Degree-of-Freedom-Based Instantaneous Energetic Cost of Robotic Biped Gait With Benchmarking Implications

2015 ◽  
Author(s):  
Dustyn Roberts ◽  
Joseph Quacinella ◽  
Joo H. Kim
Keyword(s):  
Gait Cycle ◽  
Electrical Energy ◽  
Biped Robot ◽  
Degree Of Freedom ◽  
Energetic Cost ◽  
Lower Body ◽  
Cost Of Transport ◽  
System Parameters ◽  
Robotic Gait ◽  
Dc Servomotor

Instantaneous robotic gait energetics is evaluated at each joint actuator, and is characterized relative to those of humans. A degree-of-freedom (DOF)-based instrumentation system is designed for instantaneous evaluation of electrical energy expenditure (EE) rates at each DC servomotor, and implemented into a DARwIn-OP biped robot. The robot’s EE rates for the entire lower body are in agreement with its periodic gait cycle, and their trends between gait phases are similar to those of humans. The robot’s cost of transport (COT) as a function of normalized speed is also in agreement with the human COT with respect to its convexity. The contrasting distributions of EE throughout the robot and human DOFs and the robotic COT curve’s considerably large magnitudes and small speed ranges illustrate the energetic consequences of stable but inefficient static walking in the robot versus the more efficient dynamic walking of humans. These characteristics enable the identification of the DOFs and gait phases associated with the inefficiency in the robotic gait, and reflect the differences in the system parameters and gait strategies in terms of the efficiency and stability. The proposed instrumentation system provides a quantitative benchmarking approach.

scholarly journals Terrain-blind walking of planar underactuated bipeds via velocity decomposition-enhanced control

2019 ◽  
Vol 38 (10-11) ◽  
pp. 1307-1323 ◽  
Author(s):  
Martin Fevre ◽  
Bill Goodwine ◽  
James P Schmiedeler
Keyword(s):  
Feedback Control ◽  
Biped Robot ◽  
Rate Of Change ◽  
Energetic Cost ◽  
Practical Implementation ◽  
Leg Length ◽  
Cost Of Transport ◽  
Velocity Decomposition ◽  
Novel Approach ◽  
Hybrid Zero Dynamics

In this article, we develop and assess a novel approach for the control of underactuated planar bipeds that is based on velocity decomposition. The new controller employs heuristic rules that mimic the functionality of transverse linearization feedback control and that can be layered on top of a conventional hybrid zero dynamics (HZD)-based controller. The heuristics sought to retain HZD-based control’s simplicity and enhance disturbance rejection for practical implementation on realistic biped robots. The proposed control strategy implements a feedback on the time rate of change of the decomposed uncontrolled velocity and is compared with conventional HZD-based control and transverse linearization feedback control for both vanishing and non-vanishing disturbances. Simulation studies with a point-foot, three-link biped show that the proposed method has nearly identical performance to transverse linearization feedback control and outperforms conventional HZD-based control. For the non-vanishing case, the velocity decomposition-enhanced controller outperforms HZD-based control, but takes fewer steps on average before failure than transverse linearization feedback control when walking on uneven terrain without visual perception of the ground. The findings were validated experimentally on a planar, five-link biped robot for eight different uneven terrains. The velocity decomposition-enhanced controller outperformed HZD-based control while maintaining a relatively low specific energetic cost of transport (~0.45). The biped robot “blindly” traversed uneven terrains with changes in terrain height accumulating to 5% of its leg length using the stand-alone low-level controller.

scholarly journals How does ankle push-off balance the walking speed and energy efficiency of planar biped robots?

