| 摘要: |
| 目的 针对轴上拖挂轮式移动机器人中的挂车对目标轨迹精确跟踪控制问题,提出了一种能够跟踪挂车理 想运动轨迹曲线相对曲率的双环控制方法。 方法 首先通过梳理轴上拖挂轮式移动机器人受到的非完整约束建立 出运动学模型,并通过欧拉-拉格朗日方程建立其动力学模型;然后利用运动学方程推导出挂车的理想运动轨迹曲 线的相对曲率和拖车与挂车理想偏航角之差之间满足的重要函数关系式;最后基于该核心关系式,利用姿态误差 系统的外环速度控制器和动力学模型的内环比例积分反馈控制器组成的双环控制方法来实现给定的跟踪任务。 结果 仿真结果表明,对于外环系统,外环速度控制器使得姿态跟踪误差在经过一段时间的变化后全都趋近于零, 实际的姿态变量最终稳定地趋近于目标姿态变量;对于内环系统,内环比例积分反馈控制器使得速度跟踪误差经 过短暂的调整后趋近于零,实际速度值最终稳定地趋近于参考的速度值。 结论 设计的双环控制器可以有效地实现 姿态跟踪和速度跟踪,能够使挂车精确地跟踪理想运动轨迹曲线,由于在姿态跟踪过程中引入了挂车运动轨迹曲 线的相对曲率,该方法可以极大地提高轨迹跟踪的精确度 |
| 关键词: 拖挂轮式移动机器人 轨迹跟踪 曲率 双环控制 |
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| Design of Motion Control of Tractor-trailer Wheeled Mobile Robots with On-axle Hitching Based on Curvature Tracking Method |
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MIAO Shengyang,ZHOU Yusheng
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School of Mathematics and Statistics Guizhou University Guiyang 550025 China
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| Abstract: |
| Objective Aiming at the problem of precise tracking control of trailer to target trajectory for a tractor-trailer wheeled mobile robot with an on-axle hitching a double-loop control method was proposed which can track the relative curvature of ideal trajectory curve of the trailer. Methods Firstly the kinematics model of tractor-trailer wheeled mobile robot with an on-axle hitching was established by combing the nonholonomic constraints and its dynamics model was established by Euler-Lagrange equation. Then an important function relation between the relative curvature of the ideal trajectory curve of the trailer and the difference between the ideal yaw angle of the tractor and the trailer was derived by using the kinematic equation. Finally based on the core relation a double-loop control method consisting of the outerloop speed controller of the attitude error system and the inner-loop proportional-integral feedback controller of the dynamic model was used to realize the given tracking task. Results The simulation results showed that for the outer-loop system,the outer-loop speed controller made the attitude tracking error all approach to zero after a period of change and the actual
attitude variable finally approached to the target attitude variable stably. For the inner-loop system the inner-loop
proportional-integral feedback controller made the speed tracking error approach to zero after a short adjustment and the
actual speed value finally approached to the reference speed value stably. Conclusion The designed double-loop
controller can effectively realize attitude tracking and speed tracking and make the trailer accurately track the ideal
trajectory curve. Because the relative curvature of the trailer trajectory curve is introduced in the attitude tracking process
this method can greatly improve the accuracy of trajectory tracking |
| Key words: tractor-trailer wheeled mobile robot trajectory tracking curvature double-loop control |
