Purpose

The purpose of this paper is to improve control performance and safety of a real two-wheeled inverted pendulum (TWIP) robot by dealing with model uncertainty and motion restriction simultaneously, which can be extended to other TWIP robotic systems.

Design/methodology/approach

The inequality of lumped model uncertainty boundary is derived from original TWIP dynamics. Several motion restriction conditions are derived considering zero dynamics, centripedal force, ground friction condition, posture stability, control torque limitation and so on. Sliding-mode control (SMC) and model predictive control (MPC) are separately adopted to design controllers for longitudinal and rotational motion, while taking model uncertainty into account. The reference value of the moving velocity and acceleration, delivered to the designed controller, should be restricted in a specified range, limited by motion restrictions, to keep safe.

Findings

The cancelation of model uncertainty commonly existing in real system can improve control performance. The motion commands play an important role in maintaining safety and reliability of TWIP, which can be ensured by the proposed motion restriction to avoid potential movement failure, such as slipping, lateral tipping over because of turning and large fluctuation of body.

Originality/value

An inequation of lumped model uncertainty boundary incorporating comprehensive errors and uncertainties of system is derived and elaborately calculated to determine the switching coefficients of SMC. The motion restrictions for TWIP robot moving in 3D are derived and used to impose constraints on reference trajectory to avoid possible instability or failure of movement.

中文翻译：

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存在模型不确定性和运动限制的两轮倒立摆（TWIP）机器人的控制

目的

本文旨在通过同时处理模型不确定性和运动限制来提高实际两轮倒立摆（TWIP）机器人的控制性能和安全性，并将其扩展到其他TWIP机器人系统。

设计/方法/方法

集总模型不确定性边界的不等式源自原始TWIP动力学。考虑到零动力学，向心力，地面摩擦条件，姿势稳定性，控制转矩限制等，得出了几种运动限制条件。在考虑模型不确定性的同时，分别采用滑模控制（SMC）和模型预测控制（MPC）来设计纵向和旋转运动的控制器。为了确保安全，传送到设计的控制器的移动速度和加速度的参考值应限制在指定范围内，并受运动限制的限制。

发现

消除实际系统中普遍存在的模型不确定性可以改善控制性能。运动命令在维护TWIP的安全性和可靠性方面起着重要作用，可以通过提出的运动限制来确保避免潜在的运动失败，如滑倒，由于转向和身体大幅度侧倾而导致的运动，这可以确保TWIP的安全。

创意/价值

推导并综合了系统综合不确定性和系统不确定性的集总模型不确定性边界的不等式，以确定SMC的切换系数。推导了TWIP机器人在3D中运动的运动限制，并将其用于对参考轨迹施加约束，以避免可能的不稳定或运动失败。