79 results about "Kinematic calibration" patented technology

The invention discloses an inclination-angle-constraint-based kinematic calibration method for a Stewart parallel robot. The method comprises the following steps of: firstly, theoretically establishing a novel kinematic constraint, which is an inclination angle constant constraint, namely keeping two inclination angles of a motion platform of the Stewart parallel robot relative to a horizontal plane constant group by group; secondly, using a servo regulating way to physically realize the established kinematic constraint in a high-precision way; thirdly, establishing a calibration model on the basis of a principle of least square according to the kinematic constraint; and finally, identifying a model parameter by solving a nonlinear least square optimizing problem and compensating for the model parameter in a robot control software. By making full use of a characteristic that a repeating precision of a measuring instrument is superior to a position measuring precision of the measuring instrument, the method has the advantages of good calibration effect, simple measurement, high automatism in the calibrating process and the like.

The present invention provides a device for kinematic calibration of a robot, comprising a supporting member fixed to the base of a robot; a constraint link installed between the supporting member and an end-effector of the robot connected to the base of the robot through a plurality of movable links so as to constrain a distance between the base and the end-effector of the robot; two joints installed at the constraint link; a mean to detect angular rotation for measuring angular rotation of the end-effector when the end-effector of the robot moves to a predetermine posture; a mean to detect inclination of the constrain link installed at the constraint link about two mutually perpendicular axes for measuring inclination of the constraint link about X and Y axes; a mean to detect variation of the length for measuring variation of length of the constraint link.

The invention discloses a kinematic calibration system and method for an industrial robot. The kinematic calibration system comprises measurement targets placed in a working area, a robot and an end effector arranged on the robot, as well as a computer, wherein the computer is provided with a first receiving module for reading joint angle data of the robot, a second receiving module for reading detection data of three displacement sensors, a first computation module for computing the nominal coordinate positions of the measurement targets according to data of both the first receiving module and the second receiving module, and a second computation module for computing compensation data of the robot according to the difference between the nominal distance of the measurement targets and the actual distance. The kinematic calibration system can not only correct kinematic parameters of the robot to improve the absolute positioning accuracy of operation but also calibrate the relative position relationship between a workpiece and a base of the robot, is very low in cost and simple and convenient to operate, and can be widely applied to middle and small-sized enterprises.

The invention relates to an industrial robot kinematics calibration system. The industrial robot kinematics calibration system comprises a measuring device arranged at the tail end of a robot and further comprises a calibration device and a data processing device which are arranged in the robot work space. According to the device, cost is reduced, carrying and using are convenient, and the devicecan be applied to online rapid calibration of a robot on the work site. A measuring coordinate system is established on the measuring device, and the robot is calibrated; and through a method, calibration of robot body geometric parameter errors, and the conversion relation among a robot coordinate system, the measuring coordinate system and a calibration coordinate system can be achieved at the same time.

A method for measuring the space position and attitude of a target is characterized by use of said present invented large-size ball-rod instrument to measure distances, and includes such steps as measuring the distances from three fixed points on the rigid body moving in space to the three fixed point in a fixed coordinate system to obtian 9 central distances, reading them from the display of said ball-rod instrument or computer, listing 9 non-linear equations, and analyzing them to obtain the space position and attitude of said rigid body. Its advantages are simple method, low cost and high precision.

The invention discloses a method for calibrating the absolute precision of an industrial robot based on a PMPSD. The method is characterized by comprising the following steps: establishing a robot error kinematic model, constructing a space multipoint virtual constraint, and carrying out data sampling by virtue of a PSD (Position Sensitive Detector); correcting a pose of a terminal laser of the robot by virtue of a space vector relation, correcting a joint corner of the robot by virtue of the corrected pose, and replacing a joint corner obtained from a robot demonstrator and a controller; constructing a model constraint target function, and optimizing the model constraint target function by virtue of a minimizing method, so as to obtain parameter errors of the industrial robot; and finally correcting a geometric parameter nominal value by virtue of the parameter errors, so as to finish the kinematic calibration and absolute precision correction of the industrial robot. By virtue of the method for calibrating the absolute precision of the industrial robot based on the PMPSD, the error problems caused by utilizing a PSD feedback control strategy and coordinate conversion are avoided; and the method is applicable to series-connection joint type robots and plant joint type robots.

