Anticipation from sensation: using anticipating synchronisation to stabilise a system with inherent sensory delay

We present a novel way of using a dynamical model for predictive tracking control that can adapt to a wide range of delays without parameter update. This is achieved by incorporating the paradigm of anticipating synchronisation (AS), where a `slave' system predicts a `master' via delayed self-feedback. By treating the delayed output of the plant as one half of a `sensory' AS coupling, the plant and an internal dynamical model can be synchronised such that the plant consistently leads the target's motion. We use two simulated robotic systems with differing arrangements of the plant and internal model (`parallel' and `serial') to demonstrate that this form of control adapts to a wide range of delays without requiring the parameters of the controller to be changed

PID control system analysis and design

With its three-term functionality offering treatment of both transient and steady-state responses, proportional-integral-derivative (PID) control provides a generic and efficient solution to realworld control problems. The wide application of PID control has stimulated and sustained research and development to "get the best out of PID", and "the search is on to find the next key technology or methodology for PID tuning". This article presents remedies for problems involving the integral and derivative terms. PID design objectives, methods, and future directions are discussed. Subsequently, a computerized, simulation-based approach is presented, together with illustrative design results for first-order, higher order, and nonlinear plants. Finally, we discuss differences between academic research and industrial practice, so as to motivate new research directions in PID control

Feedback linearization control for a distributed solar collector field

This article describes the application of a feedback linearization technique for control of a distributed solar collector field using the energy from solar radiation to heat a fluid. The control target is to track an outlet temperature reference by manipulating the fluid flow rate through the solar field, while attenuating the effect of disturbances (mainly radiation and inlet temperature). The proposed control scheme is very easy to implement, as it uses a numerical approximation of the transport delay and a modification of the classical control scheme to improve startup in such a way that results compared with other control structures under similar conditions are improved while preserving short commissioning times. Experiments in the real plant are also described, demonstrating how operation can be started up efficiently.Ministerio de Ciencia y Tecnología DPI2004-07444-C04-04Ministerio de Ciencia y Tecnología DPI2005-0286

Computer simulation of a pilot in V/STOL aircraft control loops

The objective was to develop a computerized adaptive pilot model for the computer model of the research aircraft, the Harrier II AV-8B V/STOL with special emphasis on propulsion control. In fact, two versions of the adaptive pilot are given. The first, simply called the Adaptive Control Model (ACM) of a pilot includes a parameter estimation algorithm for the parameters of the aircraft and an adaption scheme based on the root locus of the poles of the pilot controlled aircraft. The second, called the Optimal Control Model of the pilot (OCM), includes an adaption algorithm and an optimal control algorithm. These computer simulations were developed as a part of the ongoing research program in pilot model simulation supported by NASA Lewis from April 1, 1985 to August 30, 1986 under NASA Grant NAG 3-606 and from September 1, 1986 through November 30, 1988 under NASA Grant NAG 3-729. Once installed, these pilot models permitted the computer simulation of the pilot model to close all of the control loops normally closed by a pilot actually manipulating the control variables. The current version of this has permitted a baseline comparison of various qualitative and quantitative performance indices for propulsion control, the control loops and the work load on the pilot. Actual data for an aircraft flown by a human pilot furnished by NASA was compared to the outputs furnished by the computerized pilot and found to be favorable

Taking Fitts' Slow: The Effects of Delayed Visual Feedback on Human Motor Performance and User Experience

abstract: ABSTRACT The present studies investigated the separate effects of two types of visual feedback delay – increased latency and decreased updating rate – on performance – both actual (e.g. response time) and subjective (i.e. rating of perceived input device performance) – in 2-dimensional pointing tasks using a mouse as an input device. The first sub-study examined the effects of increased latency on performance using two separate experiments. In the first experiment the effects of constant latency on performance were tested, wherein participants completed blocks of trials with a constant level of latency. Additionally, after each block, participants rated their subjective experience of the input device performance at each level of latency. The second experiment examined the effects of variable latency on performance, where latency was randomized within blocks of trials. The second sub-study investigated the effects of decreased updating rates on performance in the same manner as the first study, wherein experiment one tested the effect of constant updating rate on performance as well as subjective rating, and experiment two tested the effect of variable updating rate on performance. The findings suggest that latency is negative correlated with actual performance as well as subjective ratings of performance, and updating rate is positively correlated with actual performance as well as subjective ratings of performance.Dissertation/ThesisMasters Thesis Applied Psychology 201

Using rewards and penalties to obtain desired subject performance

Operant conditioning procedures, specifically the use of negative reinforcement, in achieving stable learning behavior is described. The critical tracking test (CTT) a method of detecting human operator impairment was tested. A pass level is set for each subject, based on that subject's asymptotic skill level while sober. It is critical that complete training take place before the individualized pass level is set in order that the impairment can be detected. The results provide a more general basis for the application of reward/penalty structures in manual control research

Extrinsic and intrinsic dynamics in visuomotor tracking

PhD ThesisHumans typically produce 2–3 submovements per second when tracking slow targets. This intermittency is altered by the addition of delays in sensory feedback suggesting that it is governed by extrinsic properties of the control loop. However, the motor cortex also exhibits an intrinsic rhythmicity at 2–3 Hz, which might influence the temporal structure of movements. This thesis examines how the interplay between extrinsic and intrinsic dynamics shapes the kinematics of tracking behaviour. I found that the dependence of submovement frequencies on extrinsic delays could be reproduced by a simple feedback controller model. This model predicted that submovements reflect frequencies at which visuomotor noise is exacerbated, and this was confirmed by perturbation experiments. However, these experiments also revealed a 2-3 Hz band-pass filtering of feedback responses irrespective of extrinsic delay. Further experimental evidence suggested this filter did not reflect properties of either visuomotor noise, the feedforward pathway, or visual processing. However, the filter exhibited features consistent with a state estimator required for optimal feedback control (OFC) in the presence of visual and motor noise. Finally, I sought evidence that this filter was implemented by motor cortical circuits. Multichannel local field potentials (LFPs) in the motor cortex of macaque monkeys were strongly correlated with submovements, at frequencies which depended on extrinsic delay. However, the dynamics of LFP cycles during submovements were independent of delay, and matched instead the properties of the state estimator in the OFC model. In summary, by combining human behavioural studies, computational modelling and monkey electrophysiology, I show how movement intermittency can be explained by the interplay of both extrinsic and intrinsic dynamics within an OFC framework. Moreover, I suggest that motor cortical rhythmicity reflects recurrent circuitry that combines sensory feedback with an internal dynamical model to form optimal estimates of required motor corrections.Indonesian Endowment Fund for Education (Lembaga Pengelola Dana Pendidikan Republik Indonesia) for supporting my PhD studies. This work would also not have been possible without the financial support of the Wellcome Trust, and the Medical Research Council