52 results about "Singular configuration" patented technology

The invention provides an ankle joint rehabilitation mechanism with driving branch chains arranged obliquely and relates to the field of rehabilitation medicine instruments. The ankle joint rehabilitation mechanism comprises a base, a movable platform, the driving branch chains and a restraining branch chain. The restraining branch chain comprises a lower rotating connecting rod, a first symmetric connecting rod, a second symmetric connecting rod and an upper arc connecting rod, wherein the lower rotating connecting rod is connected with a central shaft of the base through a bearing. The movable platform comprises a foot baffle, an upper platform body, a lower platform body and a connecting piece located between the two platform bodies, wherein the position, relative to the upper platform body, of the feet can be adjusted through the foot baffle and the connecting piece. The driving branch chains comprise the first driving branch chain, the second driving branch chain and the third driving branch chain, and the three driving branch chains are UPS branch chains arranged obliquely with the same oblique angle. By means of the structure, the movable platform can rotate in three mutually orthogonal directions, and meanwhile it can be ensured that the rotating center of the movable platform coincides with the rotating center of the ankles. The ankle joint rehabilitation mechanism is simple, stable in driving and low in cost; in addition, the driving branch chains are arranged obliquely to avoid the singular configuration of the mechanism, and good kinematic performance is achieved.

A path programming method for a plane redundancy robot to avoid obstacles and avoid singularities relates to the field of robot motion control, and especially relates to a plane redundancy robot to avoid obstacles and avoid singularities. The invention aims to solve problems that risk of hurting working personnel by existing plane redundancy robots exists in a cooperation process and the speed of joints will exceed a robot allowance scope when the end of the robot moves to a singular position. The method of the invention is carried out according to the following steps: the method of the invention relates to threads which are carried out simultaneously: the first thread relates to several steps of path programming to avoid obstacles; and the second thread relates to various steps of path programming to avoid singularities. The method of the invention ca simultaneously complete the path programming method of obstacle avoidance and singularity avoidance, so that in a cooperation process, collaborator avoidance can be completed, and avoiding of singular configuration of the robot can also be realized to reduce risks of man-machine cooperation and raise the assembling quality. The method of the invention can be applied to the field of robot motion control.

An operation command unit of a robot control device includes a first control mode that, when a near-singular configuration determination unit determines that a robot is not near a singular configuration, outputs an operation command for moving a position and/or a posture of the tip of the robot on the basis of an operation force calculated by a first force calculation unit and a second control mode that, when the near-singular configuration determination unit determines that the robot is near the singular configuration, outputs an operation command for moving the position of an operation axis set by an operation axis setting unit on the basis of an operation force calculated by a second force calculation unit and a moving direction set by the operation axis setting unit.

The invention relates to a redundant drive five degrees of freedom parallel machine tool with a large rotation angle. The redundant drive five degrees of freedom parallel machine tool with the large rotation angle includes a fixed platform, a movable platform for installing a main shaft head and a first driving branch, a second driving branch, a third driving branch and a fourth driving branch forconnecting the fixed platform and the movable platform, the structures of the first driving branch and the second driving branch are similar, and the first driving branch includes a hooke hinge, a servo driving unit, a revolute pair and a compound sphere hinge; the third driving branch includes a hooke hinge, a servo driving unit and a compound sphere hinge, the fourth driving branch includes a revolute pair, a servo driving unit, a hooke hinge and a revolute pair, and the movable platform of a machine tool and the four driving branches are hinged to form a space closed-cycle parallel mechanism; and the three-dimensional translation and the two-dimensional rotation of the space can be achieved by controlling six servo motors to drive the four branches. The redundant drive five degrees offreedom parallel machine tool with the large rotation angle has the advantages that the branch structures are simple and compact, the orientation workspace is large, the flexibility is high, the rigidity is large, and the singular configuration can be prevented, and can be used for high-speed, high-precision and efficiency machining for free-form surface in complex space.

The invention discloses a three-degree-of-freedom plane parallel mechanism with novel redundant drive branched-chains, which belongs to the technical field of machinery manufacturing. The three-degree-of-freedom plane parallel mechanism comprises a quadrangular movable platform, three identical RRR branched-chains, an extendable branched-chain, an annular guide rail and a sliding block, wherein the movement of the three identical RRR branched-chains, the extendable branched-chain and the sliding block are driven and controlled through a servo motor; and the movable platform of the mechanism has three degrees of freedom, namely two translational degrees of freedom in a plane, and a rotational degree of freedom which is vertical to the plane. Due to the redundant drive branched-chains, the parallel mechanism is high in stiffness, and simultaneously, overcomes some singular configurations in an operational process, so that the working space of the mechanism is expanded. The redundant drive branched-chains of the mechanism can simultaneously control the size and orientation of tension and pressure applied to the movable platform, and can improve the accuracy of the movable platform in an operational process better through optimizing control.

