New application note added that demonstrates the use of SAM in projects that involve inverse kinematics.

The site is redesigned and prepared for mobile devices of any size. All video links are encapsulated in popups and much content is spread over separate items.

Summary keywords

• planar mechanisms and linkage design
• simulation - animation
• CAD interface, dxf import
• synthesis
• automated constrained optimization
• video export
• documentation
• 5 languages
• support by engineers

SAM (Synthesis and Analysis of Mechanisms) is an interactive PC-software package for the design, analysis (motion and force) and optimization of arbitrary planar mechanisms. Mechanisms can either be generated via the design wizards or they can be assembled from basic components including beams, sliders, gears, belts, springs, dampers and friction elements. Also special elements like curved-slider and rack-and-pinion elements are available. SAM integrates pre-processing, numerical analysis and post processing, such as animation and xy-plots.

Zero learning time and ease of use make SAM the preferred linkage software package for engineers and educational institutes.

The mathematical foundation of the analysis kernel, which is inspired by the well-known finite element approach, offers a large number of features and overcomes many of the problems of traditional mechanism programs. Open loop, closed loop, multiple loop and even complex planetary mechanisms can equally well be analyzed due to the finite element formulation. Even the most complex mechanisms, including planetary gear trains, can be modeled within minutes 

SAM is available in English, German, Spanish, French, Dutch and Chinese.

CAD interface

The DXF import/export facility lets you export your conceptual linkage design to any CAD program to work out the details and it lets you import CAD data to easily set-up the mechanism in SAM and display the animation.

Post-processing

The analysis results can be displayed either in tabular or graphical form. The tabular listing can be viewed on the screen, send to a printer or stored in a readable formatted list file. The x/y plot option allows to plot any variable against time or any other variable. An unlimited number of functions can be combined into one x/y plot with optionally two different scalings to allow proper multiple display of variables with different amplitude ranges. It is possible to output selected data to an external file (ASCII format) for customized post-processing.

SAM can also animate the mechanism motion. As a further aid for the designer the path and velocity hodograph of any number of moving points can be drawn. Also, a complete project documentation (ASCII-format) can be automatically generated.

Keywords

• parametric
• 4-bar mechanisms
• exact linear guiding
• approximate linear guiding
• Watt, Evans
• Robberts
• Chebyshev
• Hoecken

SAM offers a set of design wizards which will help you to synthesize mechanisms for specific tasks, such as:

• Angle function generation (a minimum of 3 pairs of input/output angles are to be satisfied).
• 3-Position/angle synthesis of the coupler plane
• Approximated straight line motion (video)
• Exact straigh line motion (video)

Keywords

• user table
• multiple actuators
• linear actuator

SAM allows the definition of multiple inputs, which can either be defined in terms of absolute displacements or in terms of elemental change of shape to model relative inputs (e.g. elongation of a hydraulic cylinder or relative rotation of a robot elbow). Each of the inputs can be defined independently. Standard parametric functions are available:

• constant velocity
• polynomial
• cyclical motion
• 2nd order velocity profile
• cubic splines

These functions can be combined to form the desired input diagram. Inputs can also be read from an external ASCII file created by any user tool. This feature offers the modeling of cam profiles.

The use of multiple asynchrone motors enables simulation of scara robots and complicated pick and place machines. It is also allowed to animate multiple unconnected mechanisms at one worksheet.

Keywords

• all geometry
• single function
• multi parameter
• constrained optimization
• function or path
• mass, stiffness
• position of mass
• peak, RMS, average

The optimization module of SAM Professional offers constrained single-function multi-parameter optimization. Constraints are a combination of rules defined by the user to refuse specific solutions. The user defined expressions offer an unlimited area to describe these rules. Simple default constraints like x,y positions, masses or gear ratios are available via short user interface interactions.

As an example SAM can optimze the mechanism such that a certain linkage point follows a predefined path as good as possible. Parameters for this process are multiple x,y postions of nodes, choosen by the user. SAM runs the optimization fully automated and at the end presents the best solution.

Another application is to minimize the peak or RMS value of the driving torque by adding a compensating mass and let SAM determine the optimal value of the mass and its position. In stead of minimizeing the torque, the torque curve can be compared with a user defined profile as a reference.

The goal for optimization can be the minimization or maximization of a variety of properties (peak, RMS, average, ...) or the difference between the actual and the target behaviour of a mechanism, such as:

• Trajectory of a node (with of without prescribed timing)
• Any motion or force quantity (as function of time or another quantity)

SAM seeks the optimum by modifying the following properties within user-defined ranges:

• geometry of mechanism
• element properties, such mass, spring constant, transmission ratio and mass position

SAM offers two optimization process modes:

• fully automated, SAM builds the best solution
• manual, the user can observe separate intermediate solutions

SAM uses a combination of a pure Monte-Carlo technique and an evolutionary algorithm, which makes a good deal between performance and perfect convergation. The video section of this website shows clear examples of optimization.

SAM is equipped with a large library of basic elements, including:

• beam, slider
• curved slider
• belt, gear
• rack-and-pinion
• sensor
• spring, damper and friction element (both translational and rotational)
• non-linear spring, gas spring
• motor

These components allow the analysis of a huge variety of linkage mechanisms. The unique mathematical foundation of the program offers a large number of features and overcomes many of the problems of traditional mechanism programs. Open loop, closed loop and even multiple loop mechanisms are treated in the same way and even the most complex mechanisms, including planetary gear trains, can be modeled within minutes.

CAD interface
The DXF import/export facility lets you export your conceptual mechanism design to any CAD program to work out the details and it lets you import CAD data to easily set-up the mechanism in SAM or to perform animation of the final mechanism. Imported CAD parts may be used as illustrative parts of the mechanism.

Available graphic components:

• point
• line
• circle
• rectangle
• centreline
• polyline/polygon
• Beziér curve
• text and text box with call out

The intersection of graphic components is "dynamic", which means it stays up to date when subjected components are modified. Graphic points can be reused for the construction of the mechanism. All graphic items have editable line and fill colors.

Graphic shapes can be attached to moving elements of the mechanism. Also the drawing order of parts can be changed, resulting in realistic presentations.

We have uploaded a new instruction video to our YouTube channel TutorialsSAM that shows the two-position-synthesis of a 4-bar-mechanism based on a graphical construction using centrelines.

2 videos showing (the making of) a differential belt XY drive have been uploaded to YouTube.

• Animation of the motion
• How the modelling is done

Keywords

• positions, angles, length
• derivatives
• force and torque
• power
• bearing forces
• path, hodograph
• user expressions
• export

Once the mechanism has been constructed and the inputs have been defined any of the following kinematic quantities can be calculated (all relative or absolute):

• nodal position, displacement, velocity, acceleration
• angles, angular velocity and acceleration

Furthermore SAM can perform force-analysis, thus enabling the calculation of:

• driving torque (force)
• reaction forces in bearings
• internal forces in elements
• required or transmitted power

User defined results (SAM Professional):

The formula parser combines simulation results in an unlimited number of expressions that can be displayed as curves in the graph. The parser accepts all generic mathematical functions as well as logical and cumulative functions (integration/differentiation). The latter functions are a strong tool for defining constrained optimization.