Hybrid Differential Dynamic Programming for Planar Manipulation Primitives
This work addresses the problem of executing planar manipulation primitives like pushing and pivoting for robotics, representing an incremental improvement in hybrid control methods.
The paper tackles the challenge of planning and controlling manipulation primitives with frictional contact switches by developing a hybrid differential dynamic programming algorithm, which generates closed-loop trajectories in one to five seconds with one to two hybrid switches and stabilizes them on a real pushing system.
We present a hybrid differential dynamic programming (DDP) algorithm for closed-loop execution of manipulation primitives with frictional contact switches. Planning and control of these primitives is challenging as they are hybrid, under-actuated, and stochastic. We address this by developing hybrid DDP both to plan finite horizon trajectories with a few contact switches and to create linear stabilizing controllers. We evaluate the performance and computational cost of our framework in ablations studies for two primitives: planar pushing and planar pivoting. We find that generating pose-to-pose closed-loop trajectories from most configurations requires only a couple (one to two) hybrid switches and can be done in reasonable time (one to five seconds). We further demonstrate that our controller stabilizes these hybrid trajectories on a real pushing system. A video describing our work can be found at https://youtu.be/YGSe4cUfq6Q.