Serial Kinematics based Motion Simulator - Evaluation of safety of the Passenger

Abstract

Serial kinematics based motion simulation is a recent development and was ushered in by the introduction of the KUKA Robocoaster in 2001. The Robocoaster employs a 6-DoF industrial robot (KUKA KR-500) equipped with 2 seats at its tool centre point (TCP). Since 2001, the Robocoaster (and derived systems) has been a subject of active research and has been successfully transferred to the amusement industry. DLR has developed various iterations of the Robocoaster: In 2004-05, we presented the ‘KUKA Mars Mission’; this was the first time visual cues were incorporated with the Robocoaster system. Next, we developed the ‘RoboSim 4-D’ simulator that addressed the shortcomings of the earlier efforts, was lower in cost and had improved safety features. This version is in-use (as an offline simulator) at several amusement parks. The latest version, called the ‘DLR Robot Motion Simulator’ (DLRRMS) includes an additional linear axis at the base of the robot; which makes the setup a 7 DoF simulator. This version is used for both, online and offline simulations. Adaptation of an industrial robot into a motion simulator introduces a new set of challenges with regards to human and robot safety (i.e. prevention of damage to the setup as a secondary safety aim) and hence an appropriate safety infrastructure was deployed. To validate the potency of this system, it was subjected to several tests which involved effectuating high accelerations at the TCP by inducing sudden braking. The resulting accelerations were initially measured using an inertial measurement unit (IMU) and later, using an Anthropomorphic test device (ATD) commonly known as ’crash test dummy’. In this paper, we present the finding of safety analysis tests undertaken with an ATD placed in the simulator cell. We focus our attention to critical motions (e.g. flexion, inflexion etc.) of the head-neck region and also illustrate the software features such as the ‘watchdog application’ which offers extra functionalities that complement the existing safety features.