Transient behaviour of ITER poloidal field coils

Transient voltages occur on the terminals of superconducting coils and may lead to internal over-voltages. The main objective of this work was to calculate the transient electrical behaviour and internal voltage distribution within the ITER poloidal field (PF) coils at four scenarios and was made using the PF 3 and PF 6 coils as examples. The calculated maximum voltages will be used for definition of amplitudes and voltage waveforms for the tests of the high-voltage insulation of the coils

Transient behaviour of ITER poloidal field coils

Transient voltages occur on the terminals of superconducting coils and may lead to internal over-voltages. The main objective of this work was to calculate the transient electrical behaviour and internal voltage distribution within the ITER poloidal field (PF) coils at four scenarios and was made using the PF 3 and PF 6 coils as examples. The calculated maximum voltages will be used for definition of amplitudes and voltage waveforms for the tests of the high-voltage insulation of the coils

Trajectory Optimization Through Contacts and Automatic Gait Discovery for Quadrupeds

In this work we present a trajectory Optimization framework for whole-body motion planning through contacts. We demonstrate how the proposed approach can be applied to automatically discover different gaits and dynamic motions on a quadruped robot. In contrast to most previous methods, we do not pre-specify contact switches, timings, points or gait patterns, but they are a direct outcome of the optimization. Furthermore, we optimize over the entire dynamics of the robot, which enables the optimizer to fully leverage the capabilities of the robot. To illustrate the spectrum of achievable motions, here we show eight different tasks, which would require very different control structures when solved with state-of-the-art methods. Using our trajectory Optimization approach, we are solving each task with a simple, high level cost function and without any changes in the control structure. Furthermore, we fully integrated our approach with the robot's control and estimation framework such that optimization can be run online. By demonstrating a rough manipulation task with multiple dynamic contact switches, we exemplarily show how optimized trajectories and control inputs can be directly applied to hardware.Comment: Video: https://youtu.be/sILuqJBsyK

Robust Whole-Body Motion Control of Legged Robots

We introduce a robust control architecture for the whole-body motion control of torque controlled robots with arms and legs. The method is based on the robust control of contact forces in order to track a planned Center of Mass trajectory. Its appeal lies in the ability to guarantee robust stability and performance despite rigid body model mismatch, actuator dynamics, delays, contact surface stiffness, and unobserved ground profiles. Furthermore, we introduce a task space decomposition approach which removes the coupling effects between contact force controller and the other non-contact controllers. Finally, we verify our control performance on a quadruped robot and compare its performance to a standard inverse dynamics approach on hardware.Comment: 8 Page