The rapid popularization of hardware devices

such as intelligent terminals

has made makes it convenient to interact with the computer

thereby enabling people to initially enjoy the advantages of natural human-computer interaction.The increase in successful applications of many handwritten recognition systems has made sketch-based interactive technology with sketch and handwritten recognition a major research area.Teaching through computer aids has become the most commonly used teaching method and can effectively help students understand knowledge in the textbook better.Kinematics is a branch of theoretical mechanics and is the basis of various engineering disciplines.In kinematics courses

teachers usually use a handwritten or force diagram on the blackboard to help students understand the abstract principles or formulas.In the teaching process

students study most of the movements and the results through imagination;thus

they cannot intuitively feel and understand theoretical knowledge.Therefore

the abstract nature of theoretical knowledge and the difficulty in concluding the diagram lead to learning difficulties.At present

many achievements in the use of computer aids in physics courses have been made

but most of these achievements are based on images

videos

and other materials.Thus

teachers can only teach through display

which lacks interaction

and the teaching content and form are inflexible.Modern computer technology should be applied to solve the problems encountered in physics teaching.On the basis of the traditional teaching form

the advantages of modern computer technology should be fully utilized to construct an intuitive and flexible education model

which not only can help teachers explain the abstract physics theory but also can provide students with a flexible and active learning platform.Therefore

we provide a method to recognize the mechanism of the handwritten kinematics diagram and simulate the motion of the mechanism. On the basis of the analysis on the common mechanisms in the teaching of kinematics

this study summarizes 16 common links.On the basis of the analysis on these links

we divide the constituent primitives of the link diagram into seven categories

namely

straight line

broken line

circle

point

arc

rectangle

and triangle.Then

we propose a recognition algorithm for links based on the recognition of the handwritten primitives.In the process of link drawing

each stroke is recognized and the types of strokes are recorded.First

the stroke geometry is extracted and used in stroke recognition to identify the type of stroke.From the analysis on the users' habit of drawing the diagram

we can summarize the link with the composition of and the relationship among the primitives to establish a link library.When the link drawing is finished

we can derive a list of the types of strokes.Then

we compose the list of the types of strokes and the relative positions between strokes to recognize the links through matching with the link library.This study establishes the constraint relationship

which conforms to the users' intention and implements position correction to the link in the organization diagram.Finally

the simulation of the movement process of the mechanism is achieved on the basis of a 2D physics engine. The recognition of 16 types of common links in kinematics teaching was achieved.The recognition accuracy rate of most of the links was 90% or more

among which the recognition accuracy rate of ball

rod

and line reached 100%.Meanwhile

the average accuracy rate of recognition was 93.25%.Moreover

the average accuracy rate of recognition of seven types of primitives commonly used in the links was 94%. This study summarizes 16 types of links used in the teaching of kinematics

analyzes the positional relationship between the links

and determines the position constraint relationship among the links.According to the elements of the links and the relative relationship between the primitives

we design a link library for the kinematic mechanism diagram.In this study

we propose a link recognition method based on primitive recognition

and this method can be used to recognize the links by matching the composition of and the relationship among the primitives.The relative position and connection relationship of the primitives in the link are calculated and matched with the link library.On the basis of the position constraint relationship of the links in the schematic of the mechanism

the attribute parameters of the position constraints in each link are analyzed and the position correction rules between the links are designed.Position correction is achieved for the users' handwritten input.Experimental results show that the method can recognize the handwritten kinematic links and correct the constraint relationship between these links.By correcting the position of the links

we obtain the motion diagram of the mechanism that conforms to the users' intention.In addition

we design the simulation platform of the motion process and simulate the movement process.This method exhibits high recognition rate for any kinematic link inputted by different users in the sample database and supports the user-defined combination of links to form the personalized organization and simulate the movement process.