Fault-tolerant parallel six-component force sensor

Abstract

During some key force measuring tasks in the harsh environment such as aerospace, national defense, deep-sea exploration, higher working reliability is required. The design concept of fault-tolerance is proposed in the design of parallel six-component force sensor. Two kinds of fault-tolerant parallel structure force sensor without pre-stressing platform and two kinds of fault-tolerant and fully pre-stressed parallel structure force sensor using modified spherical pairs, together with another three kinds of wheel-spoke fault-tolerant force sensor are proposed. Compared with traditional Stewart platform-based sensor, the structural characteristics of the sensors are analyzed. The complete mathematic models including the models before and after signal fault are established by using theory of screw and the relations between stiffness and force distribution. The unified mathematic model is suitable for all the fault-tolerant six-component force sensor with different structures proposed in this paper. Calibration study of a sensor prototype without fault and with signal fault is carried out and non-linear errors are analyzed. The research of the paper provides not only theoretical basis and practical significance for the study on high reliable six-component force sensor, but also a new applied orientation for the redundant parallel mechanism.