Stability and Motion Control of a Unicycle (1st Report: Dynamics of a Human Riding Unicycle and Its Modeling by Link Mechanisms)

1994 ◽  
Vol 6 (2) ◽  
pp. 175-182
Author(s):  
Zaiquan Sheng ◽  
◽  
Kazuo Yamafuji
Keyword(s):  
Motion Control ◽  
Nonholonomic Constraint ◽  
Control Method ◽  
Equations Of Motion ◽  
Dynamic Equations ◽  
Lateral Stability ◽  
New Model ◽  
Dynamic Motion ◽  
The Stability ◽  
General Method

In this paper, the dynamic characteristics of a human riding a unicycle are first analyzed by observation.: Based on observation and analysis, we discovered that the rider's body, thighs and shanks create two closed link loops; and this special mechanism plays an important role in the stability of the unicycle. We then developed a new model with two closed link mechanisms and one turntable to emulate a human riding a unicycle by a robot. Considering the nonholonomic constraint between the wheel and ground and applying recently developed general method to compute the multi-closed link mechanisms' dynamic motion, we obtained the dynamic equations of motion for this new model. Using these equations, simulation is conducted under the proposed control method. The simulation result indicates that both longitudinal and lateral stability of a human riding a unicycle can be satisfactorily emulated by the new model.

Vehicle Lateral Motion Control Based on Estimated Stability Regions

2017 ◽  
Author(s):  
Yiwen Huang ◽  
Yan Chen
Keyword(s):  
Measurement Errors ◽  
Local Stability ◽  
Stability Region ◽  
Control Method ◽  
Linearization Method ◽  
Stability Control ◽  
Lateral Stability ◽  
Shortest Distance ◽  
The Stability ◽  
Yaw Moment

This paper presents a novel vehicle lateral stability control method based on an estimated lateral stability region on the phase plane of vehicle yaw rate and lateral speed, which is obtained through a local linearization method. Since the estimated stability region does not only describe vehicle local stability, but also define the oversteering and understeering characteristics, the proposed control method can achieve both local stability and vehicle handling stability. Considering the irregular geometric shape of the estimated stability region, a stability analysis algorithm is designed to determine the distance between vehicle states and stability region boundaries. State estimation or measurement errors are also incorporated in the distance calculation. Based on the calculated shortest distance between vehicle states and stability boundaries, a direct yaw moment controller is designed to maintain vehicle states stay within the stability region. CarSim® and Simulink® co-simulation is applied to verify the control design through a cornering maneuver. The simulation results show that the proposed control method can make the vehicle stay within the stability region successfully and thus always operate in a safe manner.

scholarly journals Universal Walking Control Framework of Biped Robot Based on Dynamic Model and Quadratic Programming

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xiaokun Leng ◽  
Songhao Piao ◽  
Lin Chang ◽  
Zhicheng He ◽  
Zheng Zhu
Keyword(s):  
Motion Control ◽  
Dynamic Characteristics ◽  
Control Method ◽  
Constraint Equation ◽  
Biped Robot ◽  
Equation System ◽  
Whole Body ◽  
Optimal Controller ◽  
Control Framework ◽  
The Stability

Biped robot research has always been a research focus in the field of robot research. Among them, the motion control system, as the core content of the biped robot research, directly determines the stability of the robot walking. Traditional biped robot control methods suffer from low model accuracy, poor dynamic characteristics of motion controllers, and poor motion robustness. In order to improve the walking robustness of the biped robot, this paper solves the problem from three aspects: planning method, mathematical model, and control method, forming a robot motion control framework based on the whole-body dynamics model and quadratic planning. The robot uses divergent component of motion for trajectory planning and introduces the friction cone contact model into the control frame to improve the accuracy of the model. A complete constraint equation system can ensure that the solution of the controller meets the dynamic characteristics of the biped robot. An optimal controller is designed based on the control framework, and starting from the Lyapunov function, the convergence of the optimal controller is proved. Finally, the experimental results show that the method is robust and has certain anti-interference ability.

