Design, modeling, and verification of a test bench for braking simulation of 1/4 vehicle

Brake-by-wire systems are one of the key components in intelligent/unmanned vehicles that have attracted worldwide attention. Testing and evaluation of brake-by-wire systems are a significant step during the development of the technology of vehicular braking and further the advancement of intelligent/unmanned vehicles. Using the test bench to simulate different road adhesion coefficients (i.e. road surfaces) and to complete the testing and evaluation of the vehicle braking systems is of great significance and importance. A test bench for simulation of vehicular braking of 1/4 vehicle is presented and investigated in this article. It is composed of a motor, two rollers, a 1/4 vehicle suspension system, a magnetic powder clutch, a flywheel, sensors, a signal acquisition and processing system, and a controller. The wheel and vehicle speeds are simulated by the rollers and flywheel speeds, respectively. The translational kinetic energy of 1/4 vehicle is simulated by the rotational kinetic energy of the flywheel. The signal acquisition and processing system is used to acquire and process the experimental signals, such as rotational speeds and torques during tests. The magnetic powder clutch with adjusted applied currents in the test bench is used to real-timely simulate roads with different adhesion coefficients. Based on the working principle of the test bench and the fundamentals of vehicle dynamics, the prototype of the test bench is established and the simulation approach of the translational kinetic energy of 1/4 vehicle is investigated. The mathematical model of the real-time simulation about roads with different adhesion coefficients based on the magnetic powder clutch with real-time controllable transmitted torque is established. With the built 1/4 vehicle braking systems based on the test bench and road, and the corresponding established models, the comparison and analysis of the simulation results of various road surfaces are conducted. Experiments are sequentially implemented to verify the feasibility and effectiveness of the test bench.