| The emergence of parallel machine tool (PMT) is considered as the most revolutionary development for design of machine tool in 20th century. PMT enjoy following advantages over traditional five-coordinates NC machine tools: high stiffness weight ratio, high feed speed, high environmental suitability, high additional technology value etc. But it also has shortcomings such as small workspace, limited area for backhaul movement, complex of moving control and difficult for precision compensation.Hybrid machine tool (HMT), which combines serial structure with parallel structure, has very vast application vistas in industry. HMT has the advantages of both traditional NC machine tool and PMT.HMT possesses such advantages as: more degree of freedom for control, big workspace, simple structure, good dexterity, high machining precision, high machining speed, position decoupling with orientation, easy NC programming et al, HMT can meet need of numerical control machining for large parts with complex surfaces. It is becoming an important research direction for high speed, high efficiency and flexible machining equipments.A novel 1PS+4TPS type HMT is proposed in this dissertation, invention patents have been applied for it. Theory and method of Mechanism design, kinematical analysis of main feed mechanism, NC automatic programming, direct interpolation algorithm and post-processor algorithm are studied deeply and systematically for this 4-dof HMT in this dissertation.First, the 1PS+4TPS type HMT's distribution project is proposed through mechanism design of hybrid machine, and aiming at special structure of HMT, mathematical model of inverse displacement is set ,for the control relation of virtual and actual mapping is set.Kinematic analysis for main feed mechanism of 1PS+4TPS type HMT is done through establishing kinematic equivalent model, one and two order effect coefficient matrixes for main feed mechanism are derived.Free-surfaces are fitted and sculpted based on NURBS(Non-Uniform Rational... |
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