scholarly journals Walking Gait of a Biped with a Wearable Walking Assist Device

2015 ◽  
Vol 12 (04) ◽  
pp. 1550018 ◽  
Author(s):  
Yannick Aoustin
Keyword(s):  
Dynamic Model ◽  
Unique Solution ◽  
Energy Cost ◽  
Assist Device ◽  
Double Support ◽  
Kinematic Chains ◽  
Walking Gait ◽  
Time Period ◽  
Single Support Phase ◽  
Support Phase

A ballistic walking gait is designed for a planar biped equipped with a wearable walking assist device. The biped is a seven-link planar biped with two legs, two feet, and a trunk. The wearable walking assist device is composed of a bodyweight support, two upper legs, two lower legs, and two shoes. The dynamic model of the biped with its walking assist device, containing two closed kinematic chains, is calculated by virtually cutting each of both loops at one of their point. In the single support phase, the biped with its assist device moves due to the existence of a momentum, produced mechanically, without applying active torques in the inter-link joints. The biped and this assist device are controlled with impulsive torques at the instantaneous double support to obtain a cyclic gait. The impulsive torques are applied in the six inter-link joints of the biped and in several inter-link joints of the wearable walking assist device. The following distributions of impulsive torques, in the knees or the ankles, hips and knees, hips and ankles, or knees and ankles and the fully assist device, are compared with the case of no assistance for the biped. Each time, an infinity of solutions exists to find the impulsive torques. An energy cost functional defined from these impulsive torques is minimized to determine a unique solution. Numerical results show that for a given time period and a given length of the walking gait step, the assistance of the hips is a good compromise to help the biped.

scholarly journals Implementation and Integration of Fuzzy Algorithms for Descending Stair of KMEI Humanoid Robot

2020 ◽  
pp. 372-388
Author(s):  
Wulandari Puspita Sari ◽  
R. Sanggar Dewanto ◽  
Dadet Pramadihanto
Keyword(s):  
Humanoid Robot ◽  
Fuzzy Logic Controller ◽  
Integrated Control ◽  
Step Length ◽  
Smooth Transition ◽  
Double Support ◽  
Walking Gait ◽  
Single Support Phase ◽  
Support Phase ◽  
Double Support Phase

Locomotion of humanoid robot depends on the mechanical characteristic of the robot. Walking on descending stairs with integrated control systems for the humanoid robot is proposed. The analysis of trajectory for descending stairs is calculated by the constrains of step length stair using fuzzy algorithm. The established humanoid robot on dynamically balance on this matter of zero moment point has been pretended to be consisting of single support phase and double support phase. Walking transition from single support phase to double support phase is needed for a smooth transition cycle. To accomplish the problem, integrated motion and controller are divided into two conditions: motion working on offline planning and controller working online walking gait generation. To solve the defect during locomotion of the humanoid robot, it is directly controlled by the fuzzy logic controller. This paper verified the simulation and the experiment for descending stair of KMEI humanoid robot. 

scholarly journals Walking Trajectory Optimization With Rotation of the Feet for a Planar Bipedal Robot With Four-Bar Knees

2012 ◽  
Author(s):  
Arnaud Hamon ◽  
Yannick Aoustin
Keyword(s):  
Knee Joint ◽  
Trajectory Optimization ◽  
The Other ◽  
Bipedal Robot ◽  
Double Support ◽  
Walking Gait ◽  
Parametric Optimization Problem ◽  
Four Bar Linkage ◽  
Reference Trajectories ◽  
Support Phase

The design of a knee joint is a key issue in robotics and biomechanics to improve the compatibility between prosthesis and human movements and to improve the bipedal robot performances. We propose a novel design for the knee joint of a planar bipedal robot, based on a four-bar linkage. The dynamic model of the planar bipedal robot is calculated. We design walking reference trajectories with double support phases, single supports with a flat contact of the foot in the ground and single support phases with rotation of the foot around the toe. During the double support phase, both feet rotate. This phase is ended by an impact on the ground of the toe of one foot, the other foot taking off. The single support phase is ended by an impact of the swing foot heel, the other foot keeping contact with the ground through its toe. For both gaits, the reference trajectories of the rotational joints are prescribed by polynomial functions in time. A parametric optimization problem is presented for the determination of the parameters corresponding to the optimal cyclic walking gaits. The main contribution of this paper is the design of a dynamical stable walking gait with double support phases with feet rotation, impacts and single support phases for this novel bipedal robot.

