Control of velocity and position in single joint movements

Abstract

Previous research on single joint movements has lead to the development of models of control that propose that movement speed and distance are controlled through an initial pulsatile signal that can be modified in both amplitude and duration. However, the manner in which the amplitude and duration are modulated during the control of movement speed and distance remains controversial. We now report two studies that were designed to test and refine the pulse-step model of movement control. In our first study, participants move at a series of speeds to a single spatial target. In this task, acceleration duration (pulse-width) varied substantially across targets, and was negatively correlated with peak acceleration (pulse-height). In a second experiment, we removed the spatial target, but required movements at three speeds similar to those used in the first study. In this task, acceleration amplitude varied extensively across the speed targets, while acceleration duration remained constant across the three speeds. Taken together, our current findings demonstrate that pulse-width measures can be modulated independently from pulse-height measures, and that a positive correlation between such measures is not obligatory, even when sampled across a range of movement speeds. In addition, our findings suggest that pulse-height modulation plays a primary role in controlling movement speed and specifying target distance, whereas pulse-width mechanisms are employed to correct errors in pulse-height control, as required to achieve spatial precision in final limb position.

Achieving Closed‐Loop Control Simulation of Human‐Artefact Interaction: A Comparative Review

“…Sanders [32] proposed two stages of response execution, namely, (i) response programming, which suggests logical control, and which seems to correspond to Costello's large-scale movement planning, and (ii) motor adjustment, which is supposed to produce "instructed muscle tension", in other words, it specifies the force required. This also seems to be in agreement with findings that the velocity and position control signals that are input to response execution are generally considered to be discrete and pulsatile [33].…”

Lateralized motor control processes determine asymmetry of interlimb transfer

“…A great deal of previous work on single-joint movements directed toward targets of varied amplitude has shown that acceleration amplitude (Sainburg and Schaefer, 2004b, Mutha and Sainburg, 2007), initial EMG peak amplitude (Corcos et al, 1989, Gottlieb et al, 1989, Gottlieb et al, 1990) or the initial amplitude of the time derivative of a force pulse (Ghez and Gordon, 1987, Gordon and Ghez, 1987a, 1987b)is specified prior to movement. In contrast, acceleration duration is modulated during the course of motion to correct for improperly specified amplitudes (Brown and Cooke, 1990, Cooke and Brown, 1990, Gottlieb, 1996, Mutha and Sainburg, 2007). In order to understand these control processes in more detail, Yadav and Sainburg (Yadav and Sainburg, 2011, 2014a) conducted simulations that combined two controllers in sequence: a predictive controller and an impedance controller.…”

Limb Dominance Results from Asymmetries in Predictive and Impedance Control Mechanisms

“…In addition, these ideas have more recently gained support from empirical studies [36] [37] [38] [39] [40]. Predictive control mechanisms seek to optimize a combination of kinematic and dynamic costs of movement [8] [29] [36].…”