We present a 3-phase hybrid controller that jumps to a required height. The launch trajectory is obtained through contact implicit Direct Collocation, a mathematical program with complimentary constraints (MPCC). The trajectory is followed by an Operational Space Controller (OSC). Separate OSCs were made for the flight and landing phases. The controller we made is robust against a wide range of system mass fluctuations, state estimation errors, and terrain geometry. The controller works for a range of jump height requirements for a given system mass distribution, estimation error, and terrain. It is sensitive to low coefficient of friction, solver parameters, and phase switch error when direct collocation fails. Please find the complete report here

Our controller demonstrates the following key findings:

• The controller works effectively for a family of jump heights, considering various terrains characterized by factors like slope and coefficient of friction ($\mu$).
• It exhibits stability across a wide range of slopes, and it can stabilize post-landing without requiring adjustments.

During experimentation, we observed challenges that warrant careful examination in future work:

1. Direct Collocation

   • Very sensitive to solver settings.
   • Lower-cost "solutions" may result in infeasible trajectories.

2. Phase Switch Robustness

   • Consider exploring the use of contact forces for a more robust phase switch.

3. Optimal Control with Slip

   • Introduce complementary constraints in Optimal Control with Slip (OSC) to facilitate slip in the system.

These observations provide valuable insights for further investigation and improvement of the controller. The final results are shown here

Supported OS: Ubuntu 22.04

mkdir venv
python -m venv venv
venv\Scripts\activate
pip install -r requirements.txt

• Anirudh Kailaje (@KailajeAnirudh)
• Dhruv Parikh (@git-dhruv)

Copyright <2023>

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