Inertial Delay Control Research Articles

Robust control of unmanned sea surface vehicle using inertial delay control

Robust control of unmanned sea surface vehicle using inertial delay control

Motion Planning and Coordinated Control of Underwater Vehicle-Manipulator Systems with Inertial Delay Control and Fuzzy Compensator

This paper presents new motion planning and robust coordinated control schemes for trajectory tracking of the underwater vehicle-manipulator system (UVMS) subjected to model uncertainties, time-varying external disturbances, payload and sensory noises. A redundancy resolution technique with a new secondary task and nonlinear function is proposed to generate trajectories for the vehicle and manipulator. In this way, the vehicle attitude and manipulator position are aligned in such a way that the interactive forces are reduced. To resist sensory measurement noises, an extended Kalman filter (EKF) is utilized to estimate the UVMS states. Using these estimates, a tracking controller based on feedback Linearization with both the joint-space and task-space tracking errors is proposed. Moreover, the inertial delay control (IDC) is incorporated in the proposed control scheme to estimate the lumped uncertainties and disturbances. In addition, a fuzzy compensator based on these estimates via IDC is introduced for reducing the undesired effects of perturbations. Trajectory tracking tasks on a five-degrees-of-freedom (5-DOF) underwater vehicle equipped with a 3-DOF manipulator are numerically simulated. The comparative results demonstrate the performance of the proposed controller in terms of tracking errors, energy consumption and robustness against uncertainties and disturbances.

A robust hybrid nonlinear guidance law for intercepting a non-cooperative maneuvering target

ABSTRACTThis paper has proposed a new robust hybrid nonlinear guidance law, which accounts for a missile’s terminal line-of-sight (LOS) angle constraint, in order to intercept a non-cooperative maneuvering target. The proposed hybrid nonlinear guidance strategy consists of two phases; in the first phase, a guidance law named PIGL is derived from prescribed performance control and the inertial delay control method. In PIGL, a revised prescribed performance function is put forward, and a prescribed performance controller with unknown uncertainties is then derived. The controller smoothly drives both the LOS angle and its rate to a predesigned small region under unknown uncertainties that are induced by target’s maneuvers within a fixed time. Then, a guidance law named SIGL is activated, which is derived from sliding mode control and inertial delay control. By driving the desired sliding mode variable to zero within a finite time, the SIGL guidance law is able to achieve high terminal interception accuracy. The robustness of both of the proposed sub-guidance laws has been proved explicitly in this paper. The hybrid guidance law has the advantage of a tunable convergence rate of the LOS angle and the rate of the LOS angle at the beginning period, by which an excessive large initial maneuver can be avoided. Meanwhile, the hybrid guidance law also has the advantage of lower sensitivity to errors in the estimation of the time-to-go.

A Novel Integral Sliding Mode-Type Continuous Guidance Law With Autopilot Lag for Intercepting Non-Cooperative Maneuvering Targets

This paper proposes an integral sliding mode guidance law with the constraints of the line-of-sight angle and its rate for the interception of a non-cooperative maneuvering target. The analytical guidance law is derived using an integral sliding mode control and an inertial delay control allowing for unknown uncertainties. The guidance law is further advanced to achieve exponential convergence and high terminal guidance accuracy with autopilot lag. This is accomplished by applying dynamic surface control and fractional order filters. Finally, the finite-time stability of the guidance law with and without missile autopilot lag is demonstrated. In addition to its robustness and precision, there are other benefits of this proposed guidance law. First, the proposed guidance law can effectively attenuate an abrupt change in guidance commands during the terminal homing phase in the presence of uncertainties without prior information. Second, the design parameters in the inertial delay control are decoupled with the integral sliding mode control. This decoupling supplies more degrees of freedom to regulate the performance of guidance commands. Third, the finite-time convergence of the proposed guidance law is guaranteed while accounting for the approximated second-order dynamics and uncertainties of the missile autopilot. Theoretical analysis and numerical simulations were conducted to demonstrate the efficiency of the proposed guidance law.