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110119
Author(s):  
Qiaoli Ji ◽  
Zhihui Qian ◽  
Lei Ren ◽  
Luquan Ren
Keyword(s):  
Energy Efficiency ◽  
Gait Cycle ◽  
Walking Speed ◽  
Biped Robot ◽  
Step Length ◽  
Cost Of Transport ◽  
Biped Robots ◽  
Walking Gait ◽  
Motion Performance ◽  
Step Transition

Ankle push-off is defined as the phase in which muscle-tendon units about the ankle joint generate a burst of positive power during the step-to-step transition in human walking. The dynamic walking of a biped robot can be effectively realized through ankle push-off. However, how to use ankle push-off to balance the walking speed and energy efficiency of biped robots has not been studied deeply. In this study, the effects of the step length (the inter-leg angle is 40°, 50°, and 60°), torque and timing of ankle push-off on the walking speed and energy efficiency of biped robots were studied. The results show that when the step length is 50°, the push-off torque is 30 N· m and the corresponding push-off timing occurs at 43% of the gait cycle, the simulated robot obtains a highly economical walking gait. The corresponding maximum normalized walking speed is 0.40, and the minimum mechanical cost of transport is 2.25. To acquire a more economical walking gait of biped robots, the amount of ankle push-off and the push-off timing need to be coordinated. The purpose of this study is to provide a reference for the influence of ankle push-off on the motion performance of biped robots.

Energy expenditure of a biped walking robot: instantaneous and degree-of-freedom-based instrumentation with human gait implications

Robotica ◽  
2016 ◽  
Vol 35 (5) ◽  
pp. 1054-1071 ◽  
Author(s):  
Dustyn Roberts ◽  
Joseph Quacinella ◽  
Joo H. Kim
Keyword(s):  
Energy Expenditure ◽  
Dynamic Balance ◽  
Biped Robot ◽  
Human Gait ◽  
Walking Robots ◽  
Time Duration ◽  
Cost Of Transport ◽  
Biped Walking ◽  
Double Support ◽  
Robotic Gait

SUMMARYEnergy expenditure (EE) is an important criterion for design and control of biped walking robots. However, the cause-effect analyses enabled by total EE, which is lumped over a time duration and all system degrees-of-freedom (DOFs), are limited. In this study, robotic gait energetics is evaluated through a DOF-based instrumentation system designed for instantaneous evaluation of bidirectional current and applied voltage at each joint actuator. The instrumentation system includes a dual-module arrangement of buffers and attenuators, and accommodates and synchronizes the voltage and current measurements from multiple actuators. For illustrative purposes, this system is implemented at each DC servomotor in a biped robot, DARwIn-OP, to analyze the electrical EE rates for walking at various speeds. In addition, a DOF-based model of instantaneous human EE rate is employed to enable quantitative characterization of robotic walking EE relative to that of humans. The robot's instantaneous lower-body EE rates are consistent with its periodic walking cycle, and their relative trends between single and double support phases are analogous to those of humans. The robotic cost of transport (COT) curve as a function of normalized speed is also consistent with the human COT in terms of its convexity. Conversely, the contrasting distributions of EE throughout the robot and human DOFs and the robotic COT curve's considerably larger magnitudes, smaller speed ranges, and higher sensitivity to speed illustrate the energetic consequences of stable but inefficient static walking in the biped robot relative to the more efficient dynamic walking of humans. These energetic characteristics enable the identification of the joints and gait cycle phases associated with inefficiency in biped robotic gait, and reflect the noticeable differences in the system parameters (rigid and flat versus segmented feet) and gait control strategies (bent versus straight knees, instants of peak ankle actuator torques, static versus dynamic balance stability). The proposed general instrumentation provides a quantitative approach to benchmarking human gait as well as general guidelines for the development of energy-efficient walking robots.