The invention discloses a kinematic calibration method for a series-parallel robot. The kinematic calibration method comprises the following steps that 1, a series-parallel robot geometric error modelis established based on a rotational amount theory; 2, the pose error of the tail end of the series-parallel robot is obtained based on the spatial position detection information of the laser tracker; 3, a geometric error source is identified on the basis of a Liu estimation method; and 4, error compensation is carried out step by step based on a correction controller output method. The kinematiccalibration method has the advantages of being high in precision and efficiency, convenient for industrial field application, and can be implemented on the basis of the robot tail end full-dimensional or few-dimensional pose error detection information; and according to the kinematic calibration method, an error model capable of meeting the completeness, the minimum and the continuity is established, the physical significance of model variables is definite, the ill-posed problem of the identification matrix is effectively solved, the identification precision of the error source and the stability of the identification result are improved, and therefore the compensation precision is improved.

The invention relates to a method for kinematic calibration of a six-degree-of-freedom robot based on monocular vision. The method comprises the steps that an MDH model of the six-degree-of-freedom robot is built, and instruction displacement of the tail end of the six-degree-of-freedom robot and the coordinate transformation relation (please see the formula in specifications) between a monocular vision sensor installed on the six-degree-of-freedom robot and the tail end of the six-degree-of-freedom robot are obtained according to an initial calibration variable U; according to the initial calibration variable U of the six-degree-of-freedom robot, grading ranging and optimizing are conducted on multiple sets of displacement delta' of the monocular vision sensor installed on the six-degree-of-freedom robot through an absolute value coding checkerboard; actual displacement delta of the tail end of the six-degree-of-freedom robot is obtained, and multiple sets of observed variables Vk are obtained; and the constraint relation is used, the multiple sets of observed variables Vk are combined to optimize the calibration variable U, whether the calibration variable U reaches positioning precision or not is judged, if yes, the kinematic calibration of the six-degree-of-freedom robot is completed, and otherwise, returning is conducted. Compared with the prior art, the method for the kinematic calibration of the six-degree-of-freedom robot based on the monocular vision has the advantages that ranging precision is high, practicability is high, and the cost is saved.

The invention discloses a kinematics calibration method and system for a flexible robot. The method comprises: obtaining the nominal position and posture of a linkage joint segment under zero linkageangle error according to the nominal joint angle of the linkage joint segment; driving the linkage joint segment to reach the nominal rope length of the linkage joint segment by using a parameter decoupling driving structure, obtaining the actual position and posture of the linkage joint segment, finally, obtaining the linkage angle error of the linkage joint segment according to the nominal position and posture of the linkage joint segment and the actual position and posture of the linkage joint segment; and obtaining the linkage angle error of the robot according to the linkage angle errorsof multiple linkage joint segments. The technical problem that the kinematics error parameters of the existing wire drive flexible robot are numerous, strong coupling between the parameters due to theseries-parallel structure, and the parameter calibration precision is low are overcome, and the calibration precision of the robot is improved.

A two-degree-of-freedom rotational parallel mechanism with two continuous rotating axes comprises a fixed platform, a movable platform, and three branch chains which can connect the fixed platform with the movable platform, wherein the first branch chain and the second branch chain are both composed of upper connecting rods and lower connecting rods; the upper connecting rod and the lower connecting rod of the first branch chain are correspondingly connected to the movable platform and the fixed platform through a ball pair and a hook joint; the upper connecting rod and the lower connecting rod of the second branch chain are both connected to the movable platform and the fixed platform through a rotating pair; the upper connecting rods and the lower connecting rods of the two branch chains are connected through moving pairs; two ends of a connecting rod of a third branch chain are correspondingly connected to the movable platform and the fixed platform through the hook joint and the rotating pair; an axis of the rotating pair, connected to the movable platform, of the second branch chain, is overlapped with the axis of the rotating pair, connected to the movable platform through the hook joint, of the third branch chain; the axis of the rotating pair, connected to the fixed platform, of the second branch chain, is parallel to the axis of the rotating pair of the third branch chain. According to the mechanism, the two continuous rotating axes are provided, so that the kinematics calibration and control are easily achieved; in addition, few single-degree-of-freedom moving pairs are provided, so that the rigidity of the whole mechanism is high.

