华南理工大学学报(自然科学版) ›› 2024, Vol. 52 ›› Issue (4): 51-58.doi: 10.12141/j.issn.1000-565X.230368

• 机械工程 • 上一篇    下一篇

基于速度控制的机器人轨迹摩擦补偿控制算法

叶伯生 李思澳 谭帅 李晓昆 金雄程 邵柏岩   

  1. 华中科技大学 机械科学与工程学院,湖北 武汉 430074
  • 收稿日期:2023-05-31 出版日期:2024-04-25 发布日期:2023-11-08
  • 作者简介:叶伯生(1966-),男,博士,副教授,主要从事机器人控制技术、数控技术研究。E-mail:yebosh@hust.edu.cn
  • 基金资助:
    湖北省重点研发计划项目(2021BAA197)

Trajectory Friction Compensation Algorithm for Robots Based on Velocity Control

YE Bosheng LI Siao TAN Shuai LI Xiaokun JIN Xiongcheng SHAO Baiyan   

  1. School of Mechanical Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China
  • Received:2023-05-31 Online:2024-04-25 Published:2023-11-08
  • About author:叶伯生(1966-),男,博士,副教授,主要从事机器人控制技术、数控技术研究。E-mail:yebosh@hust.edu.cn
  • Supported by:
    the Key R&D Program of Hubei Province(2021BAA197)

摘要:

目前机器人已在工业生产制造中得到广泛的应用,但由于机器人系统中关节摩擦等因素的影响,机器人的轨迹跟踪精度难以满足高精度生产的需求。为减少机械结构中非线性摩擦因素和系统中未建模干扰等因素对机器人运行稳定性和加工精度的影响,文中提出了一种速度模式下的摩擦补偿控制算法。首先,基于傅里叶级数和5次多项式混合的方式设计最优激励轨迹,通过最小二乘法完成动力学参数的预辨识,并利用Levenberg-Marquardt法对预辨识结果进行迭代寻优,从而建立更为精确的机器人动力学模型;然后,基于李雅普诺夫方法设计机器人轨迹跟踪控制算法,将最速离散跟踪微分器中采集的关节角度输入所设计的轨迹跟踪控制算法中,得到实时的关节速度补偿值,将补偿值实时输入机器人中实现摩擦补偿控制;最后,以六自由度串联机器人为实验对象,对所设计的摩擦补偿控制算法进行实验验证。结果表明,相对于摩擦补偿前,机器人的末端轨迹跟踪精度提升约35%,从而验证了文中所提算法在机器人摩擦补偿领域的有效性。

关键词: 摩擦补偿, 参数辨识, 轨迹, 跟踪微分器

Abstract:

Currently, robots are extensively utilized in industrial manufacturing. However, due to the influence of joint friction and other factors in the robot system, the robot trajectory tracking accuracy is difficult to meet the requirements of high-precision production. In this study, a friction compensation control algorithm in speed mode was proposed to mitigate the impact of non-linear friction factors in the mechanical structure and unmodelled disturbances on the robot’s operational stability and machining precision. The optimal excitation trajectory was designed by a combination of Fourier series and fifth-order polynomial. Dynamic parameters were then pre-identified by the least squares method and iteratively optimized through the Levenberg-Marquardt method to establish a more precise robot dynamic model. Subsequently, the Lyapunov method was adopted to design the trajectory tracking control algorithm, and the joint angles collected in the steepest discrete tracking differentiator were fed into the control algorithm to calculate the real-time compensation. The compensation value was then applied in the robot, which effectively achieving friction compensation. The proposed algorithm was validated by employing a six-degree-of-freedom serial robot as an experimental subject. The results demonstrate that the trajectory tracking error is reduced by approximately 35%, as comparing with that under the non-compensation conditions, which confirms the efficacy of the algorithm in the realm of robot friction compensation.

Key words: friction compensation, parameter identification, trajectory, tracking differentiator

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