomotion, maximal power, and maximal strength.

scholarly journals Estimation of the energy costs of locomotion in the Iberian pig(Sus mediterraneus)

2000 ◽  
Vol 83 (1) ◽  
pp. 35-41 ◽  
Author(s):  
M. Lachica ◽  
J. F. Aguilera
Keyword(s):  
Heat Production ◽  
Energy Cost ◽  
Live Weight ◽  
Energy Costs ◽  
Net Energy ◽  
Mean Values ◽  
A Value ◽  
Cost Of Locomotion ◽  
Iberian Pig ◽  
Energy Cost Of Locomotion

The energy cost of locomotion of four Iberian pigs was measured in two experiments conducted when the animals averaged 41·3 (se 0·1) kg (first experiment) and 84·1 (se 0·1) kg (second experiment). The heat production of the pigs was determined when standing or walking at a speed of 0·555 m/s on a treadmill enclosed in a confinement-type respiration chamber, on different slopes (-10·5, 0, and +10·5 % in the first experiment, and -5·25, 0 and +10·5 % in the second experiment). The energy costs of locomotion, estimated from the coefficients of linear regressions of heat production per kg body weight (BW) on distance travelled, were in the first experiment 2·99, 3·31 and 5·88 J/kg BW per m for -10·5, 0, and +10·5 % inclines respectively, and 2·56, 2·84 and 7·13 J/kg BW per m for -5·25, 0 and +10·5 % inclines respectively, in the second experiment. The net energy cost of locomotion on the level appeared to be independent of live weight, attaining a value of 2·98 J/kg BW per m. Also, it was found that within experiments the net energy cost of walking on negative slopes was similar to that for locomotion on the level, indicating that no energy was recovered on vertical descent. Mean values were 3·11 and 2·72 kJ/kg BW per m for the light and heavy pigs respectively. The energy cost of raising 1 kg BW one vertical metre was found to be 27·1 J/kg BW per m in the first experiment and 40·0 J/kg BW per m in the second experiment. Correspondingly, the calculated efficiency for upslope locomotion appeared to decline with increasing BW, resulting in average values of 36·2 and 24·5 %.

Increasing Mobile Robot Efficiency and Versatility Through Manipulation-driven Adaptation

2021 ◽  
pp. 1-18
Author(s):  
Raymond Kim ◽  
Anirban Mazumdar ◽  
Varun Madabushi ◽  
Eric Dong
Keyword(s):  
Energy Efficiency ◽  
Permanent Magnets ◽  
Mobile Robotics ◽  
Legged Locomotion ◽  
Experimental Results ◽  
Robot System ◽  
Improve Energy Efficiency ◽  
Cost Of Energy ◽  
Broad Variety ◽  
The Cost

Abstract Terrestrial mobile robotics are increasingly important to a range of missions including planetary exploration, search and rescue, logistics, and national security. Many of these missions require the robot to operate on a broad variety of terrain. Wheels are ideal for energy efficiency but can suffer catastrophic failure when presented with obstacles or complex ground. Legs can help navigate obstacles but at the cost of energy efficiency. Physical adaptation can enable a robot to benefit from both modes of locomotion. This paper describes a new approach to physical adaptation through manipulation. Specifically, this paper examines how manipulators can be used to change the vehicle's mode of locomotion and improve energy efficiency and versatility. This paper presents “swappable propulsors”, which can be easily attached/detached to adapt the vehicle through the use of permanent magnets. A new robot system that uses its manipulator to discretely switch between wheeled and legged locomotion is created. The experimental results demonstrate how this approach provides a unique combination of energy efficiency and versatility. This work describes the design of swappable propulsors, analyzes how to manipulate them, and describes how they can be used to improve performance. This work extends on prior work with additional analysis, an improved robot prototype, and new experimental results.

Coupled-Oscillator Model of Locomotion Stability With Elastically-Suspended Loads

2011 ◽  
Author(s):  
Jeffrey Ackerman ◽  
Justin Seipel
Keyword(s):  
Simple Model ◽  
Energy Cost ◽  
Fundamental Property ◽  
Suspended Load ◽  
Oscillator Model ◽  
Rough Terrain ◽  
Stability Of Motion ◽  
Coupled Oscillator ◽  
Coupled Oscillator Model ◽  
Suspended Loads

Elasticity is a fundamental property of dynamic locomotion and is generally thought to affect the efficiency and stability of motion. In particular, it is becoming increasingly apparent that elastically-suspended loads are common in biology and useful for carrying loads. For example, the Suspended Load Backpack reduces the peak forces and energy cost during locomotion. In this paper, we present a simple model of locomotion to examine the effect of elastically-suspended loads on the peak forces, energy cost, and stability during locomotion. The results from the model show that elastically-suspended loads reduce the peak forces, energy cost, and stability of locomotion compared to rigidly-attached loads, thus indicating that a tradeoff exists between the decreased stability of locomotion and the reduction of peak forces and energy cost. We discuss this tradeoff and the implications of reduced stability on locomotion over rough terrain and the maneuverability of a system.

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