Narrowband Generation of High-Level Acoustic Noise with Closed-Loop Control from Accelerometers

Purpose The purpose of this study is to present a novel hybrid closed-loop control method together with its performance validation for the dexterous prosthetic hand. Design/methodology/approach The hybrid closed-loop control is composed of a high-level closed-loop control with the user in the closed loop and a low-level closed-loop control for the direct robot motion control. The authors construct the high-level control loop by using electromyography (EMG)-based human motion intent decoding and electrical stimulation (ES)-based sensory feedback. The human motion intent is decoded by a finite state machine, which can achieve both the patterned motion control and the proportional force control. The sensory feedback is in the form of transcutaneous electrical nerve stimulation (TENS) with spatial-frequency modulation. To suppress the TENS interfering noise, the authors propose biphasic TENS to concentrate the stimulation current and the variable step-size least mean square adaptive filter to cancel the noise. Eight subjects participated in the validation experiments, including pattern selection and egg grasping tasks, to investigate the feasibility of the hybrid closed-loop control in clinical use. Findings The proposed noise cancellation method largely reduces the ES noise artifacts in the EMG electrodes by 18.5 dB on average. Compared with the open-loop control, the proposed hybrid closed-loop control method significantly improves both the pattern selection efficiency and the egg grasping success rate, both in blind operating scenarios (improved by 1.86 s, p < 0.001, and 63.7 per cent, p < 0.001) or in common operating scenarios (improved by 0.49 s, p = 0.008, and 41.3 per cent, p < 0.001). Practical implications The proposed hybrid closed-loop control method can be implemented on a prosthetic hand to improve the operation efficiency and accuracy for fragile objects such as eggs. Originality/value The primary contribution is the proposal of the hybrid closed-loop control, the spatial-frequency modulation method for the sensory feedback and the noise cancellation method for the integrating of the myoelectric control and the ES-based sensory feedback.

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Robotic Telepresence

Proceedings of the Human Factors Society Annual Meeting ◽

10.1177/154193128603000110 ◽

1986 ◽

Vol 30 (1) ◽

pp. 43-44 ◽

Cited By ~ 6

Author(s):

George C. Mohr

Keyword(s):

Cognitive Functions ◽

Closed Loop ◽

Industrial Robot ◽

Space Station ◽

Human Operator ◽

Closed Loop Control ◽

Loop Control ◽

Novel Approach ◽

Operator Tasks ◽

High Level

The Air Force sees a need for a militarized robot, designed to perform flight line maintenance and repair operations during a chemical/biological/radiological attack, or to assist man in space operations such as constructing a space station or performing such tasks as satellite inspection, diagnosis, repair, modification or deactivation. Obviously, these tasks require more than the pre-programmed behavior of an industrial robot. To obtain the high degree of adaptability required, the robot needs either the closed-loop control of a human operator, or a high level “artificial intelligence” capable of emulating human cognitive functions. Robotic telepresence is a novel approach to closed-loop control. By coupling the human operator's visual, tactile, motor and cognitive functions with a remote robot's “head, eyes, and hands,” the human operator is placed effectively “in-the-scene.” With this approach, the natural synergism between the human visual system and hands is exploited to endow the robotic system with human-like capacities to inspect, evaluate, and manipulate. Through robotic telepresence technology, the essential human operator tasks can then be performed in a lethally hazardous environment without exposing the human operator directly.

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The Impact of Visual Feedback Type on the Mastery of Visuo-Motor Transformations

Zeitschrift für Psychologie ◽

10.1027/2151-2604/a000084 ◽

2012 ◽

Vol 220 (1) ◽

pp. 3-9 ◽

Cited By ~ 4

Author(s):

Sandra Sülzenbrück

Keyword(s):

Empirical Research ◽

Visual Feedback ◽

Closed Loop ◽

Motor Planning ◽

Visual Input ◽

Closed Loop Control ◽

Loop Control ◽

Feedback Type ◽

Effective Use ◽

The Impact

For the effective use of modern tools, the inherent visuo-motor transformation needs to be mastered. The successful adjustment to and learning of these transformations crucially depends on practice conditions, particularly on the type of visual feedback during practice. Here, a review about empirical research exploring the influence of continuous and terminal visual feedback during practice on the mastery of visuo-motor transformations is provided. Two studies investigating the impact of the type of visual feedback on either direction-dependent visuo-motor gains or the complex visuo-motor transformation of a virtual two-sided lever are presented in more detail. The findings of these studies indicate that the continuous availability of visual feedback supports performance when closed-loop control is possible, but impairs performance when visual input is no longer available. Different approaches to explain these performance differences due to the type of visual feedback during practice are considered. For example, these differences could reflect a process of re-optimization of motor planning in a novel environment or represent effects of the specificity of practice. Furthermore, differences in the allocation of attention during movements with terminal and continuous visual feedback could account for the observed differences.

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