Optimization of Semiautomated Calibration Algorithm of Multichannel Electrotactile Feedback for Myoelectric Hand Prosthesis

The main drawback of the commercially available myoelectric hand prostheses is the absence of somatosensory feedback. We recently developed a feedback interface for multiple degrees of freedom myoelectric prosthesis that allows proprioceptive and sensory information (i.e., grasping force) to be transmitted to the wearer instantaneously. High information bandwidth is achieved through intelligent control of spatiotemporal distribution of electrical pulses over a custom-designed electrode array. As electrotactile sensations are location-dependent and the developed interface requires that electrical stimuli are perceived to be of the same intensity on all locations, a calibration procedure is of high importance. The aim of this study was to gain more insight into the calibration procedure and optimize this process by leveraging a priori knowledge. For this purpose, we conducted a study with 9 able-bodied subjects performing 10 sessions of the array electrode calibration. Based on the collected data, we optimized and simplified the calibration procedure by adapting the initial (baseline) amplitude values in the calibration algorithm. The results suggest there is an individual pattern of stimulation amplitudes across 16 electrode pads for each subject, which is not affected by the initial amplitudes. Moreover, the number of user actions performed and the time needed for the calibration procedure are significantly reduced by the proposed methodology.The research was supported by Tecnalia Research & Innovation, Spain, and the Ministry of Education, Science and Technological Development of Republic of Serbia (Project no. 175016). The authors would like to thank all the volunteers who participated in this study

Experimental archeology and serious games: challenges of inhabiting virtual heritage

Experimental archaeology has long yielded valuable insights into the tools and techniques that featured in past peoples’ relationship with the material world around them. However, experimental archaeology has, hitherto, confined itself to rigid, empirical and quantitative questions. This paper applies principles of experimental archaeology and serious gaming tools in the reconstructions of a British Iron Age Roundhouse. The paper explains a number of experiments conducted to look for quantitative differences in movement in virtual vs material environments using both “virtual” studio reconstruction as well as material reconstruction. The data from these experiments was then analysed to look for differences in movement which could be attributed to artefacts and/or environments. The paper explains the structure of the experiments, how the data was generated, what theories may make sense of the data, what conclusions have been drawn and how serious gaming tools can support the creation of new experimental heritage environments

Silmien liikkeiden simulointi etäläsnäolorobotissa

Tiivistelmä. Koronaviruspandemian takia etätyöskentely on lisääntynyt valtavasti. Opiskelijat katsovat luentoja kotoaan ja työkaverit näkevät toisiaan vain videokuvan välityksellä. Kysymykseksi jää, voiko läsnäoloa parantaa etätyöskentelyssä äänen ja videokuvan lisäksi. Tässä työssä esitellään järjestelmä, joka kopioi käyttäjän silmien liikettä robotin silmien liikkeiksi reaaliajassa. Käyttäjän kasvoja kuvaamalla saadaan tietoon käyttäjän silmien asento tunnistamalla kuvasta kasvot ja sitten rajaamalla silmät. Silmien asentojen tieto lähetetään UDP (User Datagram Protocol) tiedonsiirtoprotokollan avulla toiselle tietokoneelle. Siellä tieto otetaan vastaan ja lähetetään virtuaalikoneelle, jolla käytetään ROS2 (Robot Operating System 2) käyttöjärjestelmää. ROS2-järjestelmässä käytetään action client ja data publisher -osaohjelmia. Data publisher lähettää action clientille paikkatietoa, jonka avulla robotin liikkuminen tapahtuu. Action client antaa käskyjä robotin XL-320 -servoille, jotka liikuttavat robotin silmiä samaan asentoon käyttäjän kanssa. Järjestelmän viivettä testattiin pyytämällä käyttäjää katsomaan puolelta toiselle ja mittaamalla viivettä videokuvasta. Aikaväli valittiin käyttäjän silmien liikkeiden ja robotin silmien liikkeiden pysähtymisen välillä. Viivettä syntyi tietokoneen laskiessa tunnistusalgorimejä ja robotin liikuttaessa servoja. Tuloksena saatu viive on liian pitkä luomaan luonnollista etäläsnäolokokemusta.Simulation of eye movement in a telepresence robot. Abstract. Because of the Coronavirus pandemic, remote working has been increasing significantly. Students watch lectures from home and coworkers see each other only through video. Question remains whether presence can be improved with remote working in addition to voice and video. In this project a system was developed that copies user’s eye movements to robot’s eye movements in real time. Filming the user’s face will give the user’s eyes position by recognizing their face and then cropping their eyes. The eyes position is sent with UDP (User Datagram Protocol) data transfer protocol to another computer. There information is received and sent to virtual machine, which uses ROS2 (Robot Operating System) operating system. ROS2 system uses action client and data publisher nodes. Data publisher sends position information to action client which controls the robot. Action client gives commands to robot’s XL-320 servo motors, which move robot’s eyes to same position as the user’s. System’s delay was tested by asking user to look from side to side and measuring the delay from video. Time interval was chosen between the end of user’s eye movement and the end of robots eye movement. Delay was produced with computer calculating recognition algorithms and robot moving the servos. Resulting delay is too long to create natural telepresence experience