Evolved Transistor Array Robot Controllers

Abstract

For the first time a field programmable transistor array (FPTA) was used to evolve robot control circuits directly in analog hardware. Controllers were successfully incrementally evolved for a physical robot engaged in a series of visually guided behaviours, including finding a target in a complex environment where the goal was hidden from most locations. Circuits for recognising spoken commands were also evolved and these were used in conjunction with the controllers to enable voice control of the robot, triggering behavioural switching. Poor quality visual sensors were deliberately used to test the ability of evolved analog circuits to deal with noisy uncertain data in realtime. Visual features were coevolved with the controllers to automatically achieve dimensionality reduction and feature extraction and selection in an integrated way. An efficient new method was developed for simulating the robot in its visual environment. This allowed controllers to be evaluated in a simulation connected to the FPTA. The controllers then transferred seamlessly to the real world. The circuit replication issue was also addressed in experiments where circuits were evolved to be able to function correctly in multiple areas of the FPTA. A methodology was developed to analyse the evolved circuits which provided insights into their operation. Comparative experiments demonstrated the superior evolvability of the transistor array medium.

Recent advances in evolutionary and bio-inspired adaptive robotics: Exploiting embodied dynamics

“…Even though the controllers were evolved to produce very efficient behaviour in the environment shown in Fig. 3 (with variations during evaluation trials as outlined earlier), and exploited robot-environment dynamics particular to this environment, our methodology still made them general enough to be able to successfully perform the task (find the target and stay at it) in unseen variations of the environment where the target had been moved to a different location or the shape of the environment has been altered [40] (see Fig. 4).…”

“…Right: FPTA compared on avoider behaviour with an array of dynamical units and with a dynamical neural network with a pre-defined architecture difficult than most previous ER visual behaviours and has not been attempted before [90]. For further details of the experimental setup see [40].…”

“…Evolvable hardware (EHW), or evolutionary electronics [117], is the application of evolutionary search algorithms to the design of electronic circuits [24,25,41,75,76,96]. This is a field in which our group has made recent advances, namely, the first demonstration of transistor level analog electronic controllers evolved directly in hardware for non-trivial visually guided robot behaviours [40]. This section describes this work and puts it in the context of recent developments in evolutionary robotics (ER) [90,123].…”

“…Careful empirical measurements were used to model motor responses and sensor readings. Motor and sensor noise was introduced at a level empirically determined to match the real behaviour [40]. The simulator operated at a configurable discrete time step.…”

“…Such robustness is essential for transferring to the real world and operating in realistic conditions. The discrete nature of the sampling, and the use of the nearest sample to the actual position of the simulated robot, adds further noise and coarseness which increases the pressure to produce general, robust solutions [40]. In some of the experiments using vision, additional features and obstacles were introduced into the modelled arena through Computer Generated Imagery (CGI) injection into the sampled images.…”