Introduction:

Our artefacts, from small devices to buildings and cities, are, or are becoming, cyber-physical socio-technical systems, with tightly interwoven physical material and computational parts. We build such systems, laboriously placing material components, laboriously programming computational ones, laboriously integrating the parts, laboriously maintaining the resulting structures. In contrast, trees grow, adapting their form and function to the environmental conditions, and trees self-repair, using the same mechanisms as for growth. These properties allow trees to be gardened—planted, fed, pruned, trained—to meet human needs.

Many authors have expressed the desire to replace our current laborious classical engineering with a more agile “self-*” approach. Our vision here is of construction by directed growth, through gardening macroscopic cyber-physical artefacts formed from a growing, integrated combination of material and virtual subsystems. This is a novel approach to designing, implementing, and maintaining the wealth of cyber-physical artefacts that comprise our “built environment”, including: housing, schools, hospitals, shops, and factories; transport, power, and communication infrastructures. The objective is an unconventional embodied computational process that will produce autonomous, adaptive, robust systems in a controllable and cost-effective manner.

The overall objective of computational growth is to be able to “grow” macroscopic objects that comprise both physical and computational aspects (cyber-physical systems, “smart” materials, etc). The related field of physical self-assembly focuses on the material side: evolving or designing nano- and micro-scale assemblers, or micro-scale artificial cells, that can manipulate and position matter. The computational control of such devices (how and where to position the relevant material; how and when to divide and replicate) is typically assumed to be a relatively trivial matter of programming. Little consideration is given to scalability, adaptability, correctness, or other computer science issues relating to the macro scale of cyber-physical artefacts. Here we consider the matters in the context of an unconventional computational framework.

@inproceedings(Stepney++:grocyphy:2019,
  author = "Susan Stepney and Ada Diaconescu and Ren{\'e} Doursat 
            and Jean-Louis Giavitto and Julian F. Miller and Antoine Spicher",
  title = "Evolving, Growing, and Gardening Cyber-Physical Systems",
  pages = "89-101",          
  crossref = "Armstrong-2019"
)

@proceedings(Armstrong-2019,
  editor = "Rachel Armstrong",
  title = "Experimental Architecture: Designing the Unknown",
  booktitle = "Experimental Architecture: Designing the Unknown",
  publisher = "Routledge",
  year = 2019
)