Function based control for bilateral systems in tele-micromanipulation

Design of a motion control system should take into account (a) unconstrained motion performed without interaction with environment or any other system, and (b) constrained motion with system in contact with environment or other systems. Control in both cases can be formulated in terms of maintaining desired system configuration what makes essentially the same structure for common tasks: trajectory tracking, interaction force control, compliance control etc. The same design approach can be used to formulate control in bilateral systems aimed to maintain desired functional relations between human and environment through master and slave motion systems. Implementation of the methodology is currently being pursued with a custom built Tele-micromanipulation setup and preliminary results concerning force/position tracking and transparency between master and slave are clearly demonstrated

Biomechanical Risk Factors for Knee Osteoarthritis in Young Adults: The Influence of Obesity and Gait Instruction

With increasing rates of obesity, research has begun to focus of co-morbidities of obesity such as osteoarthritis. The majority of existing research has focused on older adults as the group most likely to suffer from osteoarthritis. The purpose of this study was to determine if overweight and obese young adults exhibit biomechanical risk factors for knee osteoarthritis, and to determine if young adults with biomechanical risk factors of osteoarthritis can modify these with instruction. This purpose was divided into two separate studies. Study 1: Thirty adults between 18-35 years old were recruited into three groups according to body mass index: normal, overweight, and obese. Participants walked through the lab while we collected 3-d kinematic and kinetic data. Overweight and obese young adults walked with similar gait compared to normal weight young adults. Study 2: Nine young adults between 18-35 years were recruited who walked with stiff-knee gait. Baseline measures of gait were collected in the form of 3-d kinematics and kinetics as participants walked through the laboratory. They then completed the gait instruction program which consisted of four blocks of training. Each block included ten single steps where the participant was provided feedback, followed by 100 practice steps around the laboratory. Participants were successful in increasing sagittal plane kinematics and kinetics of interest in the study. Conclusion: Identifying individuals who had biomechanical risk factors of osteoarthritis according to body mass index was not possible. According to the results of our study, obese and overweight young adults are not at increased risk of osteoarthritis compared to normal weight young adults. Individuals who may be at increased risk due to stiff-knee gait were able to improve their gait following instruction

Benchmarking Cerebellar Control

Cerebellar models have long been advocated as viable models for robot dynamics control. Building on an increasing insight in and knowledge of the biological cerebellum, many models have been greatly refined, of which some computational models have emerged with useful properties with respect to robot dynamics control. Looking at the application side, however, there is a totally different picture. Not only is there not one robot on the market which uses anything remotely connected with cerebellar control, but even in research labs most testbeds for cerebellar models are restricted to toy problems. Such applications hardly ever exceed the complexity of a 2 DoF simulated robot arm; a task which is hardly representative for the field of robotics, or relates to realistic applications. In order to bring the amalgamation of the two fields forwards, we advocate the use of a set of robotics benchmarks, on which existing and new computational cerebellar models can be comparatively tested. It is clear that the traditional approach to solve robotics dynamics loses ground with the advancing complexity of robotic structures; there is a desire for adaptive methods which can compete as traditional control methods do for traditional robots. In this paper we try to lay down the successes and problems in the fields of cerebellar modelling as well as robot dynamics control. By analyzing the common ground, a set of benchmarks is suggested which may serve as typical robot applications for cerebellar models

Origins of choice-related activity in mouse somatosensory cortex.

During perceptual decisions about faint or ambiguous sensory stimuli, even identical stimuli can produce different choices. Spike trains from sensory cortex neurons can predict trial-to-trial variability in choice. Choice-related spiking is widely studied as a way to link cortical activity to perception, but its origins remain unclear. Using imaging and electrophysiology, we found that mouse primary somatosensory cortex neurons showed robust choice-related activity during a tactile detection task. Spike trains from primary mechanoreceptive neurons did not predict choices about identical stimuli. Spike trains from thalamic relay neurons showed highly transient, weak choice-related activity. Intracellular recordings in cortex revealed a prolonged choice-related depolarization in most neurons that was not accounted for by feed-forward thalamic input. Top-down axons projecting from secondary to primary somatosensory cortex signaled choice. An intracellular measure of stimulus sensitivity determined which neurons converted choice-related depolarization into spiking. Our results reveal how choice-related spiking emerges across neural circuits and within single neurons

