Application of the Stewart Platform in the High Speed High Accuracy Domain

目前迫切需要小型、普遍适用、高速、高精度的装配机构，用于微电子和其他类似物体的装配。高速微定位机设计困难，造价昂贵，难以保持良好的工作状态。Stewart平台具有作为六自由度微定位器的应用潜力。它已成功地应用于低速、低精度的应用中。它提供了卓越的机械刚度，是容易和成本有效的制造。在Stewart平台作为高速、高精度制造或装配机的应用方面还没有研究。这个操作领域在质量动力学中发展出重要的非线性惯性项，使控制变得困难。该项目考察了解耦和线性化质量动力学的运动学综合技术。在线性化运动方程的基础上，建立了该机构的状态变量模型。对高速、高精度运动进行仿真控制。该仿真反映了市售组件。研究了多余腿对消除侧隙和提高稳定性的影响。Stewart平台还具有同时作为定位器和主动抵制外部施加的振动载荷的潜力。目前也正在研究这种做法的可行性。

A critical need exists for small, universally applicable, high speed, high accuracy assembly mechanisms for assembly of microelectronics and other similar objects. High speed micropositioners are difficult to design, expensive to build, and difficult to maintain in satisfactory working order. The Stewart platform has potential for application as a six degree of freedom micropositioner. It has been successfully applied in low speed, low accuracy applications. It provides exceptional mechanical stiffness and is easy and cost effective to manufacture. No research has been done in the application of the Stewart platform as a high speed, high accuracy manufacturing or assembly machine. This realm of operation develops significant nonlinear inertial terms in the mass dynamics, which render control difficult. This project examines kinematic synthesis techniques to decouple and linearize the mass dynamics. A state variable model of the mechanism is being developed which is based upon the linearized equations of motion. Control is simulated for high speed, high accuracy motion. The simulation reflects commercially available components. The influence of extra, redundant legs in eliminating backlash and enhancing stability are also studied. The Stewart platform also has potential to simultaneously act as a positioner and actively reject externally applied vibration loads. The feasibility of this is also being developed.