Energy Consumption Evaluation of 3 DOF Impedance-Controlled Robots Using Sinusoidal and Sigmoid Input Trajectory Functions

This study aims to investigate the impact of different input trajectory functions on the energy consumption of a 3 degree-of-freedom (DOF) robot controlled by an impedance controller. Industrial robot manipulators, such as painting robots, require arm position control; however, situations may arise where obstacles exist between the robot and its environment, necessitating the avoidance of harm to both itself and other entities. Impedance control enables the dynamic relationship between the robot and the environment to be managed. The force exerted by the robot on the environment is dependent on the endpoint position of the robot and the corresponding impedance. The input trajectory function employed in impedance control affects the interaction distance of the impedance force, which, in turn, impacts the interaction force and torques in the joints, thereby influencing the robot's energy consumption. To optimize the impedance controller parameters, the Bees Algorithm was used to minimize positioning errors for three input trajectory functions: step, sinusoidal, and sigmoid. The study compared the energy consumption of each input trajectory function and presented the results in numerical and graphical formats. The study concluded that the input trajectory function has a significant impact on the energy consumption of the robot. The step function was found to be the simplest to implement but caused the highest energy consumption. The study contributes to a better understanding of the impact of input trajectory functions on the energy consumption of robots controlled by impedance controllers. The findings could be beneficial in selecting the most energy-efficient trajectory function for a specific robot manipulation task.