Action ability modulates time‑to‑collision judgments

Time-to-collision (TTC) underestimation has been interpreted as an adaptive response that allows observers to have more time to engage in a defensive behaviour. This bias seems, therefore, strongly linked to action preparation. There is evidence that the observer’s physical fitness modulates the underestimation effect so that people who need more time to react (i.e. those with less physical fitness) show a stronger underestimation effect. Here we investigated whether this bias is influenced by the momentary action capability of the observers. In the first experiment, participants estimated the time-to-collision of threatening or non-threatening stimuli while being mildly immobilized (with a chin rest) or while standing freely. Having reduced the possibility of movement led participants to show more underestimation of the approaching stimuli. However, this effect was not stronger for threatening relative to non-threatening stimuli. The effect of the action capability found in the first experiment could be interpreted as an expansion of peripersonal space (PPS). In the second experiment, we thus investigated the generality of this effect using an established paradigm to measure the size of peripersonal space. Participants bisected lines from different distances while in the chin rest or standing freely. The results replicated the classic left-to-right gradient in lateral spatial attention with increasing viewing distance, but no effect of immobilization was found. The manipulation of the momentary action capability of the observers influenced the participants’ performance in the TTC task but not in the line bisection task. These results are discussed in relation to the different functions of PPS

Decentralized nonlinear output-feedback stabilization with disturbance attenuation

As a continuation of our recent work [2], this note addresses the problem of decentralized robust output-feedback stabilization with disturbance attenuation for large-scale systems with strong nonlinear interconnections. We target a first constructive solution to this decentralized control problem without requiring common matching and growth conditions appearing in the past literature. The proposed decentralized output-feedback laws achieve internal global asymptotic stability in the sense of Lyapunov and external stability in the sense of Sontag [21], [22].link_to_subscribed_fulltex

Implementation of PID, bang-bang and backstep-ping controllers on 3D printed ambidextrous robot hand

Robot hands have attracted increasing research interest in recent years due to their high demand in industry and wide scope in number of applications. Almost all researches done on the robot hands were aimed at improving mechanical design, clever grasping at different angles, lifting and sensing of different objects. In this chapter, we presented the detail classification of control systems and reviewed the related work that has been done in the past. In particular, our focus was on control algorithms implemented on pneumatic systems using PID controller, Bang-bang controller and Backstepping controller. These controllers were tested on our uniquely designed ambidextrous robotic hand structure and results were compared to find the best controller to drive such devices. The five finger ambidextrous robot hand offers total of 13 degrees of freedom (DOFs) and it can bend its fingers in both ways left and right offering full ambidextrous functionality by using only 18 pneumatic artificial muscles (PAMs).Anthony Huynh, Luke Steele, Michal Simko, Luke Kavanagh and Alisdair Nimm