Effect of Heel to Toe Walking on Time Optimal Walking of a Biped During Single Support Phase

2014 ◽  
Author(s):  
Tara Farizeh ◽  
Mohammad Jafar Sadigh
Keyword(s):  
Whole Body ◽  
Maximum Speed ◽  
Flat Foot ◽  
Double Support ◽  
Time Optimal ◽  
Foot Model ◽  
Two Phases ◽  
Single Support Phase ◽  
Toe Walking ◽  
Support Phase

Dynamic modeling of a biped has gained lots of attention during past few decades. While stability and energy consumption were among the first issues which were considered by researchers, nowadays achieving maximum speed and improving pattern of motion to reach that speed are the important targets in this field. Walking model of bipeds usually includes two phases, single support phase (SSP), in which only the stance foot is in contact with the ground while the opposite leg is swinging; and double support phase (DSP) in which the swing leg is in contact with the ground in addition to the rear foot. It is common in the simplified model of walking to assume the stance leg foot, flat during the entire SSP; but one may know that for human walking, there is also a sub-phase during SSP in which the heel of stance foot leaves the ground while the whole body is supported by toe link. Actually in this sub phase the stance leg foot rotates around the toe joint. This paper is trying to study the effect of toe-link and heel to toe walking model on dynamic and specially speed of walking compare to flat foot model.

A force-resisting balance control strategy for a walking biped robot under an unknown, continuous force

Robotica ◽  
2014 ◽  
Vol 34 (7) ◽  
pp. 1495-1516
Author(s):  
Yeoun-Jae Kim ◽  
Joon-Yong Lee ◽  
Ju-Jang Lee
Keyword(s):  
External Force ◽  
Control Strategy ◽  
Balance Control ◽  
Biped Robot ◽  
Second Step ◽  
Double Support ◽  
Zero Moment ◽  
External Forces ◽  
Single Support Phase ◽  
Support Phase

SUMMARYIn this paper, we propose and examine a force-resisting balance control strategy for a walking biped robot under the application of a sudden unknown, continuous force. We assume that the external force is acting on the pelvis of a walking biped robot and that the external force in the z-direction is negligible compared to the external forces in the x- and y-directions. The main control strategy involves moving the zero moment point (ZMP) of the walking robot to the center of the robot's sole resisting the externally applied force. This strategy is divided into three steps. The first step is to detect an abnormal situation in which an unknown continuous force is applied by examining the position of the ZMP. The second step is to move the ZMP of the robot to the center of the sole resisting the external force. The third step is to have the biped robot convert from single support phase (SSP) to double support phase (DSP) for an increased force-resisting capability. Computer simulations and experiments of the proposed methods are performed to benchmark the suggested control strategy.

Biped Walking Control Based on Quadratic Programming and Differential Inequalities

2020 ◽  
Author(s):  
Stella Diniz Urban ◽  
Bruno Vilhena Adorno
Keyword(s):  
Quadratic Programming ◽  
Center Of Mass ◽  
Bipedal Walking ◽  
Differential Inequalities ◽  
Double Support ◽  
Cycle Simulation ◽  
Minimum Height ◽  
Joint Limits ◽  
Single Support Phase ◽  
Support Phase

This paper presents a novel method to control a bipedal walking based on quadratic programming and differential inequalities using geometric primitives. We allow the center of mass to move anywhere inside the support polygon during the walking cycle, as opposed to classic methods, which usually rely on tracking a desired trajectory for the zero moment point. The constraints keep the robot balance, the pelvis above a minimum height, and prevent the violation of joint limits during the complete walking cycle. Simulation results using the legs of the Poppy humanoid robot show that the trajectories of the closed-loop system converge to the desired center of mass position during the double support phase and the swing foot's trajectories converge to the desired pose during the single support phase while all constraints are obeyed.

scholarly journals Optimal reference trajectories for walking and running of a biped robot

Robotica ◽  
2001 ◽  
Vol 19 (5) ◽  
pp. 557-569 ◽  
Author(s):  
C. Chevallereau ◽  
Y. Aoustin
Keyword(s):  
Biped Robot ◽  
Physical Parameters ◽  
Polynomial Functions ◽  
Minimal Energy ◽  
Double Support ◽  
Cyclic Motion ◽  
Under Construction ◽  
Single Support Phase ◽  
Reference Trajectories ◽  
Support Phase

The objective of this study is to obtain optimal cyclic gaits for a biped robot without actuated ankles. Two types of motion are studied: walking and running. For walking, the gait is composed uniquely of successive single support phases and instantaneous double support phases that are modelled by passive impact equations. The legs swap their roles from one single support phase to the next one. For running, the gait is composed of stance phases and flight phases. A passive impact with the ground exists at the end of flight. During each phase the evolution of m joints variables is assumed to be polynomial functions, m is the number of actuators. The evolution of the other variables is deduced from the dynamic model of the biped. The coefficients of the polynomial functions are chosen to optimise criteria and to insure cyclic motion of the biped. The chosen criteria are: maximal advance velocity, minimal torque, and minimal energy. Furthermore, the optimal gait is defined with respect to given performances of actuators: The torques and velocities at the output of the gear box are bounded. For this study, the physical parameters of a prototype, which is under construction, are used. Optimal walking and running are defined. The running is more efficient for high velocities than the walking with respect to the studied criteria.

scholarly journals From stable walking to steering of a 3D bipedal robot with passive point feet

