Architectures for Rapid Prototyping of Model-based Robot Controllers

Rapid Prototyping (RP) in control design can be defined as a computer assisted process aimed at recursively validating dynamic models of complex plants and mechatronic systems and/or designing and testing digital control algorithms for realtime applications. Rapid prototyping of digital control algorithms requires integrated hardware/software architectures, allowing fast and systematic interactions between the algorithmic design phase and the experimental testing. The design phase is performed with the support of a computer-aided control design environment, where simulations are performed on accurate models of the specific equipment under investigation; after that, a rapid transfer of the algorithm on the target hardware is necessary to validate it experimentally. It is therefore necessary to have a complete prototyping environment, where different controller blocks are readily available, with structure and parameters easily modifiable to be tested on the simulated plant and downloaded on the target hardware platform for realtime validation. The present chapter introduces the state of the art on RP, critically surveys and discusses general issues related to both HW and SW aspects that are at the basis of RP; furthermore it describes in some details the solution implemented by the authors at the Experimental Robotics Laboratory of Politecnico di Torino. A test case, devoted to the problem of modelling and compensation of nonlinear friction in rotating robot arms is presented. Finally, a critical appraisal of the proposed solution, in the light of the gained experience, is discussed and future developments are pointed out.