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A wheeled mobile robotic system (WMR) is a kind modular robotic, nonlinear and the system subjected to nonholonomic constraints. It is impossible to obtain an exact dynamics model due to unknown parameters, unpredictable and irregular features, external disturbance. This paper proposes an adaptive robust controller to guide WMR to follow the desired trajectory. The cascade control system is applied...
This paper presents the adaptive hydraulic active suspension applied to the six-wheel off-road vehicle. Both four-link articulated mechanical structure and power transported hydraulic system are constructed. Nonlinear mathematical model is established for the nonlinear uncertain hydraulic system. The advantages of self adaptive suspensions and active suspensions are combined and introduced into the...
Compared with mechanical steering system, hydraulic steering system and electric power assisted system, Steer By Wire (SBW) system has the advantage of variable steering ratio, easy assembling and enhancement of active safety, etc.. Due to only electric link but no mechanical link between steering wheel and front wheel, the force between front wheel and steering wheel, which is of great importance...
This paper studied the point stabilization problem for a constrained autonomous lawnmower. A constrained kinetic model is established first. The authors proposed a backstepping adaptive controller to solve the stabilizing control design problem. The proposed approach has been numerically verified.
This paper proposes a model-free fuzzy controller (MFFC) for wheeled inverted pendulums (WIPs) control problem. The main purpose of this paper is to develop a self-dynamic balancing and motion control strategy. A simple necessary and sufficient condition for analytically determining the stability of a wheeled inverted pendulum system is established. Finally, experimental results show that the proposed...
This paper presents inverted pendulum with moving reference for the testing of stabilizing control algorithms. The proposed system extends classical inverted pendulum by incorporating two moving masses. The motion of the two masses, that slide along the horizontal plane, is controllable for the purpose of platform stabilization. The usefulness of the idea presented is demonstrated using computer simulations...
The paper firstly presents a mobile humanoid robot whose upper human-like body is rigidly mounted on the mobile platform with three wheels: two driving wheels and one caster wheel. The wheeled mobile platform moves on the ground subjected to nonholonomic constraints. Then the static equilibrium of the robot on a plane is discussed and tip-over stability of mobile humanoid robot moving on the slope...
A two-loop cascade adaptive controller is proposed for a non-stable, non-linear, strong coupling system using backstepping and fuzzy neural network. The proposed approach uses fuzzy neural networks to approximate unknown nonlinear function. Then, use backstepping to design adaptive controller to realize self-balancing control of robot. The simulation results indicate that both speediness and stability...
In this paper, a novel analytic projection method is proposed to calculate the prototype parameters of the reconfigurable mobile robot. The equivalent latitudinal and longitudinal stability margins of the mobile robot are investigated with non-linear characteristics. The Harmony Search (HS) method is also applied to obtain the optimal configurations.
The importance of the robots for home, public places and many other places are increasing. In order to realize autonomous work in such dynamic and unknown environment, recognizing external world is required. In addition, robots also have to move quickly and work accurately. In this paper, the control system for a two wheels driven redundant mobile manipulator with a monocular camera as a visual sensor...
An LQG control strategy is proposed and tested for a wheeled inverted pendulum robot. We show how a reduced set of sensors, as compared to other solutions that can be found in the literature, can be used to observe all state variables of interest for stabilization. A Kalman-Bucy estimator is used to estimate the unmeasured variables and to filter those that are directly measured. An LQR feedback strategy...
This paper addresses a time-optimal manipulator control strategy of a free-floating space robot with constraint on reaction torque induced by the manipulator motion. When a manipulator of a space robot is controlled, rotational motion of the base body is induced by the reaction torque. Assuming that reaction wheels are used to cancel the reaction and to stabilize the base attitude, the torque limitation...
This paper deals with a control approach dedicated to stable limit cycle generation for underactuated mechanical systems. The proposed approach is based on partial nonlinear feedback linearization and dynamic control for optimal periodic reference trajectories tracking. Simulation results and experiments show the efficiency of the proposed approach.
When a mobile robot performs some special tasks, such as carrying a heavy load, moving on a slope or rough terrain, particularly contacting with the environment, it may become unstable even overturn. First, the paper presents a mobile humanoid robot whose upper human-like body is mounted on the mobile platform supported by three wheels (two driving wheels and one caster wheel) and subjected to nonholonomic...
The parallel two-wheeled robot is a natural instability body, like traditional inverted pendulum, so it is necessary to use very effective control means to make it stabilize. The study on parallel two-wheeled robot emphasizes on walking balance control technology. In the paper the system configuration and mathematic modelling of the prototype are described. According to linear system theory, the state-feedback...
This paper proposes a new leg-wheel hybrid jumping robot ldquoAirHopperrdquo. AirHopper is expected to overcome uneven terrain, which is difficult to move around for ordinary vehicles which carry supplies for disaster areas or isolated districts. To acquire high mobility and jumping, AirHopper consists of the following mechanisms. 1) 4 legs that are widely spread like a spider for stability, 2) active...
This paper concerns the control of an autonomous high mobility wheel-legged rover crossing uneven terrains. A new control strategy, using active redundancies of the robot, leads to elaborate a posture control based on the potential field approach of the stability measurement. Then a decoupled posture and trajectory control algorithm based on the velocity model of the robot is proposed. Last, simulation...
This paper addresses the issue of implementing an intelligent velocity controller on the Platform for Ambulating Wheels (PAW). The PAW robot is a hybrid quadrupedal wheeled-legged robot that can bound, gallop, roll and brake at high speeds and perform inclined turning. The goal of implementing intelligent control is to increase the robotpsilas versatility and autonomy in order to traverse various...
Robots must be designed with consideration for reconfiguring body pose during operation if they are to address more challenging environments. Researchers have mostly relied on static stability methods to monitor the possibility of rollover in stationary or slow moving vehicles. However, little research in dynamic stability is being conducted for robots capable of reconfiguring their pose to overcome...
This paper reports an enhanced mechanical design and stability analysis of a new stair-climbing robotic wheelchair for the disable and elderly. The mechanism is based on a pair of rotational multi-limbed structures pivotally mounted on the opposite sides of the base. The corresponding short arm, long arm and support triangle comprising each rotational multi-limbed structure are actuated to rotate...
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