利用补偿提高精密定位平台的定位精度

系统误差在较大程度上影响精密定位平台的定位精度，必须采取适当措施进行消除。反相补偿法可以大幅度消除系统误差的影响，是一种易行有效、花费较少的补偿手段。运用反相补偿法原理，从误差曲线中分离出系统误差并与其反相曲线叠加以消除系统误差的影响。给出了对精密定位平台宏动工作台和微动工作台进行补偿的具体实例，补偿后定位精度分别从17.4μm提高到1.3μm和从137.6 nm提高到22.2nm。理论分析和实验结果都表明，反相补偿法对于降低系统误差十分有效，但对于随机误差效果不佳。

Improvement of positioning precision for precise stage with compensation

System errors should be removed to improve the precision of a precise positioning stage because of their influence to affection the precision. As a mean of effective and lowly-costing compensation, the reverse compensation could be mainly used to eliminate the errors. According the principle of the reverse compensation, the error curve of a stage is reversed to match negatively the original one that was measured and drawn before, so that the largest proportion of error, which is just the system error, could be separated and removed. The positioning stage described in this paper has a 2-layer structure, in which the lower is macro-stage and the upper is micro-one. The macro-stage is driven by precision ball lead-screw and positioned by optical grating. And the micro-stage is driven by PZT and uses an inductance as sensor. The positioning precision of the macro-stage is measured as 17.4μm before compensation, which is, obviously, too big to conform to the requirements of micro-stage’s moving. The precision is improved to 1.3μm after using the principle described above, then the macro-stage satisfies the need of precision positioning. As the same, the precision of micro-stage is improved from 137.6nm to 22.2nm, which accomplishes nano-scale positioning successfully. The experiment shows that the reverse compensation is effective to eliminate the system errors, and on the other hand, it also shows that the method is not very good at removing the random errors because it is impossible to find the reverse curve to match.