Do you want to create a mechanism that satisfy the required motion?
There are mainly three types of mechanism creation:
Function Generation
When the rotary motion of the input and output links are correlated.
Path Generation
When a point on the coupler of a mechanism is to be along a prescribed path
Motion Generation
When the mechanism is design to guide a rigid body in a prescribed path
In this post we will see how the 3DEXPERINECE CATIA Apps can be used for function generation.
Problem statement: Design a four-bar mechanism to coordinate three position of the input and the output links as follows:
θ1 = 20° φ1 = 35°
θ2 = 35° φ2 = 45°
θ3 = 50° φ3 = 60°
Solution steps:
- Open assembly design
- Inset a part 3D Part
- Rename the Part as A
- Edit the 3D shape
- Create a binary link
- Hide Part A
- Insert three more 3D Parts and rename them as B, C & D respectively
- Edit 3D Shape of each part and create binary links
- Create four revolute joints to create the four bar mechanism
- Switch to Engineering Rules Capture App
- Create Knowledge Engineering Specification
- Create a parameter of type real and pin it
- Similarly create other nine parameters
- Set parameters according to required three positions of the input and output links
- Create an Action
- Enter the code and link parameters
- Link output A to length of part A
- Similarly link respective output and length of part
- Run the Action or update the Physical Product
Code:
/* Input ph1, ph2, ph3. th1, th2, th3 */ /* Output a, b, c, d */ let ph1, ph2, ph3, th1, th2, th3, p1, p2, p3, a, b, c ,d, t1, t2, t3, a1, a2, a3, del, rad, del1, del2, del3 (Real) th1 = /*Link Parameter A*/ th2 = /*Link Parameter A*/ th3 = /*Link Parameter A*/ ph1 = /*Link Parameter A*/ ph2 = /*Link Parameter A*/ ph3 = /*Link Parameter A*/ rad = 4*atan(1)/180 p1 = cos(ph1*rad) p2 = cos(ph2*rad) p3 = cos(ph3*rad) t1 = cos(th1*rad) t2 = cos(th2*rad) t3 = cos(th3*rad) a1 = cos((th1-ph1)*rad) a2 = cos((th2-ph2)*rad) a3 = cos((th3-ph3)*rad) del = p1*(t2-t3)+t1*(p3-p2)+(p2*t3-p3*t2) del1 = a1*(t2-t3)+t1*(a3-a2)+(a2*t3-a3*t2) del2 = p1*(a2-a3)+a1*(p3-p2)+(p2*a3-p3*a2) del3 = p1*(t2*a3-t3*a2)+t1*(a2*p3-a3*p2)+a1*(p2*t3-p3*t2) a=del/del1 c=-del/del2 b= (a*a+c*c+1-(2*a*c*del3)/del)**0.5 d= 1 /*Link Parameter A*/= a /*Link Parameter B*/= b /*Link Parameter C*/= c /*Link Parameter D*/= d /*Link Physical Product */->Update()
| Downloadable 3DXML | Preview |
💪Powers of Engineering Rules Capture(ERC) ✅ Rule (a set of instructions to control the relationship between parameters) ✅ Check (to ensure that some conditions are fulfilled) ✅ Reaction (o react to the modification of an attribute) ✅ List (create a list of objects or parameters that you can manage) ✅ Visual Basic Action (Creates a Visual Basic action) ✅ Python Script (Creates a python script) ✅ Action (Creates an action, Enterprise Knowledge Language (EKL)) Courses: Explore the Templates and Rules Designer Role Discover Enterprise Knowledge Language Certification: 3DEXPERIENCE Templates & Rules Designer - Associate
Want to Simulate & Analyze your Mechanism
You can do that using combination of Apps like MSD and MSE
💪Powers of Mechanical System Design(MSD) ✅ Contact (⭐ friction, collision, etc.) ✅ Gravity ⭐ ✅ Axial Spring ✅ Bushing 💪Powers of Mechanical System Experience(MSE) ✅ Position Excitation ✅ Velocity Excitation ✅ Force Excitation ✅ Torque Excitation ✅ Sequence of Excitation ✅ Probes (⭐ position, speed, acceleration, joint force, etc.) ✅ Plots ✅ Traces Courses: Practice CATIA Mechanical Systems Design Practice CATIA Mechanical Systems Experience Certification: 3DEXPERIENCE Mechanical Motion Designer - Associate
Download and use more Mechanisms
Edu Mechanism Monday Assembly Design