The invention relates to a random attitude measurement method for kinematic calibration of a five-shaft hybrid machine tool. The five-shaft hybrid machine tool includes a machine tool work bench and a parallel main shaft head. The parallel main shaft head has two rotation freedom degrees and a translation freedom degree; and relative motion with two translation freedom degrees can be formed by the parallel main shaft and the machine tool work bench. The measurement method is characterized in that a dial indicator is fixed on a moving platform of the parallel main shaft head of the hybrid machine tool along a normal direction; gauge blocks are fixed on the machine tool work bench. The dial indicator extends a delta 1 range by controlling motion of the five-shaft hybrid machine tool, wherein the corresponding displacement of the dial indicator at directions of the three machine tool translation shafts including an X shaft, a Y shaft, and a Z shaft are delta x, delta y, and delta z; inverse cosine functions of ratios of the delta x, delta y, and delta z to a delta 1 are equal to included angles alpha, beta, and gamma between the normal direction of the moving platform and the X shaft, the Y shaft, and the Z shaft respectively, thereby obtaining a moving platform attitude. According to the measurement method, only the dial indicator and the gauge blocks are needed; and the method has characteristics of simple operation, and high economy and practicability. And a random attitude measurement value with high precision can be obtained.

The invention discloses a multi-freedom-degree parallel mechanism. The multi-freedom-degree parallel mechanism is composed of a motion platform, a fixed platform and three supporting chins connecting the two platforms. The motion platform of the parallel mechanism can achieve motion output of the three supporting chains, the mechanism is simple, machining and manufacturing are easy, a kinematics model is simple, so that kinematics calibration and control become easy. Meanwhile, the number of mechanism joints is small, and the structural rigidity is improved.

The invention discloses an industrial robot step-by-step calibration system and method. The calibration system comprises a tail end measuring device arranged on a robot flange, as well as a movable double-ball device, a fixed three-ball-seat device, a counter, a computer and the like which are matched with a robot. The calibration method comprises first-step calibration: calibrating kinematics parameters of the robot by using a wide-area distance error; and second-step calibration: based on the result of the first-step calibration, calibrating the pose of a robot-based coordinate system by using a position error. Furthermore, the calibration method can also comprise the following steps: firstly, calibrating the measurement error of the tail end measurement device; and then carrying out the first-step calibration and the second-step calibration. The calibration system has the advantages of being portable, low in cost and the like; meanwhile, the calibration method improves the precision and reliability of kinematics calibration, calibration of the robot-based coordinate system is achieved, then the absolute positioning precision of the robot is improved, and the application range of the robot in precision manufacturing is widened.

The invention relates to a 2PRU (Pseudo-Random Upstream) and CRS (Central Reservation System) spatial parallel robot mechanism. The 2PRU and CRS spatial parallel robot mechanism is formed by a motion platform, a fixed platform and three branch chains, wherein the three branch chains are used for connecting the motion platform and the fixed platform, the first branch chain and the second branch chain in the three branch chains are the same in structure and are respectively formed by a universal joint pair, a rotating pair, a moving pair and connecting rods among the universal joint pair, the rotating pair and the moving pair from top to bottom, and the third branch chain in the three branch chains is formed by a ball pair, a rotating pair, a cylinder pair and connecting rods among the ball pair, the rotating pair and the cylinder pair from top to bottom. According to the 2PRU and CRS spatial parallel robot mechanism disclosed by the invention, three movable motion output can be realized, the mechanism is simple, processing and manufacturing are easy, a kinematic model is simple, kinematic calibration and control can be easier, meanwhile, joints of the mechanism are less, and the structure rigidity is increased.

The invention relates to a 2PR and PRS spatial parallel robot mechanism. The 2PR and PRS spatial parallel robot mechanism comprises a moving platform, a fixed platform and three branch chains for connecting the two platforms; the first branch chain and the second branch chain in the three branch chains are the same in structure, and each of the first branch chain and the second branch chain comprises a revolute pair, a sliding pair and a connecting rod therebetween from the top down; the third branch chain in the three branch chains comprises a ball pair, a revolute pair, a sliding pair and connecting rods among the ball pair, the revolute pair and the sliding pair. According to the 2PR and PRS spatial parallel robot mechanism, three mobile movement output can be realized, the mechanism is simple, the processing and the manufacturing are easy, and the kinematic model is simple and can enable kinematic calibration and control to be easy; meanwhile, the mechanism is less in joint, so that the structural rigidity is improved.

