Underactuated comanipulation for ultrasound breast exams

Anja Marx (1, 2) , Marie-Aude Vitrani (1, 3) , Serge Muller (2) , Guillaume Morel (1, 3)

1 ISIR - Institut des Systèmes Intelligents et de Robotique
2 GE Healthcare - General Electric Medical Systems [Buc]
3 AGATHE - Assistance aux Gestes et Applications THErapeutiques

— We investigate the possibility of providing adequate task assistance using under-actuated robots for human-robot tool co-manipulation. This novel approach optimizes robot-user synergy without taking into account any a priori knowledge of parameters depending on the user. Six different actuation modes were compared for a localization and scanning task. The best performance gain was achieved for 1 degree of under-actuation. I. COMANIPULATION FOR MEDICAL APPLICATIONS Co-manipulated devices are systems in which the robot and the user work together to manipulate the same tool. This paradigm is particularly interesting for medical applications , because co-manipulation devices allow the physician to remain with the patient during the intervention. In an ideal co-manipulated system, the medical movement remains unchanged. The robot acts as a device providing active support to improve performance and make the gesture safer. This paper focuses on co-manipulation systems intended to guide the user by imposing kinematic constraints on the tool. Schneider et al. propose a semi-passive device called " Passive Arm with Dynamic Constraints " (PADyC, [1]). Its mechanical design allows limiting of tool motions according to a planned task. A geometrical zone is defined in which the surgeon can move freely. When moving out of the zone the surgeon feels forces applied by the robot to move him/her back inside the prescribed zone. This geometrical guidance function is also proposed in [2] and [3]. Davies et al. present a robot for knee surgery named ACROBOT (Active Constraint ROBOT). The co-manipulation does not result from a mechanical constraint but is provided by force control. Different force constraint regions can be defined for the robot. The basic idea behind active constraint control is to gradually increase the stiffness of the robot as it approaches the predefined restricted areas. The same principle is used to control the Surgicobot robot (based on a haptic device) which can be programmed with a desired apparent stiffness within a relatively wide range, but without force sensors [4]. To the best of our knowledge, all systems within this latter class have sufficient actuated degrees of freedom (DOFs) to perform the task without a human user. However, imposing the desired kinematic constraints generally does not require as many actuators. The immediate advantage of actuating less DOFs (i.e. using an under-actuated robot regarding the

Domaines: Sciences de l'ingénieur [physics]

Anja Marx, Marie-Aude Vitrani, Serge Muller, Guillaume Morel. Underactuated comanipulation for ultrasound breast exams. IEEE EMBS, Jul 2013, OSAKA, Japan. ⟨10.1109/EMBC.2013.6610639⟩. ⟨hal-01171248⟩