Mathematical modelling and backstepping adaptive sliding mode control for multi-stage hydraulic cylinder

Abstract

Multi-stage hydraulic cylinder is widely used in large scale erecting devices. It can provide longer stroke from an initial package than single stage cylinder. It is divided into telescopic type and synchronous type. However, its structure is complicated. In order to get the characteristics of multi-stage hydraulic cylinder, motion model was established based on node chamber method. The LuGre friction model was improved considering the lubricant film. The contact force model was optimised using the equivalent damping model of the hysteresis factor. Simulations of erection process driven by telescopic and synchronous hydraulic cylinder were completed. Backstepping adaptive sliding mode controller was designed for multi-stage hydraulic cylinder. The proposed controller has a better performance compared to PID controller and ordinary sliding mode controller. The chattering has been reduced by using the saturation function instead of the sign function.