求救关于模型修改的问题

我现在做一个模型修改的问题,想让模型的模态和实验数值相符,想用公差最小来解决,但是
在nastran算的时候老是说我的公式有问题,我是菜鸟,大家帮忙看看哪里有问题,谢谢大家

$ ...STRUCTURAL RESPONSE IDENTIFICATION
$ FREQ_1
DRESP1 1 FREQ1 FREQ 1
$ FREQ_2
DRESP1 2 FREQ2 FREQ 2
$ FREQ_3
DRESP1 3 FREQ3 FREQ 3
DRESP2 4 OBJJ 1
DRESP1 1 2 3
DEQATN 1 OBJJ( FREQ1 ,FREQ2 ,FREQ3 ) = SQRT ( ( FREQ1 - 14 )
** 2 + ( FREQ2 - 16.9 ) ** 2 + ( FREQ3 -28.496 ) ** 2 )
$ ...CONSTRAINTS
$ ...OPTIMIZATION CONTROL
下面是f06里面的错误信息
SER FATAL MESSAGE 224 (PRERMM)
MIXED MODE USAGE BY THE ARITHMETIC OPERATOR - IS INVALID DURING DEQATN
EQUATION PROCESSING.
USAGE IS BETWEEN SINGLE PRECISION REAL AND INTEGER OPERANDS
*** COMPILATION DIAGNOSTIC INFORMATION ***
1. STATEMENT TYPE: DEQATN EQUATION
2. EQUATION ID NUMBER: 1
3. EQUATION:
OBJJ(FREQ1,FREQ2,FREQ3)=SQRT((FREQ1-14)**2+(FREQ2-16.9)**2+(FREQ3-2
8.496)**2)
谢谢各位