Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore

Autonomous Cooperative Operation Between Industrial Cooperative Humanoid Robot and An Electric Passive Balancer

Hiroaki Hanaia, Mikio Ozawa, Toshiki Hirogaki and Eiichi Aoyama

Graduate School of Science and Engineering, Doshisha University, 1-3 Tatara-Miyakodani, Kyotanabe city, Kyoto 610-0394, Japan


In this report, we propose a novel method for the autonomous decentralized coordination of an industrial cooperative robot and electric passive balancer in the manufacturing fields. Here, a passive balancer is a device that detects the weight of a suspended object with a built-in force sensor and assists a human in its vertical transport by bearing the weight of the suspended object with a servo motor. To realize cooperative work with humans, the passive balancer is impedance-controlled.
We compared the coordination of an assist device and a human with the coordination of an assist device and a cooperative robot, demonstrating that there was a difference between the cooperation with a human and that with a cooperative robot in terms of vibrations during the operation.
A method for measuring and identifying the characteristics of balancers using inexpensive wireless sensors was discussed. In addition, we compared the assist-coordination of a human with that of a cooperative robot. Consequently, it was observed that the equivalent mass and time constant could be identified by applying thrust to the passive balancer with a step input and measuring the acceleration, and the viscosity of the passive balancer depended on the operating force. It was found that vibrations that do not occur in human-assisted coordination do occur during assistive coordination with a cooperative robot. It also was confirmed that the vibration phenomenon, which did not occur in the case of human cooperation, was observed in the case of cooperation with a cooperative robot.
It is expected that this vibration is caused by the interference between the position control of the robots, including the cooperating robot and impedance control of the passive electric balancer. However, there is no sufficient robot control model to describe this phenomenon. In this study, we attempted to identify a robot control model using wireless force and acceleration sensors. In the experiment, we observed the acceleration of the robot arm's hand tip during a sudden change in force.

Keywords: FA, Cooperative robot, Humanoid robot, Cooperative humanoid robot, Assist motion, Electric passive balancer, Autonomous cooperative operation, Wireless measurement, Bluetooth, Human motion, Impedance control, decentralized control, System model identification, Force vibration.

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