Robotica ◽  
2012 ◽  
Vol 30 (7) ◽  
pp. 1119-1130 ◽  
Author(s):  
Ching-Long Shih ◽  
J. W. Grizzle ◽  
Christine Chevallereau
Keyword(s):  
Closed Loop ◽  
Control Design ◽  
Asymptotically Stable ◽  
Closed Loop System ◽  
Bipedal Robot ◽  
Walking Gait ◽  
Straight Line ◽  
Natural Symmetry ◽  
Single Support Phase ◽  
Support Phase

SUMMARYThis paper exploits a natural symmetry present in a 3D robot in order to achieve asymptotically stable steering. The robot under study is composed of 5-links and unactuated point feet; it has 9 DoF (degree-of-freedom) in the single-support phase and six actuators. The control design begins with a hybrid feedback controller that stabilizes a straight-line walking gait for the 3D bipedal robot. The closed-loop system (i.e., robot plus controller) is shown to be equivariant under yaw rotations, and this property is used to construct a modification of the controller that has a local, but uniform, input-to-state stability (ISS) property, where the input is the desired turning direction. The resulting controller is capable of adjusting the net yaw rotation of the robot over a step in order to steer the robot along paths with mild curvature. An interesting feature of this work is that one is able to control the robot's motion along a curved path using only a single predefined periodic motion.

scholarly journals Immediate effects of a novel walking assist device with auxiliary illuminator on patients after acute strokes

2019 ◽  
Vol 39 (02) ◽  
pp. 115-124
Author(s):  
Wan-Yun Huang ◽  
Sheng-Hui Tuan ◽  
Min-Hui Li ◽  
Xin-Yu Liu ◽  
Pei-Te Hsu
Keyword(s):  
Gait Speed ◽  
Stride Length ◽  
Stance Phase ◽  
Gait Cycle ◽  
Swing Phase ◽  
Heel Strike ◽  
Assist Device ◽  
Double Support ◽  
Strike Angle ◽  
Support Phase

Background: Many patients after acute stage of stroke are present with abnormal gait pattern due to weakness or hypertonicity of the affected limbs. Facilitation of normal gait is a primary goal of rehabilitation on these patients.Objective: We aimed to investigate whether walking assist device with auxiliary illuminator (quad-cane with laser) providing visual feedback during ambulation could improve parameters of gait cycle immediately among patients with subacute and chronic stroke.Methods: This was a cross-sectional study and 30 participants (male 23, female 7, group 1) with mean age [Formula: see text] years were recruited. Among them, 22 used ankle-foot orthosis [(AFO), group 2] and 8 did not use AFO (group 3) at usual walking. All the participants walked along a strait corridor with even surface for 20[Formula: see text]m without and with using a quad-cane with laser, respectively. A gait analyzer (Reha-Watch1 system) was used to measure the changes of the parameters of gait cycle, including stride length, cadence, gait speed, stance phase, swing phase, duration of single support and double support, the angle between toes and the ground at the time of toe-off (the toe-off angle) and the angle between calcaneus and the ground at the time of heel-strike (the heel-strike angle), before and with the use of a quad-cane with laser.Results: The increase in the heel-strike angle reached a significant difference in groups 1 2, and 3 ([Formula: see text], and [Formula: see text], respectively). However, the stride length, the gait speed, the cadence, percentage of the stance phase, swing phase, single-support phase, and double-support phase in a gait cycle, and the toe-off angle showed no significant change with the use of quad-cane with laser.Conclusion: Patients after acute stroke had an immediate and significant increase in the heel-stroke angle by using a quad-cane with laser during ambulation, which might help the patients to reduce knee hyperextension moment and lessen the pressure of heel at loading phase.

scholarly journals Feedback control of an underactuated planar bipedal robot with impulsive foot action

Robotica ◽  
2005 ◽  
Vol 23 (5) ◽  
pp. 567-580 ◽  
Author(s):  
Jun Ho Choi ◽  
J. W. Grizzle
Keyword(s):  
Design Method ◽  
Zero Dynamics ◽  
Bipedal Robot ◽  
Double Support ◽  
Hybrid Zero Dynamics ◽  
Foot Model ◽  
Poincaré Return Map ◽  
Efficient Gait ◽  
Single Support Phase ◽  
Support Phase

A planar underactuated bipedal robot with an impulsive foot model is considered. The analysis extends previous work on a model with unactuated point feet of Westervelt et al. to include the actuator model of Kuo. The impulsive actuator at each leg end is active only during the double support phase, which results in the model being identical to the model with unactuated point feet for the single support phase. However, the impulsive foot actuation results in a different model for the double support map. Conditions for the existence of a hybrid zero dynamics for the robot with foot actuation are studied. A feedback design method is proposed that integrates actuation in the single and double support phases. A stability analysis is performed using a Poincaré return map. As in Kuo's model, a more efficient gait is demonstrated with an impulsive foot action.

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