Kinematic comparison of single degree-of-freedom robotic gait trainers

2021 ◽  
Vol 159 ◽  
pp. 104258
Author(s):  
Jeonghwan Lee ◽  
Lailu Li ◽  
Sung Yul Shin ◽  
Ashish D. Deshpande ◽  
James Sulzer
Keyword(s):  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Robotic Gait

scholarly journals Evaluation of a FO-PID Controller in a Buck DC/DC Converter Model

2019 ◽  
pp. 1-8
Author(s):  
German A Munoz-Hernandez ◽  
Ana S Damian-Mora ◽  
Jose Ramirez-Espinoza ◽  
Jesus Chavez-Galan
Keyword(s):  
Fractional Order ◽  
Pid Controller ◽  
Nonlinear Models ◽  
Electrical Energy ◽  
Degree Of Freedom ◽  
Pid Controllers ◽  
Adaptive Controllers ◽  
Operational Conditions ◽  
Linear And Nonlinear ◽  
Common Device

The applications of electrical energy converters are wide. It is a common device that can be found in almost every apparatus, both industrial and domestic. This work will deal with linear and nonlinear models of DC/DC converters. Those models will used to probe, by simulation, classic and advance controllers. PID controllers have shown a good response regulating DC/DC converters, for that reason the inclusion of two more degree of freedom due to the Integral and derivative of Fractional Order, could improve the performance of these controllers. Furthermore, Piecewise modeling can be useful to obtain adaptive controllers whose parameters change at different operational conditions.

Efficiency of uphill locomotion in nocturnal and diurnal lizards

1996 ◽  
Vol 199 (3) ◽  
pp. 587-592 ◽  
Author(s):  
C Farley ◽  
M Emshwiller
Keyword(s):  
Body Mass ◽  
Low Cost ◽  
Minimum Cost ◽  
Mechanical Work ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
Unit Distance ◽  
Cost Of Locomotion ◽  
Average Body Mass ◽  
Average Body

Nocturnal geckos can walk on level ground more economically than diurnal lizards. One hypothesis for why nocturnal geckos have a low cost of locomotion is that they can perform mechanical work during locomotion more efficiently than other lizards. To test this hypothesis, we compared the efficiency of the nocturnal gecko Coleonyx variegatus (average body mass 4.2 g) and the diurnal skink Eumeces skiltonianus (average body mass 4.8 g) when they performed vertical work during uphill locomotion. We measured the rate of oxygen consumption when each species walked on the level and up a 50 slope over a range of speeds. For Coleonyx variegatus, the energetic cost of traveling a unit distance (the minimum cost of transport, Cmin) increased from 1.5 to 2.7 ml O2 kg-1 m-1 between level and uphill locomotion. For Eumeces skiltonianus, Cmin increased from 2.5 to 4.7 ml O2 kg-1 m-1 between level and uphill locomotion. By taking the difference between Cmin for level and uphill locomotion, we found that the efficiency of performing vertical work during locomotion was 37 % for Coleonyx variegatus and 19 % for Eumeces skiltonianus. The similarity between the 1.9-fold difference in vertical efficiency and the 1.7-fold difference in the cost of transport on level ground is consistent with the hypothesis that nocturnal geckos have a lower cost of locomotion than other lizards because they can perform mechanical work during locomotion more efficiently.

A suspension system with quasi-zero stiffness characteristics and inerter nonlinear energy sink

2020 ◽  
pp. 107754632097290
Author(s):  
You-cheng Zeng ◽  
Hu Ding ◽  
Rong-Hua Du ◽  
Li-Qun Chen
Keyword(s):  
Integrated Control ◽  
Harmonic Approximation ◽  
Nonlinear Energy Sink ◽  
Suspension System ◽  
Degree Of Freedom ◽  
System Parameters ◽  
Suspension Systems ◽  
Control Scheme ◽  
Energy Sink ◽  
Nonlinear Energy

