The state-of-the-art and open problems in stablizing platforms for pointing and tracking

Stabilized platforms are required for two needs: (1) isolating vibrating machinery from a precision bus, and (2) quieting and precisely pointing a payload attached to a noisy, coarsely pointed bus. The early technology was based on platforms with simple passive struts, distributed in some geometry between the bus and the payload. Passive isolators have since improved. Also, active struts have augmented and sometimes replaced passive struts. To date, most research in this field has been concentrated on developing struts, so strut technology is becoming relatively mature. However, several struts are needed to support the payload, so the complex interactions between struts is critical, especially when performing pointing and tracking. Pertinent issues include: supporting the payload; making the struts function in unison in as many axes as possible; fault tolerance; control over a large range of bandwidth, stroke and load. Efforts at different sites are continuing relatively independently and, so far, very little attention has been given to developing optimization methods for matching platform design to applications. In this presentation, we will discuss the state-of-the-art platforms developed to deal with specific applications and present an overview of the performance characteristics of these different platforms. Using these models, we formulate various applications, and problems arising from these applications, that are not addressed by the existing technology. These problems deal with the geometry of the platform, control, DOF, and fault tolerance concerns.