Lee, Yisoo Tsagarakis, Nikos Lee, Jinoh 2024-01-19T14:30:55Z 2024-01-19T14:30:55Z 2021-09-05 2021-07 0924-090X https://pubs.kist.re.kr/handle/201004/116820 This paper analyzes operational space dynamics for redundant robots with un-actuated joints and reveals their highly nonlinear dynamic impacts on operational space control (OSC) tasks. Unlike conventional OSC approaches that partly address the under-actuated system by introducing rigid grasping or contact constraints, we deal with the problem even without such physical constraints which have been overlooked, yet it includes a wide range of applications such as free-floating robots and manipulators with passive joints or unwanted actuation failure. In addition, as an intuitive application example of the drawn result, an OSC is formulated as an optimization problem to alleviate the dynamics disturbance stemmed from the un-actuated joints and to satisfy other inequality constraints. The dynamic analysis and the proposed control method are verified by a number of numerical simulations as well as physical experiments with a 7-degrees-of-freedom robotic arm. In particular, we consider joint actuation failure scenarios that can be occurred at certain joints of a torque-controlled robot and practical case studies are performed with an actual redundant robot arm. English SPRINGER CONTROL FRAMEWORK UNIFIED APPROACH PASSIVE JOINTS MANIPULATORS FORCE DYNAMICS MOTION TORQUE Study on operational space control of a redundant robot with un-actuated joints: experiments under actuation failure scenarios Article 10.1007/s11071-021-06545-6 1 NONLINEAR DYNAMICS, v.105, no.1, pp.331 - 344 NONLINEAR DYNAMICS 105 1 331 344 scie scopus 000658587600005 2-s2.0-85107649135 Engineering, Mechanical Mechanics Engineering Mechanics Article CONTROL FRAMEWORK UNIFIED APPROACH PASSIVE JOINTS MANIPULATORS FORCE DYNAMICS MOTION TORQUE Nonlinear robot dynamics Operational space formulation Robot control Under-actuated robot