Design and experimental study of electrical and mechanical brake for mine hoist

To meet the requirement of the braking response of the coal mine hoist, a new electromechanical braking technology for mine hoists is proposed, the principle of electromechanical braking of mine hoists is demonstrated, and the detailed parameters and braking performance of electromechanical brakes are given. Index, an electromechanical brake test platform with large load and high response is developed. Experiments show that the maximum positive pressure of the designed electromechanical brake reaches 33 KN, which meets the requirement of positive pressure of mine hoist. The braking error is less than 10 %, and the braking gap elimination time is less than 0.1 s. There is a linear relationship between motor current input and brake positive pressure output, with a slope of 4.17 and an intercept of 0.62. The screw displacement output and the brake pressure output have a cubic relationship, and the zero error is small. Through research, a new idea is provided for the development of electromechanical brakes for coal mine hoist.

Clamping force control based on dynamic model estimation for electromechanical brakes

The electromechanical brake (EMB) is expected to be utilized for future brake systems due to its many advantages. In this paper, keeping commercialization of the EMB in mind, a new EMB clamping force controller is proposed to overcome the limitations of the existing controller, namely, the extra cost for sensor installation and response delay. To design the controller, both mechanical parts and electrical parts in the EMB have to be mathematically analyzed. Also, dynamic models, clamping force, and friction torque are estimated to generate some feed-forward terms of the controller. With an estimation of the contact point where brake pads start to come into contact with a disk wheel, the clamping force is expressed as a polynomial curve versus the motor angle. The estimated clamping force is evaluated in comparison with measured values by a load cell. The proposed controller is based on an adaptive sliding mode control method with an adaptive law reducing errors of the friction torque model. Lastly, the performance of the entire control system is compared with that of the existing controller on a test bench.

Design and optimization of a cam-actuated electrohydraulic brake system

Although different types of brake-by-wire mechanism including electrohydraulic brakes, electromechanical brakes, electronic wedge brakes and distributed electrohydraulic brakes have been developed in the past two decades, there is still an increasing demand for further improvement and also for development of new brake mechanisms in the automotive industry because of the escalating requirements for higher safety and better performance. This paper proposes a novel brake-by-wire system based on the cam actuation mechanism. The proposed cam-actuated electrohydraulic brake system is a combination of an electrical component, a mechanical component and a hydraulic component. The unique feature of the proposed cam-actuated electrohydraulic brake system is that the characteristics of the motor torque amplification can be optimized by careful design of the cam shape. The overall structure of the cam-actuated electrohydraulic brake system is described, and the dynamic model of the system is developed. Optimum design of the cam-actuated electrohydraulic brake system is obtained by multi-objective optimization, and the obtained simulation results are discussed. The compactness and the self-contained characteristics of the design enable the brake system to be installed on each wheel, allowing fully independent control of each wheel for better stability control.