Motion control method for non-guiding device active telescopic mechanism of hybrid robot

Abstract

The invention discloses a motion control method for a non-guiding device active telescopic mechanism of a hybrid robot. The method comprises the following steps: (1) establishing a robot position inverse solution model, and determining that an active telescopic mechanism with passive rotation exists in the robot; (2) the expected robot tail end pose is substituted into an inverse kinematics algorithm, and the passive rotation angle of the telescopic mechanism under the expected configuration is solved; and (3) the passive rotation angle is added to a position instruction of a control system, the motor output rotation number is compensated, and the mechanism runs to the correct position. Coupling feeding caused by the passive rotation angle of the mechanism can be compensated in real time in a robot motion control system. The active telescopic mechanism compensated by the control system does not need to add a guide device and does not need to independently design a rotating pair rotating around the moving axis, the structural form is simple, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of robots, and in particular to a motion control method for an active telescopic mechanism of a hybrid robot without a guide device. Background Art

[0002] The active telescopic mechanism is an important component of the hybrid robot and is directly related to the performance and manufacturing cost of the entire equipment system. At present, the active telescopic mechanism of the hybrid robot is mostly equipped with a guide device.

[0003] Invention patent CN104985596A discloses a five-degree-of-freedom hybrid robot, whose active telescopic mechanism includes a servo motor, an outer tube, a moving rod, a guide key, a ball screw, and a nut; the servo motor is installed at one end of the outer tube, and a guide key is provided at the other end of the outer tube to cooperate with the keyway on the moving rod; a rotating device that moves around the moving axis is separately provided at the end of the moving rod, and the other end is fixedly connected to the nut; the nut cooperates with the ball screw through a threaded pair; under the drive of the motor and the action of the guide key, the nut and the moving rod only undergo linear feed motion relative to the outer tube; the active telescopic mechanism caused by the change in the position of the entire machine produces a rotation around the moving axis relative to the moving platform, which is realized through the rotating pair at the front end of the moving rod.

[0004] In order to ensure the normal operation of the mechanism, the active telescopic mechanism of invention patent CN104985596A needs to separately design a guide key and a rotating device at the end. This method increases the complexity of the mechanism, increases the requirements for manufacturing and assembly precision, and increases production costs. Summary of the invention

[0005] The purpose of the present invention is to provide a motion control method for an active telescopic mechanism without a guide device which can be used to simplify the design of an active telescopic mechanism of a hybrid robot and reduce the manufacturing cost and has strong practicality.

[0006] The technical solution adopted by the present invention to solve the technical problem is:

[0007] A motion control method for an active telescopic mechanism of a hybrid robot without a guide device, the active telescopic mechanism comprising a servo motor, an outer tube, an inner rod, a nut and a lead screw; one end of the outer tube is fixedly connected to the motor, and the inner wall surface of the other end is in sliding contact with the outer wall surface of the inner rod; the nut is installed on the end surface of the inner rod and connected to the ball screw through a threaded pair, the ball screw is connected to the motor drive shaft, the motor drive shaft drives the ball screw to rotate, and the nut matched with the ball screw realizes axial feeding;

[0008] The motion control method of the active telescopic mechanism without a guide device comprises the following steps:

[0009] (1) Establish an inverse model of the robot's position and clarify that there is an active telescopic mechanism with passive rotation in the robot;

[0010] (2) Substituting the desired robot end position into the inverse kinematics algorithm to solve the passive rotation angle of the telescopic mechanism under the desired position;

[0011] (3) The passive rotation angle is added to the position command of the control system to compensate for the motor output speed so that the mechanism runs to the correct position.

[0012] The ball screw is connected to the motor drive shaft through a reducer or a coupling.

[0013] Further, according to steps (1) to (3) of the motion control method, the specific method is as follows:

[0014] Establish the inverse kinematics model of the hybrid robot:

[0015] θ=IN(X)

[0016] Θ a =(θ a,1 ...θ a,n ) T , Θ c =(θ c,1 ...θ c,m ) T

[0017] X=(x1...x n ) T

[0018] Where, IN represents the inverse model of the hybrid robot; Θ represents all joint variables in the hybrid robot; Θ a represents all active joint variables; θ a,i represents the i-th active joint variable (i=1~n); Θ c represents all passive joint variables in the hybrid robot; θ c,j represents the jth passive single-degree-of-freedom joint variable (j=1~m); X represents the generalized variable of the hybrid robot; x i represents the ith generalized variable.

