精密并联机器人系统误差的分析与补偿

为减小机构末端定位误差,提高精密并联机器人运动精度,以6-HTRT并联机构为结构模型,分析了机构的各种制造误差。首先在机构上开发了一种新型虎克铰链,同时采用了预紧装置;然后在控制系统中引入DSP高性能数据处理器;最后,用矢量构造的方法计算机构速度Jacobian矩阵,用数值法计算位置正解,用构造法计算误差Jacobian矩阵,对机构末端误差进行补偿。通过以上措施,可以使系统的精度提高到机构重复运动精度的3倍左右,满足精密并联机器人工作的精度要求。其中,软件误差补偿算法不受并联机构类型的限制,有较大的适用范围。

Error analysis and correction for high-precision parallel robots

Mechanism manufacturing errors in a 6-HTRT parallel robot were analyzed to reduce mechanism end errors and enhance high-precision parallel robot motion accuracy. A Hooke's joint was developed with a pre-strain set in the parallel robot. Digital signal processing was used in the control system. The mechanism end errors were corrected by using the vector construction method to calculate the mechanism velocity Jacobian matrix, using numerical methods to calculate position forward solutions, and using the construction method to calculate error Jacobian matrix. The result shows that the system precision is increased to three times the mechanism repeat motion precision, which meets the high-precision parallel robot precision requirements. The software based error correction method is not confined to only parallel mechanisms but can be for a wide range of mechanisms.