Nonlinear adaptive backstepping hierarchical control of robotized crane using high-gain observer for autonomous construction

Traditionally, mobile crane is controlled by a human operator using a remote controller. Human labors are required to operate crane systems when cranes are used to undertake some construction tasks. This research aims to achieve automatic crane control using computer system rather than manual control by operators. A nonlinear adaptive backstepping hierarchical control algorithm is developed for a mobile crane and some experiments are conducted to verify the feasibility of the developed control algorithm. The control framework is shown in Figure 1.

Figure 1 Hierarchical control framework of nonlinear adaptive backstepping hierarchical control

The COPMA 430_ENG mobile crane is used in this study to verify the feasibility and accuracy of the developed backstepping algorithms. A 2D pyramid shape concrete block structure is implemented as a prototype structure to be constructed using the mobile crane. The objective of this experiment is to lift and transport the third-level concrete block from the truck, and finally place it on the concrete blocks that have already been laid out (as shown in Figure 2(d)). The whole construction process is fully automated, and the experimental results are presented in Figure 2.

(a) Initial position

(b) Lifting

(c) Transporting

(d) Placing

Figure 2 Construction process of the 2D pyramid using the robotized mobile crane