This paper addresses the problem of attitude/altitude control of a quadrotor. The main contribution consists in developing a simple Linear Parameter Varying model which includes the motor dynamics and weight variations. Afterwards, a reference model is introduced and an error model is derived. An integral action is thus naturally included in the loop. The proposed controller takes the form of a static output feedback which is synthesised using the Linear Matrix Inequalities framework. Thanks to a relaxation method the nonlinear terms are removed from the matrix inequalities. The controller in then reconstructed as a combination of the integral of the error, the actual output and the preview reference signal. Simulations are conducted for a scenario showing the ability of the design method to handle different performance objectives.