Fast audio-haptic prototyping with mass-interaction physics

International audienceThis paper presents ongoing work on the topic of physical modelling and force-feedback interaction. Specifically, it proposes a frame- work for rapidly prototyping virtual objects and scenes by means of mass-interaction models, and coupling the user and these objects via an affordable multi-DoF haptic device. The modelled objects can be computed at the rate of the haptic loop, but can also operate at a higher audio-rate, producing sound. The open-source design and overall simplicity of the proposed system makes it an interesting solution for introducing both physical simulations and force-feedback interaction, and also for applications in artistic creation. This first implementation prefigures current work conducted on the develop- ment of modular open-source mass-interaction physics tools for the design of haptic and multisensory applications

Bilateralno upravljanje zasnovano na zadacima za primjene u mikrosustavima

Design of a motion control system, convenient for a wide range of applications in industry, space, biology, medicine, particularly including more than one physics environment is very important. Well known control architectures like trajectory tracking, compliance control, interaction force control are scientific milestones which has common control task: to maintain d esired system configuration. In this concept, motion control system can be an unconstrained motion-performed interaction with neither environment nor any other system, or constrained motion-system in contact with environment and/or other systems. This paper provides the function based design approach to formulate control of constrained system particularly bilateral systems in micromanipulation applications. The control objective a imed to maintain desired functional relations between human and environment defining convenient tasks and their proper relations on master and slave motion systems. Preliminary results concerning position tracking, force control and transparency between master and slave systems are clearly demonstrated.Sinteza slijednog sustava prikladnog za široki raspon primjena u industriji, svemiru, biologiji, medicini te posebno za primjene koje obuhvaćaju više raličitih fizikalnih okruženja, vrlo je važna. Dobro poznate strukture upravljanja poput slijeđenja trajektorije, usklađenog upravljanja i upravljanja interakcijskom silom predstavljaju znanstvene prekretnice koje imaju zajednički upravljački cilj: održavanje željene konfiguracije sustava. U ovom konceptu, slijedni sustav može biti sustav bez ograničenja i bez interakcije s okolinom ili ostalim sustavima, odnosno može biti sustav s ograničenjima koji je spregnut s okolinom i/ili drugim sustavima. Ovaj članak opisuje funkcijski zasnovanu sintezu sustava upravljanja za sustav s ograničenjima, a posebno za bilateralne sustave u mikromanipulacijskim primjenama. Cilj upravljanja je održavanje željenih funkcionalnih relacija izmežu čovjeka i okoline definirajući prikladne zadaće i njihove odgovarajuće relacije za glavni i podređeni slijedni sustav. Preliminarni rezultati vezani uz upravljanje pozicijom, upravljanje silom te veza izmeđ u glavnog i podređ enog sustava su jasno prezentirani

Blindsight: Proximity Sensing and Wireless Haptic Feedback

A staggering 98 percent of blind people have experienced head-level accidents with some requiring professional medical assistance. Current technologies such as the white cane and guide dogs come with a significant flaw: the inability to detect objects at head-level. As such, the objective of this project was to create a more effective and affordable means to detect and prevent head-level injuries in blind people. Blindsight uses ultrasonic sensors to detect obstacles and transmits this information to haptic vibration motors which will then alert the user of incoming obstacles

The effect of voluntary modulation of the sensory-motor rhythm during different mental tasks on H reflex

Objectives: The aim of this study was to explore the possibility of the short-term modulation of the soleus H reflex through self-induced modulation of the sensory-motor rhythm (SMR) as measured by electroencephalography (EEG) at Cz. Methods: Sixteen healthy participants took part in one session of neuromodulation. Motor imagery and mental math were strategies for decreasing SMR, while neurofeedback was used to increase SMR. H reflex of the soleus muscle was elicited by stimulating tibial nerve when SMR reached a pre-defined threshold and was averaged over 5 trials. Results: Neurofeedback and mental math both resulted in the statistically significant increase of H reflex (p = 1.04·10− 6 and p = 5.47·10− 5 respectively) while motor imagery produced the inconsistent direction of H reflex modulation (p = 0.57). The average relative increase of H reflex amplitude was for neurofeedback 19.0 ± 5.4%, mental math 11.1 ± 3.6% and motor imagery 2.6 ± 1.0%. A significant negative correlation existed between SMR amplitude and H reflex for all tasks at Cz and C4. Conclusions: It is possible to achieve a short-term modulation of H reflex through short-term modulation of SMR. Various mental tasks dominantly facilitate H reflex irrespective of direction of SMR modulation. Significance: Improving understanding of the influence of sensory-motor cortex on the monosynaptic reflex through the self-induced modulation of cortical activity