Robust Position Tracking Control Research Articles

Performance Recovery Tracking-Controller for Quadcopters via Invariant Dynamic Surface Approach

In this paper, a robust position tracking controller is proposed using an invariant dynamic surface approach in a cascade control system structure. There are two main contributions. The first is to design a dynamic surface giving the desired tracking-performance with a time-varying cutoff frequency automatically adjusted by the proposed auto-tuner, which can enhance the reliability of the resulting control system. The second is to derive the inner- and outer-loop control laws driving the closed-loop trajectories to the dynamic surface, incorporating a disturbance observer with the use of only nominal plant parameters. A reduction of plant parameter dependence can be accomplished by the second contribution. The realistic simulation results confirm the advantages of the proposed technique.

Correction to: Extended State Observer Based Robust Position Tracking Control for DC Motor with External Disturbance and System Uncertainties

This paper proposes an extended state observer-based robust position tracking control for DC motor with external disturbance and system uncertainties. In this control strategy, external disturbance and acceleration dynamics, including uncertainty of the input parameter, are lumped in the disturbance using acceleration dynamics. An extended state observer (ESO) is designed to estimate the disturbance and full states, whereas a position tracking controller is designed to compensate for the disturbance. The stability of a closed-loop system is investigated using Lyapunov theory. The proposed method guarantees the semi-global uniform ultimate boundedness of the position tracking error using only position feedback for unknown nonlinear systems with external disturbance. The proposed method is simple and robust against external disturbance and parameter uncertainties. In addition, only nominal parameter values of the input gain are required. The proposed method was experimentally verified, and it exhibited improved position tracking performance compared to other methods using state feedback and ESO-based conventional DC motor models.

Extended State Observer Based Robust Position Tracking Control for DC Motor with External Disturbance and System Uncertainties

Extended State Observer Based Robust Position Tracking Control for DC Motor with External Disturbance and System Uncertainties

Robust Position Tracking Control and Ground Contact Detection of a Cheetaroid-I Leg by a Disturbance Observer

Quadruped robot systems are being intensively investigated as a new means of transportation systems with multi-purposes. As the operation conditions of such systems, such as a payload and gait speed, are demanding, the control of the robotic legs is challenging. In addition, the dynamics of such systems is subjected to large disturbances and parameter variations due to the ground contact and the complicated mechanical structure. In this paper, a robust control algorithm based on a disturbance observer (DOB) is proposed for the control of legs of a quadruped robot, Cheetaroid-I. The DOB enables rejecting disturbances caused by the ground contact, payload, etc, and detecting the ground contact without force sensors. The proposed method is verified by experimental results.

Robust Position Tracking Control of an Electro-Hydraulic Actuator in the Presence of Friction and Internal Leakage

This paper proposes an improved robust position controller for the electro-hydraulic actuator system using the varying boundary layered sliding mode control scheme. The proposed scheme has the ability to improve the position tracking performance of the actuator in the presence of friction and internal leakage. The former is represented using the LuGre model while later is modelled as a turbulent flow. To evaluate the effectiveness of the proposed method, MATLAB simulations are carried out under friction and leakage effects. Its performance is compared with the conventional PID and fuzzy PID (FPID) methods. Finally, an experimental rig that comprises of a single-rod and double acting hydraulic cylinder is set up to validate the proposed idea. The software development is carried out in the DSpace 1104 environment using a TMS320F240 digital signal processor. The superiority of the proposed method over the PID and FPID in terms of tracking position is highlighted by simulation and experimental results.

On the robust control of two manipulators holding a rigid object

In this paper, a control architecture is developed for the closed chain motion of two six-joint manipulators holding a rigid object in a three-dimensional workspace. Dynamic and kinematic constraints are combined with the equations of motion of the manipulators to obtain a dynamical model of the entire system in the joint space. Reduced-order dynamic equations are then developed with regard to the position and force control variables. Robust control laws are then determined such that the force and position control design is decoupled. The control laws that will be discussed are: a robust position tracking controller that yields an exponentially stable position tracking error result, and a robust force tracking controller that yields adjustable bounds on the force tracking error.