The invention discloses a geometric error modeling method and device of a parallel hybrid robot. The method comprises the following steps that according to a perturbation theory and a D-H matrix method, an original geometric error model of the parallel hybrid robot is derived, and a passive error and a structural error in the parallel hybrid configuration is determined; according to the closed-loop constraint of robot joint chains, a structural error endogenous constraint of the parallel hybrid configuration is determined, and the flow of solving the mathematical expression of the corresponding constraint relation is determined; and according to the transitive relation of the passive error, the structural error, the processes and the terminal end moving platform pose error, the linear independent and the optimal structural error combination conforming to the error endogenous constraint relation is extracted based on a matrix decomposition and simulation method. According to the method,the geometric error modeling problem of the parallel hybrid robot is solved, and therefore the geometric error model of the parallel hybrid robot is built more accurately and universally, so that a priori geometric error model which is more effective and more convenient can be provided for the field of precision research such as kinematic calibration of the parallel hybrid robot, and the method is simple and easy to implement.

The invention relate to a kinematic calibration method of an industrial robot. An intermediate connecting rod coordinate system is established by combination of DH and MDH rules in the establishment process of a kinematic model of the industrial robot, and a minimum parameter set to be identified is obtained. The measurement process is simple and easy to operate by fixing any measuring equipment and any target point, and taking the pose of the robot relative to the measurement coordinate system and the position of the target point relative to the robot end coordinate system as parameters to beidentified. The kinematic model of the industrial robot and the measurement process model are combined, and the nonlinear identification model of the whole calibration system is obtained. The nonlinear equation solving problem is transformed into a nonlinear optimization problem to be solved. The kinematic calibration method of the industrial robot achieves complete minimum parameter set modeling, the calibration model is simpler, and the real parameters of the robot are directly solved based on the nonlinear optimization idea. The method has the advantages of simple operation, friendly userinterface and strong practicability.

The invention provides an industrial robot kinematic calibration method based on a coordinate measuring instrument. The method comprises a main control module, a power supply module, a display module,a storage module, a bluetooth module and a positioning module. One end of the bluetooth module is connected to the main control module, and the other end of the bluetooth module is wirelessly connected with a bluetooth tag arranged on the body of a worker; the positioning module is connected with the main control module; and the main control module is connected with the display module and the storage module. Through the design of the bluetooth tag, the device is simple in structure, cheap in price, easy to integrate and can be widely used.

The invention relates to kinematic calibration. The present invention relates to a calibration method for numerical controlled machine tools (1), which uses a kinematic model to generate a compensation model for the positioning error occurring with the movement of the linear (X, Y, Z) and rotation axes (B, C, A) of a machine tool (1). The calibration method measures the positions of a calibrationball (6) with a measurement sequence which includes the combined movement of the calibration ball (6) around two rotation axes (C, B or C, A), wherein the measurements around a first rotation axis (C)include at least two rotational position movements around a second axis (B or A).

A mechanical arm kinematics parameter calibration method based on an inertial measurement unit comprises the steps that firstly, the relation expression among the linear speed under a mechanical arm tail end Cartesian coordinates, the speed relation under the joint space and the jacobian matrix is constructed, and derivation is conducted; secondly, normalization processing is conducted on the derived relational expression; thirdly, the linear acceleration under the mechanical arm tail end Cartesian space and the angle, the angle speed and the angle acceleration under the mechanical arm joint space are obtained; fourthly, the recursive least-squares method is utilized for conducting mechanical arm parameter identification, and the mechanical arm kinematics parameter calculated value in eachdirection is obtained; and fifthly, the root-mean-square value is obtained from the obtained three values, the mechanical arm kinematics parameter final estimated value at the time is output, and a curve is drawn. By means of the mechanical arm kinematics parameter calibration method, the mechanical arm kinematics calibration cost is reduced. Along with constant improvement of the inertial measurement unit technology, the measuring precision is higher and higher, the precision of the calibration result is higher and higher, and the mechanical arm kinematics parameter calibration method has wider development prospects.