Publications

2023

D.J. Braun, Y. Chen, and Y. Li, Learning Finite-Horizon Nonlinear Optimal Control Policies with Unknown Control-Affine Dynamics, 2023 (under review).
S.Y. Kim and D.J. Braun, Variable Stiffness Floating Spring Leg: Performing net-zero Energy Cost Tasks not Achievable using Fixed Stiffness Springs, 2023 (under review).
S.Y. Kim and D.J. Braun, Controllable Mechanical-domain Energy Accumulators, IEEE International Conference on Robotics and Automation, 2023 (accepted).
C. Mathews and D.J. Braun, Design of a Variable Stiffness Spring with Human-Selectable Stiffness, IEEE International Conference on Robotics and Automation, 2023 (accepted).
C. Dempsey and D.J. Braun, Novel Spring Mechanism Enables Iterative Energy Accumulation under Force and Deformation Constraints, IEEE International Conference on Robotics and Automation, 2023 (accepted).
Y. Chen, Y. Li, and D.J. Braun, Data-driven Iterative Optimal Control for Switched Dynamical Systems, IEEE Robotics and Automation Letters, vol. 8, no. 1, pp. 296-303, 2023.

2022

C. Mathews and D. J. Braun, Design of Parallel Variable Stiffness Actuators, IEEE Transactions on Robotics, 2022 (accepted).
T. Zhang and D. J. Braun, Theory of Fast Walking With Human-Driven Load-Carrying Robot Exoskeletons, vol. 30, pp. 1971-1981, IEEE Transactions on Neural Systems and Rehabilitation Engineering, 2022.

2021

S. Y. Kim and D. J. Braun, Novel Variable Stiffness Spring Mechanism: Modulating Stiffness Independent of the Energy Stored by the Spring, pp. 8232-8237, IEEE-RSJ International Conference on Intelligent Robots and Systems, 2021.

C. W. Mathews and D. J. Braun, Parallel Variable Stiffness Actuators, pp. 8225-8231, IEEE-RSJ International Conference on Intelligent Robots and Systems, 2021.

T. Zhang and D. J. Braun, Human Driven Compliant Transmission Mechanism, pp. 7094-7099, IEEE International Conference on Robotics and Automation, 2021.

Y. Chen and D. J. Braun, Iterative Online Optimal Feedback Control, vol. 66, no. 2, pp. 566-580, IEEE Transactions on Automatic Control, 2021.

2020

Y. Chen and D. J. Braun, Iterative Online Optimal Feedback Control, vol. 66, no. 2, pp. 566-580, IEEE Transactions on Automatic Control, 2021 (Accepted).

S. Kim, T. Zhang, and D.J. Braun, Variable Stiffness Springs for Energy Storage Applications, IEEE International Conference on Robotics and Automation, Paris, FR, 2020.

Y. Chen and D. J. Braun, Hardware-in-the-Loop Iterative Optimal Feedback Control without Model-based Future Prediction, IEEE International Conference on Robotics and Automation, Paris, FR, 2020.

A. Sutrisno and D. J. Braun, How to Run 50% Faster without External Energy, vol. 6, no. 13, eaay1950, Science Advances, 2020.

2019

D.J. Braun, Y.Chen, L. Li, Operational Space Control under Actuation Constraints using Strictly Convex Optimization, vol. 36, no. 1, pp. 302-309, IEEE Transactions on Robotics, 2019.

Y. Chen and D.J. Braun, Hardware-in-the-Loop Iterative Optimal Feedback Control without Model-based Future Prediction, vol. 35, no. 6, pp. 1419-1434, IEEE Transactions on Robotics, 2019.

D.J. Braun, V. Chalvet, Chong T.-H., S.S. Apte and N. Hogan, Variable Stiffness Spring Actuators for Low Energy Cost Stiffness Modulation, vol. 35, no. 6, pp. 1435-1449, IEEE Transactions on Robotics, 2019.

E.S. Altinkaynak and D.J. Braun, Multiphase and Multivariable Linear Controllers that Account for the Joint Torques in Normal Human Walking, IEEE Transactions on Biomedical Engineering, 2019.

Y. Li, H. Yu, and D.J. Braun, Algorithmic Resolution of Multiple Impacts in Nonsmooth Mechanical Systems with Switching Constraints, IEEE International Conference on Robotics and Automation, Montreal, CA, pp. 7639-7645, May 2019.

