in the design of the antiskid braking system (ABS) of an aircraft, the braking moment is one of the most important parameters, because it influences not only the deceleration and the taxiing distance of an aircraft, b...in the design of the antiskid braking system (ABS) of an aircraft, the braking moment is one of the most important parameters, because it influences not only the deceleration and the taxiing distance of an aircraft, but also the strength and the fatigue life of the landing gear. Furthermore, the determination of braking moment will be concerned in the reasonableness of the demands proposed for the material design of a brake. For this reason, through setting up the mechanical model of a wheel and tyre under taxiing and braking, dynamic simulations on the optimal closed-loop control of braking moment are carried out by means of the nonlinear control theory. The simulation results show that the difference between the real output of the ABS and the expected one can tend to the minimum under the optimal control. And also, this optimal control can guarantee the braking moment to change smoothly.展开更多
A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake sys- tem was constructed, limit conditions were defined, and the law of temperature rise of brake shoes duri...A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake sys- tem was constructed, limit conditions were defined, and the law of temperature rise of brake shoes during emergent brake course was analyzed and calculated by using finite element software. By analyzing the calculation results, the law of tempera- ture change of surface of brake disk and shoes during the braking process was found. The law of brake shoes surface tempera- ture distribution and the law of temperature change along with thickness of brake shoes at brake time 0.5 s, 1.0 s and 1.5 s was analyzed. A hoisting machine emergent braking test was carried out. Finally, the author concluded that velocity rebound in the process of hoisting machine emergent brake is due to decreased friction coefficient caused by the temperature rise of the brake shoes surface.展开更多
为满足煤矿提升机制动响应要求,提出了一种新型矿井提升机机电制动技术,论证了矿井提升机机电制动原理,给出了机电制动器的详细参数和制动性能,开发大负载、高响应机电制动测试平台。实验表明,设计的机电制动器最大正压达到33 k N,满足...为满足煤矿提升机制动响应要求,提出了一种新型矿井提升机机电制动技术,论证了矿井提升机机电制动原理,给出了机电制动器的详细参数和制动性能,开发大负载、高响应机电制动测试平台。实验表明,设计的机电制动器最大正压达到33 k N,满足矿井提升机正压要求;制动误差小于10%,制动间隙消除时间小于0.1 s;电机电流输入与制动正压输出之间存在线性关系,斜率为4.17,截距为0.3;螺杆位移输出与制动压力输出呈三次方关系,零位误差小。通过对矿井提升机电机械制动系统的优化实验研究,可为煤矿提升机机电制动器的开发提供新思路。展开更多
文摘in the design of the antiskid braking system (ABS) of an aircraft, the braking moment is one of the most important parameters, because it influences not only the deceleration and the taxiing distance of an aircraft, but also the strength and the fatigue life of the landing gear. Furthermore, the determination of braking moment will be concerned in the reasonableness of the demands proposed for the material design of a brake. For this reason, through setting up the mechanical model of a wheel and tyre under taxiing and braking, dynamic simulations on the optimal closed-loop control of braking moment are carried out by means of the nonlinear control theory. The simulation results show that the difference between the real output of the ABS and the expected one can tend to the minimum under the optimal control. And also, this optimal control can guarantee the braking moment to change smoothly.
基金Supported by the National Natural Science Foundation of China （50875252）
文摘A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake sys- tem was constructed, limit conditions were defined, and the law of temperature rise of brake shoes during emergent brake course was analyzed and calculated by using finite element software. By analyzing the calculation results, the law of tempera- ture change of surface of brake disk and shoes during the braking process was found. The law of brake shoes surface tempera- ture distribution and the law of temperature change along with thickness of brake shoes at brake time 0.5 s, 1.0 s and 1.5 s was analyzed. A hoisting machine emergent braking test was carried out. Finally, the author concluded that velocity rebound in the process of hoisting machine emergent brake is due to decreased friction coefficient caused by the temperature rise of the brake shoes surface.
文摘为满足煤矿提升机制动响应要求,提出了一种新型矿井提升机机电制动技术,论证了矿井提升机机电制动原理,给出了机电制动器的详细参数和制动性能,开发大负载、高响应机电制动测试平台。实验表明,设计的机电制动器最大正压达到33 k N,满足矿井提升机正压要求;制动误差小于10%,制动间隙消除时间小于0.1 s;电机电流输入与制动正压输出之间存在线性关系,斜率为4.17,截距为0.3;螺杆位移输出与制动压力输出呈三次方关系,零位误差小。通过对矿井提升机电机械制动系统的优化实验研究,可为煤矿提升机机电制动器的开发提供新思路。
