Kinematic analysis, workspace definition, and self-collision avoidance of a quasi-spherical parallel manipulator

Bilateral teleoperation has witnessed significant development since the mid-20th century, addressing challenges related to human presence in environments with constraints or a lack of skilled professionals. This paper presents the kinematic and self-collision analyses of the quasi-Spherical Parallel Manipulator, a three-legged parallel robot used as a haptic master device. The device is designed for remote center of motion-constrained operation in the telesurgical field. Inverse and forward kinematics are thoroughly analyzed to study working modes, singular configurations, and implement a haptic control architecture. The research explores the operative and reachable workspaces of the possible working modes, comparing them to find the most suitable one. Results highlight how the addition of the self-collision phenomenon impacts the working mode choice, drastically reducing most of the modes' operative workspaces. An anti-collision control algorithm is finally introduced to maintain the architecture within its reachable workspace.