Nullspace Control of Robotic Arm Task Prioritization Considering Emotional Information

In order to make the human-robot interaction more anthropomorphic, so that the robot expresses interaction actions with emotional information during the interaction, a trajectory optimised control method of the robot arm is proposed to express the emotional factors. They include an emotional kinematics feature mapping part, a multitasking priority setting part, and a zero-space control part. The eight three-dimensional emotional mappings in the Pleasure-Arousal-Dominance (PAD) emotion model are mapped to the three kinematic features of the joints of the robotic arm, and then the emotional information influences the amplitude, jitteriness, and end-effector offset of the interaction action by the zero-space control method in the joint space. The method ensures that the normal interaction task is performed by the zero-space characteristic, while the emotional information is expressed by the motion characteristics, which enables the robot to generate interaction actions with different emotional information. It solves the problem of unclear connection between emotional information and robot arm movement expression identified in previous studies. Taking hand waving as an example, we simulate two kinds of iconic emotions and normal hand waving movements, and show that the generated robot arm movements can better express different emotions and achieve better human-robot interaction.