The invention discloses a parallel serial embarkation mechanism motion planning method based on sea wave active compensation. According to the parallel serial embarkation mechanism motion planning method, the structure of a parallel serial embarkation system is analyzed and decomposed, thus a six-degree-of-freedom parallel platform and a three-degree-of-freedom serial gangway ladder kinematic module are established, motion quantity distribution is conducted on two subsystems through a jacobian matrix pseudo-inverse technique, present mission situation and constrained situation of the subsystems are combined, motion quantity of the system is optimized by using a gradient projection method, and the situation of singularity postures of the system is avoided. According to the parallel serial embarkation mechanism motion planning method, the kinematics multi-solution problem of degree-of-freedom redundancy of a parallel serial mechanism is effectively solved, meanwhile, factors such as joint spacing and the mechanism singularity postures are comprehensively considered, space motion distribution of the parallel serial mechanism is optimized to great extent, input parameters are providedfor control of the parallel serial embarkation system, and demands of operation and maintenance under actual working situation are met.

The invention belongs to the field of judgment of singular configurations of mechanical arms, in particular relates to a quick judging method for a singular configuration of a six-degree-of-freedom mechanical arm. The method comprises the steps of: reading present angle values of six joints from an angle encoder of the six-degree-of-freedom mechanical arm; judging if the angles of the six joints do not exceed respective actual movement ranges; judging the angle of the third joint; judging the angle of the second joint; and judging the angle of the fifth joint. The method applies a plane geometry method to the judgment of the singular configuration of the mechanical arm. The method theoretically has no errors to guarantee the judgment precision of the singular configuration of the six-degree-of-freedom mechanical arm; and the judgment process of the method is simpler compared with the calculation of a singular value of a jacobian matrix so as to guarantee the judgment speed of the singular configuration of the six-degree-of-freedom mechanical arm.

This invention discloses a kind of single ply parallel connection three degree of freedom one-piece compliance accurate positioning platform that has redundancy. This invention includes base and motion platform. The motion platform and the base are connected by four group compliance positioning amplification frames. The four group amplification frames are in 900 rotating symmetry on the four sides of the motion platform. This invention can achieve nanometer positioning accuracy; the positioning platform has good operationality. It can avoid singular position, solve the coupling problem of input and output and increase its working flexibility. This invention can enlarge the motion scope by using secondary grade or more high level compliance amplification frame.

The invention aims at overcoming the defects in the prior art and provides a new parallel connection robot structure. Position and pose conversion of two movement and three rotation of a workbench in a work space is achieved. The parallel connection mechanism should have the beneficial effects of overcoming the strange position and shape of the mechanism and improving the movement and force transmission performance of the mechanism. As shown by the abstract drawing, according to the overall structure of the mechanism, four branch chains are distributed between a fixed platform and a movable platform, two branch chains containing central symmetry rotating rods 2 are completely consistent in structure, two branch chains containing arc sliders are roughly the same, only the arc radiuses of the sliders is different, and when the two branch chains move on the fixed platform, the two arc sliders cannot generate interference. The parallel connection mechanism with the five freedom degrees of two movement and three rotation is simple in structure and easy to produce and machine, and can be applied to the fields of machining platforms of five axis linkage machine tools, position and pose adjustment of some important precise instruments, simulation platforms and the like.

The embodiment of the invention provides a robot singular configuration avoiding admittance control method, device and system. The admittance control method comprises the steps that firstly, performance indexes of a target robot are determined according to the current joint angle of the target robot and at least comprise a translation performance index and a rotation performance index, that is, decoupling of translation movement and rotation movement in a cartesian space is achieved; then a virtual constraint deformation quantity and a rigidity vector are determined based on the translation performance index and the rotation performance index; target virtual constraint force is determined based on the virtual constraint deformation quantity and the rigidity vector; and the target joint angle is determined based on the target virtual constraint force. It is known that the scheme adopts a robot jacobian matrix minimum singular value for evaluating the robot performance indexes, so that whether the robot approaches a singular configuration or not is judged; and since the gradient variance of the performance indexes in the scheme is small, jitter can be avoided at the moment when the virtual constraint force is applied in the human-machine interaction process.

