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.

scholarly journals Constrained Quadratic Programming and Neurodynamics-Based Solver for Energy Optimization of Biped Walking Robots

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Liyang Wang ◽  
Ming Chen ◽  
Xiangkui Jiang ◽  
Wei Wang
Keyword(s):  
Energy Consumption ◽  
Quadratic Programming ◽  
Energy Optimization ◽  
Biped Robot ◽  
High Energy ◽  
Walking Robots ◽  
Biped Robots ◽  
Biped Walking ◽  
Joint Torques ◽  
Force Moment

The application of biped robots is always trapped by their high energy consumption. This paper makes a contribution by optimizing the joint torques to decrease the energy consumption without changing the biped gaits. In this work, a constrained quadratic programming (QP) problem for energy optimization is formulated. A neurodynamics-based solver is presented to solve the QP problem. Differing from the existing literatures, the proposed neurodynamics-based energy optimization (NEO) strategy minimizes the energy consumption and guarantees the following three important constraints simultaneously: (i) the force-moment equilibrium equation of biped robots, (ii) frictions applied by each leg on the ground to hold the biped robot without slippage and tipping over, and (iii) physical limits of the motors. Simulations demonstrate that the proposed strategy is effective for energy-efficient biped walking.

scholarly journals Contact-Dependent Balance Stability of Biped Robots

2018 ◽  
Vol 10 (2) ◽  
Author(s):  
Carlotta Mummolo ◽  
William Z. Peng ◽  
Carlos Gonzalez ◽  
Joo H. Kim
Keyword(s):  
Stability Boundary ◽  
Theoretical Models ◽  
Biped Robot ◽  
Walking Robots ◽  
Stability Boundaries ◽  
Biped Robots ◽  
Double Support ◽  
Contact Configuration ◽  
Multiple Contacts ◽  
Balance Stability

A theoretical–algorithmic framework for the construction of balance stability boundaries of biped robots with multiple contacts with the environment is proposed and implemented on a robotic platform. Comprehensive and univocal definitions of the states of balance of a generic legged system are introduced with respect to the system's contact configuration. Theoretical models of joint-space and center of mass (COM)-space dynamics under multiple contacts, distribution of contact wrenches, and robotic system parameters are established for their integration into a nonlinear programing (NLP) problem. In the proposed approach, the balance stability capabilities of a biped robot are quantified by a partition of the state space of COM position and velocity. The boundary of such a partition provides a threshold between balanced and falling states of the biped robot with respect to a specified contact configuration. For a COM state to be outside of the stability boundary represents the sufficient condition for falling, from which a change in the system's contact is inevitable. Through the calculated stability boundaries, the effects of different contact configurations (single support (SS) and double support (DS) with different step lengths) on the robot's balance stability capabilities can be quantitatively evaluated. In addition, the balance characteristics of the experimental walking trajectories of the robot at various speeds are analyzed in relation to their respective stability boundaries. The proposed framework provides a contact-dependent balance stability criterion for a given system, which can be used to improve the design and control of walking robots.

The Dynamics and Control of a Biped Walking Robot With Seven Degrees of Freedom

1996 ◽  
Vol 118 (4) ◽  
pp. 683-690 ◽  
Author(s):  
Ching-Long Shih
Keyword(s):  
Degrees Of Freedom ◽  
Biped Robot ◽  
The Body ◽  
Walking Robot ◽  
Walking Test ◽  
Biped Walking ◽  
Double Support ◽  
Dynamics And Control ◽  
Biped Walking Robot ◽  
And Control

This research studies the dynamics and motion control of a biped walking robot with seven degrees of freedom. The main features of the biped robot include variable length legs and a translatable balance weight in the body. The statically stable walking of the biped robot is implemented by maintaining the center-of-gravity (cg) inside the convex region of the supporting foot/feet during both single-support and double-support phases. The dynamically stable walking of the biped robot is realized by maintaining the zero moment point (ZMP), which is the virtual total ground reaction point, within the region of the supporting foot during the single-support phases. An implementation of a prototype biped BR-1 and its experimental walking test results are described. The biped robot is able to walk on an even floor both statically and dynamically. On a flat plane, the biped can walk with a speed of 8 cm/second statically, and 20 cm/second dynamically.

scholarly journals DESIGN, DYNAMIC MODIFICATION, AND ADAPTIVE CONTROL OF A NEW BIPED WALKING ROBOT

