scholarly journals Simulation of Disturbance Recovery Based on MPC and Whole-Body Dynamics Control of Biped Walking

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2971 ◽  
Author(s):  
Xuanyang Shi ◽  
Junyao Gao ◽  
Yizhou Lu ◽  
Dingkui Tian ◽  
Yi Liu
Keyword(s):  
Large Scale ◽  
Center Of Mass ◽  
Biped Robot ◽  
Optimization Method ◽  
Stability Control ◽  
Body Motion ◽  
Whole Body ◽  
Human Beings ◽  
Foot Placement ◽  
Body Dynamics

Biped robots are similar to human beings and have broad application prospects in the fields of family service, disaster rescue and military affairs. However, simplified models and fixed center of mass (COM) used in previous research ignore the large-scale stability control ability implied by whole-body motion. The present paper proposed a two-level controller based on a simplified model and whole-body dynamics. In high level, a model predictive control (MPC) controller is implemented to improve zero moment point (ZMP) control performance. In low level, a quadratic programming optimization method is adopted to realize trajectory tracking and stabilization with friction and joint constraints. The simulation shows that a 12-degree-of-freedom force-controlled biped robot model, adopting the method proposed in this paper, can recover from a 40 Nm disturbance when walking at 1.44 km/h without adjusting the foot placement, and can walk on an unknown 4 cm high stairs and a rotating slope with a maximum inclination of 10°. The method is also adopted to realize fast walking up to 6 km/h.

scholarly journals Sliding Balance Control of a Point-Foot Biped Robot Based on a Dual-Objective Convergent Equation

2021 ◽  
Vol 11 (9) ◽  
pp. 4016
Author(s):  
Yizhou Lu ◽  
Junyao Gao ◽  
Xuanyang Shi ◽  
Dingkui Tian ◽  
Yi Liu
Keyword(s):  
Balance Control ◽  
Center Of Mass ◽  
Biped Robot ◽  
Optimization Method ◽  
Contact Forces ◽  
Joint Torque ◽  
Whole Body ◽  
Physical Constraints ◽  
Equilibrium Control ◽  
Control Framework

The point-foot biped robot is highly adaptable to and can move rapidly on complex, non-structural and non-continuous terrain, as demonstrated in many studies. However, few studies have investigated balance control methods for point-foot sliding on low-friction terrain. This article presents a control framework based on the dual-objective convergence method and whole-body control for the point-foot biped robot to stabilize its posture balance in sliding. In this control framework, a dual-objective convergence equation is used to construct the posture stability criterion and the corresponding equilibrium control task, which are simultaneously converged. Control tasks are then carried out through the whole-body control framework, which adopts an optimization method to calculate the viable joint torque under the physical constraints of dynamics, friction and contact forces. In addition, this article extends the proposed approach to balance control in standing recovery. Finally, the capabilities of the proposed controller are verified in simulations in which a 26.9-kg three-link point-foot biped robot (1) slides over a 10∘ trapezoidal terrain, (2) slides on terrain with a sinusoidal friction coefficient between 0.05 and 0.25 and (3) stands and recovers from a center-of-mass offset of 0.02 m.

Unifying Representations and Large-Scale Whole-Body Motion Databases for Studying Human Motion

2016 ◽  
Vol 32 (4) ◽  
pp. 796-809 ◽  
Author(s):  
Christian Mandery ◽  
Omer Terlemez ◽  
Martin Do ◽  
Nikolaus Vahrenkamp ◽  
Tamim Asfour
Keyword(s):  
Large Scale ◽  
Human Motion ◽  
Body Motion ◽  
Whole Body

scholarly journals Robots that look like humans: A brief look into humanoid robotics

2018 ◽  
Author(s):  
Eiichi Yoshida
Keyword(s):  
Degrees Of Freedom ◽  
Large Scale ◽  
Humanoid Robots ◽  
Pattern Generation ◽  
Human Robot Interaction ◽  
Cognitive Robotics ◽  
Body Motion ◽  
Upper Body ◽  
Whole Body ◽  
Robot Interaction

This article provides a brief overview of the technology of humanoid robots. First, historical development and hardware progress are presented mainly on human-size full-body biped humanoid robots, together with progress in pattern generation of biped locomotion. Then, «whole-body motion» – coordinating leg and arm movements to fully leverage humanoids’ high degrees of freedom – is presented, followed by its applications in fields such as device evaluation and large-scale assembly. Upper-body humanoids with a mobile base, which are mainly utilized for research on human-robot interaction and cognitive robotics, are also introduced before addressing current issues and perspectives.

scholarly journals Can foot placement during gait be trained? Adaptations in stability control when ankle moments are constrained

2021 ◽  
Author(s):  
Laura A. Hoogstad ◽  
Anina Moira van Leeuwen ◽  
Jaap H. van Dieen ◽  
Sjoerd M. Bruijn
Keyword(s):  
Prolonged Exposure ◽  
Center Of Mass ◽  
Stability Control ◽  
Local Dynamic ◽  
Foot Placement ◽  
Ankle Moment ◽  
Training Tool ◽  
Local Dynamic Stability ◽  
After Effect ◽  
Placement Accuracy

