| Electromechanical Braking system (EMB), as a branch of brake-by-wire, is a promising concept to replace the traditional hydraulic braking system. The benefits of EMB include simple structure, compact size, concise cabin layout, potential for better vehicle performance and fuel economy and environment- friendly. Big suppliers, such as Bosch,Siemens,Continental Teves have carried out researches on EMB and obtained many valuable approaches.Actuator is the key component of EMB system to generate braking force. On the basis of the literature study of current R&D approaches, a systematic design method and a unique EMB actuator structure are developed, which adopts DC PM torque motor with planetary gear system inside its rotor. This configuration can greatly reduce the axial dimension thus fulfill the spatial limitation in addition to generate and transmit the motor driving torque efficiently. The EMB actuator prototype for a car front disk brake is developed. The strength checking and braking performance verification are carried out.The operation principle and characteristics of the EMB actuator are studied. Mathematical and simulation models of EMB actuator are built, including torque motor with its friction property, transmission, and load property. The EMB control system utilizes cascaded force, speed and current control loops. Simulation research on motor and actuator performance is conducted under Matlab/Simulink environment. The correctness / rationality of the design of EMB actuator and control structure are verified. The control parameters of three loop controllers are tuned to fulfill the requirement of EMB control system.EMB actuator test bench is designed. Its mechanical components and measurement and control system are developed. Researches on torque motor performance and load property are carried out on the bench. The torque motor working curves and parameters are given. The relation between clamping force and screw displacement is studied.
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