Shigeyuki Shimachi

Adapter for contact force sensing of the da Vinci robot.

At present, the da Vinci® surgical robot system does not provide haptic feedback. One of the authors has proposed a contact‐force sensing method called the ‘overcoat method’, in which the instrument/driver is supported by force sensors. In the da Vinci robot, the instrument jaws are powered by a wire‐pulley mechanism; thus, in order to apply the overcoat method to the da Vinci system, we must transfer the power through a frame that is supported by force sensors.

Measurement of force acting on surgical instrument for force-feedback to master robot console

Abstract For fine surgical operation by slave robot, master robot needs the information of the contact force loaded on the tip of the surgical instrument. One of major problems in sensing the force is frictional disturbance between the trocar and the instrument. One of authors proposed a new method named overcoat method where the whole instrument is supported by force sensors. This paper tried to construct a force measuring system with the trocar type of the overcoat method. It discussed about the compensations of gravity and acceleration force of the instrument in relation to the pose and motion of the instrument. The tried system measured the tip-loaded force in absolute accuracy about 0.3 N and in sensitivity about 0.05 N.

Contact force measurement of instruments for force-feedback on a surgical robot: acceleration force cancellations based on acceleration sensor readings

For delicate operations conducted using surgical robot systems, surgeons need to receive information regarding the contact forces on the tips of surgical instruments. For the detection of this contact force, one of the authors previously proposed a new method, called the overcoat method, in which the instrument is supported by sensors positioned on the overcoat pipe. This method requires cancellation of the acceleration forces of the instrument/holder attached to the overcoat sensor. In the present report, the authors attempt to use acceleration sensors to obtain the acceleration forces of the instrument/holder. The new cancellation method provides a force-detection accuracy of approximately 0.05-0.1 N for a dynamic response range of up to approximately 20 Hz, compared to approximately 1 Hz, which was achieved by using acceleration forces based on the theoretical robot motion.

Regulated Slippage on Laminated Sheets (Qualitative Understanding of Skill and its Extension)

As one of the human skills on daily works, we know a handling work that gives regulated slippage for laminated sheets. The handling work is operated in various forms, such as picking out one sheet from laminating papers, counting the number of sheets or bills, and around various materials like as paper sheets, bills, cloth sheets of every size. In this paper, the mechanism for sliding the regularly laminated sheets is observed qualitatively, and is expressed as a sequence of some brief elemental functions. Then, we understand the skill of the various forms seen in the real world as diversity of means to realize those elemental functions. Furthermore, in the process of extended deployment of looking for what can be used as a realization mean of a elemental function, it showed a new possibility that the regulated slippage can be given for the towel or cloth laminated sheets between which we do not see any slippage on daily life. This is shown an example of the validity of the qualitative understanding of skill and its extension.

The Grinding Wheel Interference on the Variable Lead Screw.

The Vacuum pump composed of the variable lead screw is noticed as a potential one that has high power efficiency. In case of the variable lead screw, the grinding wheel has only a point contact with the screw surface. One of the authors tried the grinding by the method that has easy way of calculating the contact point of the mating surfaces. The try resulted in the interference of the grinding wheel and the screw. Accordingly, this paper proposes another way of positioning of grinding wheel and analyzing the contact point. This paper discusses the interference in the axial plane of grinding wheel for the convenience of the wheel design. Then, size and pose of grinding wheel that could avoid the interference are examined numerically. The proposed setting method is clarified to be effective for the interference avoidance. The limitation of pose change of grinding wheel is showed in the relation with the interfered position of surfaces.

Buckling-Like Beam Deformation for Parts Assembly.

In assembling parts, we sometimes have to use large deformation of flexible parts. Buckling deformation of beam has been analyzed mainly for the strength of beam that supports large longitudinal load, but not for the large deflection. We know a rare research for assembling a beam into a hole in a specially deformed beam case, where the beam has small longitudinal load and the deflecting end(DE)lies on the tangent of fixed end of the beam(TFEB). This paper deals with large load acting at the DE and large deformation where the position of DE offsets itself largely from the TFEB and sets itself on shortened position along the TFEB compared with the beam length. Jumping position from a type of beam deformation to another type and the DE traces of those types are clarified and checked experimentally.