• Generally Robotic Surgical tools have 4 DOF compared to 2 DOF in manual laparoscopic surgery where extra DOF provides surgeons increased dexterity and reduced fatigue but  mechanical design turns complicated due to the additional DOFs.
• Hence, there is need to address the issue of coupled DOF in robotic surgical tools to simplify control strategies and enhance the effectiveness of these advanced medical instruments

The present invention discloses a minimally invasive surgical tool for robotic surgery with disengaged Degrees of Freedom (DOF) consists of:

• A hollow shaft
• Four driving motors with integrated encoders at the base
• A tool tip

Further, the said tool tip comprises:

• A pair of graspers
• A pair of pulleys
• Four pairs of tethers for the 4 DOF wound over cylinders
• Tether guides to guide the ropes as the tool’s grasper pitches

1. The said tethers are attached to the motors, with three pairs of tethers passing through the hollow shaft to actuate the graspers at the tool’s end.
2. Further the tether guides ensures that the midplane of the grasper pulley aligns with the tether’s symmetry line to minimize wire fraying.
3. The tether is 0.7 mm in diameter with a minimum breaking strength of 120N
4. Tether guides helps to guide the rope as the tool’s grasper pitches, where tether wraps over these guide and slides past them when actuated.
5. The tethers are characteristically crimped at the position of the grasper ensuring a positive drive without slippage.
6. Further, provides an alternate proposal for routing the tethers without using a tether diverting pin, where circular guides are offset by a distance equal to the distance between the mid-planes of the grasper pulleys ensures law of belting