Some Motivation: Why We Are Engineers:

Basic Actions of Problem Solving:

• Understanding the problem
  • Simulation can be very useful to help understand what factors are important.
• Generate possible solutions to the problem
  • The solutions that the designer can come up with are very dependent on the designer's experience and knowledge.
• Evaluate solutions
  • Simulation can provide very valuable insights during design evaluation.
• Decide which solution is best.
  • The designer must perform comparisons between problem formulation and design evaluation results.

Inverse Kinematics Using Adams:

• Digital reverse engineering
• Drive 0 DOF mechanisms and measure the forces required to cause motion.

Forward Kinematics Using Adams:

• Design Evaluation
• Replace ideal motions and find the actual performance of the mechanism.

Design Updates to Door:

• Damper mechanism

Model Updates:

• Make a rigid door flexible
• Contact between the wall and the door
• Contact between the door and the doorstopper
• Ideal door opening motion
• Parameterise the door model

Why Add Flexible Parts to Your Models:

• Better loading predictions
  • The flexible component is the focus
  • Question: What is the system doing to my component?
• Improved model fidelity
  • Model performance is the focus
  • Question: What is the flexible component doing to my system?

Forces in Adams:

•  Single Component Force
  • Runtime direction
  • Action only
• Single-Component Torque
  • Runtime direction
  • action only
• Torque vector
• Force Vector
• General Force
  

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  Impact Contact in Adams:

• Ideal rigid body contact:
  • Infinitely stiff
  • No damping
• Impact contact uses a penalty method to approximate ideal rigid body contact.
  • Nonlinear stiffness
  • Linear damping with displacement-based smoothing function

• Use Hertz contact to approximate contact stiffness.
• For damping, ensure that contact bodies penetrate sufficiently to reach the specified Cmax.

Function Builder Overview:

Function builder is used to help the user define mathematical functions in Adams.

There are two function builder modes, and the functions the user has access to depend on the current mode.

• Expression mode: Used for parameterisation and design study functions.

• Run time mode: Used to define functions that are evaluated during a simulation.

• To access the function builder:
  • In runtime mode
    • Right-click and select 'function builder'.
    • Use the '...' button
  • In expression mode
    • Right click -> parameterise -> expression builder

• Getting help with functions:
  • Read the function description at the bottom of the function builder
  • Adams/Solver help -> functions
• Populating function requirements:
  • Type in required values
  • Use the assist feature
  • Insert object data tool

• Important information:
  • Adams is not case sensitive on Windows.
  • To specify powers use '**' (e.g. 2^2 = 2**2 in Adams)
  • Simulation time = time
  • Pi = pi
  • Adams solver assumes radians unless otherwise specified.

• Troubleshooting functions:
  • Use verify to check function syntax
  • Use the plot feature to ensure the function produces the intended results

Design Variables:

• Define independent parameters that can be tied to objects
• Used during DOE's and optimisation studies

Step Function:

• Approximates an ideal mathematical step
• Used to switch quantities on or off
• Syntax:
  • Step(x, x1, y1, x2, y2)
    • x - independent variable
    • x1 - initial value of the independent variable
    • f1 - initial step function value
    • x2 - final value
    • f2 - final step function value
    • Note: x1 < x2

Spline Functions:

• The model may require the use of a catalogue or test data:
  • Empirical data from suppliers:
    • Nonlinear compliances
    • Curves for torque vs. motor speed
  • Measured data:
    • accelerometer data
    • Tyre lateral force is a function of lateral slip

This data can be incorporated using a spline and one of the two interpolation functions:

• Cubic-fitting method: CUBSPL
• Akima-fitting method: AKISPL

• The Akima spline function:
  • Syntax: AKISPL(x, z, spline, iord)
    • x - Independent variable
    • z - Optional second independent variable (set to 0 if not used)
    • Spline – Name of spline containing the required characteristic
    • iord – order of the interpolated point (usually = 0)

Displacement Functions:

Sensors and Simulation Scripts:

Deactivating a joint based on its reaction force by using a sensor and a simulation script.

Design Studies:

Trial and error method:

Design Study:

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