... Robust stability and stability radius for variational control systems, Abstract Appl.Analysis Vol. 2008, Article ID 381 791 , 1– 29, ISSN 1085-3375454 Robust Control, Theory and Applications 10−310−210−1100−3.5−3−2.5−2−1.5−1pλM(a)10−310−210−11002.533.544.55pμn(b)10−310−210−1100−10 9. 5 9 −8.5−8−7.5pλm(c)10−310−210−1100−4−3.5−3−2.5−2−1.5pμ1(d)Fig. ... r7τ6−r8τ7+ r 9 τ8with,τ=t −t1t2−t1The choice,r1= 12870, r2= 91 520, r3= 288288r4= 524160, r5= 600600, r6= 443520r7= 20 592 0, r8= 5 491 2, r 9 = 6435464 Robust Control, Theory ... robots.These methods range from sliding mode techniques Aguilar et al. ( 199 7), Wang et al. (20 09) ,466 Robust Control, Theory and Applications ...