Recently, it is very popular in medical field to adopt robot surgery such as robot-assisted minimally invasive surgery
(RMIS). However, there are some problems in the robot surgery. It is very hard to get the touch feeling of the organs
during the surgical operation because the surgeons cannot touch and feel repulsive force from the organs directly. So, this
work proposes a squeeze mode of single magneto-rheological (MR) sponge to realize viscoelastic property of human
organs or skins and undertake a theoretical analysis of MR sponge. In addition, its effectiveness is verified through
experimental tests. The similarity between MR sponge and real organs is identified and desired repulsive force of each
organs can be achieved by proper selection of MR sponge cell associated with controlled input current.
This paper presents a 7 degrees-of-freedom (7-DOF) haptic master which is applicable to the robot-assisted minimally
invasive surgery (RMIS). By utilizing a controllable magneto-rheological (MR) fluid, the haptic master can provide
force information to the surgeon during surgery. The proposed haptic master consists of three degrees motions of X, Y, Z
and four degrees motions of the pitch, yaw, roll and grasping. All of them have force feedback capability. The proposed
haptic master can generate the repulsive forces or torques by activating MR clutch and MR brake. Both MR clutch and
MR brake are designed and manufactured with consideration of the size and output torque which is usable to the robotic
surgery. A proportional-integral-derivative (PID) controller is then designed and implemented to achieve torque/force
tracking trajectories. It is verified that the proposed haptic master can track well the desired torque and force occurred in
the surgical place by controlling the input current applied to MR clutch and brake.
In this study, a 7-DOF slave robot integrated with the haptic master is designed and its dynamic motion is controlled.
The haptic master is made using a controllable magneto-rheological (MR) clutch and brake and it provides the surgeon
with a sense of touch by using both kinetic and kinesthetic information. Due to the size constraint of the slave robot, a
wire actuating is adopted to make the desired motion of the end-effector which has 3-DOF instead of a conventional
direct-driven motor. Another motions of the link parts that have 4-DOF use direct-driven motor. In total system, for
working as a haptic device, the haptic master need to receive the information of repulsive forces applied on the slave
robot. Therefore, repulsive forces on the end-effector are sensed by using three uniaxial torque transducer inserted in the
wire actuating system and another repulsive forces applied on link part are sensed by using 6-axis transducer that is able
to sense forces and torques. Using another 6-axis transducer, verify the reliability of force information on final end of
slave robot. Lastly, integrated with a MR haptic master, psycho-physical test is conducted by different operators who can
feel the different repulsive force or torque generated from the haptic master which is equivalent to the force or torque
occurred on the end-effector to demonstrate the effectiveness of the proposed system.