Student: Angel LICONA

Keywords:: Haptics, Simulation, Hands-on Training, Dual-User

Supervised with Minh Tu PHAM (director)

Period: started in January 2017, defended in March 2020

Financed by CONACYT Mexico

Summary :
Haptic simulators usually provide solutions to autonomously train oneself without any danger, typically to perform repetitive attempts to get familiar or to improve oneself on a given gesture. It can correspond to usual gestures to get used to or for rare and difficult cases which could be encountered in real life but which need to be mastered, more particularly under stress conditions. Nevertheless, for difficult cases, it remains useful for a trainer to guide the trainees’ motions, while keeping the advantages of haptic simulators, for a more accurate and efficient training. Classically, a trainer can directly guide the hands of a trainee to perform a correct motion. Yet, this ”four hand fellowship” does not permit for the trainee to feel and dose the correct level of force to apply on their device in case of interaction of their tool with its environment as the efforts are shared between both persons.
Dual-user systems have been designed in a first approach as a mean for two operators to cooperate remotely on a shared task. To do so, these systems extend the master-slave classical teleoperation architecture by adding a second master manipulated by a second operator. In fact, a dual-user system can be seen as a particular case of more generic multiple master/single slave (MMSS) teleoperation systems. The main concept with dual-user systems is that the users share the slave control according to a dominance factor (α ∈ [0, 1]). When α = 1 (respectively 0), the trainer (respectively trainee) has full control Chebbi et al.on the trainee’s (respectively trainer’s) device and on the slave. When 0 < α < 1, both users share the slave control with a dominance (over the other user) which is function of α. According to the architectures found in the literature, the effect of α on the force feedback provided to the users differs. Their usage has then been enlarged from cooperation to training purposes by Chebbi et al. [1] Indeed, dual-user systems are a practicable solution to the problem of rendering the four hand fellowship in the haptic training: it can reproduce this important force information simultaneously to both users, each one interacting with their own haptic interface. Nonetheless, solutions found in the literature do not permit a clear force training (during demonstrations and evaluations) nor they enable the addition of other trainees in the same simulation without dramatically increasing the complexity of the architecture.
This work is based on the ESC Energy-based Dual-User architecture designed by a former PhD student from the Robotics Working Group of Ampere laboratory: Fei Liu [2]. This architecture enabled the aforementioned force training for a one-degree-of-freedom system. This work has been extended to n dof at first for same haptic devices (joint control) and then to simulators where the slave device has different kinematics compared to the master ones (cartesian control). An adaptive mechanism to permit to automatically change the value of α and set the authority back to the trainer when the trainee performs a bad/dangerous gesture, had been designed by Fei Liu. In this work, we enhanced it by decreasing the number of parameters from 3 to 1 which makes it easier for the trainer to tune it according to the current task. This architecture has also been expanded to host several trainees for parallel demonstrations and public evaluations, with a linear raise of complexity in the architecture’s design. At last, a first user feedback has been performed to evaluate the pedagogical usefulness but the experiments were not conclusive. A new experimental protocol is proposed.

[1] Chebbi, B.; Lazaroff, D.; Bogsany, F.; Liu, P. X.; Ni, L. & Rossi, M. Design and implementation of a collaborative virtual haptic surgical training system IEEE International Conference Mechatronics and Automation, 2005, 2005, 1, 315-320 Vol. 1
[2] Dual-user haptic training system, PhD thesis, defended on 09/22/2016 at INSA Lyon, France