.. index:: pair: page; Introduction

Introduction
============

**OCS2** is a C++ toolbox tailored for **O**\ ptimal **C**\ ontrol for 
**S**\ witched **S**\ ystems (OCS2). The toolbox provides an efficient 
implementation of the following algorithms:

* **SLQ**\: Continuous-time domain constrained DDP
* **iLQR**\: Discrete-time domain constrained DDP
* **SQP**\: Multiple-shooting algorithm based on `HPIPM <href="https://github.com/giaf/hpipm"/>`__
* **IPM**\: Multiple-shooting algorithm based on nonlinear interior point method
* **SLP**\: Sequential Linear Programming based on `PIPG <href="https://arxiv.org/abs/2009.06980"/>`__

OCS2 handles general path constraints through Augmented Lagrangian or 
relaxed barrier methods. To facilitate the application of OCS2 in robotic 
tasks, it provides the user with additional tools to set up the system 
dynamics (such as kinematic or dynamic models) and cost/constraints 
(such as self-collision avoidance and end-effector tracking) from a 
URDF model. The library also provides an automatic differentiation 
tool to calculate derivatives of the system dynamics, constraints, and 
cost. To facilitate its deployment on robotic platforms, the OCS2 
provides tools for ROS interfaces. The toolbox’s efficient and 
numerically stable implementations in conjunction with its user-friendly 
interface have paved the way for employing it on numerous robotic 
applications with limited onboard computation power. 

|GitHub| Source code on GitHub: `leggedrobotics/ocs2 <https://github.com/leggedrobotics/ocs2>`_

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