具有弱耦合无奇异特征的空间移动并联机构及运动学分析

针对并联机构输入/输出强耦合、存在奇异位形,影响实时控制的问题,设计一种弱耦合、无奇异空间移动并联机构,机构由两条CRR拓扑结构支链和一条UPS支链组成.利用螺旋理论分析了支链运动螺旋和约束螺旋,通过修正的Kutzbach-Grübler公式计算了机构自由度.选取支链驱动副,锁住驱动副得到约束螺旋,通过约束螺旋是否满秩...

The Design and Kinematics Analysis of a Spatial Moving Parallel Mechanism with Weak Coupling and Non-singularity

The problem of parallel mechanism’s strong input/output coupling and singular configuration affecting real-time control,parallel mechanism with weak coupling,non-singularity and having three translational degrees of freedom is designed.Parallel mechanism is composed of two CRR-limbs and one UPS-limb.The spiral theory is used to analyse movement and constraint spirals of limb,the modified Kutzbach-Grüblerformula calculating the freedom of this mechanism.Selecting every limb’s driving pair and locking the driving pair to get the constraint screw,the selected input of mechanism is reasonable by whether the rank of constraint screws is full.The relationship between the parameters of input and the parameters of output are analyzed,meanwhile,the positive and negative analytic solutions of the mechanism are obtained by elimination method.The relationship between the velocity and acceleration of the input and output of partial decoupling is obtained by analyzing the expression equation of the position.The velocity Jacobian matrix of the mechanism by the derivative of the equation of position with respect to time is researched to obtain the singular configuration of this mechanism and the results show that there are no singular configurations under normal motion conditions.According to the structure parameters of the mechanism,the working space of the central point of the mechanism is calculated and it is continuous and void free in this region.The trajectory of the center point of the moving platform is planned by using the quintic polynomial,and the variation law of the kinematic input parameters is obtained.The results provide a theoretical basis for dynamic analysis and real-time control of this mechanism.