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ABSTRACT: This study discusses robust control problems related to the fall of two-wheel motor vehicles during parking or low-speed driving. The robotic motorcycle includes a new rotary axis that can vary the position of the total center of gravity. Some authors have already reported preliminary control demonstrations using a typical PID controller and simple LQR. Moreover, the mathematical model of a robotic motorcycle derived using multibody dynamics methods and its optimal regulator simulation were developed. However, an experimental investigation of a robust control strategy for practical implementation has not yet been conducted. Therefore, this study proposes a practical method based on applying a sliding mode controller (SMC) to improve robust stability in a real usage environment. Here, we introduce the control system design combining a novel mathematical model, including a minor PID control loop and the SMC, with its hyperplane designed by the frequency-shaped optimal regulator. Finally, its effectiveness is verified by experiments using an actual robotic motorcycle.

This study discusses the verification of the control system for realizing autonomous standing up from the parking mode of a novel motorcycle with a self-stabilizing mechanism, named “MOTOROiD,” and ensuring its stability on low-speed driving. MOTOROiD has a novel rotary axis that can vary the position of the total center of gravity, referred to as the active mass center control system (AMCES). In the previous study, the authors derived a mathematical model using Lagrange’s equation of motion, designed a control system for standing up from the parking mode, and ensured the motorcycle’s stability by using a two-degree-of-freedom control system based on the established model. However, the robustness of the proposed system was not fully verified. The previous study only verified the robustness of the mass variation with a numerical simulation example. Therefore, this study demonstrates the effectiveness of the proposed control system using several numerical simulations with variations in the system parameters. The simulation conditions are set by considering the characteristics of MOTOROiD in realistic situations related to a parked motorcycle. We consider three cases: (i) MOTOROiD is parked on a sloped ground, (ii) the angle of inclination at parking mode is not as assumed, and (iii) MOTOROiD is influenced by Coulomb friction. We set the simulation parameters based on these cases. Consequently, we confirm that MOTOROiD can stand up autonomously under all these conditions, thereby demonstrating the practicality of the proposed control system.

A comprehensive study on the dynamics of dissolved elements (Mg, Al, Si, P, Ca, V, Cr, Mn, Fe, Ni, Zn, As, Sr, Y, W, and U) in Lake Biwa was carried out using a clean technique. Lake water samples ( n = 523) were collected from six stations in the North Basin and three stations in the South Basin. River water samples ( n = 178) were collected from 14 major rivers flowing into the North Basin. Rainwater samples ( n = 89) were collected at Otsu. The river water was enriched with Mn, Al, Fe, P, and Zn and the rainwater was enriched with Zn, Al, Fe, and Mn compared to North Basin water during winter mixing. The residence times of dissolved species were estimated on the basis of input through the rivers and rain. The residence times for Ca, Mg, and Sr were about 8 years, the same as that for water. Mn, Al, Fe, and Zn showed the shortest residence times (0.05?0.19 year). A budget calculation suggested that more than 60% of the input of dissolved Si, P, V, Cr, Mn, Fe, Ni, and Zn was scavenged and retained in the lake sediments and/or discharged as suspended particles. [ABSTRACT FROM AUTHOR]