In this study, a novel adaptive backstepping control method is proposed to handle the position tracking problem of the permanent magnet synchronous motor (PMSM) system with unknown load torque. Firstly, a novel load torque update law which is different from the traditional load torque update law is obtained based on the position error and estimated torque error. Then, a novel adaptive backstepping controller is presented under the circumstance of estimated load torque. The asymptotic stability of the overall system is verified by using Lyapunov stability theory. The novel load torque update law guarantees the accurate estimation and improves the convergence speed of the estimated load torque. The designed controller improves the position tracking performance and ensures stability of the closed-loop system. Finally, real-time experiment results with LINKS-RT platform intuitively exhibit that the proposed control method ensures position tracking performance and retains good load torque disturbance attenuation.

Global warming-induced melting and thawing of the cryosphere are severely altering the volume and timing of water supplied from High Mountain Asia (HMA), adversely affecting downstream food and energy systems relied upon by billions of people. The construction of more reservoirs designed to regulate streamflow and produce hydropower is a critical part of strategies for adapting to these changes. However, these projects are vulnerable to a complex set of interacting processes that are destabilizing landscapes throughout the region. Ranging in severity and the pace of change, these processes include glacial retreat and detachments, permafrost thaw and associated landslides, rock-ice avalanches, debris flows, and outburst floods from glacial lakes and landslide-dammed lakes.The end result is large amounts of sediment being mobilized that can fill up reservoirs, cause dam failure, and degrade power turbines. Here, we recommend forward-looking design and maintenance measures and sustainable sediment management solutions that can help transition towards climate change-resilient dams and reservoirs in HMA, in large part based on improved monitoring and prediction of compound and cascading hazards.

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