Friction compensation for a benchmark system with load friction plus joint flexibility and damping is addressed. This is a problem of controlling a sandwich dynamic system with a non-smooth nonlinearity. Several non-adaptive and adaptive compensation designs are analyzed, based on a state feedback output tracking model reference adaptive control scheme. Sufficient output matching conditions are derived for friction compensation. Approximate linear parametrizations of nonlinear friction are developed for adaptive friction compensator designs. Simulation results verify the desired system performance.