Patent ID: 8457856

Claim:
A method for estimating parameters for a self-energized brake mechanism having a moving part, a brake pad, a brake disc, a caliper, and a wedge profile, the method comprising the acts of: applying a same actuator force to the brake mechanism and simultaneously to a dynamical model of the brake mechanism; calculating deviations based on measured state variables of the brake mechanism and simulated state variables of the dynamical model; and producing the estimated parameters by online minimization, wherein the parameters are a friction coefficient and an air gap of the brake pad and the brake disc, the act of calculating deviations comprises the acts of: calculating relative deviations: ɛ v a = v a mes - v a sim v a max , ⁢ ɛ x a = x a mes - x a sim x a max , and calculating a summed weighted deviation: ε c =( w x a ε x a +w v a ε v a ), the dynamical model is: [ x . a v . a ] = [ f 1 ⁡ ( x ) f 2 ⁡ ( x , d ) ] + [ g 1 g 2 ] ⁢ u where state and input coordinate functions are as follows: f 1 ⁡ ( x ) = v a , ⁢ f 2 ⁡ ( x , d ) = ( k 0 ⁢ v a ⁢ tan ⁢ ⁢ φ w + s 0 ⁡ ( x a ⁢ tan ⁢ ⁢ φ w - δ ) ) ⁢ ( μ ⁢ ⁢ cos ⁢ ⁢ φ w - sin ⁢ ⁢ φ w ) m 1 , ⁢ g 1 = 0 , ⁢ g 2 = 1 m 1 ⁢ cos ⁢ ⁢ φ a the online minimization is provided by a proportional and an integral portion of the sum deviation: μ n+1 =( P μ ε c +I μ ∫ε c dt )+μ, δ n+1 =−( P δ δ c +I δ ∫ε c dt )+δ n , where P and I are minimization parameters, and the estimated parameters are adjusted alternately in time.