The compliant_stabilizer library includes the algorithm based on the paper:
@article{zhou2016stabilization,
title={Stabilization of bipedal walking based on compliance control},
author={Zhou, Chengxu and Li, Zhibin and Wang, Xin and Tsagarakis, Nikos and Caldwell, Darwin},
journal={Autonomous Robots},
volume={40},
pages={1041--1057},
year={2016},
publisher={Springer}
}
and the OpenSoT Task implementation.