Efficient Bezier Velocity Optimization for Free-Floating Space Manipulators
Organizations: Department of Computer Science, Rutgers, the State University of New Jersey, Piscataway, NJ, USA · Department of Mechanical and Aerospace Engineering, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
Abstract
We present FAVOR (Free-floating Arm Velocity Optimization with Recursive Sensitivities), a planner for collision-free reaching, tracking, and prescribed-time pre-grasp interception on an unactuated spacecraft. It optimizes Bezier joint-velocity curves with linear velocity, acceleration, and continuity constraints. Decision dimension is independent of rollout resolution. Analytical recursive sensitivities provide task and clearance gradients through the coupled base-arm motion. Parallel evaluation, caching, and incremental collision discovery reduce computation. With a seven-DoF arm and five simulated spacecraft models, FAVOR achieves 99.8% point-to-point success with 1.779 s mean computation, versus 62.9% and 50.270 s for an IK-initialized position-spline baseline. Means include failures and timeouts. FAVOR completes 30 of 36 tracking cases, versus 15 for single-step QP, and all 36 interception instances, versus 22 for the spline baseline. A controlled ablation shows that finite differences increase mean planning time 4.7-fold.
Figures & tables
| [mm/s] | [mrad/s] | |
|---|---|---|
| V0 | ||
| V1 | ||
| V2 | ||
| V3 | ||
| V4 |
| FAVOR | Spline (random) | Spline (IK) | RRT | |||||
|---|---|---|---|---|---|---|---|---|
| Spacecraft | [%] | Time [s] | [%] | Time [s] | [%] | Time [s] | [%] | Time [s] |
| CALIPSO | 99.2 | 7.282 | 10.4 | 58.704 | 12.0 | 58.097 | 0.0 | |
| Landsat 7 | 100.0 | 0.548 | 48.0 | 45.922 | 56.0 | 52.448 | 0.0 | |
| Hubble | 100.0 | 0.320 | 50.4 | 50.459 | 90.4 | 47.281 | 0.0 | |
| SMAP | 100.0 | 0.262 | 64.0 | 46.631 | 74.4 | 48.115 | 0.0 | |
| QuikSCAT | 100.0 | 0.482 | 60.0 | 39.210 | 81.6 | 45.408 | 0.0 | |
| Method | Success [%] | [mm] | [rad] | Avg. time [s] |
| Static | ||||
| FAVOR (stop) | 85.2 | 5.74 | 0.0031 | 0.293 |
| FAVOR (refine) | 85.2 | 3.14 | 0.0103 | 3.968 |
| FAVOR (IK) | 85.2 | 7.3 | 0.0308 | 4.037 |
| Single-step QP | 37.0 | 4.71 | 0.00275 | 4.325 |
| Dynamic | ||||
| FAVOR | Spline (random) | Spline (IK) | ||||
|---|---|---|---|---|---|---|
| Object | [%] | Time [s] | [%] | Time [s] | [%] | Time [s] |
| Payload box | 100.0 | 2.754 | 22.2 | 39.736 | 83.3 | 32.669 |
| Canister | 100.0 | 3.332 | 22.2 | 39.617 | 38.9 | 36.978 |
| Overall | 100.0 | 3.043 | 22.2 | 39.676 | 61.1 | 34.824 |
| Variant | Success [%] | Plan [s] | Assembly [ms] |
|---|---|---|---|
| FAVOR (full) | 100.0 | 1.635 | 1.924 |
| No cache | 100.0 | 3.301 | 2.079 |
| Independent assembly | 100.0 | 2.557 | 8.246 |
| Finite differences | 92.0 | 7.613 | – |
Robot Motion Planning
Robot motion planning finds safe, feasible paths and trajectories for robots moving through constrained, changing environments.
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