Nonlinear Trajectory Tracking Control Research Articles

Design of a Nonlinear PID Neural Trajectory Tracking Controller for Mobile Robot based on Optimization Algorithm

Design of a Nonlinear PID Neural Trajectory Tracking Controller for Mobile Robot based on Optimization Algorithm

A nonlinear trajectory tracking controller for mobile robots with velocity limitation via fuzzy gains

This paper proposes a fuzzy controller for trajectory tracking with unicycle-like mobile robots. Such controller uses two Takagi–Sugeno (TS) fuzzy blocks to generate its gains. The controller is able to limit the velocity and control signals of the robot, and to reduce the errors arising from its dynamics as well. The stability of the developed controller is proven, using the theory of Lyapunov. Experimental results show that the use of the proposed controller is attractive in comparison with the use of a controller with fixed saturation function.

Trajectory linearization control for a miniature unmanned helicopter

Trajectory linearization control (TLC) approach is applied to design a nonlinear trajectory tracking controller for a miniature unmanned helicopter. The controller is based on nonlinear model derived from Newton-Euler equations, with collective and cyclic pitches being regarded as actual controls. Via model simplifications, the nonlinear helicopter model can be transformed into a cascaded form including four subsystems. Corresponding with the simplified cascaded structure, the proposed controller is constructed by synthesizing TLC designs for subsystems. Each of them includes designs of a pseudo-inversion and an error regulator. A summarized TLC algorithm for the unmanned helicopter is listed briefly after the detailed controller design process. Simulation results are provided to demonstrate performances of the closed-loop system.

A Novel Nonlinear Control Law with Trajectory Tracking Capability for Nonholonomic Mobile Robots: Closed-Form Solution Design

A novel nonlinear robust trajectory tracking control law for nonholonomic mobile robot is presented in this paper. This approach can be applied to generate trajectory tracking control commands on nonholonomic mobile robot movement. The design objective is to specify one nonlinear robust control law that satisfies the H2 performance, for the nonlinear trajectory tracking control of nonholonomic mobile robot. In general, it is hard to obtain the closed-form solution from this nonlinear trajectory-tracking problem. Fortunately, because of the skew symmetric property of the trajectory tracking system of the nonholonomic mobile robot and adequate choice of state variable transformation, the H2 trajectory-tracking problems can be reduced to solving one nonlinear time varying Riccati-like equations. Furthermore, one closed-form solution to this nonlinear time varying Riccati-like equation can be obtained with very simple forms for the preceding control design. Finally, there are two practical testing conditions: circular and square like reference trajectories are used for performance verifications.

An Approximate Backstepping Based Trajectory Tracking Control of a Gun Launched Micro Aerial Vehicle in Crosswind

This paper considers the question of obtaining a nonlinear trajectory tracking control law for a comprehensive design of a Gun Launched Micro Aerial Vehicle (GLMAV) despite unknown aerodynamic effo...

Nonlinear trajectory tracking control of a new autonomous underwater vehicle in complex sea conditions

Autonomous underwater vehicles (AUVs) navigating in complex sea conditions usually require a strong control system to keep the fastness and stability. The nonlinear trajectory tracking control system of a new AUV in complex sea conditions was presented. According to the theory of submarines, the six-DOF kinematic and dynamic models were decomposed into two mutually non-coupled vertical and horizontal plane subsystems. Then, different sliding mode control algorithms were used to study the trajectory tracking control. Because the yaw angle and yaw angle rate rather than the displacement of the new AUV can be measured directly on the horizontal plane, the sliding mode control algorithm combining cross track error method and line of sight method was used to fulfill its high-precision trajectory tracking control in the complex sea conditions. As the vertical displacement of the new AUV can be measured, in order to achieve the tracking of time-varying depth signal, a stable sliding mode controller was designed based on the single-input multi-state system, which took into account the characteristic of the hydroplane and the amplitude and rate constraints of the hydroplane angle. Moreover, the application of dynamic boundary layer can improve the robustness and control accuracy of the system. The computational results show that the designed sliding mode control systems of the horizontal and vertical planes can ensure the trajectory tracking performance and accuracy of the new AUV in complex sea conditions. The impacts of currents and waves on the sliding mode controller of the new AUV were analyzed qualitatively and quantitatively by comparing the trajectory tracking performance of the new AUV in different sea conditions, which provides an effective theoretical guidance and technical support for the control system design of the new AUV in real complex environment.

Alternative trajectory-tracking control approach for marine surface vessels with experimental verification

SUMMARYExperiments with a nonlinear trajectory-tracking controller for marine unmanned surface vessels are reported. The tracking controller is designed using a nonlinear robust model-based sliding mode approach. The marine vehicles can track arbitrary desired trajectories that are defined in Cartesian coordinate as continuous functions of time. The planar dynamic model used for the controller design consists of 3 degrees of freedom (DOFs) of surge, sway, and yaw. The vessel only has two actuators, so the vessel is underactuated. Therefore, only two outputs, which are functions of the 3-DOF, can be controlled. The Cartesian position of a control point on the vessel is defined as the output. The orientation dynamics is not directly controlled. It has been previously shown that the orientation dynamics, as the internal dynamics of this underactuated system, is stable. The result of field experiments show the effectiveness of tracking control laws in the presence of parameter uncertainty and disturbance. The experiments were performed in a large outdoor pond using a small test boat. This paper reports the first theoretical development and experimental verification of the proposed model-based nonlinear trajectory-tracking controller.

