Force-based control for human-robot cooperative object manipulation
Doctoral thesis, 2021
This thesis examines the aforementioned issues related to PHRI. First, the instability arising due to a time delay is addressed. For this purpose, the time delay in the system is modeled with the exponential function, and the effect of system parameters on the stability of the interaction is examined analytically. The proposed method is compared with the state-of-the-art criteria used to study the stability of PHRI systems with similar setups and high human stiffness. Second, the unknown human grasp position is estimated by exploiting the interaction forces measured by a force/torque sensor at the robot end effector. To address cases where the human interaction torque is non-zero, the unknown parameter vector is augmented to include the human-applied torque. The proposed method is also compared via experimental studies with the conventional method, which assumes a contact point (i.e., that human torque is equal to zero). Finally, the translation/rotation problem in shared object manipulation is tackled by proposing and developing a new control scheme based on the identification of the ongoing task and the adaptation of the robot's role, i.e., whether it is a passive follower or an active assistant. This scheme allows the human to transport the object independently in all degrees of freedom and also reduces human effort, which is an important factor in PHRI, especially for repetitive tasks. Simulation and experimental results clearly demonstrate that the force required to be applied by the human is significantly reduced once the task is identified.
physical human-robot collaboration
human-robot interaction control
Ramin Jaberzadeh Ansari
Chalmers, Electrical Engineering, Systems and control
Task-based role adaptation for human-robot cooperative object handling
IEEE Robotics and Automation Letters,; Vol. 6(2021)p. 3592-3598
Human grasp position estimation for human–robot cooperative object manipulation
Robotics and Autonomous Systems,; Vol. 131(2020)
R. Jaberzadeh Ansari, J. Sjöberg, Y. Karayiannidis, "On the stability of admittance control for physical human-robot interaction under delays"
Areas of Advance
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4982
Opponent: Associate Professor Andrea Cherubini, Université de Montpellier, France