Trajectory Generation for Flexible-Joint Space Manipulators

Abstract

Space manipulator arms often exhibit significant joint flexibility and limited motor torque. Future space missions, including satellite servicing and large structure assembly, may involve the manipulation of massive objects, which will accentuate these limitations. Currently, astronauts use visual feedback on-orbit to mitigate oscillations and trajectory following issues. Large time delays between orbit and Earth make ground teleoperation difficult in these conditions, so more autonomous operations must be considered to remove the astronaut resource requirement and expand robotic capabilities in space. Trajectory planning for autonomous systems must therefore be considered to prevent poor trajectory tracking performance. We provide a model-based trajectory generation methodology that incorporates constraints on joint speed, motor torque, and base actuation for flexible-joint space manipulators while minimizing total trajectory time. Full spatial computer simulation results, as well as physical experiment results with a single-joint robot on an air bearing table, show the efficacy of our methodology.

Trajectory Tracking of a Robot Arm Using Image Sequences

“…The results showed that the suggested IWOA-PSO successfully lessened the robot's jerk while increasing its productivity. In their paper [10], a model-based methodology was provided for trajectory generation for a flexible-joint space manipulator grasping a massive object. Methodologies were provided to generate a feed-forward motor trajectory given a desired link-side trajectory and to generate a desired linkside trajectory while minimizing total trajectory time subject to dynamic constraints.…”

Transmission efficiency of one tooth difference sine tooth profile planetary reducer

“…Due to the characteristics of launch, flight, and polar environment work, the structural size of space exploration and unmanned aerial vehicles (UAV) manipulator is required to be as small as possible, and the weight must be as light as possible [ [1] , [2] , [3] , [4] ]. The University of Illinois in the United States designed a small quad-rotor prototype with a light mechanical arm having two Degrees-Of-Freedom (2-DOF) and carried out its motion control experiments in a two-dimensional plane [ 5 ].…”

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“…In addition to high structural flexibility, motor torque limits and joint flexibility are additional considerations emphasized in [ 44 ] which presented a model-based autonomous generation method for trajectories assuming base excitation and large time delays for any communications with earth. Computer simulations for verification were presented alongside validation by laboratory experiments on an air-bearing table.…”