Triple Scissor Extender: A 6-DOF Lifting and Positioning Robot
This addresses a domain-specific problem in robotics for tasks requiring high-reach positioning, but it appears incremental as it builds on existing scissor and actuator designs.
The paper tackles the problem of reaching high ceilings with precise positioning by introducing a 6-DOF robotic mechanism using three scissor mechanisms and linear actuators, resulting in a proof-of-concept prototype with evaluated kinematic properties and control.
We present a novel 6 DOF robotic mechanism for reaching high ceilings and positioning an end-effector. The end-effector is supported with three scissor mechanisms that extend towards the ceiling with 6 independent linear actuators moving the base ends of the individual scissors. The top point of each scissor is connected to one of three ball joints located at the three vertices of the top triangular plate holding the end-effector. Coordinated motion of the 6 linear actuators at the base allows the end-effector to reach an arbitrary position with an arbitrary orientation. The design concept of the Triple Scissor Extender is presented, followed by kinematic modeling and analysis of the the Inverse Jacobian relating actuator velocities to the end-effector velocities. The Inverse Jacobian eigenvalues are determined for diverse configurations in order to characterize the kinematic properties. A proof-of-concept prototype has been designed and built. The Inverse Jacobian for use in differential control is evaluated through experiments.