In this article, a novel vibration control scheme of suspension systems is proposed. It combines the advantages of quasi-zero stiffness isolator, nonlinear energy sink absorber, and inerter. This proposed scheme can achieve low transmissibility, low amplitude, and low additional weight and resolve the conflict between riding comfort and handling stability. Strong nonlinear vibration equations of a quarter-vehicle suspension system are established. It also presents the detailed process of high-order harmonic approximation to obtain steady-state responses. Moreover, approximate solutions are validated by a numerical method. Furthermore, based on riding comfort and handling stability, the following four suspension systems are evaluated and compared, namely, 2-degree-of-freedom quarter-vehicle model, 2-degree-of-freedom quarter-vehicle with quasi-zero stiffness isolator, 2-degree-of-freedom quarter-vehicle with inerter-nonlinear energy sink absorber, and 2-degree-of-freedom quarter-vehicle integrated control scheme with quasi-zero stiffness and inerter-nonlinear energy sink. It is found that the integrated control scheme with quasi-zero stiffness and inerter-nonlinear energy sink can significantly improve the riding comfort and handling stability at the same time. In addition, the effects of system parameters are studied carefully. The results show that based on the reasonable design of the control system parameters, better riding comfort and handling stability can be obtained. In short, this article provides a theoretical basis for integrating quasi-zero stiffness isolators and inerter-nonlinear energy sink absorbers to improve the riding comfort and handling stability.

scholarly journals Learning an Efficient Gait Cycle of a Biped Robot Based on Reinforcement Learning and Artificial Neural Networks

2019 ◽  
Vol 9 (3) ◽  
pp. 502 ◽  
Author(s):  
Cristyan Gil ◽  
Hiram Calvo ◽  
Humberto Sossa
Keyword(s):  
Reinforcement Learning ◽  
Gait Cycle ◽  
Biped Robot ◽  
Q Learning ◽  
Nao Robot ◽  
Simulated Environment ◽  
Proposed Model ◽  
Normal Speed ◽  
Multi Level ◽  
Efficient Gait

Programming robots for performing different activities requires calculating sequences of values of their joints by taking into account many factors, such as stability and efficiency, at the same time. Particularly for walking, state of the art techniques to approximate these sequences are based on reinforcement learning (RL). In this work we propose a multi-level system, where the same RL method is used first to learn the configuration of robot joints (poses) that allow it to stand with stability, and then in the second level, we find the sequence of poses that let it reach the furthest distance in the shortest time, while avoiding falling down and keeping a straight path. In order to evaluate this, we focus on measuring the time it takes for the robot to travel a certain distance. To our knowledge, this is the first work focusing both on speed and precision of the trajectory at the same time. We implement our model in a simulated environment using q-learning. We compare with the built-in walking modes of an NAO robot by improving normal-speed and enhancing robustness in fast-speed. The proposed model can be extended to other tasks and is independent of a particular robot model.

Gait synthesis for a 12-degree-of-freedom biped robot by the LIPM

2018 ◽  
Author(s):  
Christian Alberto Matilde Dominguez ◽  
Eduardo Morales Sanchez ◽  
Gerardo Israel Perez Soto
Keyword(s):  
Biped Robot ◽  
Degree Of Freedom ◽  
Gait Synthesis

scholarly journals The rising cost of warming waters: effects of temperature on the cost of swimming in fishes

2011 ◽  
Vol 8 (2) ◽  
pp. 266-269 ◽  
Author(s):  
Andrew M. Hein ◽  
Katrina J. Keirsted
Keyword(s):  
Water Temperature ◽  
Fish Species ◽  
Global Climate ◽  
Swimming Performance ◽  
Metabolic Cost ◽  
Quantitative Model ◽  
The Body ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
The Cost

Understanding the effects of water temperature on the swimming performance of fishes is central in understanding how fish species will respond to global climate change. Metabolic cost of transport (COT)—a measure of the energy required to swim a given distance—is a key performance parameter linked to many aspects of fish life history. We develop a quantitative model to predict the effect of water temperature on COT. The model facilitates comparisons among species that differ in body size by incorporating the body mass-dependence of COT. Data from 22 fish species support the temperature and mass dependencies of COT predicted by our model, and demonstrate that modest differences in water temperature can result in substantial differences in the energetic cost of swimming.

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