A 4DOF Tool Actuator Unit

In this project, I designed and developed a 4DOF tool actuator to articulate commercial handheld laparoscopic instruments with wrist. The actuator mechanism can hold manual wristed laparoscopic tools and manipulate them. It consists of a wrist actuator unit and a roll/grasp actuator unit. For the wrist actuator unit, I used a novel structure of the 2DOF 5R Spherical Parallel Mechanism. I studied the kinematics and singularities of the proposed mechanism in detail and then optimized the link lengths to achieve maximum dexterity and workspace in minimum weight and space. For the roll/grasp mechanism, I designed a cylindrical mechanism to provide these two DOFs simultaneously. I developed a prototype and calibrated its kinematics using NDI optic vision camera. I also tested the load capacity of the mechanism by applying external moment using constant force springs.

Publications and patents:

• Hanifeh S, Alamdar A, Farahmand F, Mirbagheri A. An Adapting Mechanism to Manipulate Manual Wristed Laparoscopic Instruments by a Robotic Surgery System. 2017.

• Farahmand F, Mirbagheri A, Behzadipour S, Alamdar A, Hanifeh S, Khadem SM, Moradi MM, Adapting manual laparoscopic surgical instruments for robotic telesurgery applications. US patent application US 15/151,869. Granted 2019.

• Alamdar A, Farahmand F, Behzadipour S, Mirbagheri, A geometrical approach for configuration and singularity analysis of a new non-symmetric 2DOF 5R Spherical Parallel Manipulator; Mechanism and Machine Theory, 2020

• Alamdar A, Hanifeh Sh, Farahmand S, Mirbagheri A. A modified agile-eye mechanism for robotic manipulation of wristed laparoscopic instruments; in preparation.