  The need to increase the flexibility of production lines is calling for
robots to collaborate with human workers. However, existing interactive
industrial robots only guarantee intrinsic safety (reduce collision impact),
but not interactive safety (collision avoidance), which greatly limited their
flexibility. The issue arises from two limitations in existing control software
for industrial robots: 1) lack of support for real-time trajectory
modification; 2) lack of intelligent safe control algorithms with guaranteed
collision avoidance under robot dynamics constraints. To address the first
issue, a jerk-bounded position controller (JPC) was developed previously. This
paper addresses the second limitation, on top of the JPC. Specifically, we
introduce a jerk-based safe set algorithm (JSSA) to ensure collision avoidance
while considering the robot dynamics constraints. The JSSA greatly extends the
scope of the original safe set algorithm, which has only been applied for
second-order systems with unbounded accelerations. The JSSA is implemented on
the FANUC LR Mate 200id/7L robot and validated with HRI tasks. Experiments show
that the JSSA can consistently keep the robot at a safe distance from the human
while executing the designated task.