The control point concept for nonlinear trajectory-tracking control of autonomous helicopters with fly-bar

An alternative approach for automatic trajectory-tracking control of small unmanned helicopters with fly-bar is proposed. This approach uses the spatial three-dimensional coordinates of a point on the helicopter's local coordinate frame other than its centre of gravity, called the control point, and the helicopter's yaw angle as four control outputs. The helicopter is assumed to have four independent control inputs. With this choice of control outputs, the helicopter's input–output model becomes a square control system, which opens the possibility of implementation of many robust nonlinear control methods that are suitable for such systems. The helicopter, which has six rigid body degrees of freedom (DOFs), has two underactuated DOFs (UA-DOFs). It is proved that the zero-dynamics of the UA-DOFs are inherently stable, leading to a stable control system. A sliding mode controller is designed for trajectory-tracking of the outputs. It is verified via simulations that the response of the control outputs and UA-DOFs are in fact stable.

고속 권상운동과 흔들림억제 궤적추종을 위한 천정주행 크레인의 퍼지 비선형 적응제어

천정주행 크레인의 고속 권상작업 및 흔들림 억제 궤적추종을 위한 비선형 적응제어 방법을 제시한다. 천정주행 크레인의 흔들림 운동은 트롤리의 가속도. 권상로프의 길이 및 권상속도와 강하게 결합되어 있다. 이는 비간섭 제어 기반의 흔들림 억제 궤적추종 제어법칙을 설계하는데 있어 장애요인으로 작용한다. 이러한 문제를 해결하기 위해, 트롤리의 가속도와 권상속도의 영향을 최소화하는 방법으로 불확실성이 존재하는 경우에도 흔들림 운동의 궁극적 균일 유계성을 보장하는 퍼지 비선형 적응형 흔들림 억제 궤적추종제어법칙을 제안한다. 특히, 제안한 방법은 파라미터 변화. 외란 등을 포함한 시스템 불확실성을 퍼지 불확실성 관측기를 이용하여 보상한다. 따라서, 퍼지관측기의 근사화 오차가 영으로 수렴할 때 추종오차 및 흔들림 각도의 궁극적 한계치는 영으로 감소한다. 끝으로 제안한 방법의 성능검증을 위한 모의실험 견과를 제시한다. Nonlinear adaptive control of overhead cranes is investigated for anti-sway trajectory tracking with high-speed hoisting motion. The sway dynamics of two dimensional underactuated overhead cranes is heavily coupled with the trolley acceleration, hoisting rope length, and the hoisting velocity which is an obstacle in the design of decoupling control based anti-sway trajectory tracking control law To cope with this obstacle. we propose a fuzzy nonlinear adaptive anti-sway trajectory tracking control law guaranteeing the uniform ultimate boundedness of the sway dynamics even in the presence of uncertainties in such a way that it cancels the effect of the trolley acceleration and hoisting velocity on the sway dynamics. In particular. system uncertainties, including system parameter uncertainty unmodelled dynamics, and external disturbances, are compensated in an adaptive manner by utilizing fuzzy uncertainty observers. Accordingly, the ultimate bound of the tracking errors and the sway angle decrease to zero when the fuzzy approximation errors decrease to zero. Finally, numerical simulations are performed to confirm the effectiveness of the proposed scheme.

Flatness‐Based Trajectory Tracking Control of an Underconstrained Cable Suspension Manipulator

AbstractCable suspension manipulators support a payload platform in space by several spatially arranged cables with computercontrolled winches. The winches are mounted either fixed or on movable trolleys. Compared to conventional cranes, it is possible to control not only the translational motion of the payload but also its orientation in order to perform, for example, assembly tasks. By this, cable suspension manipulators combine the ability of cranes to support heavy payloads in a large workspace with the dexterity of robot manipulators.The present contribution treats nonlinear trajectory tracking control of cable suspension manipulators that are kinematically undetermined and statically determined. In particular, the cable suspension manipulator Cablev [4] is considered that has been developed at University of Rostock (Fig. 1). Its payload platform is supported by three cables with winches mounted on trolleys that move themselves on a gantry. Thus, the payload platform may perform sway motions with three degrees of freedom while the cable lengths are kept fixed. Applications are, for example, precise handling and assembling large and heavy components on construction sites or on shipyards. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Trajectory Tracking for Unmanned Air Vehicles With Velocity and Heading Rate Constraints

This paper considers the problem of constrained nonlinear trajectory tracking control for unmanned air vehicles (UAVs). We assume that the UAV is equipped with longitudinal and lateral autopilots which reduces the 12-state model to a six-state model with altitude, heading, and velocity command inputs. One of the novel features of our approach is that we explicitly account for heading rate and velocity input constraints. For a UAV, the velocity is constrained to lie between two positive constants, and therefore presents particular challenges for the control design. We propose a control Lyapunov function (CLF) approach. We first introduce a CLF for the input constrained case, and then construct the set of all constrained inputs that are with respect to this CLF. The control input is then selected from this feasible set. The proposed approach is applied to a simulation scenario, where the UAV is assigned to transition through several targets in the presence of multiple dynamic threats.