scholarly journals Dynamic Imbalance Analysis and Stability Control of Galloping Gait for a Passive Quadruped Robot

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Chunlei Wang ◽  
Ting Zhang ◽  
Xiaohui Wei ◽  
Yongjun Long ◽  
Shigang Wang
Keyword(s):  
Stability Criterion ◽  
Center Of Mass ◽  
Zero Point ◽  
Stability Control ◽  
Quadruped Robot ◽  
Peak Time ◽  
Flight Phase ◽  
Trunk Posture ◽  
The Stability ◽  
Necessary And Sufficient

Some imbalance and balance postures of a passive quadruped robot with a simplified mathematical model are studied. Through analyzing the influence of the touchdown angle of the rear leg on the posture of the trunk during the flight phase, the stability criterion is concluded: the closer are the two moments which are the zero time of the pitching angle and the peak time of the center of mass, the better is the stability of the trunk posture during the flight phase. Additionally, the validity of the stability criterion is verified for the cat, greyhound, lion, racehorse, basset hound, and giraffe. Furthermore, the stability criterion is also applicable when the center of the mass of body is shifted. Based on the stability criterion, the necessary and sufficient condition of the galloping stability for the quadruped robot is proposed to attain a controlled thrust. The control strategy is designed by an optimization dichotomy algorithm for seeking the zero point of the balance condition. Through the control results, it is demonstrated that the imbalance posture of the trunk could be stabilized by adjusting the stiffness of four legs.

Normalized Energy Stability Margin Based Analysis of Omni-Directional Static Walking of a Quadruped Robot on Rough Terrain

2011 ◽  
Vol 383-390 ◽  
pp. 7401-7405
Author(s):  
Lei Zhang ◽  
Shan Gao
Keyword(s):  
Stability Criterion ◽  
Simulation Experiment ◽  
Stability Margin ◽  
Quadruped Robot ◽  
Center Of Gravity ◽  
Energy Stability ◽  
Rough Terrain ◽  
The Stability

With Normalized Energy Stability Margin(Sne ) as stability criterion, this paper studies the tumbles of omni-directional static walking of a quadruped robot around the line connecting two adjacent supporting legs on rough terrain, proposes the method to improve the stability of quadruped robot by increasing the (Sne ) value, which is realized by lowering the height of center of gravity(COG), and finally substantiates the feasibility of the method through a simulation experiment.

scholarly journals Stabilized controller of a two wheels robot

2020 ◽  
Vol 9 (4) ◽  
pp. 1357-1363
Author(s):  
Ahmad Fahmi ◽  
Marizan Sulaiman ◽  
Indrazno Siradjuddin ◽  
I Made Wirawan ◽  
Abdul Syukor Mohamad Jaya ◽  
...  
Keyword(s):  
Control Method ◽  
Control Function ◽  
Balance Control ◽  
Linear Quadratic Regulator ◽  
Zero Point ◽  
Stability Control ◽  
Pole Placement ◽  
Linear Quadratic ◽  
Balancing Robot ◽  
The Stability

The Segway Human Transport (HT) robot, it is dynamical self-balancing robot type. The stability control is an important thing for the Segway robot. It is an indisputable fact that Segway robot is a natural instability framework robot. The case study of the Segway robot focuses on running balance control systems. The roll, pitch, and yaw balance of this robot are obtained by estimating the Kalman Filter with a combination of the pole placement and the Linear Quadratic Regulator (LQR) control method. In our system configuration, the mathematical model of the robot will be proved by Matlab Simulink by modelling of the stabilizing control system of all state variable input. Furthermore, the implementation of this system modelled to the real-time test of the Segway robot. The expected result is by substitute the known parameters from Gyro, Accelero and both rotary encoder to initial stabilize control function, the system will respond to the zero input curve. The coordinate units of displacement response and inclination response pictures are the same. As our expected, the response of the system can reach the zero point position. 

