Nonlinear Output Feedback Control of Flexible Rope Crane Systems With State Constraints

Ning Sun,Tong Yang,Xin Xin,Jianyi Zhang,Yongchun Fang

doi:10.1109/access.2019.2942054

Ning Sun, Tong Yang + Show 3 more

Open Access

https://doi.org/10.1109/access.2019.2942054

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Abstract

When the suspension rope of the crane system is relatively long and its mass cannot be simply ignored compared with that of the payload, or when the crane rope is underwater, it will exhibit flexible characteristics, that is, the bending deformation will occur during swing. Undoubtedly, unreasonable bending deformation of the crane rope will further excite larger-amplitude payload swing, which will seriously influence the efficiency and safety. To this end, for flexible rope crane systems, this paper carries out in-depth analysis and puts forward an effective control method. Specifically, by introducing the concept of lumped mass method and virtual spring, a nonlinear dynamic model is established. Furthermore, in order to solve the problem that velocity signals are not measurable, a nonlinear control strategy, which does not need velocity signals for feedback, is proposed in this paper. Finally, rigorous theoretical analysis and a series of experimental results verify the effectiveness of the proposed control strategy.

Highlights

In recent decades, the control problem of underactuated and mechatronic systems have been a hot topic [1]–[15], among which crane systems are a typical representative
At present, the automation level of crane systems is still unsatisfactory to some extent, since most crane systems still rely heavily on manual operation
Designing effective control methods for cranes is important from a practical perspective

Summary

INTRODUCTION

The control problem of underactuated and mechatronic systems have been a hot topic [1]–[15], among which crane systems are a typical representative. N. Sun et al.: Nonlinear Output Feedback Control of Flexible Rope Crane Systems With State Constraints further stimulate the large-scale payload swing, which will reduce the system lifting efficiency, and lead to serious safety accidents. Reference [55] simplifies the model of flexible rope bridge cranes and further proposes a linear feedback controller with the crane rope deformation velocity signal. After a careful literature review, for flexible rope cranes, since much fewer works are reported, many open practical problems need to be solved. In this paper, we will propose a nonlinear output feedback control method for flexible rope cranes without utilizing velocity signal feedback or other signals which are difficult to measure.

CRANE DYNAMICS

EXPERIMENTS AND ANALYSIS

CONCLUSION