@InProceedings{benallegue:iros:2021,
  author    = {Benallegue, Mehdi and Cisneros, Rafael and Benallegue, Abdelaziz and Tanguy, Arnaud and Escande, Adrien and Morisawa, Mitsuharu and Kanehiro, Fumio},
  title     = {On compliance and safety with torque-control for robots with high reduction gears and no joint-torque feedback},
  booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems},
  year      = {2021},
  address   = {Prague, Czech Republic},
  month     = {September 27-October 1},
  url       = {https://ieeexplore.ieee.org/document/9636081},
  keywords  = {Torque, Gears, Trajectory tracking, Friction, Torque control, Position control, Safety},
  doi       = {10.1109/IROS51168.2021.9636081},
  abstract  = {In this paper we report the safety-oriented framework for controlling the torque in the case of robots with high reduction gears and having no joint torque feedback. This kind of robots suffer from high joint friction and low backdrivability, requiring high gains and integral feedback, which can be dangerous. Our optimization-based framework includes feasibility and safety features borrowed from position control, and we introduce novel ones. We show how we limit the integral terms using a QP-based anti-windup which produces the optimal torque that maintains the best performances under safety limits. We show also a new controller for null-space compliance, providing strong guarantees of convergence in the task-space and ignoring the corresponding null-space where the robot can be moved freely. We validate these features with experiments on one 9 DoF arm of the robot HRP-5P performing a Cartesian task, and then a dual Cartesian / admittance task.}
}