Determining the Viability of the Use of Magneto-Rheological Fluid in a Low Cost Stroke Rehabilitation Device

<p>There are over 15 million people affected by strokes worldwide with a third left disabled. It is estimated that only 5 to 20 % regain upper limb functionality. However, research has shown that repetitive movement on the affected limb improves motor relearning. With the number of people affected by strokes rising each year the demand has begun straining hospital resources, therefore there is a need for some therapy to be moved away from clinical settings and into a person’s home. Robot assisted therapy is a growing field aiming to meet this demand. However currently there are no low cost devices able to actively exercise and strengthen a person’s hand during the acute (early) stage of stroke rehabilitation. This study is a part of a larger project involving the development of a low cost, assistive stroke rehabilitation device requiring a controllable damper. The aim of the study is to determine whether the use of magnetorheological fluid in a controllable damper is viable for use in the planned rehabilitation device. A rotary damper configuration was chosen as it can be made compact and avoid fluid leakage. To be deemed suitable for the application, the viscous torque of the damper needed to be controllable with varying input current. The required damping torques produced must be repeatable and needs to be generated below 34 C, the specified maximum operating temperature of the system. The performance of three vane designs for the rotary damper were investigated. These three designs were layered discs, a paddle and a helix. A test rig using a pulley configuration was designed and constructed to quantify the performance of the vane designs. The test rig recorded the opposing force and temperature measurements for each damper design. The measurements of interest were the off-state (no input current) torque, the achievable torque range, and also the consistency of the measurements. Experiments were conducted with the damper containing air to determine the pre-existing friction between the vane and housing, and water and motor oil were used as the damper fluid to investigate the performance of the designs with known fluid viscosities. Lastly experiments containing magneto-rheological fluid were conducted to determine the controllability and consistency of the viscous torque of each design. The paddle design was selected based on its range and consistency of produced torque, simplicity of the design and expected economical manufacture. With an input current of 0 to 2 A the damper produced a viscous torque range of 0.0036 Nm to 0.044 Nm, which was the equivalent opposing force of approximately 7.3 N. During testing of the various damper designs, a few imperfections were found. A modified version of the chosen damper was constructed to determine whether those features were manufacturing artifacts. It was found that the force measurements became smoother and previous periodic oscillations in the measurements were eliminated. The viscous torque of the paddle design was found to be controllable within the given operational conditions and therefore the use of magnetorheological fluid is a viable solution for use in a low cost stroke rehabilitation device.</p>

Determining the Viability of the Use of Magneto-Rheological Fluid in a Low Cost Stroke Rehabilitation Device

<p>There are over 15 million people affected by strokes worldwide with a third left disabled. It is estimated that only 5 to 20 % regain upper limb functionality. However, research has shown that repetitive movement on the affected limb improves motor relearning. With the number of people affected by strokes rising each year the demand has begun straining hospital resources, therefore there is a need for some therapy to be moved away from clinical settings and into a person’s home. Robot assisted therapy is a growing field aiming to meet this demand. However currently there are no low cost devices able to actively exercise and strengthen a person’s hand during the acute (early) stage of stroke rehabilitation. This study is a part of a larger project involving the development of a low cost, assistive stroke rehabilitation device requiring a controllable damper. The aim of the study is to determine whether the use of magnetorheological fluid in a controllable damper is viable for use in the planned rehabilitation device. A rotary damper configuration was chosen as it can be made compact and avoid fluid leakage. To be deemed suitable for the application, the viscous torque of the damper needed to be controllable with varying input current. The required damping torques produced must be repeatable and needs to be generated below 34 C, the specified maximum operating temperature of the system. The performance of three vane designs for the rotary damper were investigated. These three designs were layered discs, a paddle and a helix. A test rig using a pulley configuration was designed and constructed to quantify the performance of the vane designs. The test rig recorded the opposing force and temperature measurements for each damper design. The measurements of interest were the off-state (no input current) torque, the achievable torque range, and also the consistency of the measurements. Experiments were conducted with the damper containing air to determine the pre-existing friction between the vane and housing, and water and motor oil were used as the damper fluid to investigate the performance of the designs with known fluid viscosities. Lastly experiments containing magneto-rheological fluid were conducted to determine the controllability and consistency of the viscous torque of each design. The paddle design was selected based on its range and consistency of produced torque, simplicity of the design and expected economical manufacture. With an input current of 0 to 2 A the damper produced a viscous torque range of 0.0036 Nm to 0.044 Nm, which was the equivalent opposing force of approximately 7.3 N. During testing of the various damper designs, a few imperfections were found. A modified version of the chosen damper was constructed to determine whether those features were manufacturing artifacts. It was found that the force measurements became smoother and previous periodic oscillations in the measurements were eliminated. The viscous torque of the paddle design was found to be controllable within the given operational conditions and therefore the use of magnetorheological fluid is a viable solution for use in a low cost stroke rehabilitation device.</p>

