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.

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 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.

Numerical synthesis of three-dimensional gait cycles by dynamics optimization

Robotica ◽  
2010 ◽  
Vol 29 (3) ◽  
pp. 445-459 ◽  
Author(s):  
Tarik Saidouni
Keyword(s):  
Optimization Problem ◽  
Dynamic Models ◽  
Three Dimensional ◽  
Design Parameters ◽  
Double Support ◽  
Locomotion System ◽  
Joint Coordinates ◽  
Parametric Optimization Problem ◽  
Independent Parameters ◽  
Support Phase

SUMMARYThe present paper aims at generating three-dimensional cyclic gait of a biped with a locomotion system having anthropomorphic characteristics. Kinematic and dynamic models of both single and double support phases are extensively developed with a special attention devoted to the double support phase. A variety of gait constraints defining a feasible walk is taken into account. Joint trajectories are approximated by cubic spline functions connected at uniformly distributed knots. Joint coordinates at knots, walking phase durations, and independent parameters at phase transitions are the design parameters of a parametric optimization problem. Therefore, only the pattern organization and the gait speed are explicitly specified. The effectiveness of the proposed method is verified and discussed through some simulation results.

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.

START, STOP AND TRANSITION OF VELOCITIES OF AN UNDER-ACTUATED BIPEDAL ROBOT WITHOUT REFERENCE TRAJECTORIES

2004 ◽  
Vol 01 (02) ◽  
pp. 349-374 ◽  
Author(s):  
CHRISTOPHE SABOURIN ◽  
OLIVIER BRUNEAU ◽  
JEAN-GUY FONTAINE
Keyword(s):  
Control Strategy ◽  
The Other ◽  
Dynamic Walking ◽  
Bipedal Robot ◽  
Maximum Torque ◽  
On Line ◽  
Real Robot ◽  
The One ◽  
Technological Limitations ◽  
Reference Trajectories

In this paper, we propose a control strategy allowing us to perform the transition of velocities included in [0 m/s; 1 m/s] for the dynamic walking of a virtual under-actuated robot (RABBIT) without reference trajectories. This strategy of control enables us to carry out the transition from stop towards walking and the reverse process. The interest of this method is that, on the one hand, the intrinsic dynamics of the system are exploited by using a succession of active and passive phases and, on the other hand, the control strategy is very simple to implement on-line. Moreover, we apply this method by taking into account the technological limitations related to experimentation on the real robot such as dry and viscous frictions, maximum torque, and maximum power.

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.

Sign in / Sign up

Export Citation Format

Share Document