[0019] Assume that the kth active joint (k≤n) adopts the active telescopic mechanism, and there is a passive rotation angle caused by the change of the mechanism configuration.

[0020] Now given any terminal position of the hybrid robot, that is, any set of generalized variables (x1...x n ) T According to the inverse solution model of the hybrid robot, the target telescopic mechanism length and passive rotation angle can be obtained:

[0021] θ a,k =IN k(x1,x2,...,x n )

[0022]

[0023] In the formula, θ a,k and θ c,k They represent the length of the active telescopic mechanism (the distance between the two hinge points connecting the dynamic and static platforms) and the passive rotation angle at the desired end position; IN k and They respectively represent the mapping relationship from generalized variables to the target telescopic mechanism length and passive rotation angle.

[0024] Input the passive rotation angle information into the control system to compensate the motor input speed of the target telescopic mechanism:

[0025]

[0026] In the formula, It represents the motor output revolutions required for the nut to produce correct feed on the target telescopic mechanism; p is the lead of the screw; g represents the mapping relationship between the desired target telescopic mechanism length, the axial linear feed caused by the passive rotation angle, the nut lead, and the motor output revolutions required for the nut to produce correct feed on the target telescopic mechanism.

[0027] The beneficial effects of the present invention are:

[0028] The present invention can compensate for the coupled feed caused by the passive rotation angle of the mechanism in real time in the robot motion control system; the active telescopic mechanism after compensation by the control system does not need to add a guide device, and does not need to separately design a rotating pair that rotates around the moving axis, the structure is simple, and the manufacturing cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural diagram of the active telescopic mechanism of a hybrid robot using a lead screw transmission mechanism without a guide device;

[0030] Figure 2 It is a flow chart of the compensation principle of a screw drive mechanism without a guide device;

[0031] Figure 3 It is a detailed flow chart of the compensation principle of the screw drive mechanism without a guide device;

[0032] Figure 4 Is adopted Figure 1 Figure 1. A diagram of a hybrid robot with an active telescopic mechanism structure. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0034] A motion control method for an active telescopic mechanism of a hybrid robot without a guide device, wherein the active telescopic mechanism is as follows: Figure 1 As shown, it includes a servo motor 1, an outer tube 2, an inner rod 3, a nut 4, and a ball screw 5. One end of the outer tube 2 is fixedly connected to the servo motor 1, and the inner wall surface of the other end is in sliding contact with the outer wall surface of the inner rod 3. The nut 4 is fixedly connected to the end surface of the inner rod 3 and is connected to the ball screw 5 through a threaded pair. The ball screw is connected to the motor drive shaft and is driven by the servo motor 1 to achieve axial feeding.

[0035] like Figure 2 , Figure 3 As shown, the motion control method of the active telescopic mechanism without a guide device comprises the following steps:

[0036] (1) Establish an inverse model of the robot's position and clarify that there is an active telescopic mechanism with passive rotation in the robot; (2) Substitute the desired robot end position into the inverse kinematics algorithm to solve the passive rotation angle of the telescopic mechanism under the desired position; (3) Add the passive rotation angle to the position command of the control system to compensate for the motor output speed so that the mechanism runs to the correct position.

[0037] According to steps (1) to (3) of the motion control method, the specific method is as follows:

[0038] Establish the inverse kinematics model of the hybrid robot:

[0039] θ=IN(X)

[0040] Θ a =(θ a,1 ...θ a,n ) T , Θ c =(θ c,1 ...θ c,m ) T

[0041] X=(x1...x n ) T

[0042] Where, IN represents the inverse model of the hybrid robot; Θ represents all joint variables in the hybrid robot; Θa represents all active joint variables; θ a,i represents the i-th active joint variable (i=1~n); Θ c represents all passive joint variables in the hybrid robot; θ c,j represents the jth passive single-degree-of-freedom joint variable (j=1~m); X represents the generalized variable of the hybrid robot; x i represents the ith generalized variable.

[0043] Assume that the kth active joint (k≤n) adopts the active telescopic mechanism, and there is a passive rotation angle caused by the change of the mechanism configuration.

[0044] Now given any terminal position of the hybrid robot, that is, any set of generalized variables (x1...x n ) T According to the inverse solution model of the hybrid robot, the target telescopic mechanism length and passive rotation angle can be obtained:

[0045] θ a,k =IN k (x1,x2,...,x n )

[0046]

[0047] In the formula, θ a,k and θ c,k They represent the length of the active telescopic mechanism (the distance between the two hinge points connecting the dynamic and static platforms) and the passive rotation angle at the desired end position; IN k and They respectively represent the mapping relationship from generalized variables to the target telescopic mechanism length and passive rotation angle.