L. Li and D.J. Braun, Constrained Feedback Control by Prioritized Multi-objective Optimization, IEEE International Conference on Robotics and Automation, Montreal, CA, pp. 9496-9501, May 2019.

E.S. Altinkaynak and D.J. Braun, A Phase-Invariant Linear Torque-Angle-Velocity Relation Hidden in the Human Walking Data, vol. 27, no. 4, pp. 702-711, IEEE Transactions on Neural Systems & Rehabilitation Engineering, 2019.

A. Sutrisno and D.J. Braun, Enhancing Mobility with Quasi-passive Variable Stiffness Exoskeletons, IEEE Transactions on Neural Systems & Rehabilitation Engineering, vol. 27, no. 3, pp. 487-496, 2019. This paper has been highlighted by IEEE Transactions on Neural Systems & Rehabilitation Engineering!

F. A. Yaghmaie and D.J. Braun, Reinforcement Learning for a Class of Continuous-time Input Constrained Optimal Control Problems, Automatica, vol. 99, pp. 221-227, 2019.

2018

Y. Chen, L. Roveda and D.J. Braun, Efficiently Computable Constrained Optimal Feedback Controllers, IEEE Robotics and Automation Letters, vol. 4, no. 1, pp. 121-128, 2018.

D.J. Braun, V. Chalvet and A. Dahiya, Positive-Negative Stiffness Actuators, IEEE Transactions on Robotics, vol. 35, no. 1, pp. 162-173, 2018.

V. Chalvet and D. J. Braun, Criterion for the Design of Low Power Variable Stiffness Mechanisms, IEEE International Conference on Robotics and Automation, Brisbane, AU, May 2018. poster

H.-F. Lau, A. Sutrisno, T.-H. Chong, D.J. Braun, Stiffness Modulator: A Novel Actuator for Human Augmentation, IEEE International Conference on Robotics and Automation, pp. 7742-7748, 2018.

2017

V. Chalvet and D.J. Braun, Algorithmic Design of Low Power Variable Stiffness Mechanisms, IEEE Transactions on Robotics, vol. 33, no. 6, pp. 1508-1515, 2017.

C. Tze-Hao, V. Chalvet and D.J. Braun, Analytical Conditions for the Design of Variable Stiffness Mechanisms, IEEE International Conference on Robotics and Automation, Singapore, SG, pp. 1241-1247, May 2017.

A. Dahiya and D.J. Braun, Efficiently Tuneable Positive-Negative Stiffness Actuator, IEEE International Conference on Robotics and Automation, Singapore, SG, pp. 1235-1240, May 2017.

V. Chalvet and D.J. Braun, Criterion for the Design of Low Power Variable Stiffness Mechanisms, IEEE Transactions on Robotics, vol. 33, no. 4, 1002-1010, 2017.

J. Nakanishi, A. Radulescu, D.J. Braun and S. Vijayakumar, Spatio-Temporal Stiffness Optimization in Movements with Switching Dynamics, Autonomous Robots, vol. 41, no. 2, pp. 273-291, 2017.

D.J. Braun, A. Sutas and S. Vijayakumar, Self-tuning Bistable Parametric Oscillator: Near-optimal Amplitude Maximization without Model Information, Physical Review E, 95, 012201, 2017.

A. Radulescu, J. Nakanishi, D.J. Braun and S. Vijayakumar, Optimal Control of Variable Stiffness Policies: Dealing with Switching Dynamics and Model Mismatch, J.-P. Laumond et al. (eds.), Geometric and Numerical Foundations of Movements, Springer Tracts in Advanced Robotics, vol. 117, pp. 393-419, 2017.

2008-2016

D.J. Braun, S. Apte, O. Adiyatov, A. Dahiya and N. Hogan, Compliant Actuation for Energy Efficient Impedance Modulation, IEEE International Conference on Robotics and Automation, Stockholm, SE, pp. 636-641 , May 2016.

D.J. Braun, Optimal parametric feedback excitation of nonlinear oscillators, Physical Review Letters, 116, 044102, 2016.

