Injury Criteria Overview

• Head Injury Criteria

• Developed by the automotive industry, it is the most common criteria applied to the robot human collisions. It seeks to quantify the probability and severity of trauma (be it concussion or other head injury). The HIC number is based on the translational acceleration of the center of mass of the head and is determined by the HIC equation:
• The time interval is chosen such that it maximizes the HIC number associated with the collision. Typical time interavals are 15 ms and 36 ms, with the shorter being associated with direct contact collision while the longer associates better with concussive injuries.

• Danger Index (Ikuta, 2003)

• The Danger Index was among the first attempts of indices developed specifically for robot human collisions and is given by the equation robot=i=1niwhere =FFc, and F is the producible impact force and Fc is the critical impact force necessary for injury. Here, n is the total number of safety strategies

• Chamois Laceration Index (Hittner 1986)

• A laceration index developed by the automotive industry, it was used to compare different automotive glass designs. The test consists of 2 layers of chamois cloth layered over a test dummy head being subjected to a the event in question. The amount of laceration on the chamois clothe is supposed to represent a comparable amount on human skin and tissue and ranked according to the following scale.

• Manipulator Safety Index (Zinn)

• The MSI was developed by Mike Zinn of Khatib’s AI laboratory. It seeks to apply a mass spring model to characterize the collision between a robotic manipulator and a headform. It utilizes the HIC as its basis, replacing the time averaged acceleration term with a term relying on moment of inertia, characteristic frequency of the system and contact interface stiffness.