Does the Motor System Need Intermittent Control?

Abstract

Explanation of motor control is dominated by continuous neurophysiological pathways (e.g., transcortical, spinal) and the continuous control paradigm. Using new theoretical development, methodology, and evidence, we propose intermittent control, which incorporates a serial ballistic process within the main feedback loop, provides a more general and more accurate paradigm necessary to explain attributes highly advantageous for competitive survival and performance.

Semidiscretization for Time-Delayed Neural Balance Control

“…Indeed, for certain balancing tasks, intermittent control works better than continuous control [46]. These observations have prompted many investigators to develop mathematical models which emphasize a role for event-and clock-driven intermittent control strategies [1,5,9,10,11,12,13,24,25,31,47,48]. Here we consider the possibility that the neural feedback lies somewhere between these two extremes.…”

Intermittent control of unstable multivariate systems with uncertain system parameters

“…However, if "success" depends upon adaptability and flexibility, then regulation and stability need only be minimally sufficient, while biological priority is given to a high bandwidth of decision making. Maximising the bandwidth of state dependent motor decision making requires that selection and optimisation of control structure and design are implemented within the sensorimotor feedback loop [1,2]. An on-board, bio-inspired architecture suitable for adaptable robots operating in complex, changing environments, for example operating safely in close physical proximity with humans, *Supported by EPSRC EP/F068514/1, EP/F069022/1, EP/F06974X/1.…”

“…In short, intermittent v. continuous control trades state dependent online flexibility for control bandwidth [2]. The intermittent rather than continuous use of sensory information to update control signals implies an event trigger determining when to use sensory information, a discrete sampling/initialisation process and a hold process constructing a time varying control trajectory ( Fig.…”

“…A disadvantage of intermittent control (IC) is the reduction in control bandwidth. Benefits are (i) the event related possibility to iteratively reinitialise the control basis and (ii) the availability of predictively stabilised time for state dependent selection and optimisation [1,2,4].…”

“…Recent theoretical and methodological advances have provided new experimental evidence that while human sustained tracking masquerades as continuous control, humans actually uses sensory feedback intermittently to sequentially update intervals of open loop predictive control [2,5,6]. An attribute of open loop predictive control of unstable systems, is that control is sensitive to inaccurate model values of physical system parameters.…”