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Updated On
September 27, 2024

Vibration and Oscillation in Stewart Platform

Stewart Platform:

A Stewart platform is a type of mechanical linkage that uses six actuators arranged in a parallel configuration to provide movement in multiple directions and orientations. In industry, Stewart platforms are used for tasks such as welding, milling, and assembly, due to their ability to provide six degrees of freedom and high precision. Other potential applications for Stewart platforms include aircraft simulators, robot manipulators, and haptic devices for virtual reality.

Importance of Oscillation mode in Stewart Platform:

One of the key real-life applications of using oscillation movement in a Stewart platform is in the field of flight simulation. In a flight simulator, a Stewart platform can be used to create a realistic simulation of the motion of an aircraft. The platform is typically mounted on a base that can move in six degrees of freedom, allowing it to simulate the roll, pitch, and yaw of the aircraft, as well as its vertical and lateral movement. By driving the platform's actuators in real-time, the simulator can recreate the motion of the aircraft in response to the pilot's inputs, providing a highly realistic training experience for pilots. In this application, the oscillation mode of the platform is critical for ensuring that the simulation behaves in a stable and predictable manner.

Head of Boeing 747 on a large stewart platform

Importance of Vibration mode in Stewart Platform:

On the other hand,One of the most famous applications of using vibration mode in Stewart platform is in the field of haptic feedback and Shaking tables. Shaking tables are typically used to show that a product can withstand dynamic loads without compromising important structural or functional integrity under predetermined conditions. It can be utilized to locate mechanical defects and performance problems caused by accumulated stress effects, which can then be addressed before it is put into service. For example, in a driving simulation, the platform could be used to simulate the feeling of driving over different road surfaces, with the vibrations varying to match the road conditions. In this application, the vibration movement of the platform is used to enhance the realism of the simulation and provide a more immersive experience for the user.

Roll, Pitch and Yaw:

Before getting into the details of creating vibration and oscillation modes in Acrome’s Stewart platform, Brief information must be given about Roll, pitch and yaw.

Roll, pitch, and yaw are three rotational degrees of freedom that describe the orientation of a body in space. Roll refers to rotation around the body's longitudinal axis, pitch refers to rotation around its lateral axis, and yaw refers to rotation around its vertical axis. These terms are commonly used in the context of aircraft and spacecraft, where they describe the orientation of the vehicle in relation to the horizon. In a vehicle with wings, for example, roll would refer to the rotation of the wings around the fuselage, pitch would refer to the angle of the nose of the aircraft relative to the horizon, and yaw would refer to the direction in which the nose of the aircraft is pointing. Understanding and controlling roll, pitch, and yaw is critical for safe and stable flight.

Acrome Stewart Platform
Animation of Plane's Roll, pitch, and yaw

Implementation of Vibration and Oscillation in Stewart Platform:

The vibration mode is self-explanatory: The Stewart Platform begins to vibrate continuously for the specific duration and then turns off automatically. The duration can either be between 0 to 15 seconds or 0 to 30 seconds depending on the frequency provided by the user.Vibration mode affects the Roll and Pitch axes primarily. In this mode; a cosine wave for pitch axis and a sinusoidal wave for roll axis are generated. As these waves are perpendicular to each other, a phase difference of 90 degrees occurs and it creates a well-known vibration pattern. Frequency and Amplitude of the waves can be set manually from the interface.In the case of the oscillation mode; roll, pitch and yaw axes can be affected individually or in-couples as well. Equal phase sinusoidal wave motion patterns are created for all of the axes. Again the Period and the range of oscillation for each axis can be set manually from the interface. Moreover, The duration of the oscillatory movement is imputed by the user. Setting the range for any of the axes will prevent that axis from oscillating.

Vibration and Oscillation settings user interface of acrome stewart platform software
Oscillation movement user interface of acrome stewart platform software
Vibration and Oscillation settings user interface of acrome stewart platform software

Movement of X-Y-Z Axes will be added to Oscillation mode in a future update. Stay tuned.

Please contact us and let us help you with your 6-DoF application requirements including vibration, oscillation or other motion topics as well and don't forget to check out our demonstration video for these new features !

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Author

Serhan Argun
R&D Manager

Discover Acrome

Acrome was founded in 2013. Our name stands for ACcessible RObotics MEchatronics. Acrome is a worldwide provider of robotic experience with software & hardware for academia, research and industry.