Dynamic Brake Test Stand 2021-01-1274

Nowadays, inertia dynamometers or roller dynamometers are used for the development and testing of vehicle brakes. However, these testing methods are either entirely unable to simulate dynamical conditions, close to real driving maneuvers, or they can do so approximately only at very high costs. This means that brakes, braking systems and brake-related assistance systems such as the ESC system can ultimately only be tested in a full prototype of the car, or before that on hardware-in-the-loop test stands. In the case of the ESC, these test stands have to simulate the behavior of the brake and the surrounding vehicle in real time, then stimulate the interfaces of the ESC sensors accordingly, and finally evaluate the reaction of the ESC system in different situations. The problem here, however, is that the braking system can only be approximated by simulations. Nevertheless, it would be important to be able to carry out detailed stability tests with real hardware on suitable brake test benches. To close this gap in testing, Kempten University of Applied Sciences in Germany has developed a vehicle-brake-system test stand that, in contrast to inertia brake test stands, is able to generate a realistic wheel-spin-up to simulate an ABS braking maneuver on real brake-system hardware. To achieve the necessary dynamics, a low-cost approach was used, based on two asynchronous motors connected by a controllable clutch, in which one motor simulates the speed of the vehicle, while the other defines the speed of the wheel. The test bench was developed as a demonstrator and is currently being extended for use in series development. This paper describes the basic theory of this dynamic brake test stand.