This paper considers proportional-integral-plus (PIP) control of non-linear systems defined by state-dependent parameter models, with particular emphasis on three practical demonstrators: a microclimate test chamber, a 1/5th-scale laboratory representation of an intelligent excavator, and a full-scale (commercial) vibrolance system used for ground improvement on a construction site. In each case, the system is represented using a quasi-linear state-dependent parameter (SDP) model structure, in which the parameters are functionally dependent on other variables in the system. The approach yields novel SDP-PIP control algorithms with improved performance and robustness in comparison with conventional linear PIP control. In particular, the new approach better handles the large disturbances and other non-linearities typical in the application areas considered.
Key research output for EPSRC GR/R94442/01, assessed as Tending to Internationally Leading for Research Quality. It is a step towards a long-term goal in nonlinear PIP control theory, with wide industrial relevance. The third application referred to in this paper represents a world first for operational use of automated vibro-lance ground compaction (contact: Bachy Solentache Ltd., Burscough, UK). RAE_import_type : Journal article RAE_uoa_type : General Engineering