Six degrees of freedom
The six degrees of freedom , English six degrees of freedom (6DoF), relating to the freedom of movement of a rigid body in three dimensional space.
A body with freedom of movement in six degrees of freedom can roll its position through translations along the three perpendicular axes forwards / backwards, up / down and left / right, combined with changes in orientation through rotations around the three perpendicular axes, known as rolling (rotation around the Longitudinal axis), nod (rotation around the transverse axis) and yaw (rotation around the vertical axis), change freely.
robotics
Serial and parallel kinematics of machines are usually designed to position an end effector with six degrees of freedom consisting of three translations and three rotations. This enables a direct relationship between the positions of actuators and the configurations of the machine through their direct and inverse kinematics .
Arms of robots are described by their degrees of freedom . This number usually refers to the number of uniaxial swivel joints in the arm, with a higher number providing increased flexibility in positioning a tool. This is a practical method, as opposed to the abstract definition of degrees of freedom, which measures the ability of a system to position itself.
In 2007, the inventor of Segway , Dean Kamen , introduced a prototype of a robotic arm with 14 degrees of freedom for DARPA . Humanoid robots typically have 30 or more degrees of freedom, with each arm having six degrees of freedom, each foot five or six, and the torso and neck a few more degrees of freedom.
technology
The term is important for the analysis and measurement of properties of mechanical systems, especially biomechanical systems , which must take into account all six degrees of freedom. The six degrees of freedom are now measured using magnetic or electromagnetic sensors, which transmit the position and angle data to a processing unit.
An example of motion with six degrees of freedom is the motion of a ship at sea. It can be described as:
Translation:
- Forward and backward movement along the X-axis or longitudinal axis ("rapid").
- Left and right movement along the Y-axis or transverse axis (" Schwojen ").
- Up and down movement along the Z-axis or vertical axis ("diving").
Rotation:
- Tilting from side to side around the X-axis (" rolling" ).
- Tilting back and forth around the Y-axis ( "pitching ").
- Left and right rotation around the Z axis ( "yaw ").
Operating modes
There are three modes of operation of the six degrees of freedom. These types are direct, semi-direct (conditional), and non-direct regardless of the time left to complete the maneuver, the energy left to complete the maneuver, and finally, regardless of whether the movement is Commanded via a biological unit (human) or a robotic unit (computer).
- Direct: A degree of freedom can be controlled directly without meeting special conditions. It can be described as a normal operation. (One aileron on a normal airplane)
- Semi-direct: A degree of freedom can be controlled if special conditions are met. ( Reverse thrust of an aircraft)
- Non-direct: A degree of freedom can only be controlled by interacting with its environment ( Nick movement of a boat in the water).
Combinations of these types also exist on some vehicles. An example of the space shuttle when it is moving in space. The movement can be controlled via all six degrees of freedom. However, if the space shuttle is in the earth's atmosphere on its return, not all six degrees of freedom can be controlled directly for technical reasons.
Game controls
The six degrees of freedom also relate to movement in video games.
First person shooter games usually allow five degrees of freedom: forwards / backwards, left / right, up / down, yaw (left / right rotation) and nod (look up / down). When a game allows control of the incline, it is sometimes described as having a freedom of movement of six degrees of freedom. However, this is not entirely correct as this tilt is only a limited rotation.
The term 6Dof is sometimes used to describe games that allow free movement but do not necessarily meet all the criteria of the six degrees of freedom. Games that allow free movement are e.g. B. Dead Space 2 and to a lesser extent Homeworld .
Examples of games with full control of the six degrees of freedom include: a. Shattered Horizon , Descent , Retrovirus, Miner Wars , Space Engineers , Forsaken, Overload and Vendetta Online .
Devices for tracking movements ( tracking ), such as TrackIR, are used for head tracking six degrees of freedom. This device is often used in flight simulators or simulators of other vehicles to see through the cockpit, which can help locate opponents or prevent accidents in the game.
The Razer Hydra is a PC controller that tracks the position and rotation of two wired nunchuks, allowing the six degrees of freedom on each hand.
The SpaceOrb 360 is a computer input device with six degrees of freedom, which was first produced in 1996 by the SpaceTec IMC company.
Individual evidence
- ^ Richard P. Paul: Robot Manipulators: Mathematics, Programming, and Control. MIT Press, 1981.
- ^ Dean Kamen: Transcript of "Dean Kamen introduces a new arm prosthesis". Retrieved May 7, 2017 .
- ^ John J. Craig: Introduction to Robotics: Mechanics and Control. Addison-Wesley, 1986.
- ↑ Ship movements - water sports dictionary. Retrieved May 7, 2017 .
- ↑ TrackIR. Retrieved May 7, 2017 .
- ↑ Razer Hydra Portal 2 Bundle Gaming Controller - PC Motion Sensor - Razer Germany. (No longer available online.) Archived from the original on January 3, 2017 ; accessed on May 7, 2017 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
