Interactive locomotion: Investigation and modeling of physically-paired humans while walking

In spite of extensive studies on human walking, less research has been conducted on human walking gait adaptation during interaction with another human. In this paper, we study a particular case of interactive locomotion where two humans carry a rigid object together. Experimental data from two persons walking together, one in front of the other, while carrying a stretcher-like object is presented, and the adaptation of their walking gaits and coordination of the foot-fall patterns are analyzed. It is observed that in more than 70% of the experiments the subjects synchronize their walking gaits; it is shown that these walking gaits can be associated to quadrupedal gaits. Moreover, in order to understand the extent by which the passive dynamics can explain this synchronization behaviour, a simple 2D model, made of two-coupled spring-loaded inverted pendulums, is developed, and a comparison between the experiments and simulations with this model is presented, showing that with this simple model we are able to reproduce some aspects of human walking behaviour when paired with another human.

§C4: after initial contact by email, individuals willing to participate in the study will be invited to the BioRob Lab to perform the experiment. Before the experiment, the researcher will make sure that the person has fully understood the aim of the research, as well as other relevant information detailed in the information sheet. The participant will have the opportunity to ask for clarifications, and then may sign the consent form.
I suggested a couple of amendments to the information sheet and to the email that will be sent out for recruitment. Co-applicant Lanini agreed to make these corrections in the final version of these documents:

1] Information sheet;
Linking information about risks (i.e. "What are the risks"] to insurance of EPFL for any possible damage will increase the coherence of the information sheet and facilitate the participant's understanding.

2] Recruitment email:
The email is addressed to students only. However, according to selection criteria specified in the protocol, participants might be from 18 to 40 years old. In order to meet selection criteria, the email should state that researchers are looking for: "students or EPFL collaborators". Moreover, the email should specify that the payment (20.-chf/h] is awarded to participants as compensation for the time spent in the research. I suggest to avoid expressions such as "votre participation, récompensée par 20 chf/h", or "you will help us to learn about... and you will receive 20 chf/h", since they seem to suggest that the money is given as a "salary" or as an incentive for participating. An alternative way to encourage participation may be to explain in the email that the research aims to contribute to the development of robotic assistants. The project is OK for a approval but • there is too little mention of how data to be anonymized and how are data to be stored and made openly available (DMP)? • the phrasing ("receive" or "recompense") concerning the 20 CHF and the fact that it is paid on an hourly basis suggests that it is a salary; I would change the wording if this is not so.

C2!
If!data!or!information!held!by!a!third!party!will!be!used,!please!explain!how!you! will!obtain!these!data.!! You%should%confirm%that%the%information%will%be%obtained%in%concordance%with%the%CH%Federal%law%on%data%protection%("Loi% fédérale%sur%la%protection%des%données"%-%RS%235.1).% The%information%will%be%obtained%in%concordance%with%the%CH%Federal%law%on%data% protection%("Loi%fédérale%sur%la%protection%des%données"%-%RS%)% % % Sincères salutations, Jessica Lanini ****************************** Call for participants At the Biorobotics Laboratory (BioRob, EPFL) we are evaluating human-human interaction in shared locomotor tasks and are looking for participants to take part in a our study. The study will focus on aspects of interaction when participants walk together while carrying a stretcher-like object. Subjects will also be asked to fill out a short questionnaire afterwards. Overall, the experiment will take about 90 minutes. We are looking for students of all backgrounds. There are no special skills required. The study will take place at BioRob, EPFL between 1 and 30 September 2015. Through you participation, you will help us to learn about human-human interaction and locomotion and you will receive 20 CHF/hr. If you are interested, please reply to this email and we will get in touch with you soon.