The dynamic model of redundantly actuated mobile robots with powered caster wheels is derived based on vehicle dynamics. The contact stability problem of wheeled mobile robots is introduced and stable contact condition that characterizes the bounds of contact stability is derived. Sliding mode observer is proposed to estimate the robot velocity using wheel angular velocity and joint torque info...

Quadrupedal robots working outdoors are very slow robots prone to tumble down in the presence of perturbations. This paper presents a novel gaitadaptation method that enables walking-machine gaits to autonomously adapt to environmental perturbations, including the slope of the terrain, by finding the gait parameters that maximize robot’s dynamic stability. Experiments with the SILO4 quadruped r...

(FFNN) is used to compensate for the robot dynamics. The FFNN computes the required torques to drive the robot manipulator to achieve desired tracking. The stability of combined PI kinematic and FFNN computed torque is proved by Lyapunov theory. Simulation results are carried out for 3 DOF articulated robot manipulator to evaluate the controller performance.

In this paper, partial leg exchange gait for twin-frame walking robot is proposed. This twin-frame walking robot doesn’t have the degrees of freedom (DOF) for moving the center of gravity (CG). Thus, it is impossible to increase the stability margin actively. But using this proposal method, CG can move in the leg exchange phase and obtain enough stability margins. Proposal gait motion is verifi...

In this paper, a new method was proposed for the navigation of a mobile robot in an unknown dynamic environment. The robot could detect only a limited radius of its surrounding with its sensors and it went on the shortest null space (SNS) toward the goal. In the case of no obstacle, SNS was a direct path from the robot to goal; however, in the presence of obstacles, SNS was a space around the r...

A control law for the automatic guidance is proposed in this paper as if each obstacle exerts upon the mobile robot a repulsion, which varies inversely with the distance between the robot and the obstacle, and becomes infinite as the robot approaches the obstacle. Stability of the automatic guidance is studied when the mobile robot deviates from the ideal path. The results lead to criteria of s...

Consideration of manipulator dynamics and external disturbances in robot control system design can enhance the stability and performance properties of the whole system. In this paper, we present an approach to solve the control problem when the inertia parameters of robot are unknown, and at the same time robot is subjected to external force disturbances. This approach is based on simultaneous ...

The objective of the paper is to investigate walking stability of picking wheel robot in the fields of medium speed and high load complex operating environment. Firsly, we analyze the influence on walking control for simplified dynamic model of picking robot and its remaining (instabilities), guarantee the stability and convergence of simplified system for tracking errors using the Lyapunov the...

A robust fuzzy control is developed for robot manipulators to guarantee both global stability and Performance. Robot dynamics under consideration may include large nonlinear uncertainties, such as nonlinear load variations and unmodelled dynamics. Fuzzy sets are chosen based on performance requirements and stability regions of the control system. For each fuzzy set, a sub-control is designed, b...