Fig 1.
Illustrative diagram depicting 6DoF medical robotic systems (a)(b) and the concept of motion trajectories in different spaces (c).
Three types of trajectories involved in the motion compensation: joint, platform, and target. To send the target from G back to the desired position L in operational space, a motion of the platform from P1 to P2 is needed, and such a motion can be implemented by changing the actuator lengths from J1 to J2 in the joint space. As shown, performing a straight-line trajectory in one space can result in a highly curved trajectories in other spaces.
Fig 2.
Signal flow diagram of the robotic motion compensation system.
Fig 3.
(a)(b)(c): System response to step like target deviations. (a) Input motion. (b) Target trajectory with orientation shown every 0.15 seconds. (c) Target displacement versus time. (d) Integrated trajectory errors for 100 simulations using randomly generated 6D input motion within 2mm/1deg. Errors were normalized to target-S planning case.
Fig 4.
(a)(b)(c): System response to sinusoidal target motion deviation. (a) Input sinusoidal target motion. (b) Target trajectory shown every 0.2 seconds. (c) Target displacement versus time. (d) Integrated target trajectory errors for 100 simulations using randomly generated input motion within 2 mm / 1 deg. Errors were normalized to target-S planning case.
Fig 5.
Different trajectory planning strategies for real-time motion compensation of volunteer head motion showing strong respiratory coupling.
Fig 6.
Different trajectory control/planning strategies for real-time motion compensation of a prostate tumor using a 6DoF robotic treatment table.