A NEW STABILITY CRITERION FOR HUMAN SEATED TASKS WITH GIVEN POSTURES

2012 ◽  
Vol 09 (03) ◽  
pp. 1250015 ◽  
Author(s):  
BRADLEY HOWARD ◽  
JINGZHOU YANG
Keyword(s):  
Stability Analysis ◽  
Stability Criterion ◽  
Center Of Mass ◽  
Reaction Force ◽  
Joint Torque ◽  
Human Model ◽  
Digital Human Model ◽  
Applied Forces ◽  
The Stability ◽  
Digital Human

In digital human modeling (DHM), the analysis of postural stability has five main goals: to determine if a posture is stable or unstable through an explicit criterion; to quantify the level of stability or provide a margin of stability that accounts for the height of the center of mass (COM) above the support plane(s); to be valid in the presence of externally applied forces and moments; be able to assess stability when multiple noncoplanar support planes exist, as is the case with seated postures; and to give insight into the support reaction force (SRF) distribution. To date, there is not a method for analyzing stability that can effectively meet each goal. This paper presents a new stability criterion and stability analysis that accomplishes each intended goal. The stability analysis is derived from the calculation of joint torque using the recursive Lagrangian dynamic formulation. A 56-degree-of-freedom (DOF) articulated digital human model is used to model seated postures to demonstrate the proposed stability criterion. Different given postures with different external load cases are presented.

Quadruped Robot Omni-Directional Walking on a Slope Based on Static Balance

2012 ◽  
Vol 591-593 ◽  
pp. 1436-1440
Author(s):  
Wen Yu Zhang ◽  
Lei Zhang
Keyword(s):  
Computer Simulation ◽  
Structural Stability ◽  
Stability Criterion ◽  
Quadruped Robot ◽  
Static Balance ◽  
Gait Transition ◽  
Uneven Terrain ◽  
Transition Problem ◽  
Walking Environment ◽  
The Stability

Quadruped robot is widely developed on the basis of bionic technology and has good structural stability and flexibility in uneven terrain. It is required of the quadruped robot to keep static balance while transportation task is executed. In this paper, first, the unstable problems during static walking on a slope have been analyzed in detail, and the stability criterion which considering affections of slope walking environment has been proposed. Based on static balance, the falling over problem and tumbling around the line connecting two support feet during gait transition problem have been solved. The gaits are planned to ensure omni-directional stable walking on a slope. Through walking experiments by computer simulation, the validity of the proposed method has been verified.

Stability Analysis of Elastic Vibration of Flexible Manipulator Arm Based on Routh Criterion

2013 ◽  
Vol 404 ◽  
pp. 182-187
Author(s):  
Yuan Chen ◽  
Guang Rui Liu ◽  
Wen Jing Wu
Keyword(s):  
Stability Analysis ◽  
Transfer Function ◽  
Stability Criterion ◽  
Elastic Vibration ◽  
Flexible Manipulator ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Manipulator Arm ◽  
The Stability ◽  
Necessary And Sufficient

dynamic model of flexible manipulator arm having end position addition mass is deduced in the first place in this paper , then the state space expression and transfer function using drive moment as input and using elastic vibration of end position as output of flexible manipulator arm are obtained . the necessary and sufficient condition assuring stability of flexible manipulator arm system is obtained using Routh criterion , and the stability criterion of the elastic motion of end position is deduced . the influence of end position addition mass and drive joint rotary inertia on the elastic motion stability of end position of manipulator arm is analyzed based on the stability criterion .

scholarly journals Stability Criterion for Dynamic Gaits of Quadruped Robot

2018 ◽  
Vol 8 (12) ◽  
pp. 2381 ◽  
Author(s):  
Yan Jia ◽  
Xiao Luo ◽  
Baoling Han ◽  
Guanhao Liang ◽  
Jiaheng Zhao ◽  
...  
Keyword(s):  
Dynamic Stability ◽  
Stability Criterion ◽  
Quadruped Robot ◽  
Stability Criteria ◽  
Irregular Terrain ◽  
Quadruped Robots ◽  
Simulation Results ◽  
Zero Moment ◽  
The Stability ◽  
Dynamic Gait

Dynamic-stability criteria are crucial for robot’s motion planning and balance recovery. Nevertheless, few studies focus on the motion stability of quadruped robots with dynamic gait, none of which have accurately evaluated the robots’ stability. To fill the gaps in this field, this paper presents a new stability criterion for the motion of quadruped robots with dynamic gaits running over irregular terrain. The traditional zero-moment point (ZMP) is improved to analyze the motion on irregular terrain precisely for dynamic gaits. A dynamic-stability criterion and measurement are proposed to determine the stability state of the robot and to evaluate its stability. The simulation results show the limitations of the existing stability criteria for dynamic gaits and indicate that the criterion proposed in this paper can accurately and efficiently evaluate the stability of a quadruped robot using such gaits.

