Middlesex were 310-6 in reply to Warwickshire County Cricket Club's first innings score of 362-8 declared.
With the sun out at Lords, Middlesex started their first innings and lost Robson for twelve after he was bowled by Oliver Hannon-Dalby
Nick Gubbins made eight and Dawid Malan twelve as Middlesex crashed to 65-3.
However, Chris Rogers and Neil Dexter moved the score on before Rogers went for 85.
Dexter finally went for 70 and Simpson for for 53 as Middlesex closesd on 310-6 in the 96th over.