Kick it with elasticity: Safety and performance in human–robot soccer

Abstract

The RoboCup community has one definite goal [38]: winning against the human world soccer champion team by the year 2050. This implies real tackles and fouls between humans and robots, rising safety concerns for the robots and even more important for the human players. Nowadays, similar questions are discussed in the field of physical human-robot interaction (pHRI), but mainly in the context of industrial and service robotics applications.The first part of our paper is an attempt for a pHRI view on human-robot soccer. We take scenes from real soccer matches and discuss what could have happened if one of the teams consisted of robots instead of humans. The most important result is that elastic joints are needed to reduce the impact during collisions. The second and third part consider conversely, how the robot can handle the impact of kicking the ball and how it can reach the velocity of human-level soccer. Again joint elasticity is the key point.Overall, the paper analyzes a vision far ahead. However, all our conclusions are based on concrete simulations, experiments, derivations, or findings from sports science, forensics, and pHRI.

A pure signal-based stiffness estimation for VSA devices

“…The VSA-II dynamic model is given by eqs. (4)(5), and its nominal parameters were presented in [2]. In particular, the nominal values for the motor parameters were set there to be B N = 7.…”

“…No matter if the objective of using VSA joints is safety [1], [2], obtaining explosive motions [3], [4], or optimizing some performance criteria [5], [6], for accurate control purposes the current value of the stiffness is always needed. However, there are no sensors available for a direct measure of the stiffness, in particular that can be used on line (i.e., during dynamic robot operation).…”

RoboCup Humanoid League Rule Developments 2002–2014 and Future Perspectives

“…The use of compliance in control and construction of the actuators and links as well as soft materials on the outer shells will be necessary for improved soccer capabilities, such as running, high-speed kicks, robustness to falls, and safe robot-robot and human-robot physical interaction [11]. To test the robustness of robots drop test may be introduced.…”

Reaching desired states time-optimally from equilibrium and vice versa for visco-elastic joint robots with limited elastic deflection

“…First insights for accelerating undamped elastic joints optimally were given in [7], [8], the influence of damping was afterwards analyzed in [9]. While these works considered unconstrained systems, [10] derived the maximum possible velocity for an elastic joint that has limited elastic deflection, i.e.…”