Series mechanical arm forward kinematics modeling method based on improved D-H method

Abstract

The invention discloses a series mechanical arm forward kinematics modeling method based on an improved D-H method. The series mechanical arm forward kinematics modeling method comprises the steps that a series mechanical arm connecting rod coordinate system {i} is established; the D-H parameters of the series mechanical arm are analyzed, and the situation that the D-H parameters cannot completely describe the relative position of the mechanical arm connecting rod coordinate system is found; inserting a virtual D-H coordinate system, wherein the direction of the Z axis of the virtual D-H coordinate system is randomly selected; a D-H method is used for analyzing the connecting rod parameters of the series mechanical arm containing the virtual D-H coordinate system, and the parameters are substituted into a transformation general formula of a mechanical arm connecting rod coordinate system {i} relative to a mechanical arm connecting rod coordinate system {i-1}; a sitting transformation matrix of two adjacent connecting rods of each joint of the series mechanical arm is established, and description of a series mechanical arm tail end connecting rod coordinate system {n} relative to a base coordinate system {0} is established, namely, a series mechanical arm forward kinematics equation is established. According to the method, a virtual D-H coordinate system can be randomly added, the surveying and mapping process is simplified, the calculation process is high in repeatability, and programming operation is facilitated; the method is suitable for forward kinematics modeling of series mechanical arms of any configuration.

Description

Technical field [0001] The present invention relates to a modeling method, in particular, a series of tandem mechanical arms based on the improved D-H method. Background technique [0002] The series robotic arm can be seen as an open motion chain, which is formed by rotating or moving joint by a series of connectors. In order to study the displacement relationship between the operand of the operating arm, a coordinate system can be fixed on each link, and then the relationship between these coordinate systems can be described. DENAVIT and HARTENBERG propose a generic method (ie method) that describes the spatial relationship of adjacent two connectors with a 4 × 4 homogeneous transform matrix, thereby deriving "the" hand claw coordinate system "relative to" reference coordinate system "The equivalent homogeneous transform matrix, establish the forward motion equation of the operating arm. [0003] If the adjacent two link I and the link I-1 are connected by the joint I, each lin...

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Problems solved by technology

[0023] The purpose of the present invention is to solve the problem that the traditional D-H method cannot fully describe the relative positional relationship between the origin of the coordinate system {i-1} and the origin of the coordinate system {i} when modeling the forward kinematics of some relatively complex serial manipulators, and provides A modeling method for forward kinematics of serial manipulators based on the improved D-H method. This method can add a virtual D-H coordinate system arbitrarily according to needs, and simplify the D-H parameter surveying and mapping process. At the same time, the calculation process of this method is highly repeatable and easy to program. The method is suitable for forward kinematics modeling of tandem manipulators with arbitrary configurations

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