Wind load simulations and inertia scaling using an industrial robot arm

Abstract

Existing wind load simulators such as wind tunnels and fans have multiple disadvantages, especially when used in a scaled-down environment. This paper proposes to simulate wind loads by using an admittance-controlled industrial robot arm rigidly attached to a research object. Admittance control should make it possible to simulate wind loads and a specific amount of inertia that is higher than the inertia of the original research object. The goal is to verify whether an admittance-controlled industrial robot arm is suitable for wind load and inertia simulations and what the limitations of this simulation method are. The scope of this research is limited to three Degrees of Freedom. First, the admittance controller is tested on a computer simulation model before execution on a Hardware-in-the-loop setup. It is found that an admittance-controlled robot arm is well capable of simulating both wind loads and a specific amount of inertia. However, there are some limitations. The motion controller of the industrial robot should be able to change the end-effector position within a frequency of 50 Hz. Frequencies above 333 Hz result in the most accurate simulations. The upper range of inertia that can be simulated is restricted by the maximum joint torques the robot can apply. The lower range is restricted by the inertia of the real object, the applied wind loads, and the sampling frequency of the admittance control loop.