Dongkai Zhang

Saturated tracking control for nonholonomic mobile robots with dynamic feedback

The saturated tracking control problem is addressed for nonholonomic mobile robots with dynamic feedback in this paper. A finite-time control technique and the virtual-controller-tracked method are adopted in this paper. The main contribution and innovation can be summarized as follows. First, the smooth kinematic tracking controller of Jiang et al. is taken as a virtual control law for the dynamic feedback model. Second, a continuous and bounded dynamic feedback controller is proposed to make the generalized velocity converge to the kinematic (virtual) controller in a finite time for any initial values of tracking errors in the specified attraction region. Third, all of the states of the tracking error system are proved to go to zero as time goes to infinity. In the mean time, the control inputs are bounded by the prespecified bounds at any time. Finally, the simulation results show the effectiveness of the proposed control design approach.

Semiglobal Stabilization for Nonholonomic Mobile Robots Based on Dynamic Feedback With Inputs Saturation

This paper investigates the semiglobal stabilization problem for nonholonomic mobile robots based on dynamic feedback with inputs saturation. A bounded, continuous, time-varying controller is presented such that the closed-loop system is semiglobally asymptotically stable. The systematic strategy combines finite-time control technique with the virtual-controller-tracked method, which is similar to the back-stepping procedure. First, the bound-constrained smooth controller is presented for the kinematic model. Second, the dynamic feedback controller is designed to make the generalized velocity converge to the prespecified kinematic (virtual) controller in a finite time. Furthermore, the rigorous proof is given for the stability analysis of the closed-loop system. In the mean time, the position and torque inputs of robots are proved to be bounded at any time. Finally, the simulation results show the effectiveness of the proposed control approach.

Adaptive stabilization of stochastic non-holonomic systems with non-homogeneous uncertainties

This paper discusses the adaptive state-feedback stabilization of stochastic non-holonomic systems with non-homogeneous uncertainties with respect to inputs. Based on the backstepping approach and switching control strategy, we present adaptive state-feedback controllers such that the closed-loop system can be stabilized in probability. In the end, simulation examples are provided to illustrate effectiveness of the controllers.

State-feedback stabilisation for stochastic non-holonomic systems with Markovian switching

This paper investigates the state-feedback stabilisation of stochastic non-holonomic systems with Markovian switching. Based on the backstepping approach, state-feedback controllers are firstly designed for stochastic non-holonomic systems with Markovian switching. A switching control strategy for the original system is given which can guarantee that the closed-loop system is almost asymptotically stabilised at the zero equilibrium in probability. In the end, a simulation example is provided to illustrate effectiveness of the controller.

State-feedback stabilisation for stochastic non-holonomic mobile robots with uncertain visual servoing parameters

The stabilising problem of stochastic non-holonomic mobile robots with uncertain parameters based on visual servoing is addressed in this paper. The model of non-holonomic mobile robots based on visual servoing is extended to the stochastic case, where their forward velocity and angular velocity are both subject to some stochastic disturbances. Based on backstepping technique, state-feedback stabilising controllers are designed for stochastic non-holonomic mobile robots. A switching control strategy for the original system is presented. The proposed controllers guarantee that the closed-loop system is asymptotically stabilised at the zero equilibrium point in probability.

Finite-time robust stabilization of dynamic feedback nonholonomic mobile robots based on visual servoing with input saturation

In this paper, the finite-time robust stabilization problem is addressed in the presence of uncalibrated visual parameters for a class of dynamic feedback nonholonomic robots based on visual servoing with input saturation. The objective is to design a nonsmooth and bounded state feedback law such that the robots system is both Lyapunov stable and finite-time convergent within any given settling time. A new saturated switching controller is proposed directly based on the original system, which can effectively avoid the problem of singularity caused by using state or input transformation. Finally, the simulation results show the effectiveness of the proposed control design approach.

Adaptive stabilization of stochastic nonholonomic systems with uncertain parameters and time-varying coefficients

Abstract This paper investigates the adaptive state-feedback stabilization of stochastic nonholonomic systems which have both uncertain parameters and time-varying coefficients. The state-scaling and backstepping techniques are exploited in the design of controllers. The adaptive state-feedback stabilizing controllers and switching control strategy are proposed so that the closed-loop system can be stabilized in probability. In the end, two simulation examples are provided to illustrate effectiveness of controllers.

Finite-Time Stabilization of Dynamic Nonholonomic Wheeled Mobile Robots with Parameter Uncertainties

The finite-time stabilization problem of dynamic nonholonomic wheeled mobile robots with parameter uncertainties is considered for the first time. By the equivalent coordinate transformation of states, an uncertain 5-order chained form system can be obtained, based on which a discontinuous switching controller is proposed such that all the states of the robots can be stabilized to the origin equilibrium point within any given settling time. The systematic strategy combines the theory of finite-time stability with a new switching control design method. Finally, the simulation result illustrates the effectiveness of the proposed controller.

Robust saturated finite-time stabilization for nonholonomic mobile robots based on visual serving feedback

In this paper, the robust saturated stabilization problem is considered for a class of nonholonomic mobile robots based on visual servoing feedback with uncalibrated camera parameters. In comparison with existing methods, the new design method is directly based on the original inputs of the original systems, i.e., the saturated practical inputs instead of the transformed inputs. A piecewise continuous and bounded control law is presented by applying the multi-step switch control strategy and the theory of finite-time stability. The controller can stabilize the nonholonomic robots to the equilibrium point in a finite time. Finally, the simulation results show the effectiveness of the proposed control approach.