Constant speed maintaining apparatus for vehicle

A constant speed maintaining apparatus for use in a vehicle comprising:

• a vehicle speed detecting means for detecting a present speed V(t) of the vehicle;
• a cruise control means for producing a control valve U(t);
• a target speed setting means for setting a target speed Vd(t);
• and
• an actuator for changing the opening degree of a throttle valve of a vehicle engine based on the control value U(t) to maintain the present speed V(t) substantially equal to said target speed Vd(t);
• said cruise control means comprising:
• a differentiation means for calculating a differentiated present speed V(t);
• a parameter estimation means for calculating an estimated parameter b.sub.est based on said present speed V(t), differentiated present speed V(t), and control value U(t);
• and
• a control value calculation means for calculating said control value based on said target speed Vd(t), present speed V(t), differentiated present speed V(t), and estimated parameters b.sub.est ;
• wherein said parameter estimation means carries out the following calculation to produce said estimated parameter b.sub.est :
• b.sub.est ={V9t.sub.1).multidot.V(t.sup.0)-V(t.sub.0).multidot.V(t.sub.1)}/.DELTA.
• .DELTA.=V(t.sub.1).multidot.U(t.sub.0)-V(t.sub.0).multidot.U(t.sub.1)
• wherein V(t.sub.1), V(t.sub.1) and U(t.sub.1) are the values obtained in the present operation cycle and V(t.sub.0), V(t.sub.0), and U(T.sub.0) are the values obtained in the previous operation cycle.

A constant speed maintaining apparatus for use in a vehicle comprising:

• a vehicle speed detecting means for detecting a present speed V(t) of the vehicle;
• a cruise control means for producing a control value U(t);
• a target speed setting means for setting a target speed Vd(t);
• and
• an actuator for changing the opening degree of a throttle valve of a vehicle engine based on the control value U(t) to maintain the present speed V(t) substantially equal to said target speed Vd(t);
• said cruise control means comprising:
• a differentiation means for calculating a differentiated present speed V(t);
• a parameter estimation means for calculating an estimated parameter b.sub.est based on said present speed V(t), differentiated present speed V(t), and control value U(t);
• and
• a control value calculation means for calculating said control value based on said target speed Vd(t), present speed V(t), differentiated present speed V(t), and estimated parameters B.sub.est ;
• wherein said control value calculation means carries out the following calculation (I) to produce said control value U(t);
• U(t)=U(t-L)+{Vd(t)-V(t-L)+Ae.multidot.E(t)}/b.sub.est (I)
• wherein Ae is a predetermined constant, E(t) is a difference between the present speed V(t) and the target speed Vd(t), and L is a predetermined period of time.