Basin of Attraction of the Simplest Walking Model

2001 ◽  
Author(s):  
A. L. Schwab ◽  
M. Wisse
Keyword(s):  
Equations Of Motion ◽  
Basin Of Attraction ◽  
Mapping Method ◽  
Walking Robots ◽  
Natural Energy ◽  
Walking Motion ◽  
The Stability ◽  
The Basin Of Attraction ◽  
General Method ◽  
Small Disturbances

Abstract Passive dynamic walking is an important development for walking robots, supplying natural, energy-efficient motions. In practice, the cyclic gait of passive dynamic prototypes appears to be stable, only for small disturbances. Therefore, in this paper we research the basin of attraction of the cyclic walking motion for the simplest walking model. Furthermore, we present a general method for deriving the equations of motion and impact equations for the analysis of multibody systems, as in walking models. Application of the cell mapping method shows the basin of attraction to be a small, thin area. It is shown that the basin of attraction is not directly related to the stability of the cyclic motion.

scholarly journals WIP Vehicle Control Method Based on Improved Artificial Potential Field Subject to Multi-obstacle Environment

2020 ◽  
Vol 49 (3) ◽  
pp. 320-334
Author(s):  
Ming Yue ◽  
Yigao Ning
Keyword(s):  
Potential Field ◽  
Nonholonomic Constraint ◽  
Control Method ◽  
Artificial Potential Field ◽  
Control Performance ◽  
Safe Distance ◽  
Security Issue ◽  
Repulsive Potential ◽  
The Stability ◽  
Key Parameter

This paper presents a control method for a WIP vehicle in multi-obstacle environment based on improved artificial potential field. Firstly, an improved artificial potential field (IAPF) is developed, where a safe distance is introduced to the existing repulsive potential field to solve the security issue, while the local minima can also be eliminated in the meantime. Next, an obstacle avoidance controller is designed based on the IAPF, where the nonholonomic constraint and underactuated characteristic of the WIP vehicle are fully considered, and the stability condition of the system is analyzed by means of the related control theory. Moreover, to further improve the control performance, a key parameter that play an important role in the controller is adjusted by taking advantage of fuzzy logic, and detailed analyses are given to demonstrate its necessity and effectiveness. Finally, considering a motion environment that contains dense obstacles, narrow corridor and an obstacle near the target, numerical simulations are conducted to validate the proposed method, whose results indicate that the method has a good performance to control the WIP vehicle in multi-obstacle environment.

scholarly journals Study on a Two-Link Horizontal Bar Gymnastics Robot with Passive Joint (Motion Control Using Feedforward Control Based on Inverse Dynamics)

1992 ◽  
Vol 4 (6) ◽  
pp. 466-471
Author(s):  
Hiroyuki Kojima ◽  
◽  
Hiroyuki Mitomo ◽  
Yuuki Wada ◽  
Kenji Sakamoto ◽  
...  
Keyword(s):  
Motion Control ◽  
Inverse Dynamics ◽  
Control Method ◽  
Feedforward Control ◽  
Equations Of Motion ◽  
Electric Circuit ◽  
Control Voltage ◽  
Joint Motion ◽  
Control Torque ◽  
Passive Joint

This paper describes a motion control method of a twolink horizontal bar gymnastics robot with a passive joint by the use of a feedforward control based on inverse dynamics. A direct current servomotor is placed only at the second joint, and the first link is controlled by the coupling forces and the moments between the active and passive joints. The dynamic behavior of the robot is described by the use of a system with two equations of motion. In the design of the control system, the feedforward control angle of the first joint is first obtained by numerical simulation with the first equation of motion for a desired second joint angle. Then, the feedforward control torque of the servomotor is computed by applying inverse dynamics to the second equation, and the feedforward control voltage is obtained in consideration of the electric circuit of the servomotor. Furthermore, experimental results are given, and the effectiveness of the present motion control method is confirmed.

