7 results about "Screw theory" patented technology

The invention discloses a five-axis robot configuration synthesis method integrating a 2R1T parallel mechanism, and belongs to the technical field of robot manufacturing. A two-rotation and one-translation (2R1T) parallel mechanism is a core function module of a five-axis robot, most of the 2R1T parallel mechanisms are parallel mechanisms formed by connecting a plurality of kinematic pairs (such as an R pair, an S pair, a P pair, a U pair and a C pair) in series to form a kinematic branch chain and connecting a plurality of kinematic branch chains in parallel, the two ends of the kinematic branch chain are connected with a static platform and a movable platform respectively, calculation is carried out based on a PRU type kinematic branch chain, and the two-rotation and one-translation (2R1T) parallel mechanism is formed. A series of 2R1T parallel mechanism topological configurations are obtained through the spiral theory, a 2R1T parallel mechanism motion spiral system is analyzed, the 2R1T parallel mechanism and the single-degree-of-freedom joint module are reasonably configured, and it is ensured that the five-axis robot has the motion performance meeting the working requirement.

The invention discloses a gear multi-axis cooperative compensation machining method and device based on spinor error mapping. The method comprises the following steps: collecting actually measured data, and calculating a dynamic transmission error; establishing a gear contact analysis model and a dynamical model, and obtaining an equivalent tooth profile error including a tooth profile / pitch error through inversion under manufacturing realizable constraints; a machining kinematic chain model consistent with an actual gear grinding machine in structure is established based on the spinor theory, various machine tool errors are represented as spinor / displacement parameter disturbance, a linear mapping relation is established, and an error propagation model is established; calculating a sensitivity matrix, and identifying a key machine tool error source and a corresponding motion axis which have the most obvious influence on the tooth profile error; and the synchronous correction amount of each key shaft is calculated and is executed in real time during machining, so that active compensation is realized. According to the method, active compensation and accurate control over manufacturing errors of the humanoid robot joint speed reducer are achieved, the DTE amplitude of the speed reducer is effectively reduced, the local abrasion risk is reduced, and the positioning accuracy is improved.

The invention discloses a class-k type tensegrity robot shape finding method based on spinor, belongs to the field of statics analysis and rigid-flexible hybrid robots, and aims to solve the problems that a class-k type tensegrity robot shape finding process is complex, node coincidence constraint is difficult to maintain, and numerical calculation stability is difficult to maintain. The method comprises the following steps: initializing structural parameters; constructing a system pseudo-kinetic equation based on the speed spinor and the force spinor; establishing a node coincidence constraint matrix according to the topological relation, and deducing a multi-level constraint equation of positions, speeds and acceleration levels; and the angular velocity and the linear velocity of each rigid rod piece at the current moment are obtained by solving the augmented velocity spinor. And further updating the node coordinates of the rigid rod piece according to the speed spinor to realize iterative form-finding calculation. And when the free space spinor is smaller than a preset threshold value, the structure reaches a balanced configuration, and shape finding is completed.

This invention discloses a method for predicting the motion straightness of an L-shaped worktable on a mortise and tenon broaching machine. The method includes: acquiring the motion pose error of the top surface of the slider, the form and position tolerances of the assembly surface, and the structural dimensions of the worktable; calculating the pose error of the tool holder mounting surface considering the superposition of worktable form and position errors based on the aforementioned motion pose error, assembly surface form and position tolerances, and worktable structural dimensions; and calculating the motion straightness of the tool holder mounting surface of the L-shaped worktable based on the pose error of the tool holder mounting surface considering the superposition of worktable form and position errors. Based on the deformation coordination principle and the small displacement screw theory, and utilizing error propagation modeling techniques, factors such as guide rail straightness and parallelism errors, and worktable form and position errors are mapped into the motion straightness prediction model of the L-shaped worktable on the mortise and tenon broaching machine. This effectively solves the problem of accurately predicting the motion straightness of a worktable supported by multiple non-coplanar guide rails.

The invention discloses a stability control method for continuous reconstruction motion of a metamorphic robot based on nonlinear analysis, which comprises the following steps of: 1, establishing a continuous reconstruction kinematics model of the metamorphic robot by using a spinor theory so as to obtain homogeneous coordinates of centroids of all motion components; 2, establishing a pitch angle-vertical displacement two-degree-of-freedom nonlinear vibration model for continuous reconstruction of the metamorphic robot, and deducing an improved ZMP criterion containing foot wheel nonlinear vertical stiffness; and 4, converting the complex continuous reconstruction nonlinear dynamic model of the metamorphic robot into a simple linear system model for adjusting a centroid mechanism through a sliding block expected displacement deviation solver, and further converting the motion control of each leg joint with continuous reconstruction stability into the displacement control of a sliding block in the centroid mechanism. Therefore, stability control over the metamorphic robot in the continuous reconstruction process is achieved through the LQR controller optimized based on the artificial bee colony algorithm.

The application discloses a dexterous hand fruit and vegetable grabbing control method based on fuzzy variable impedance control. First, a multi-finger cooperative kinematics model is established based on the screw theory to determine the fingertip pose, the grabbing force of each finger and the multi-finger force distribution; an optimization model with the minimum contact force as the target is constructed based on force closure, and the NSGA-II algorithm is used for solving to obtain the minimum grabbing force required for stable and lossless grabbing; an impedance control model is established in the Cartesian space, the grabbing system is equivalent to a mass-spring-damper system, the influence of the impedance parameters on the grabbing performance is analyzed, and the inertia parameter and the damping coefficient are determined as the key adjustment objects; further, fuzzy control is introduced, the grabbing force error and its change rate are taken as the inputs, the inertia and the damping adjustment amount are taken as the outputs, a fuzzy adaptive variable impedance controller is constructed, and dynamic optimization of the impedance parameters and accurate tracking of the grabbing force are realized. The application can be effectively applied to the fast, stable and lossless grabbing of various fruits and vegetables in unstructured agricultural environments.

This invention relates to the field of mechanical design and manufacturing technology, specifically to a method and system for sensitivity analysis of shaft tolerances based on virtual assembly. The method includes: establishing a part deviation model using small displacement screw theory, constructing an assembly pose transfer chain, and establishing a linear mapping equation between part source deviations and assembly errors using the Jacobian matrix; extracting the sensitivity index of each tolerance term by performing partial derivative analysis on the mapping equation, thereby identifying key geometric elements and optimizing tolerance allocation. This invention significantly improves analysis efficiency by replacing large-scale random sampling with analytical differentiation. It can accurately characterize the cumulative effect of spatial nonlinear tolerances such as coaxiality and perpendicularity. While ensuring assembly accuracy, it effectively relaxes non-critical tolerance requirements, reduces manufacturing accuracy requirements and production costs, and achieves a scientific balance between assembly quality and economy.