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Development and verification of a mathematical model for robot force control via measuring AN output/input relationship and force control experiments

Journal Article


Abstract


  • This paper describes the development and verification of a mathematical model for a force control system consisting of a PUMA 560 manipulator, force sensor, and environment. Its main contribution is to present an argument that explicit open-loop dynamic models of manipulation systems used for force control are of little relevance or use. Identification techniques are used to model the system as a "black box," measuring only an output/input relationship. The explicit dynamics of the mechanical, hardware, and software elements of the manipulator are neglected; they are considered as parts of the measured output/input relationship. P+D (PD) loops are closed around each joint of the manipulator before identification to reduce uncertainties, to overcome nonlinearities, and thus to linearize the system. Close correspondence between the experimental and the simulated Bode plots for frequencies below 30 Hz indicates that the developed model is accurate enough to analyze and design a force control strategy for hard-on-hard contact applications, such as robotic drilling. A force control strategy based on a PI law for a hard-on-hard application is designed and evaluated in terms of the step response and achievable bandwidth to further validate the mathematical model of the force control system during contact. The simulated and experimental closed-loop step responses and Bode plots from the PI law prove that the mathematical model developed reflects the low-frequency features of the force control system accurately enough for design and implementation of a force control strategy for a real task.

Publication Date


  • 1997

Citation


  • Alici, G., & Daniel, R. W. (1997). Development and verification of a mathematical model for robot force control via measuring AN output/input relationship and force control experiments. International Journal of Modelling and Simulation, 17(2), 107-119. doi:10.1080/02286203.1997.11760319

Scopus Eid


  • 2-s2.0-0005053931

Web Of Science Accession Number


Start Page


  • 107

End Page


  • 119

Volume


  • 17

Issue


  • 2

Abstract


  • This paper describes the development and verification of a mathematical model for a force control system consisting of a PUMA 560 manipulator, force sensor, and environment. Its main contribution is to present an argument that explicit open-loop dynamic models of manipulation systems used for force control are of little relevance or use. Identification techniques are used to model the system as a "black box," measuring only an output/input relationship. The explicit dynamics of the mechanical, hardware, and software elements of the manipulator are neglected; they are considered as parts of the measured output/input relationship. P+D (PD) loops are closed around each joint of the manipulator before identification to reduce uncertainties, to overcome nonlinearities, and thus to linearize the system. Close correspondence between the experimental and the simulated Bode plots for frequencies below 30 Hz indicates that the developed model is accurate enough to analyze and design a force control strategy for hard-on-hard contact applications, such as robotic drilling. A force control strategy based on a PI law for a hard-on-hard application is designed and evaluated in terms of the step response and achievable bandwidth to further validate the mathematical model of the force control system during contact. The simulated and experimental closed-loop step responses and Bode plots from the PI law prove that the mathematical model developed reflects the low-frequency features of the force control system accurately enough for design and implementation of a force control strategy for a real task.

Publication Date


  • 1997

Citation


  • Alici, G., & Daniel, R. W. (1997). Development and verification of a mathematical model for robot force control via measuring AN output/input relationship and force control experiments. International Journal of Modelling and Simulation, 17(2), 107-119. doi:10.1080/02286203.1997.11760319

Scopus Eid


  • 2-s2.0-0005053931

Web Of Science Accession Number


Start Page


  • 107

End Page


  • 119

Volume


  • 17

Issue


  • 2