Stewart Platforms

The project is managed with a Simulink Project. Such project is briefly presented here.

The way the Stewart Platform is defined here.

All the geometrical parameters are defined including:

• Definition of the location of the frames
• Location/orientation of the limbs
• Size/inertia of the platforms and the limbs

Other parameters are also defined such as:

• Stiffness and damping of the struts
• Rest position of the Stewart platform

The Stewart Platform is then modeled using Simscape.

The way to model is build and works is explained here.

From the defined geometry of the Stewart platform, we can perform static analysis such as:

• Jacobian Analysis that links the velocity of each limb to the velocity of the mobile platform
• Static Forces Analysis that links the forces applied by each limb to the resulting force/torque applied to the mobile platform

From the strut stiffness, we can also perform a Stiffness Analysis that consists of determining the Stiffness matrix and Compliance matrix of the Stewart platform from the geometry.

All these analysis are described here.

The Dynamics of the Stewart platform can be identified using the Simscape model.

It is possible to:

• Determine the dynamics from the actuators to the various sensors included in the Stewart platform
• Extract State Space models for further analysis / control synthesis
• Extract the Resonant Frequencies, Modal Damping, and associated Mode Shapes

The code that is used for identification is explained here.

The use of different sensors are compared for active damping:

• Inertial Sensor in each strut
• Inertial Sensor fixed to the mobile platform
• Force Sensor in each strut
• Relative Motion Sensor in each strut

The result of the analysis is accessible here.

Some control architecture for motion control of the Stewart platform are applied on the Simscape model and compared in this document.

The cubic configuration is a special class of Stewart platform that has interesting properties.

These properties are studied in this document.

Many text books, PhD thesis and articles related to parallel robots and Stewart platforms are gathered in this document.