[0048] Input the passive rotation angle information into the control system to compensate the motor input speed of the target telescopic mechanism:

[0049]

[0050] In the formula, It represents the motor output revolutions required for the nut to produce correct feed on the target telescopic mechanism; p is the lead of the screw; g represents the mapping relationship between the desired target telescopic mechanism length, the axial linear feed caused by the passive rotation angle, the nut lead, and the motor output revolutions required for the nut to produce correct feed on the target telescopic mechanism.

[0051] According to the method of the present invention, each active telescopic mechanism of the invention patent CN104985596A can omit the guide key, keyway structure, and the rotation pair structure designed separately at the end of the moving rod. Figure 4 shown.

[0052] The above-mentioned ideal embodiments of the present invention are for inspiration. Through the above-mentioned description, relevant staff can make various changes and modifications without departing from the technical idea of ​​the present invention. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A motion control method for an active telescopic mechanism of a hybrid robot without a guide device, characterized in that: The active telescopic mechanism comprises a servo motor, an outer tube, an inner rod, a nut and a ball screw. One end of the outer tube is fixed to the motor, and the inner wall surface of the other end of the outer tube is in sliding contact with the outer wall surface of the inner rod. The nut is installed on the end surface of the inner rod and connected to the ball screw through a thread pair. The ball screw is connected to the motor drive shaft, and the motor drive shaft drives the ball screw to rotate, and the nut matched with the ball screw realizes axial feeding. The motion control method of the active telescopic mechanism is performed according to the following steps: (1) Establish an inverse model of the robot's position and clarify that there is an active telescopic mechanism with passive rotation in the robot; (2) Substituting the desired robot end position into the inverse kinematics algorithm to solve the passive rotation angle of the telescopic mechanism under the desired position; (3) The passive rotation angle is added to the position command of the control system to compensate for the motor output speed so that the mechanism runs to the correct position.

2. The motion control method of a hybrid robot without a guide device active telescopic mechanism according to claim 1, characterized in that: The ball screw is connected to the motor drive shaft through a reducer or a coupling.

3. The motion control method of a hybrid robot without a guide device active telescopic mechanism according to claim 1, characterized in that: The specific method of step (1) of the motion control method is as follows: (1) Establish the inverse kinematics model of the hybrid robot: θ=IN(X) I a =(θ a,1 ...i a,n ) T ,I c =(θ c,1 ...i c,m ) T X=(x1...x n ) T Where, IN represents the inverse model of the hybrid robot; Θ represents all joint variables in the hybrid robot; X represents the generalized variables of the hybrid robot; Θ a represents all active joint variables; θ a,i represents the i-th active joint variable (i=1~n); Θ c represents all passive joint variables in the hybrid robot; θ c,j represents the jth passive single-degree-of-freedom joint variable (j=1~m); x i represents the ith generalized variable; Assume that the kth active joint, k≤n, adopts the active telescopic mechanism, and there is a passive rotation angle caused by the change of the mechanism configuration.

4. The motion control method of a hybrid robot without a guide device active telescopic mechanism according to claim 1, characterized in that: The specific method of step (2) of the motion control method is as follows: Now, given any terminal position of the hybrid robot, that is, any set of generalized variables (x1...x n ) T ; According to the inverse solution model of the hybrid robot, the target telescopic mechanism length and passive rotation angle can be obtained: θ a,k =IN k (x1,x2,...,x n ) In the formula, θ a,k represents the length of the active telescopic mechanism at the desired end position, that is, the distance between the two hinge points connecting the moving platform and the static platform, θ c,k Indicates the passive rotation angle of the active telescopic mechanism under the desired end position; IN k and They respectively represent the mapping relationship from generalized variables to the target telescopic mechanism length and passive rotation angle.

5. The motion control method of a hybrid robot without a guide device active telescopic mechanism according to claim 1, characterized in that: The specific method of step (3) of the motion control method is as follows: input the passive rotation angle information into the control system to compensate the motor input speed of the target telescopic mechanism: In the formula, It represents the motor output revolutions required for the nut to produce correct feed on the target telescopic mechanism; p is the lead of the screw; g represents the mapping relationship between the desired target telescopic mechanism length, the axial linear feed caused by the passive rotation angle, the nut lead, and the motor output revolutions required for the nut to produce correct feed on the target telescopic mechanism.

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