Control of Active Above-Knee Prostheses Through Electromyography

Author(s):  
Sai-Kit Wu ◽  
Garrett Waycaster ◽  
Xiangrong Shen

This paper describes a new electromyography (EMG) based control approach for powered above-knee prostheses. In the proposed control approach, the EMG signals are utilized as the direct control commands to the prosthesis, and thus enable the volitional control by the wearer, not only for locomotive functions, but for arbitrary motion as well. To better integrate the AK prosthesis into the rest of the human body, the control approach incorporates a human motor control mechanism-inspired ‘active-passive’ model, which combines an active control component that reflects the wearer’s motion intention, with a passive control component that implements the controllable impedance critical to the safe and stable interaction with the environment. The effectiveness of the proposed control approach was demonstrated through the experimental results for arbitrary free swing and level walking.

Author(s):  
Sai-Kit Wu ◽  
Garrett Waycaster ◽  
Xiangrong Shen

This paper describes a new electromyography (EMG) based control approach for powered above-knee prostheses. In the proposed control approach, the EMG signals are utilized as the direct control commands to the prosthesis, and thus enable the volitional control by the wearer, not only for locomotive functions, but for arbitrary motion as well. To better integrate the AK prosthesis into the rest of the human body, the control approach incorporates a human motor control mechanism-inspired ‘active-reactive’ model, which combines an active control component that reflects the wearer’s motion intention, with a reactive control component that implements the controllable impedance critical to the safe and stable interaction with the environment. The effectiveness of the proposed control approach was demonstrated through the experimental results for arbitrary free swing and level walking.


2021 ◽  
Vol 11 (15) ◽  
pp. 6899
Author(s):  
Abdul Aabid ◽  
Sher Afghan Khan ◽  
Muneer Baig

In high-speed fluid dynamics, base pressure controls find many engineering applications, such as in the automobile and defense industries. Several studies have been reported on flow control with sudden expansion duct. Passive control was found to be more beneficial in the last four decades and is used in devices such as cavities, ribs, aerospikes, etc., but these need additional control mechanics and objects to control the flow. Therefore, in the last two decades, the active control method has been used via a microjet controller at the base region of the suddenly expanded duct of the convergent–divergent (CD) nozzle to control the flow, which was found to be a cost-efficient and energy-saving method. Hence, in this paper, a systemic literature review is conducted to investigate the research gap by reviewing the exhaustive work on the active control of high-speed aerodynamic flows from the nozzle as the major focus. Additionally, a basic idea about the nozzle and its configuration is discussed, and the passive control method for the control of flow, jet and noise are represented in order to investigate the existing contributions in supersonic speed applications. A critical review of the last two decades considering the challenges and limitations in this field is expressed. As a contribution, some major and minor gaps are introduced, and we plot the research trends in this field. As a result, this review can serve as guidance and an opportunity for scholars who want to use an active control approach via microjets for supersonic flow problems.


2021 ◽  
Vol 18 (2) ◽  
pp. 172988142199858
Author(s):  
Gianpaolo Gulletta ◽  
Eliana Costa e Silva ◽  
Wolfram Erlhagen ◽  
Ruud Meulenbroek ◽  
Maria Fernanda Pires Costa ◽  
...  

As robots are starting to become part of our daily lives, they must be able to cooperate in a natural and efficient manner with humans to be socially accepted. Human-like morphology and motion are often considered key features for intuitive human–robot interactions because they allow human peers to easily predict the final intention of a robotic movement. Here, we present a novel motion planning algorithm, the Human-like Upper-limb Motion Planner, for the upper limb of anthropomorphic robots, that generates collision-free trajectories with human-like characteristics. Mainly inspired from established theories of human motor control, the planning process takes into account a task-dependent hierarchy of spatial and postural constraints modelled as cost functions. For experimental validation, we generate arm-hand trajectories in a series of tasks including simple point-to-point reaching movements and sequential object-manipulation paradigms. Being a major contribution to the current literature, specific focus is on the kinematics of naturalistic arm movements during the avoidance of obstacles. To evaluate human-likeness, we observe kinematic regularities and adopt smoothness measures that are applied in human motor control studies to distinguish between well-coordinated and impaired movements. The results of this study show that the proposed algorithm is capable of planning arm-hand movements with human-like kinematic features at a computational cost that allows fluent and efficient human–robot interactions.


2019 ◽  
Author(s):  
N. Boulanger ◽  
F. Buisseret ◽  
V. Dehouck ◽  
F. Dierick ◽  
O. White

AbstractNatural human movements are stereotyped. They minimise cost functions that include energy, a natural candidate from mechanical and physiological points of view. In time-changing environments, however, motor strategies are modified since energy is no longer conserved. Adiabatic invariants are relevant observables in such cases, although they have not been investigated in human motor control so far. We fill this gap and show that the theory of adiabatic invariants explains how humans move when gravity varies.


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