The invention discloses a six-dimension anti-shock vibration isolation system and a manufacturing method thereof. The six-dimension anti-shock vibration isolation system comprises two parallel mechanisms and a damping mechanism, wherein the two parallel mechanisms are composed of supporting bodies, a middle suspension frame, a supporting platform and branch chains, and the damping mechanism is connected in the parallel mechanisms. By means the characteristic that singular configuration rigidity of the parallel mechanisms approximates to zero in a set degree-of-freedom direction, the direction of constraining force of the parallel mechanisms and the direction of damping force of dampers are distributed in six degrees of freedom spatially, the fact that the system has maximum damping in the minimum-rigidity degree-of-freedom direction is achieved, and shock and large impact in any degree-of-freedom direction are isolated.

The invention discloses a symmetrical parallel mechanism without singularities. The symmetrical parallel mechanism without the singularities comprises a movable platform, a fixed platform used as a frame, and four kinematic chains connecting the movable platform and the fixed platform, wherein the four kinematic chains comprise a properly constrained chain connecting the central position of the movable platform and the central position of the fixed platform, and three identical kinematic branched chains; the three kinematic branched chains are symmetrically distributed about the centre of the properly constrained chain; the parallel mechanism has three degrees of freedom and four degrees of freedom respectively through addition or no addition of a revolute pair on the properly constrained chain; and the parallel mechanisms with the two degrees of freedom both have the characteristics of symmetrical structure and no singularities. The symmetrical parallel mechanism without the singularities, which is disclosed by the invention, can be applied to the fields of motion simulators, telescope secondary mirror support mechanisms, mechanical wrists, coordinate measuring machines, micro-operation robots, machine tool spindle heads and the like, and has a wide application prospect.

The invention discloses a method for confirming the motion mode of a corresponding free node at a singular configuration part of a hinge bar system mechanism. The method comprises the following steps of: carrying out second-order derivation on a coordination function which is dependent from a mechanism to describe the corresponding free node variable quantity, to judge whether the second-order derivative is equal to zero or not at the singular configuration place, if the second-order derivative is equal to zero, the corresponding free node at the singular configuration part can move like a limiting mechanism; and if the second-order derivative is not equal to zero, the corresponding free node can move like a first-order infinite small mechanism. According to the method, the motion mode of the corresponding free node at the singular configuration place of the hinge bar system mechanism can be confirmed, the motion mode of the mechanism at the singular configuration place can be basically confirmed, the method is high in operability, the basis is provided for the singularity avoidance and the structure design of the novel space structure, and the research of the mechanism singularity and the motion bifurcation has an important impelling action, so that the method is wide in application prospect.

The invention discloses a method used for determining all singular configurations of a 9-freedom-degree mechanical arm. The 9-freedom-degree mechanical arm is composed of 4 same eccentric joints and an independent joint. The method includes the steps that 6 spinors are selected from 9 spinors forming a jacobian matrix [J]=[$[1], $[2],..,$[k]] of the 9-freedom-degree mechanical arm, and a base sub-matrix is obtained, wherein the base sub-matrix is not a full-rank matrix; a space spinor w is determined and is exchanged with all the joint spinors in the base sub-matrix; by using the condition that the 9-freedom-degree mechanical arm is in the singular configurations, w can also be exchanged with the rest of the 3 joint spinors (please see the formula in the specifications), and all the singular configurations of the 9-freedom-degree mechanical arm are determined in this way.

The invention discloses a large-work-space three-transverse-movement parallel machine tool additionally provided with two redundancy sliding freedom degrees. The large-work-space three-transverse-movement parallel machine tool comprises a machine frame, a longitudinal linear module, a transverse two-linkage linear module, a first branch chain set, a second branch chain set, a third branch chain set, a movable platform and a working table. One ends of the first branch chain set, the second branch chain set and the third branch chain set are connected with a fourth sliding block, a fifth sliding block and a third sliding block respectively, the other ends of the first branch chain set, the second branch chain set and the third branch chain set are connected with the movable platform, and all the branch chain sets are connected with the longitudinal linear module or the transverse two-linkage linear module or the movable platform through spherical hinges at the two ends, and a space parallel closed loop structure is composed; the transverse two-linkage linear module and the longitudinal linear module are installed on the machine frame in an intersected mode; the platform is driven by the three transverse movements of the three branch chain sets, the longitudinal linear modules and the transverse two-linkage linear module to move, and the large processing range of the machine tool is achieved. The three-transverse-movement parallel machine tool is flexible in movement, compact in structure, capable of evading singular positions and large in work space, and is particularly suitable for processing work of large workpieces.