2006 ◽  
Vol 03 (01) ◽  
pp. 105-126
Author(s):  
AHMAD BAGHERI ◽  
FARID NAJAFI ◽  
REZA FARROKHI ◽  
RAHMAN YOUSEFI MOGHADDAM ◽  
MOHAMMAD EBRAHIM FELEZI
Keyword(s):  
Equations Of Motion ◽  
Biped Robot ◽  
Adaptive Methods ◽  
Walking Robots ◽  
Physical Parameters ◽  
Human Beings ◽  
Adaptive Procedure ◽  
Link Length ◽  
Biped Walking ◽  
Dynamic Modification

Recently, a lot of research has been conducted in the area of biped walking robots that could be compared to human beings. The aim of this article is to control a new planar biped robot by means of an adaptive procedure. The newly designed robot is able to move on its heel like a human. After derivation of dynamic equations of motion for two states of the robot, namely, "supporting leg and trunk" and "swing leg" separately, the stability of robot is achieved by locating the zero moment point (ZMP). A dynamic modification is developed for ZMP positioning. For motion control of the robot, the physical parameters (such as mass, link length and geometry) are estimated (identified) by adaptive methods. A Matlab based software simulation is also conducted.

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.

High-Efficient Biped Walking Based on Flat-Footed Passive Dynamic Walking with Mechanical Impedance at Ankles

2012 ◽  
Vol 24 (3) ◽  
pp. 498-506 ◽  
Author(s):  
Yuta Hanazawa ◽  
◽  
Masaki Yamakita
Keyword(s):  
Energy Efficient ◽  
Mechanical Impedance ◽  
Biped Robot ◽  
Dynamic Walking ◽  
Passive Dynamic Walking ◽  
Biped Robots ◽  
Biped Walking ◽  
Double Support ◽  
High Efficient ◽  
Support Phase

In this paper, we present novel biped walking based on flat-footed Passive Dynamic Walking (PDW) with mechanical impedance at the ankles. To realize biped robot achieving high-efficient walking, PDW has attracted attention. Recently, flat-footed passive dynamic walkers with mechanical impedance at the ankles have been proposed. We show that this passive walker achieves fast, energy-efficient walking using ankle springs and inerters. For this reason, we propose novel biped walking control that mimics PDW to realize biped robots achieving fast, energy-efficient walking on level ground. First, we design a flat-footed biped robot that achieves fast, energy-efficient PDW. To achieve walking based on PDW, the biped robot then takes advantage of a virtual gravitational field that is generated by actuators. The biped robot also pushes off with the foot in the double-support phase to restore energy. By walking simulation, we show that a flat-footed biped robot achieves fast, energy-efficient walking on level ground by the proposed method.

Stability Region-Based Analysis of Walking and Push Recovery Control

2020 ◽  
Author(s):  
William Z. Peng ◽  
Hyunjong Song ◽  
Joo H. Kim
Keyword(s):  
Biped Robot ◽  
Step Length ◽  
Stability Control ◽  
Human Gait ◽  
Biped Robots ◽  
Reduced Order ◽  
Double Support ◽  
Push Recovery ◽  
The Stability ◽  
Time Required

Abstract Push recovery is a vital aspect of balance stability control in biped robots. In this work, the response of a biped system to unexpected external perturbations is analyzed for different tasks and controllers using stability criteria based on balanced and steppable regions. The steppable region for a given step length and the balanced regions for single and double support contacts are constructed for a biped robot using optimization with its system dynamics, kinematic limits, actuation limits, and contact interactions with the environment. The regions are compared with those of a human subject to demonstrate that human gait exhibits unbalanced (but steppable) phases largely absent in robotic gait. These regions are also applied to a comparative analysis against capturability, where the computed steppable region is significantly larger than the capture region of an equivalent reduced-order model. The stability regions are also used to compare the performance of controllers during a double support balancing task. The implemented hip, knee, and ankle strategy-based controller led to improved stabilization — i.e., decreased foot tipping and time required to balance — relative to an existing hip and ankle controller and a gyro feedback controller. The proposed approaches are applicable to the analysis of any bipedal task and stability controller in general.

