基于动态轨迹跟踪目标的非完整机器人运动控制设计

Wheeled robots, multi-finger manipulators and space robots with angular momentum conservation are three kinds of classic nonholonomic robots which have characteristics of simple structure and flexible movement. How to design controllers to make nonholonomic robots achieve accurate and complicated motion tasks has significant importance on both theory and applications. However, the current theoretical analysis and controller design of nonholonomic robots have not fully exploited their movement law, but rather depend on a large amount of measurements. Different from the existing researches, this project uses differential geometry theory, to reveal the movement law of nonholonomic robots. Based on the movement law, dynamical trajectory tracking targets can be designed, and nonlinear trajectory tracking control systems is established naturally. Thus, a set of trajectory tracking control methods and algorithms can be proposed to make sure that nonholonomic robots achieve a complicated motion task even with the presence of input delay and uncertainties. In particular, for a two wheeled inverted pendulum robot, the controller designs of the steering movement, obstacle avoidance and climbing movement will be investigated. The whole project contains four parts: theoretical analysises by using differential geometry theory, modeling of nonlinear control systems, controller design methods, simulations and experiments. With deeper understanding of the motion law of nonholonomic systems, it is possible to obtain new perspectives and methods and hence design high performance controller for advanced robots.

轮式机器人、多指机械手、角动量守恒的太空机器人等都是典型的非完整机器人，具有结构简单且运动灵活的特点。研究设计控制器使非完整机器人精确高效地实现复杂的运动任务具有重要的科学意义和重大的应用价值。这类问题的现有研究没有充分考虑非完整机器人机构的运动规律，所设计的控制器过于依赖大量信息的测量。和现有研究不同，本项目将利用微分几何理论，揭示非完整机器人机构运动规律。利用该运动规律设计动态轨迹跟踪目标，建立非线性轨迹跟踪控制系统模型，提出一套轨迹跟踪控制器设计方法及算法，使得非完整机器人能克服输入时滞和不确定性因素的影响完成复杂的运动任务。特别地，研究两轮式倒立摆机器人转向、避障和爬坡等运动任务的控制器设计。整个工作围绕微分几何理论分析、非线性控制系统建模、控制器设计方法和算法、仿真实验和实体实验验证等方面系统展开，加深对非完整系统运动规律的认识，为先进机器人设计高性能控制器提供新的视角与手段。

非完整轮式移动机器人具有能耗低和运动灵活等优点，目前被广泛应用于医疗服务、工业生产和航空航天等领域。与现有非完整轮式移动机器人的运动控制研究主要侧重于先进控制方法不同，本项目重点在于深入探索各种轮式移动结构在非完整约束下的运动规律，然后充分利用运动规律设计合适的力矩控制器来实现轮式移动机器人的精确运动控制。本项目基于轮式移动结构的运动规律提出了动态跟踪目标方法，该方法的核心思想是将对目标轨迹曲线的跟踪转化对曲线相对曲率的跟踪，能够有效地避免运动过程中速度误差的累计，极大地提高对目标轨迹曲线跟踪的精确性。理论分析和仿真结果表明，即使前向速度或偏航转速误差都很大，采用动态跟踪目标方法仍然能够使得轮式移动机器人精确地沿着目标轨迹曲线运动，且具有很强的鲁棒性。本项目所提的动态跟踪目标方法为非完整机械结构的精确运动控制提供了一种新的思路，有望在机器人和自动驾驶等领域得到广泛的应用。基于项目研究成果发表期刊论文7篇，培养硕士研究生5名（其中毕业1名）.