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

在许多国家和日本广泛使用的在线计算机测试控制方法已经被许多研究人员检验、接受和改进。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执行器行程的精确位移控制和位移和载荷的精确测量。在在线试验中广泛使用的电液伺服控制执行器存在结构缺陷、刚性不足和油压脉动。这些不足在多自由度系统的测试中有时会被夸大，其中一些执行器必须根据计算机的命令，根据运动方程的交互计算结果来同时控制。为了克服这些缺陷，人们开发了新型的在线测试系统。所开发的一个系统包括一个数字控制的电机，一个带有…的传输装置更多的滚珠丝杠，将电机的旋转功率转换为平移运动，以及控制整个测试过程的微型计算机。另一种系统用直线电机火炮冲床代替了螺杆式定位系统。使用这些系统的许多优点是不言而喻的。其中，必须强调的优点是加载杆可以固定在所需的准确位置。在文化自由度系统的情况下，例如，多层测试框架，必须保护执行器的位移控制不受其他执行器的移动的影响。液压执行机构往往不能满足这一要求，为了找出最佳的控制方案，对几个试验结构进行了测试。在最合适的程序下，得到的响应位移具有很高的精度。对于螺杆式系统，控制误差可以被抑制在20微米以内，对于直接D5系统，控制误差可以被抑制在5微米以内。较少

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