GlossaryΒΆ
- Actuator
Electronic device able to receive commands.
In ALMemory, actuator values contain the last command sent to the actuator.
For further details, see:
- Blocking Method
Like normal method calls, simple calls are blocking - The next instruction will be executed after the end of the previous call. All calls can raise an exception and should be encapsulated in a try-catch block. Calls can have return values.
Further details: Blocking and non-blocking calls.
- Body
In ALMotion, Body is the group gathering all joints of the robot.
Further details: “Body”, chains and joint names. See also: Whole Body Motion.
- Broker
A broker is an executable and a server that can listen to remote commands on IP and port.
Further details: Broker.
- Chain
In ALMotion, a chain is a group of joints.
Further details: “Body”, chains and joint names.
- COM
- Center Of Mass.
- DOF
Degrees of freedom Degrees of freedom (DOF) are the set of independent displacements and/or rotations that specify completely the displaced or deformed position and orientation of the body or system.
See also: joint.
- Device
Device is the common name for Actuator and Sensor.
For further details, see:
- Effector
Effectors are points allowing to control position by Cartesian methods. There are 6 effectors: “Head” , “LArm”, “LLeg”, “RLeg”, “RArm”, “Torso”.
Further details: Cartesian control.
- FRAME_ROBOT
One of the 3 spatial references used by ALMotion. This is average of the two feet positions projected around a vertical z axis. This space is useful, because the x axis is always forwards, so provides a natural ego-centric reference.
Further details: Frames.
- FRAME_TORSO
One of the 3 spatial references used by ALMotion. This is attached to NAO’s torso reference, so moves with NAO as he walks and changes orientation as he leans. This space is useful when you have very local tasks, that make sense in the orientation of the torso frame.
Further details: Frames.
- FRAME_WORLD
One of the 3 spatial references used by ALMotion. This is a fixed origin that is never altered. It is left behind when NAO walks, and will be different in z rotation after NAO has turned. This space is useful for calculations which require an external, absolute frame of reference.
Further details: Frames.
- Hardness
Hardness (named as stiffness in the Motion module) of the joint. The value is from 0.0 to 1.0, 0 means 0% and 1 means 100% (full power). In the motorboard, this percentage is directly applied to the max current. Setting the hardness to 0.5 means that the electric current limitation is reduced to 50%.
Further details: Stiffness (%). See also: Stiffness.
- Initial Pose
NAO Initial position
Pose Init
StandInit posture Specific stable posture with: kneeAngle = 40.0 deg and torsoAngle = wideAngle = 0.0 deg.
A good starting point for most of the motion animations.
Available in Choregraphe Pose library panel. Can also be reached using ALRobotPosture or using directly ALMotion joint control (see Joint control Tutorial: The Pose Init).
- Joint
Point of articulation, connection that allow motion. In ALMotion, all Degrees Of Freedom except hands are called joints.
Further details: “Body”, chains and joint names. See also: DOF.
- LoLA
- Software, part of NAOqi, in charge of the communication with almost every electronic device in robots (boards, sensors, actuators ...), excepting sound (in or out) and cameras.
- Non-blocking Method
By using the post object of a proxy, a task is created in a parallel thread. This enables you to do other work at the same time (e.g. walking while talking). Each post call generates a task id. You can use this task id to check if a task is running, or wait until the task is finished.
See also: blocking method.
Further details: Blocking and non-blocking calls.
- Pose
Combination of position and orientation of a body in a coordinate system. For example, position and orientation of the robot related to FRAME_WORLD.
Caution: not to be confused with posture.
- Position6D
A Position6D is a vector of 6 dimensions composed of 3 translations (in meters) and 3 rotation (in radians).
See also: Transform.
Further details: libalmath Overview.
- Posture
A configuration of the robot body, generally involving all joints.
Useful postures are available in Choregraphe Pose library panel. or can be reached using ALRobotPosture or using directly ALMotion joint control (see Joint control Tutorial: The Pose Init).
See Also: Predefined postures.
- SE3 Interpolation
SE3 Interpolation is used for all interpolations that are defined in Cartesian Space.
Further details: SE3 Interpolation
- Sensor
Electronic device able to return values.
For further details, see:
- Singularity
A position in the robot’s workspace where one or more joints no longer represent independent controlling variables.
Mathematically, a Jacobian mathematical matrix formulation can be used to relate the motion in joint space to the motion in Cartesian space. The singularity occurs when the inverse Jacobian becomes singular (determinant = 0).
- Spaces
ALMotion uses 3 different spatial references: FRAME_TORSO, FRAME_WORLD and FRAME_ROBOT.
Further details: Frames.
- Stiffness
The stiffness of the joint is equivalent to a torque limitation into the motors. If the joint stiffness is set to 0.0, the joint controller do nothing and the joint is free. Else with a value at 1.0 the joint is allowed to use full torque power to reach a given position.
Further details: Stiffness control. See also: Hardness.
- Support polygon
- For a rigid object in contact with a fixed environment and acted upon by gravity in the vertical direction, its support polygon is a horizontal region over which the center of mass must lie to achieve static stability. For example, for an object resting on a horizontal surface (e.g. a table), the support polygon is the convex hull of its “footprint” on the table.
- Transform
Way to describe a solid in space. It is composed of a rotation matrix and a translation.
See also: Position6D.
Further details: libalmath Overview.
- Whole Body Motion
- Whole Body Motion is a Generalized Inverse Kinematics which deals with Cartesian and joint control, balance, redundancy and task priority.