D.J. Braun, F. Petit, F. Huber, S. Haddadin, P. van der Smagt, A. Albu-Schaffer and S. Vijayakumar, Robots Driven by Compliant Actuators: Optimal Control under Actuation Constraints, IEEE Transactions on Robotics, vol. 29, no. 5, pp. 1085-1101, 2013. This paper is recipient of the 2013 King-Sung Fu IEEE Transactions on Robotics Best Paper Award. The King-Sun Fu Award recognizes the best paper published annually in IEEE Transactions on Robotics. IEEE T-RO typically receives over 650 submissions each year!

M. Howard, D.J. Braun, and S. Vijayakumar, “Transferring human impedance behavior to heterogeneous variable impedance actuators,” IEEE Transactions on Robotics, vol. 29, no. 4, pp. 847-862, 2013.

D. J. Braun, M. Howard and S. Vijayakumar, Optimal Variable Stiffness Control: Formulation and Application to Explosive Movement Tasks, Autonomous Robots, vol. 33, no.3, pp. 237-253, 2012.

D.J. Braun and M. Goldfarb, Simulation of Constrained Mechanical Systems – Part I: An Equation of Motion, ASME Journal of Applied Mechanics, vol. 79, issue 4, 041017, 2012.

D.J. Braun and M. Goldfarb, Simulation of Constrained Mechanical Systems – Part II: Explicit Numerical Integration, ASME Journal of Applied Mechanics, vol. 79, issue 4, 041018, 2012.

D.J. Braun, Jason E. Mitchell and M. Goldfarb, Actuated Dynamic Walking in a Seven-Link Biped Robot, IEEE/ASME Transactions on Mechatronics, vol. 17, no.1, pp. 147-156, 2012.

D.J. Braun, F. Petit, F. Huber, S. Haddadin, P. Smagt, A. Albu-Schaffer, and S. Vijayakumar, Optimal torque and stiffness control in compliantly actuated robots, in IEEE/RSJ International Conference on Intelligent Robots and Systems, Algarve, PT, pp. 2801–2808, October 2012.

A. Radulescu, M. Howard, D.J. Braun, and S. Vijayakumar, Exploiting variable physical damping in rapid movement tasks, in IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Kaohsiung, TWN, pp. 141–148, July 2012. Best Student Paper Award Finalist at the 2012 IEEE/ASME International Conference on Advanced Intelligent Mechatronics.

D.J. Braun, M. Howard, and S. Vijayakumar, Exploiting variable stiffness in explosive movement tasks, Robotics: Science and Systems, Los Angeles, USA, June/July 2011.

M. Howard, D.J. Braun, and S. Vijayakumar, Constraint-based equilibrium and stiffness control of variable stiffness actuators, IEEE International Conference on Robotics and Automation, Shanghai, CN, pp. 5554–5560, May 2011.

D.J. Braun, Adaptive steady-state stabilization for nonlinear dynamical systems, Physical Review E, vol. 78, no. 1, p. 016213, 2008; “Reply to Comment on Adaptive steady-state stabilization for nonlinear dynamical systems,” Physical Review E, vol. 81, no. 1, p. 038202, 2010.

D.J. Braun, M. Goldfarb, A Control Approach for Actuated Dynamics Walking in Biped Robots, IEEE Transactions on Robotics, vol. 25, no. 6, pp. 1292-1303, 2009.

D.J. Braun, M. Goldfarb, Elimination of Constrained Drift in the Numerical Simulation of Constrained Dynamical Systems, Computer Methods in Applied Mechanics and Engineering, vol. 198, no. 37-40, pp. 3151-3160, 2009.

D.J. Braun and M. Goldfarb, A controller for dynamic walking in bipedal robots, IEEE/RSJ International Conference on Intelligent Robots and Systems, St. Louis, USA, pp. 2916–2921, October 2009.

D. J. Braun, J. E. Mitchell, and M. Goldfarb, Actuated dynamic walking in biped robots: Control approach, robot design and experimental validation, IEEE-RAS International Conference on Humanoid Robots, Paris, FR, pp. 237–242, December 2009.

D.J. Braun, On the optimal shape of compressed rotating rod with shear and extensibility, International Journal of Non-linear Mechanics, vol. 43, no. 2, pp. 131–139, 2008.

T. M. Atanackovic and D.J. Braun, The strongest rotating rod, International Journal of Non-linear Mechanics, vol. 40, pp. 747–754, 2005.