Passive and dynamic gait measures for biped mechanism: formulation and simulation analysis

Robotica ◽  
2012 ◽  
Vol 31 (4) ◽  
pp. 555-572 ◽  
Author(s):  
Carlotta Mummolo ◽  
Joo H. Kim
Keyword(s):  
Simulation Analysis ◽  
Human Walking ◽  
Human Gait ◽  
Walking Robots ◽  
Weight Functions ◽  
Dynamic Walking ◽  
Biped Walking ◽  
Walking Motion ◽  
Normal Human ◽  
Dynamic Gait

SUMMARYUnderstanding and mimicking human gait is essential for design and control of biped walking robots. The unique characteristics of normal human gait are described as passive dynamic walking, whereas general human gait is neither completely passive nor always dynamic. To study various walking motions, it is important to quantify the different levels of passivity and dynamicity, which have not been addressed in the current literature. In this paper, we introduce the initial formulations of Passive Gait Measure (PGM) and Dynamic Gait Measure (DGM) that quantify passivity and dynamicity, respectively, of a given biped walking motion, and the proposed formulations will be demonstrated for proof-of-concepts using gait simulation and analysis. The PGM is associated with the optimality of natural human walking, where the passivity weight functions are proposed and incorporated in the minimization of physiologically inspired weighted actuator torques. The PGM then measures the relative contribution of the stance ankle actuation. The DGM is associated with the gait stability, and quantifies the effects of inertia in terms of the Zero-Moment Point and the ground projection of center of mass. In addition, the DGM takes into account the stance foot dimension and the relative threshold between static and dynamic walking. As examples, both human-like and robotic walking motions during single support phase are generated for a planar biped system using the passivity weights and proper gait parameters. The calculated PGM values show more passive nature of human-like walking as compared with the robotic walking. The DGM results verify the dynamic nature of normal human walking with anthropomorphic foot dimension. In general, the DGMs for human-like walking are greater than those for robotic walking. The resulting DGMs also demonstrate their dependence on the stance foot dimension as well as the walking motion; for a given walking motion, smaller foot dimension results in increased dynamicity. Future work on experimental validation and demonstration will involve actual walking robots and human subjects. The proposed results will benefit the human gait studies and the development of walking robots.

scholarly journals Optimized stable gait planning of biped robot using multi-objective evolutionary JAYA algorithm

2020 ◽  
Vol 17 (6) ◽  
pp. 172988142097634
Author(s):  
Huan Tran Thien ◽  
Cao Van Kien ◽  
Ho Pham Huy Anh
Keyword(s):  
Inverse Kinematics ◽  
Biped Robot ◽  
Step Length ◽  
Jaya Algorithm ◽  
Kinetic Chain ◽  
Biped Walking ◽  
Gait Planning ◽  
Multi Objective ◽  
Simulation And Experiment ◽  
Stable Gait

This article proposes a new stable biped walking pattern generator with preset step-length value, optimized by multi-objective JAYA algorithm. The biped robot is modeled as a kinetic chain of 11 links connected by 10 joints. The inverse kinematics of the biped is applied to derive the specified biped hip and feet positions. The two objectives related to the biped walking stability and the biped to follow the preset step-length magnitude have been fully investigated and Pareto optimal front of solutions has been acquired. To demonstrate the effectiveness and superiority of proposed multi-objective JAYA, the results are compared to those of MO-PSO and MO-NSGA-2 optimization approaches. The simulation and experiment results investigated over the real small-scaled biped HUBOT-4 assert that the multi-objective JAYA technique ensures an outperforming effective and stable gait planning and walking for biped with accurate preset step-length value.

scholarly journals Effects of Torso Pitch Motion on Energy Efficiency of Biped Robot Walking

2021 ◽  
Vol 11 (5) ◽  
pp. 2342
Author(s):  
Long Li ◽  
Zhongqu Xie ◽  
Xiang Luo ◽  
Juanjuan Li
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Biped Robot ◽  
Gait Pattern ◽  
Pattern Generation ◽  
Biped Robots ◽  
Pitch Motion ◽  
Double Support ◽  
Gait Parameters ◽  
Support Phase

Gait pattern generation has an important influence on the walking quality of biped robots. In most gait pattern generation methods, it is usually assumed that the torso keeps vertical during walking. It is very intuitive and simple. However, it may not be the most efficient. In this paper, we propose a gait pattern with torso pitch motion (TPM) during walking. We also present a gait pattern with torso keeping vertical (TKV) to study the effects of TPM on energy efficiency of biped robots. We define the cyclic gait of a five-link biped robot with several gait parameters. The gait parameters are determined by optimization. The optimization criterion is chosen to minimize the energy consumption per unit distance of the biped robot. Under this criterion, the optimal gait performances of TPM and TKV are compared over different step lengths and different gait periods. It is observed that (1) TPM saves more than 12% energy on average compared with TKV, and the main factor of energy-saving in TPM is the reduction of energy consumption of the swing knee in the double support phase and (2) the overall trend of torso motion is leaning forward in double support phase and leaning backward in single support phase, and the amplitude of the torso pitch motion increases as gait period or step length increases.

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