Stabilization control for unmanned helicopter-slung load system based on active disturbance rejection control and improved sliding mode control

Abstract

Unmanned helicopters are widely used in military and civil fields. One of the most important applications is flying with an underslung load, but the pendulum-like behavior of the load can cause damage or even forced landing to the helicopter. To solve this problem, a control strategy to stabilize the helicopter/load system based on active disturbance rejection control (ADRC) and improved sliding mode control (ISMC) algorithms is proposed in this paper. First, the helicopter/load system is modelled using Newton-Euler equations according to the multi-body dynamics theory. Then a manipulation strategy which can reduce the swing angle of the load and an overall control strategy for the helicopter/load system are presented. Specifically, ADRC is applied to attitude control due to its ability to regard the pendulum-like behavior as the internal uncertainties of the system, meanwhile ISMC to position control. Within ISMC, two sliding surfaces with adjustable weights are constructed by employing the position of the helicopter as well as the swing angle of the load. In addition, a real-time beetle antennae search algorithm is designed to online modify the weights by taking the minimum error at current time as the optimization objective. Besides, the radial basis function neural network is introduced to approach the uncertainty coefficients considering the system’s complexity. At last, relevant simulations are carried out and the results indicate that the system is capable of not only controlling the attitude and position of the helicopter precisely but also stabilizing the underslung load rapidly with ADRC and ISMC.

An innovative integrated path planning and trajectory tracking framework for a quadrotor slung load system in an urban environment

“…Now, the cable force can be computed using equation ( 8) and then substituted in equation ( 1) and equation (2). A simulation program is developed based on the equations of motion for verification and subsequent studies.…”

“…Aerial load transportation is a future real application of autonomous quadrotors that is persuaded by companies like Amazon for the delivery of goods. Various methods of load connected to a quadrotor are cable suspension; [1][2][3][4] GRASPED by a gripper-robotic arm [5][6][7] and using a manipulator. 8,9 Unfortunately, a rigid payload connection to a quadrotor degrades the attitude controller performance due to the variation of the moment of inertia.…”

Adaptive neural network sliding mode control of a nonlinear two‐degrees‐of‐freedom helicopter system

“…The above-mentioned control was designed based on the linearized helicopter model. However, in reality, the helicopter is an unstable, highly cross-coupled, and multiple-output nonlinear system [9,10]. In the process of transforming a nonlinear helicopter system into a linear one, some modes containing important information regarding the system may be ignored, which would lead to an unstable system.…”

Attitude-pendulum-sloshing coupled dynamics of quadrotors slung liquid containers

“…36–39 In addition, the modeling approach and control method are also applicable to the dynamics and control of other types of aerial vehicles transporting liquid containers for firefighting, such as tiltrotors 40 or helicopters. 41…”

“…[36][37][38][39] In addition, the modeling approach and control method are also applicable to the dynamics and control of other types of aerial vehicles transporting liquid containers for firefighting, such as tiltrotors 40 or helicopters. 41 The rest of this article is organized as the following.The section Modeling reports the modeling of a quadrotor carrying a liquid container. The method for controlling attitude-pendulum-sloshing dynamics is presented in the section Oscillation control.…”