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Habibi, Hossein
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Habibi, Hossein
Official Name
Habibi, Hossein
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Now showing 1 - 3 of 3
- PublicationWave-based control of under-actuated flexible structures with strong external disturbing forcesWave-based control (WBC) of underactuated, flexible systems considers actuator motion as launching a mechanical wave into the flexible system which it then absorbs on its return to the actuator. The launching and absorbing proceed simultaneously. This simple, intuitive idea leads to robust, generic, highly efficient, precise, adaptable controllers, allowing rapid and almost vibrationless re-positioning of the system, using only sensors colocated at the actuator-system interface. These wave-based ideas have already been shown to work on simple systems such as mass-spring strings, systems of Euler-Bernoulli beams, and flexible space structures undergoing slewing motion (rotation with lateral translation). The current work extends this strategy to systems experiencing external disturbing forces, whether body forces which endure over time, such as gravitational effects which change with system orientation, or transient forces such as from impacts or external viscous damping. The revised strategy additionally provides robustness to some sensor errors. The strategy has the controller learn about the disturbances and compensate for them, yet without needing new sensors or measurements beyond those of standard WBC.
279 - PublicationWave-based control of under-actuated flexible structures with strong external disturbing forcesWave-based control of under-actuated, flexible systems has many advantages over other methods. It considers actuator motion as launching a mechanical wave into the flexible system which it absorbs on its return to the actuator. The launching and absorbing proceed simultaneously. This simple, intuitive idea leads to robust, generic, highly efficient, precise, adaptable controllers, allowing rapid and almost vibrationless re-positioning of the system, using only sensors collocated at the actuator-system interface. It has been very successfully applied to simple systems such as mass-spring strings, systems of Euler-Bernoulli beams, planar mass-spring arrays, and flexible three-dimensional space structures undergoing slewing motion. In common with most other approaches, this work also assumed that, during a change of position, the forces from the environment were negligible in comparison with internal forces and torques. This assumption is not always valid. Strong external forces considerably complicate the flexible control problem, especially when unknown, unexpected or unmodelled. The current work extends the wave-based strategy to systems experiencing significant external disturbing forces, whether enduring or transient. The work also provides further robustness to sensor errors. The strategy has the controller learn about the disturbances and compensate for them, yet without needing new sensors, measurements or models beyond those of standard wave-based control.
303Scopus© Citations 7 - PublicationGantry crane control of a double-pendulum, distributed-mass load, using mechanical wave conceptsThe overhead trolley of a gantry crane can be moved in two directions in the plane. The trolley is attempting to control the motion of a suspended, rigid-body, distributed mass load, supported by a hook, modelled as a lumped mass, in turn connected to the trolley by a light flexible cable. This flexible system has six degrees of freedom, four variables describing the flexible, hanging load dynamics and two (directly controlled) input variables for the trolley position. The equations of motion are developed and the crane model is verified. Then a form of wave-based control (WBC) is applied to determine what trolley motion should be used to achieve a reference motion of the load, with minimum swing during complex manoeuvres. Despite the trolley's limited control authority over the complex, flexible 3-D dynamics, WBC enables the trolley to achieve very good motion control of the load, in a simple, robust and rapid way, using little sensor information, with all measurements taken at or close to the trolley.
783Scopus© Citations 28