Evaluation of a Graphic Interface to Control A Robotic Grasping Arm: A Multicenter Study

Abstract 

Laffont I, Biard N, Chalubert G, Delahoche L, Marhic B, Boyer FC, Leroux C. Evaluation of a graphic interface to control a robotic grasping arm: a multicenter study.

Objective

Grasping robots are still difficult to use for persons with disabilities because of inadequate human-machine interfaces (HMIs). Our purpose was to evaluate the efficacy of a graphic interface enhanced by a panoramic camera to detect out-of-view objects and control a commercialized robotic grasping arm.

Design

Multicenter, open-label trial.

Setting

Four French departments of physical and rehabilitation medicine.

Participants

Control subjects (N=24; mean age, 33y) and 20 severely impaired patients (mean age, 44y; 5 with muscular dystrophies, 13 with traumatic tetraplegia, and 2 others) completed the study. None of these patients was able to grasp a 50-cL bottle without the robot.

Interventions

Participants were asked to grasp 6 objects scattered around their wheelchair using the robotic arm. They were able to select the desired object through the graphic interface available on their computer screen.

Main Outcome Measures

Global success rate, time needed to select the object on the screen of the computer, number of clicks on the HMI, and satisfaction among users.

Results

We found a significantly lower success rate in patients (81.1% vs 88.7%; χ² P=.017). The duration of the task was significantly higher in patients (71.6s vs 39.1s; P<.001). We set a cut-off for the maximum duration at 79 seconds, representing twice the amount of time needed by the control subjects to complete the task. In these conditions, the success rate for the impaired participants was 65% versus 85.4% for control subjects. The mean number of clicks necessary to select the object with the HMI was very close in both groups: patients used (mean ± SD) 7.99±6.07 clicks, whereas controls used 7.04±2.87 clicks. Considering the severity of patients' impairment, all these differences were considered tiny. Furthermore, a high satisfaction rate was reported for this population concerning the use of the graphic interface.

Conclusions

The graphic interface is of interest in controlling robotic arms for disabled people, with numerous potential applications in daily life.

Key Words: Arm, Muscular dystrophies, Quadriplegia, Rehabilitation, Robotics

List of Abbreviations: ANOVA, analysis of variance, HMI, human-machine interface, LIS, locked-in syndrome, MD, muscular dystrophy