Comparison of Pixel-based Position Input and Direct Acceleration Input for Virtual Stick Balancing Tests

Kovács, Balázs Áron; Insperger, Tamás

doi:10.3311/ppme.13507

Cited by 6 publications

(10 citation statements)

References 16 publications

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“…Due to the finite number of pixels, this results in a noisy acceleration signal. Therefore, a simple re-sampling filter was used, and the input acceleration was computed asanormalSfalse(tifalse)=Kx(ti)−2x(ti−k)+x(ti−2k)Δt2,where K = 8.85 × 10 −5 m/pixel is a gain factor scaling the screen size to the manipulation length of the computer mouse [44], x ( t i ) is the mouse position measured in pixels at the time instant t i = i Δ t and k ≥ 1 is an integer filtering parameter. The sampling period was set to Δ t = 16.67 ms, which corresponds to the screen refresh rate 60 Hz.…”

Section: Methodsmentioning

confidence: 99%

“…For the actuation of the virtual environment, the input signal is the acceleration of the computer mouse moved by the subject's hand. The acceleration was determined via numerical derivation of the pixel-based position of the cursor [44]. Due to the finite number of pixels, this results in a noisy acceleration signal.…”

Section: Virtual Stick Balancing Environmentmentioning

confidence: 99%

“…The response time of the computer screen, signal filtering and the screen refresh rate introduce a machine delay τ M which is equal to the time between when an input is produced by a computer mouse and its appearance on the screen. Different computer-screen configurations have been investigated to make the machine delay as small as possible [44]. The screen response time was measured using a light sensor system, which detects black and white transition time of the screen synchronized to the mouse input.…”

Section: Machine Delay and Delay Incrementsmentioning

confidence: 99%

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Virtual stick balancing: sensorimotor uncertainties related to angular displacement and velocity

2019

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Sensory uncertainties and imperfections in motor control play important roles in neural control and Bayesian approaches to neural encoding. However, it is difficult to estimate these uncertainties experimentally. Here, we show that magnitude of the uncertainties during the generation of motor control force can be measured for a virtual stick balancing task by varying the feedback delay, τ. It is shown that the shortest stick length that human subjects are able to balance is proportional to τ 2. The proportionality constant can be related to a combined effect of the sensory uncertainties and the error in the realization of the control force, based on a delayed proportional-derivative (PD) feedback model of the balancing task. The neural reaction delay of the human subjects was measured by standard reaction time tests and by visual blank-out tests. Experimental observations provide an estimate for the upper boundary of the average sensorimotor uncertainty associated either with angular position or with angular velocity. Comparison of balancing trials with 27 human subjects to the delayed PD model suggests that the average uncertainty in the control force associated purely with the angular position is at most 14% while that associated purely with the angular velocity is at most 40%. In the general case when both uncertainties are present, the calculations suggest that the allowed uncertainty in angular velocity will always be greater than that in angular position.

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Section: Methodsmentioning

confidence: 99%

Section: Virtual Stick Balancing Environmentmentioning

confidence: 99%

Section: Machine Delay and Delay Incrementsmentioning

confidence: 99%

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Virtual stick balancing: sensorimotor uncertainties related to angular displacement and velocity

2019

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“…The tests can run on a computer, a tablet PC or a smart phone [23][24][25], however the set-ups which use monitors or any kind of digital displays suffer from the unknown latency: the object appear on the screen with unknown delay. The results in [26] shows that the time delay is typically in the range of 30-100 ms depending of the manufacturer and type of the display, and it is also shown that the delay changes stochastically. Regarding to the delay problem, the online tests are the worst, where the server-client communication is an additional stochastic latency.…”

Section: Reaction Time Testers From the Literaturementioning

confidence: 97%

Introduction of a Complex Reaction Time Tester Instrument

Zana

Zelei

2019

Period. Polytech. Mech. Eng.

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The reaction time, which is also referred as reflex delay in the literature, is an important factor in human balancing, since reaction time highly affects the ability of self stabilization. Increased reaction time delay may cause dangerous fall-over accidents related to elderly people. Reaction time depends on age, health, everyday activities, the general and actual physical and mental state of the individual and the environmental conditions.The reaction time is considered as a parameter in many of the mathematical models of the neural processes in human balancing. It is beneficial in many cases to estimate the reaction time based on experimental data.The present paper introduces the prototype of a complex reaction time tester instrument. The novelty of the instrument is that the reaction time can be measured in various combinations of sensory organs and reaction movements. The reaction time is defined as the time duration in between the initial time instant of the stimulus of the sensory organs (input signal) and the onset of the response that is typically indicated by a button or a pedal. Another novelty is that the instrument is free of any uncertain time delay, which is not the case for several instruments available.Usually, human simple reaction time is considered to be roughly about 200 ms. The shortest (aural) reaction time for skilled athletes is 85ms. In our measurements the shortest reaction time was 97 ms, and the mean about 190 ms in simple reaction cases. So our collected experimental data are in agreement with the literature.

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“…x of the input device. Both the velocity and the acceleration of the subject's hand movement were determined by a numerical derivation scheme based on the pixel position of the cursor on the screen [20,30]. Owing to the finite size of the pixels, the numerical derivation results in a noisy signal, which was compensated by a resampling filter.…”

Section: Virtual Test Environmentmentioning

confidence: 99%

Virtual stick balancing: skill development in Newtonian and Aristotelian dynamics

Kovács

Insperger

2022

J. R. Soc. Interface.

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Human reaction delay significantly limits manual control of unstable systems. It is more difficult to balance a short stick on a fingertip than a long one, because a shorter stick falls faster and therefore requires faster reactions. In this study, a virtual stick balancing environment was developed where the reaction delay can be artificially modulated and the law of motion can be changed between second-order (Newtonian) and first-order (Aristotelian) dynamics. Twenty-four subjects were separated into two groups and asked to perform virtual stick balancing programmed according to either Newtonian or Aristotelian dynamics. The shortest stick length (critical length, L c ) was determined for different added delays in six sessions of balancing trials performed on different days. The observed relation between L c and the overall reaction delay τ reflected the feature of the underlying mathematical models: (i) for the Newtonian dynamics L c is proportional to τ 2 ; (ii) for the Aristotelian dynamics L c is proportional to τ . Deviation of the measured L c ( τ ) function from the theoretical one was larger for the Newtonian dynamics for all sessions, which suggests that, at least in virtually controlled tasks, it is more difficult to adopt second-order dynamics than first-order dynamics.

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Comparison of Pixel-based Position Input and Direct Acceleration Input for Virtual Stick Balancing Tests

Cited by 6 publications

References 16 publications

Virtual stick balancing: sensorimotor uncertainties related to angular displacement and velocity

Virtual stick balancing: sensorimotor uncertainties related to angular displacement and velocity

Introduction of a Complex Reaction Time Tester Instrument

Virtual stick balancing: skill development in Newtonian and Aristotelian dynamics

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