Control as a Service (CaaS) is an emerging paradigm where low-level control of a device is moved from a local controller to the Cloud, and provided to the device as an on-demand service. Among its many benefits, CaaS gives the device access to advanced control algorithms which may not be executable on a local controller due to computational limitations. As a step toward 3D printer CaaS, this paper demonstrates the control of a 3D printer by streaming low-level stepper motor commands (as opposed to high-level G-codes) directly from the Cloud to the printer. The printer is located at the University of Michigan, Ann Arbor, while its stepper motor commands are calculated using an advanced motion control algorithm running on Google Cloud computers in South Carolina and Australia. The stepper motor commands are sent over the internet using the user datagram protocol (UDP) and buffered to mitigate transmission delays; checks are included to ensure accuracy and completeness of the transmitted data. All but one part printed using the cloud-based controller in both locations were hitch free (i.e., no pauses due to excessive transmission delays). Moreover, using the cloud-based controller, the parts printed up to 54% faster than using a standard local controller, without loss of accuracy.
The vertical movements of a trimaran, which can produce a vertical acceleration, always make people feel seasickness and cause equipment damage on the board. This paper presents a method of a trimaran vertical stabilization control. First, the trimaran mathematical equation is obtained by the numerical simulation and verified by the trimaran experiment in the water tank. Then, the vertical stabilization appendages, including T-foil and flap, are designed and installed at the bottom of the trimaran. Second, an active controller of the appendages is designed and a decoupling method is applied to decouple T-foil and flap, the attack angles of T-foil and flap are obtained in real-time, and the mathematical simulation verified the effect of the decoupling method. Finally, every hardware parts are selected and composed, then, the hardware of the control system is realized and installed on the trimaran, in water tank experiment, the controller was verified in water tank experiment and the experiment results show that it has a good vertical stabilization effect for the trimaran.
Summary
This article elaborates an adaptive fuzzy event‐triggered control design for stochastic nonlinear time‐delay systems with full‐state constraints. The prescribed constraints are ensured by employing barrier Lyapunov function. The fuzzy logic systems are exploited to approximate lumped unknown nonlinear functions. By cleverly choosing Lyapunov–Krasovskii functional, the adverse effect of time‐delay is effectively overcome. Meanwhile, the event‐triggered mechanism is adopted to save communication resource. It is illustrated that all signals of the controlled system are bounded and all states are maintained the prescribed regions at every step of recursive backstepping design. Finally, simulation results elucidate the validity of the devised scheme.
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