scholarly journals A variable structure algorithm using the (3,2)-scheme and the Fehlberg method

2015 ◽  
pp. 446-455
Author(s):  
Е.А. Новиков
Keyword(s):  
Stability Criterion ◽  
Jacobi Matrix ◽  
Variable Structure ◽  
Stability Control ◽  
Accuracy Control ◽  
Stable Method ◽  
Third Order ◽  
Structure Algorithm ◽  
The Stability ◽  
Embedded Method

Построен (3,2)-метод третьего порядка с замораживанием матрицы Якоби, в котором $L$-устойчивыми являются основная и промежуточные численные схемы. Получено неравенство для контроля точности вычислений с использованием вложенного метода второго порядка. Предложено неравенство для контроля устойчивости явного трехстадийного метода Рунге-Кутта-Фельберга третьего порядка. Сформулирован алгоритм переменной структуры, в котором на каждом шаге явный или $L$-устойчивый метод выбираются по критерию устойчивости. Приведены результаты расчетов. A third-order (3,2)-method allowing freezing the Jacobi matrix is constructed. Its main and intermediate numerical schemes are $L$-stable. An accuracy control inequality is obtained using an embedded method of second order. A stability control inequality for the explicit three-stage Runge-Kutta-Fehlberg method of third order is proposed. A variable structure algorithm is formulated. An explicit or $L$-stable method is chosen according to the stability criterion at each step. Numerical results are discussed.

scholarly journals The necessary and sufficient condition for the stability of a rigid body

2017 ◽  
Vol 13 (4) ◽  
pp. 4999-5003 ◽  
Author(s):  
W. S. Amer
Keyword(s):  
Rigid Body ◽  
Equations Of Motion ◽  
Center Of Mass ◽  
First Integrals ◽  
Body Motion ◽  
Sufficient Condition ◽  
Stability Criteria ◽  
Necessary And Sufficient Condition ◽  
The Stability ◽  
Necessary And Sufficient

In this paper, the stability of the unperturbed rigid body motion close to conditions, related with the center of mass, is investigated. The three first integrals for the equations of motion are obtained. These integrals are used to achieve a Lyapunov function and to obtain the necessary and sufficient condition satisfies the stability criteria.

On Rayleigh’s Stability Criterion for Couette Flow

1993 ◽  
Vol 48 (5-6) ◽  
pp. 703-704 ◽  
Author(s):  
D. Lortz
Keyword(s):  
Kinetic Energy ◽  
Couette Flow ◽  
Ideal Fluid ◽  
Stability Criterion ◽  
Stability Problem ◽  
Total Kinetic Energy ◽  
Coaxial Cylinders ◽  
Circular Flow ◽  
The Stability ◽  
Necessary And Sufficient

Abstract The stability problem of a stationary circular flow of an ideal fluid between two coaxial cylinders is considered. It is shown that Rayleigh's circulation criterion is necessary and sufficient for the total kinetic energy of an axisymmetric disturbance to be bounded in time.

scholarly journals Single-Leg Structural Design and Foot Trajectory Planning for a Novel Bioinspired Quadruped Robot

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Mingfang Chen ◽  
Qi Li ◽  
Sen Wang ◽  
Kaixiang Zhang ◽  
Hao Chen ◽  
...  
Keyword(s):  
Structural Design ◽  
Control Algorithm ◽  
Quadruped Robot ◽  
Rational Structure ◽  
Flight Phase ◽  
Experimental Platform ◽  
Quadruped Robots ◽  
The Stability ◽  
The Impact ◽  
Foot Trajectory

To meet the stability requirements for moving quadruped robots, it is important to design a rational structure for a single leg and plan the trajectory of the foot. First, a novel electrically driven leg mechanism for a quadruped robot is designed in this paper to reduce the inertia of the leg swing. Second, a modified foot trajectory based on a compound cycloid is proposed, which has swing-back and retraction motion and continuous velocity in the x-axis direction. Third, a Simulink platform is built to verify the correctness of the proposed foot trajectory. The simulation result shows that when the flight phase and the stand phase switch, the impact of torque is smaller than the foot trajectory before modification. Finally, an experimental platform is constructed, and a control algorithm is written into the controller to realize the foot proposed trajectory. The results of the experiment prove the feasibility of the leg mechanism and the rationality of the proposed foot trajectory.

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