Accurate coordination of mediolateral foot placement, relative to the center of mass kinematic state, is one of the mechanisms which ensures mediolateral stability during human walking. Previously, we found that shoes constraining ankle moments decreased foot placement accuracy, presumably by impairing control over movement of the swing leg. As such, ankle moment constraints can be seen as a perturbation of foot placement. Direct mechanical perturbations of the swing leg trajectory can improve foot placement accuracy as an after-effect. Here, we asked whether constrained ankle moments could have a similar effect. If confirmed, this would offer a simple training tool for individuals with impaired foot placement control. Participants (n=19) walked in three conditions; normal (baseline, 10 minutes), while wearing shoes constraining ankle moments (training, 15 minutes), and normal again (after-effects, 10 minutes). Foot placement accuracy was calculated as the percentage of variance in foot placement that could be predicted based on the center of mass kinematic state in the preceding swing phase. When walking with constrained ankle moments, foot placement accuracy decreased initially compared to baseline, but it gradually improved over time. In the after-effect condition, foot placement accuracy was higher than during baseline, but this difference was not significant. When walking with constrained ankle moments, we observed increased step width, decreased stride time and reduced local dynamic stability. In conclusion, constraining ankle moment control deteriorates foot placement accuracy. A non-significant trend towards improved foot placement accuracy after prolonged exposure to constrained ankle moments, allows for speculation on a training potential.

scholarly journals Real-time full body motion imitation on the COMAN humanoid robot

Robotica ◽  
2014 ◽  
Vol 33 (5) ◽  
pp. 1049-1061 ◽  
Author(s):  
Andrej Gams ◽  
Jesse van den Kieboom ◽  
Florin Dzeladini ◽  
Aleš Ude ◽  
Auke Jan Ijspeert
Keyword(s):  
Real Time ◽  
Humanoid Robot ◽  
Center Of Mass ◽  
Stability Control ◽  
Body Motion ◽  
Support Vector ◽  
Time Motion ◽  
Vector Machines ◽  
On Line ◽  
Full Body

SUMMARYOn-line full body imitation with a humanoid robot standing on its own two feet requires simultaneously maintaining the balance and imitating the motion of the demonstrator. In this paper we present a method that allows real-time motion imitation while maintaining stability, based on prioritized task control. We also describe a method of modified prioritized kinematic control that constrains the imitated motion to preserve stability only when the robot would tip over, but does not alter the motions otherwise. To cope with the passive compliance of the robot, we show how to model the estimation of the center of mass of the robot using support vector machines. In the paper we give detailed description of all steps of the algorithm, essentially providing a tutorial on the implementation of kinematic stability control. We present the results on a child-sized humanoid robot called Compliant Humanoid Platform or COMAN. Our implementation shows reactive and stable on-line motion imitation of the humanoid robot.

Comparing Legged Locomotion With a Sprung-Knee and Telescoping-Spring When Hip Torque is Applied

2013 ◽  
Author(s):  
Nikhil Rao ◽  
Zhuohua Shen ◽  
Justin Seipel
Keyword(s):  
Center Of Mass ◽  
Legged Locomotion ◽  
Input Power ◽  
Whole Body ◽  
Segment Model ◽  
Distinct Structure ◽  
Body Dynamics ◽  
The Stability ◽  
Special Case

Legged locomotion has been a subject of study for many years. However, the role of the knee in whole-body dynamics of locomotion is not well understood, especially for non-conservative dynamics. Based upon a hip actuated Spring-Loaded Inverted Pendulum (Hip-actuated SLIP) model, we develop a more human-like, two-segment leg model with a pin-jointed springy knee, to see what effects a knee has in the context of an applied hip torque. Overall, we find that the governing equations for the two-segment (knee) version have a distinct structure when compared to the telescoping version of SLIP. The two-segment model with a knee spring influences forces acting on the mass center in a more complex way than a telescoping spring. While a wide variation of behavior is possible for the two-segment model, here we focus on comparing the dynamics for a special case when the knee spring resting angle is 90°. For this particular choice of resting knee angle we find that the knee version of actuated SLIP can have similar locomotion dynamics to the telescoping version of actuated SLIP. This result provides one explanation for how animals and robots with multi-segmented legs could produce overall center-of-mass dynamics that are similar to models with telescoping legs. Nonetheless, despite overall similarities for this special case, small differences in the stability of locomotion are still observed. In particular, we find that the knee version tends to be slightly more stable than the telescoping SLIP in terms of the allowable size of perturbations, while requiring higher input power.

Stability Region-Based Analysis of Walking and Push Recovery Control

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
William Z. Peng ◽  
Hyunjong Song ◽  
Joo H. Kim
Keyword(s):  
Sagittal Plane ◽  
Center Of Mass ◽  
Biped Robot ◽  
Optimization Method ◽  
Order System ◽  
Double Support ◽  
Push Recovery ◽  
One Step ◽  
To Come ◽  
Time Required

Abstract To achieve walking and push recovery successfully, a biped robot must be able to determine if it can maintain its current contact configuration or transition into another one without falling. In this study, the ability of a humanoid robot to maintain single support (SS) or double support (DS) contact and to achieve a step are represented by balanced and steppable regions, respectively, as proposed partitions of an augmented center-of-mass-state space. These regions are constructed with an optimization method that incorporates full-order system dynamics, system properties such as kinematic and actuation limits, and contact interactions with the environment in the two-dimensional sagittal plane. The SS balanced, DS balanced, and steppable regions are obtained for both experimental and simulated walking trajectories of the robot with and without the swing foot velocity constraint to evaluate the contribution of the swing leg momentum. A comparative analysis against one-step capturability, the ability of a biped to come to a stop after one step, demonstrates that the computed steppable region significantly exceeds the one-step capturability of an equivalent reduced-order model. The use of balanced regions to characterize the full balance capability criteria of the system and benchmark controllers is demonstrated with three push recovery controllers. The implemented hip–knee–ankle controller resulted in improved stabilization with respect to decreased foot tipping and time required to balance, relative to an existing hip–ankle controller and a gyro balance feedback controller.

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