Gurauskis Donatas, Kilikevičius Artūras, Kasparaitis Albinas
Department of Mechanical and Material Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus g. 28, 03224 Vilnius, Lithuania.
Institute of Mechanical Science, Vilnius Gediminas Technical University, J. Basanavičiaus g. 28, 03224 Vilnius, Lithuania.
Sensors (Basel). 2021 Jan 7;21(2):360. doi: 10.3390/s21020360.
Linear displacement measuring systems, like optical encoders, are widely used in various precise positioning applications to form a full closed-loop control system. Thus, the performance of the machine and the quality of its technological process are highly dependent on the accuracy of the linear encoder used. Thermoelastic deformation caused by a various thermal sources and the changing ambient temperature are important factors that introduce errors in an encoder reading. This work presents an experimental realization of the real-time geometric and thermal error compensation of the optical linear encoder. The implemented compensation model is based on the approximation of the tested encoder error by a simple parametric function and calculation of a linear nature error component according to an ambient temperature variation. The calculation of a two-dimensional compensation function and the real-time correction of the investigated linear encoder position readings are realized by using a field programmable gate array (FPGA) computing platform. The results of the performed experimental research verified that the final positioning error could be reduced up to 98%.
线性位移测量系统，如光学编码器，广泛应用于各种精密定位应用中，以形成全闭环控制系统。因此，机器的性能及其工艺过程的质量高度依赖于所使用的线性编码器的精度。由各种热源和不断变化的环境温度引起的热弹性变形是在编码器读数中引入误差的重要因素。这项工作展示了光学线性编码器实时几何和热误差补偿的实验实现。所实现的补偿模型基于通过简单参数函数对测试编码器误差的近似以及根据环境温度变化计算线性性质的误差分量。通过使用现场可编程门阵列（FPGA）计算平台实现二维补偿函数的计算和所研究的线性编码器位置读数的实时校正。所进行的实验研究结果验证了最终定位误差可降低高达98%。