Between Two Minds: The Work of Peirce’s Energetic Interpretant

This inquiry illustrates how Peirce’s Energetic Interpretant facilitates consciousness-raising between sign users. Because it forces attention and progression of action, the Energetic Interpretant highlights perfective aspectual characteristics, namely atomistic/punctual cause-effect sign relations by featuring junctures between events: beginning, middle, end. For example, the stops and starts of events are influenced by the nature of the action, in addition to the agent’s idiosyncratic preferences and predilections. The Thirdness underlying it further perpetuates the punctual component (Vendler 1967) present in action relations, operational when effort produces resistance against an opposing force. Because effort can materialize physically, or internally, it demonstrates the continued primacy of Peirce’s categories in fostering certain consequences. Energetic Interpretants can inhibit (Secondness), i.e., attention to one stimulus, while ignoring another. Nonetheless, consciously inhibiting/resisting a force (via Energetic Interpretants) introduces control beyond the self—another’s reflections upon the conscious acts of an agent (ms 318). This influence between interlocutors satisfies Peirce’s maxim of a “common place to stand” (ms 614), demonstrating mutual comprehension of the sign’s proper effect (5.475). In fact, Energetic Interpretants may result in an effect of such proportion upon either or both interlocutors that a habit-change materializes. As such, Energetic Interpretants epitomize the perfectivity exercised by particular efforts, intimating the likelihood of their discursive success. Inherent in punctual events (versus dynamic ones) is the element of surprise, which ultimately hastens the kind of habit-change especially exhibited in Peirce’s double consciousness (5.53)—self talking to self or other.

Strategic Security in Northern Europe: The Implications of Russian Anti-Access/Area Denial Strategies in Developing Complex Threat Environments

Anti-Access/Area Denial (A2/AD) is a term that came into use to describe an environment in which an air and air defense force could use a combination of surface-launched ballistic missiles, surface and air launched cruise missiles and long-range surface-to-air missiles to prevent an opposing force from accessing or operating within a large airspace effectively. The descriptions and subsequent analyses of the penetrability of these environments often rests on assessments of the capabilities of just a few newly developed missiles and may fail to consider the additional complexity induced by the large array of the entire complement of air, land and sea launched missiles available to adversaries. This article will focus on Northern Europe as one example of the higher degrees of complexity that our air forces are likely to face should the need arise to fight and win in a 21st Century highly contested environment.

Spirale (Spiral)

The lexeme Spirale (spiral) serves as an important symbol and figure of thought in Goethe’s oeuvre that cuts across numerous discourses and disciplines, ranging from aesthetics and art history to mineralogy and geology, from botany and cosmology to anthropology and sexuality. Early on in Goethe’s life it plays a rather marginal role in his thought; yet by the year of his death in 1832, it becomes a pivotal, if contradictory, figure imbued with scientific, literary, and even metaphysical significance. Associated with such archetypal polarities as systole/diastole, male/female, and life/death, the spiral ultimately emerges in Goethe’s conceptual lexicon as a type of motion within opposing force fields whose ever greater intensification also suspends them, thereby inhibiting a higher synthesis or conceptual resolution. In brief, Goethe’s concept of the spiral works to overstep boundaries, transgress binaries, and resist stasis and closure.

Asymmetry in kinematic generalization between visual and passive lead-in movements are consistent with a forward model in the sensorimotor system

In our daily life we often make complex actions comprised of linked movements, such as reaching for a cup of coffee and bringing it to our mouth to drink. Recent work has highlighted the role of such linked movements in the formation of independent motor memories, affecting the learning rate and ability to learn opposing force fields. In these studies, distinct prior movements (lead-in movements) allow adaptation of opposing dynamics on the following movement. Purely visual or purely passive lead-in movements exhibit different angular generalization functions of this motor memory as the lead-in movements are modified, suggesting different neural representations. However, we currently have no understanding of how different movement kinematics (distance, speed or duration) affect this recall process and the formation of independent motor memories. Here we investigate such kinematic generalization for both passive and visual lead-in movements to probe their individual characteristics. After participants adapted to opposing force fields using training lead-in movements, the lead-in kinematics were modified on random trials to test generalization. For both visual and passive modalities, recalled compensation was sensitive to lead-in duration and peak speed, falling off away from the training condition. However, little reduction in force was found with increasing lead-in distance. Interestingly, asymmetric transfer between lead-in movement modalities was also observed, with partial transfer from passive to visual, but very little vice versa. Overall these tuning effects were stronger for passive compared to visual lead-ins demonstrating the difference in these sensory inputs in regulating motor memories. Our results suggest these effects are a consequence of state estimation, with differences across modalities reflecting their different levels of sensory uncertainty arising as a consequence of dissimilar feedback delays.

ABC of Neo-Newtonian dynamics of static magnetic field

I have analyzed the magnetic force between an electromagnet and a permanent magnet in accordance with Newton’s first law of motion. The analysis concluded that magnetic force of permanent magnet must work or this force must be balanced (canceled) by an opposing force. To check the results of the analysis, I have conducted thousands of experiments on the magnetic force. Reasonable amount of opposing force appeared during the experiments. Appearance of the opposing force has validated the results of the analysis.Moreover, I have successfully reduced the production of the opposing force. Resultant force exceeded to a great extent ultimately. I have made 4 working proofs of the concept. The working proofs of the concept convert the recovered resultant force into additional output power. According to Newton’s first law of motion, the emerging of the additional output power is not only absolutely natural but also is mandatory.