Damping and Transport Control of a Spherical Pendulum on an Omnidirectional Wheeled Robot During Manual Operation

Recently, several researchers investigated mobile robots. However, when transporting objects in a complex and confined environment, robots that cannot move in any direction and cannot perform a super pivot turn have a limited range of motion. Therefore, omnidirectional mobile robots have been extensively studied. Mobile robots for transporting objects are often used in factories, public facilities, and restaurants. To shorten transportation time and avoid obstacles, mobile robots sometimes rapidly accelerate, decelerate, or traverse steps, which may cause vibrations and damage to transport objects. Transporting a person may give the person a sense of unease or discomfort. Therefore, vibration control is necessary. This study proposes the manual operation of an omnidirectional mobile robot to perform vibration control of a spherical pendulum, which is a tentative transport object. A notch filter and an optimal servo system were used for vibration control of the pendulum. The vibration of the pendulum generated during operation was reduced using a notch filter, and the vibration of the pendulum excited by the disturbances was suppressed by feedback control using the optimal servo system. The control gain of the optimal servo system was reasonably determined using a genetic algorithm based on a quantitative evaluation of the operability and damping performance. The effectiveness of the control system was verified through simulations and experiments.