In this work another perturbation estimation sliding mode based control alg
orithm is introduced for a class of robotic systems in the presence of stru
ctured and unstructured uncertainties and external disturbances. The effect
s of these uncertainties are combined into a single quantity. A full order
device with the actuator voltages as control inputs is assumed in control d
esign. The decentralized control scheme with only a partial state feedback
is applied. A modification of the switching functions with perturbation est
imation is introduced. The salient features of this approach is that the pe
rturbations are effectively treated by a computationally straightforward pr
ocedure. The proposed controller is applied to a minimal configuration dire
ct drive robot mechanism.