The invention relates to a light-weight multi-freedom degree shoulder complex bionic power-assisted flexible exoskeleton. An upper arm fixing component is connected with a glenohumeral forward/retracting joint, a glenohumeral abduction/adduction joint is connected with a shoulder girdle extension/retraction joint, and a shoulder girdle lifting/dropping joint is connected with a base assembly; theglenohumeral forward/retracting joint, a glenohumeral internal rotation/external rotation joint, the glenohumeral abduction/adduction joint, the shoulder girdle extension/retraction joint and the shoulder girdle lifting/dropping joint are respectively controlled by a lasso driving unit, and each lasso driving unit is respectively mounted on the base assembly; the shoulder complex bionic power-assisted flexible exoskeleton has five freedom degrees of the extension/retraction, the abduction/adduction, and the internal rotation/external rotation of the glenohumeral joint, and the lifting/fallingand the extension/retraction of the shoulder girdle by the driving control of each lasso drive unit. The exoskeleton can effectively avoid the singular configuration and motion interference of the shoulder movement of the human body, improves the range of the shoulder movement, and reproduces the movement function of the human shoulder complex.

The invention discloses a four-degree-of-freedom parallel mechanism added with branched chain seats for rotation. The four-degree-of-freedom parallel mechanism comprises a rack, a rotation mechanism, a first branched chain seat, a second branched chain seat, a third branched chain seat, a first branched chain group, a second branched chain group, a third branched chain group and a movable platform, wherein the rack comprises a base, a first vertical column and a second vertical column; the first vertical column and the second vertical column are fixed to the two ends of the base; the rotation mechanism is installed in the rack, and the first branched chain seat and the third branched chain seat are connected with the rotation mechanism respectively; the second branched chain seat is fixed to the upper end of the base; one end of each of the first branched chain group, the second branched chain group and the third branched chain group is connected with the first branched chain seat, the second branched chain seat and the third branched chain seat respectively, and the other end is connected with the movable platform; and connection between the two ends of each of the first branched chain group, the second branched chain group and the third branched chain group is realized through a spherical hinge, thus a spatial parallel closed-loop structure is formed. The mechanism is large in working space and capable of avoiding singular configurations, improves the movement performance and rigidity, solves the problems of positive solution and certain solution of the mechanism, and simplifies a control system.

The invention discloses a three-degree-of-freedom spherical wrist based on hydraulic direct drive without singular configuration. The three-degree-of-freedom spherical wrist comprises a fixed block, an angle sensor, hydraulic motors, a rotating disc, a rotating ring and a rotating half ring. The fixed block is used for fixing the first-stage hydraulic motor. The rotating disc is rotationally connected to the fixed block through a bearing. The rotating disc and the first-stage hydraulic motor are in gear transmission. The rotating ring and the rotating disc are rotationally connected by the bearing. The second-stage hydraulic motor and the angle sensor are fixed on the inner side of the rotating ring. A shaft of the second-stage hydraulic motor penetrates an inner ring of the bearing and is fixedly connected to the rotating disc. The connection between the rotating half ring and the rotating ring is the same as the connection between the rotating ring and the rotating disc. By the adoption of the three-degree-of-freedom spherical wrist, the hydraulically driven three-degree-of-freedom spherical wrist movement does not have the singular configuration, a high-precision reducer does not need to be used and the three-degree-of-freedom spherical wrist has a series of advantages of the simple and compact structure, high power density, high load/self-weight ratio, strong bearing capacity and the like.

The invention discloses a large-working-space three-translation parallel machine tool for additional redundancy arc sliding. The machine tool comprises a frame, an arc module, a first branch chain set, a second branch chain set, a third branch chain set, a movable platform and a worktable; the lower end of the frame is fixed with a foundation through foundation bolts; the first branch chain set, the second branch chain set and the third branch chain set all consist of three sets of extension rods with the same structures; the arc module is fixed at the middle part of a main stand column of the frame; one ends of the first branch chain set and the third branch chain set are respectively connected with an upper bracket and a lower bracket of the frame, and the other ends are both connected with the movable platform; one end of the second branch chain set is connected with the arc module, and the other end is connected with the movable platform; and all the branch chain sets are connected with the frame, the arc module or the movable platform through spherical hinges at two ends to form a space parallel closed-loop structure. The large-working-space three-translation parallel machine tool, provided by the invention, is compact in structure, flexible in movement, capable of preventing singular configurations, high in rigidity, fast in dynamic response and suitable for machining of large workpieces.