MEDICAL ROBOTS

Ø An Innovative Product of both BME & Mechanical Engg.

Ø Divided into four groups

1.passive 3.active

2.synergistic 4.master-slave

Ø Master-slave is more preferrable

CAS Vs MEDICAL ROBOTS

¢ CAS is powered by surgeon

¢ NO target area is predefined

¢ used for simulating and planning the operative procedure

¢ Less accurate & unsafe

¢ Medical Robots are powered by motorised system

¢ target area should be predefined

¢ programming of instruments is necessary

¢ Highly accurate & safe

MASTER-SLAVE SYSTEMS

¢ It is a tele-operation system

¢ Non-autonamous in nature

Schematic outline of M-S system

Advantages over

active robots

ü can be handled with soft tissues

ü ergonomic situation of the surgeon can be improved

ü Used for several operative tasks

ü Slave design

ü Master Design

ü should impose a low mass load, about 30 g, on the surgeon's hand

ü it should have unnoticeable friction and damping

ü and have a bandwidth of at least 10 Hz to avoid tiring the surgeon.

LAPAROSCOPIC FORCEPS

¢ FORCEPS is a Small Master-slave System With Only One Degree of Freedom

¢ Control objective of a master-slave system is 'perfect' position tracking of the slave with 'perfect' force reflection at the master

¢ Unilateral system demerits-

i) total lack of visualisation of the slave-side

ii) accurate positioning tasks in complex environments

iii) safe handling of delicate materials

iv) reflecting material characteristics.

SHAPE MEMORY ACTUATORS

¢ Uses the shape memory effect to generate a motion

¢ It is based on the crystal structure of the alloy.

¢ Can be realised by an equilibrium between stress and strain in the wire and the temperature of the wire

¢ In forceps a spring is used to constrain the SMA wire

Not only technical aspects are the reason why robots integrate slower into the surgical theatre than in industrial environments. The most important social aspect is safety. The safety requirements for medical robots are a lot more stringent. Safety of a system can be achieved by active and passive safety mechanisms in the mechanical design of the system. The acceptance of the patients, who are possibly not used to robots,and also the acceptance of surgeons, who have to get familiar with working with robots, are an important aspect for the introduction of robots into the surgical theatre.