Table 2.

TRL definition.

TRL	Definition	Explanation
1	Basic principle observed	The idea has been formulated
2	Technology concept formulated	The concept and the application have been formulated
3	Experimental proof of concept	The first prototype has been built but not tested
4	Technology validated in lab	The prototype has been tested in laboratory on a mannequin
5	Technology validated in relevant environment	The prototype is mature in terms of design and control and has been tested on healthy subjects
6	Technology demonstrated in relevant environment	The prototype has been tested for its efficacy on subjects with motor disability or healthy subjects according to the intended scenario
7	System prototype demonstration in operational environment	The system has been tested for its intended purpose in the clinic, at home, in the factory, in sport fields
8	System complete and qualified	The system is ready to be produced in large scale
9	Actual system proven in operational environment	The system is available in the market