Prescribed performance interceptor guidance with terminal line of sight angle constraint accounting for missile autopilot lag

A prescribed performance guidance law during the terminal homing phase is proposed to intercept a non-cooperative maneuvering target in this paper. First, on the basis of sliding mode control, a prescribed performance control method based on a revised prescribed performance function is proposed to drive the sliding mode variable to zero. It leads to smooth guidance commands to fulfill the terminal line of sight angle constraint. Then, taking the autopilot's dynamics and its uncertainties into account, a robust controller is designed using dynamic surface control, sliding mode control and inertial delay control, which guarantees the reference guidance commands to be precisely tracked. The highlights of the proposed guidance law are: 1) the transient performance of guidance commands is improved, so that excessive large changes are avoided in the initial phase, 2) parameters that dominant the convergence of the predetermined sliding mode variable can be analytically determined based on the predesigned terminal tolerance, it is more convenient to achieve the prescribed convergence, 3) although uncertainties are existing in the dynamics of missile autopilot, the proposed guidance law could guarantee the terminal interception accuracy. All of the improvements are shown in numerical simulation results.

Uncertainty-Estimation-Based Approach to Antilock Braking Systems

Two new strategies based on uncertainty estimation are proposed for antilock braking systems (ABSs). In one of the strategies, the uncertainties and the disturbances are estimated using inertial delay control (IDC), and the estimates are used in a backstepping-control-based braking system. In the other strategy, in addition to uncertainties, the states are also estimated using an inertial delay observer (IDO) for a sliding-mode-control (SMC)-based braking system. No knowledge of uncertainties, disturbances, and the road adhesion friction coefficient or their bounds is assumed. The stability of the overall system is proven, and the schemes are validated by simulation and experimentation in the laboratory.

An inertial delay observer-based sliding mode control for active suspension systems

In this paper, an active suspension system based on an inertial delay observer combined with sliding mode control is proposed for a quarter-car model. The inertial delay observer estimates the states and the uncertainties and disturbances of a system simultaneously. It is an extension of the inertial delay control which estimates the uncertainties of a system but needs the measurement of all states. The proposed scheme needs only the sprung mass position sensor for its implementation. The overall stability of the system is proved. The scheme is validated by simulation and by experimentation on a laboratory set-up. The results obtained with the proposed scheme are compared with those obtained with a passive suspension scheme, an linear quadratic Gaussian observer-based scheme and an inertial delay control-based scheme.

Slip regulation for anti-lock braking systems using multiple surface sliding controller combined with inertial delay control

In this paper, a multiple surface sliding controller is designed for an anti-lock braking system to maintain the slip ratio at a desired level. Various types of uncertainties coming from unknown road surface conditions, the variations in normal force and the mass of the vehicle are estimated using an uncertainty estimation technique called the inertial delay control and then the estimate is used in the design of the multiple surface sliding controller. The proposed scheme does not require the bounds of uncertainties. The ultimate boundedness of the overall system is proved. The proposed scheme is validated by simulation under various scenarios of road friction, road gradient and vehicle loading followed by experimentation on a laboratory anti-lock braking set-up for different friction conditions.

Robust sliding mode control for a class of nonlinear systems using inertial delay control

This paper proposes a robust sliding mode control strategy for an uncertain nonlinear system subjected to time-varying disturbance. The class of system considered includes state-dependent nonlinearity in the input vector (in addition to the plant matrix). The control scheme uses inertial delay control to estimate the lumped uncertainty. The proposed control enforces sliding without using the discontinuous control and without requiring the knowledge of uncertainties or their bounds. The overall stability of the system is proved. The effectiveness of the proposed strategy is verified for model following and robust performance, by simulation of an illustrative example and an application to inverted pendulum system.

Active suspension systems for vehicles based on a sliding-mode controller in combination with inertial delay control

In this paper a new active suspension scheme for vehicles with non-linearities is proposed. The proposed scheme makes the vehicle suspension system follow a modified skyhook model and is based on the sliding-mode control strategy augmented by the so-called inertial delay control which estimates and negates the effects of the unknown road profile and the uncertainties in the suspension system. The accuracy of estimation is analysed and it is shown that the estimation error is ultimately bounded. The means to improve the accuracy of estimation are outlined and the overall stability of the suspension system is proved. The efficacy of the method is illustrated by simulation for an automobile vehicle suspension system for various road profiles.

Sliding Mode and Inertial Delay Control Based Missile Guidance

A novel formulation of sliding mode control (SMC) based proportional navigation (PN) guidance law is presented. Unlike conventional SMC-based guidance laws, the law presented here does not need any knowledge of bounds of target acceleration. The target acceleration is estimated using the so-called inertial delay control (IDC). Closed-loop stability for the guidance loop is established. Simulations are carried out by considering highly-maneuvering targets and constant as well as varying missile velocity and the results are presented to demonstrate the effectiveness of the proposed formulation.