Method and apparatus for testing motor vehicles under simulated road conditions

摘要

A chassis dynamometer apparatus and method for testing motor vehicles includes at least one roll for engaging the driven wheels of the vehicle. A power supplying and/or absorbing unit such as an electric motor supplies and/or absorbs power from the roll. In addition, a force transducer and speed sensor are coupled to the roll for providing force and speed signals. Signals representative of the desired vehicle inertia, the road load to be simulated, the forces attributable to the parasitic losses and the out-of-loop inertia of the dynamometer and vehicle are also provided. A system controller in response to the above signals controls the power supplying and/or absorbing unit in accordance with: ##EQU1## where: Vd=the desired roll velocity;PPFm=the measured force signal associated with the roll;PPPL=the dynamometer parasitic loss signal;PPRL=the road load signal;PPIo=The out-of-loop inertia of the dynamometer and vehicle;PPAc=the roll acceleration signal;P PIv=the vehicle inertia signal; andPPdt=the interval of integration.