Development of On line Test Method to Simulate Earthquake Responses by Utilizing Linear Motor Drive

在线计算机测试控制方法在日本和许多国家得到了广泛的应用，并得到了许多研究者的检验、认可和改进。采用该方法进行结构模型地震反应试验成功的关键技术是作动器行程的精确位移控制和位移、载荷的精确测量，而目前广泛应用于在线试验的电伺服控制液压作动器存在结构刚度不足、油压脉动大等缺点。在对多自由度系统进行试验时，由于多个作动器必须根据运动方程的积分计算结果，由计算机发出指令同时控制，因此，这些缺点有时会被夸大，为了克服这些缺点，人们研制了新型的在线试验系统。该系统由数控电机、传动装置和控制系统组成， ...更多信息 滚珠丝杆将电机的旋转动力转化为平移运动，微电脑控制整个测试过程。另一种系统是用直线电机直接驱动代替螺旋式定位系统，具有许多优点。其中，必须强调加载杆可以保持在所需的精确位置的优点。在多自由度系统的情况下，例如，多层测试框架，致动器的位移控制必须被保护免受其他致动器的运动的影响。液压作动器往往不能满足这一要求，本文对几个试验结构采用不同的控制方案，找出最佳的控制方案。在最佳程序下，计算结果表明，得到的响应位移具有很高的精度。螺旋式系统的控制误差可控制在20 μ m以内，直接式系统的控制误差可控制在5 μ m以内。少

The on-line computer test control method, widely utilized in many country as well as in Japan, has been examined, accepted, and improved by many researchers. The key techniques for the success of the earthquake response test of a structural model by this method are the accurate displacement control of the strokes of actuators and the precise measurements of displacements and loads.Hydraulic actuators with electro-servo control widely used in the on-line tests have the constitutional weaknesses, the insufficient rigidity and the pulsation in oil pressure. These deficiencies are sometimes exaggerated in tests on multi-degree of freedom systems where some actuators must be simultaneously controlled according to the commands from the computer based on the interration calcuation results of the equation of motion.To overcome these defects new types of the on-line test system have been developed. One system developed comprises a numerical-controlled electric motor, a trnsmission device with a … More ball screw which converts thw rotational power of the motor into translational movemants, and a micro-computer which controls the whole test procedure. amother system unilized a linear-motor firect drice instead of the screw-type positioning system.Many advantages of using these systems can be counted up. Among them, the advantage that the loading rod can be held at the exact positions required must be emphasized. Im the case of a culti-degree of freedom system, for example, a multi-story test frame, the displacement control of an actuator must be protected from the movements of other actuators. The hydtaulic actuators often fail in fulfilling this requirements.Several test structures were rested by using verious control system to find out the best control program. Under the most suitable program, the results show very high preciseness in the obtained response displacement. The control error could be surpressed within 20 microns for the screw-type system, and 5 microns for the direct dfive system. Less