Lyapunov’s Stability of Nonlinear Misaligned Journal Bearings

1995 ◽  
Vol 117 (3) ◽  
pp. 576-581 ◽  
Author(s):  
P. G. Nikolakopoulos ◽  
C. A. Papadopoulos
Keyword(s):  
Journal Bearing ◽  
Direct Method ◽  
Equations Of Motion ◽  
Orbital Stability ◽  
Element Formulation ◽  
Nonlinear Stiffness ◽  
Lyapunov Direct Method ◽  
Rotor Bearing ◽  
The Stability ◽  
General Method

In this paper the stability of nonlinear misaligned rotor-bearing systems is investigated, using the Lyapunov direct method. A finite element formulation is used to determine the journal bearing pressure distribution. Then the linear and nonlinear stiffness, damping, and hybrid (depending on both displacement and velocity) coefficients are calculated. A general method of analysis based on Lyapunov’s stability criteria is used to investigate the stability of nonlinear misaligned rotor bearing systems. The equations of motion of the rigid rotor on the nonlinear bearings are used to find a Lyapunov function using some of these coefficients, which depend on L/D ratio and the misalignment angles ψx, ψy. The analytical conditions for the stability or instability of some examined cases are given and some examples for the orbital stability are also demonstrated.

Lyapunov’s Stability of Non-Linear Misaligned Journal Bearings

1994 ◽  
Author(s):  
Padelis G. Nikoiakopouios ◽  
Chris A. Papadopouios
Keyword(s):  
Journal Bearing ◽  
Direct Method ◽  
Equations Of Motion ◽  
Orbital Stability ◽  
Element Formulation ◽  
Lyapunov Direct Method ◽  
Non Linear ◽  
Rotor Bearing ◽  
The Stability ◽  
General Method

In this paper the stability of non-linear misaligned rotor-bearing systems is investigated, using the Lyapunov direct method. A finite element formulation is used to determine the journal bearing pressure distribution. Then the linear and nonlinear stiffness, damping and hybrid (depended on both displacements and velocity) coefficients are calculated A general method of analysis based on Lyapunov’s stability criteria is used to investigate the stability of non-linear misaligned rotor bearing systems. The equations of motion of the rigid rotor on the non-linear bearings are used to find a Lyapunov function using some of the above coefficients, which are depending on L/D ratio and the misalignment angles ψa, ψr. The analytical conditions for the stability or instability of some examined cases are given and some examples for the orbital stability are also demonstrated.

scholarly journals A Manipulator Control Method Based on Deep Deterministic Policy Gradient with Parameter Noise

2021 ◽  
Author(s):  
Haifei Zhang ◽  
Xu Jian ◽  
Liting Lei ◽  
Fang Wu ◽  
Lanmei Qian ◽  
...  
Keyword(s):  
Motion Control ◽  
Control Method ◽  
State Variables ◽  
Control Approach ◽  
Environment Model ◽  
Policy Gradient ◽  
The Stability ◽  
Reinforcement Learning Models ◽  
Policy Optimization ◽  
Manipulator Control

Abstract Focusing on the motion control problem of two link manipulator, a manipulator control approach based on deep deterministic policy gradient with parameter noise is proposed. Firstly, the manipulator simulation environment is built. And then the three deep reinforcement learning models named the deep deterministic policy gradient (DDPG), asynchronous advantage actor-critical (A3C) and distributed proximal policy optimization (DPPO) are established for training according to the target setting, state variables and reward & punishment mechanism of the environment model. Finally the motion control of two link manipulator is realized. After comparing and analyzing the three models, the DDPG approach based on parameter noise is proposed for further research to improve its applicability, so as to cut down the debugging time of the manipulator model and reach the goal smoothly. The experimental results indicate that the DDPG approach based on parameter noise can control the motion of two link manipulator effectively. The convergence speed of the control model is significantly promoted and the stability after convergence is improved. In comparison with the traditional control approach, the DDPG control approach based on parameter noise has higher efficiency and stronger applicability.

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