Package rst.dynamics

In the field of physics, the study of the causes of motion and changes in motion is dynamics. In other words the study of forces and why objects are in motion. Dynamics includes the study of the effect of torques on motion.

Messages

• JointImpedance
• Pressures
• Wrench
• Torques
• Forces
• JointTorques

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Message JointImpedance

class rst.dynamics.JointImpedance

Constraint: len(.stiffness) == len(.damping)

Stiffness and damping values of multiple joints.

Code author: Christian Emmerich <cemmeric@techfak.uni-bielefeld.de>

Todo

what is SI unit of rotatory damping?

stiffness

Type :array of FLOAT32

Unit: TODO

Stiffness values of multiple joints.

(Same joints and same order as damping)

damping

Type :array of FLOAT32

Damping values of multiple joints

(Same joints and same order as stiffness) @unit(newton-meter / rad)

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message JointImpedance {

    /**
     * Stiffness values of multiple joints.
     *
     * (Same joints and same order as @ref .damping)
     */
    // @unit(TODO)
    repeated float stiffness = 1;

    /**
     * Damping values of multiple joints
     *
     * (Same joints and same order as @ref .stiffness)
     */
    // @unit(newton-meter / rad)
    repeated float damping = 2;
}

Message Pressures

class rst.dynamics.Pressures

A sequence of pressure measurements (e.g. in pneumatic systems).

Code author: Arne Nordmann <anordman@techfak.uni-bielefeld.de>

pressures

Type :array of FLOAT64

Unit: pascal

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message Pressures {

    // @unit(pascal)
    repeated double pressures = 1;

}

Message Wrench

class rst.dynamics.Wrench

Interaction force, composed of Cartesian translational forces and Cartesian rotational forces.

Code author: Arne Nordmann <anordman@cor-lab.uni-bielefeld.de>

forces

Type :rst.dynamics.Forces

3-dimensional translatory forces.

torques

Type :rst.dynamics.Torques

3-dimensional rotatory forces (moment).

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message Wrench {

    /**
     * 3-dimensional translatory forces.
     */
    required Forces forces = 1;

    /**
     * 3-dimensional rotatory forces (moment).
     */
    required Torques torques = 2;

}

Message Torques

class rst.dynamics.Torques

Cartesian 3-dimensional rotational force (moment).

To specify torques in joint space, use JointTorques instead.

Code author: Arne Nordmann <anordman@techfak.uni-bielefeld.de>

Todo

can we be more specific about the axes here?

a

Type :FLOAT32

Unit: newton-meter

Torque around the x axis.

b

Type :FLOAT32

Unit: newton-meter

Torque around the y axis.

c

Type :FLOAT32

Unit: newton-meter

Torque around the z axis.

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message Torques {

    /**
     * Torque around the x axis.
     */
    // @unit(newton-meter)
    required float a = 1;

    /**
     * Torque around the y axis.
     */
    // @unit(newton-meter)
    required float b = 2;

    /**
     * Torque around the z axis.
     */
    // @unit(newton-meter)
    required float c = 3;

}

Message Forces

class rst.dynamics.Forces

Cartesian 3-dimensional translatory force.

Code author: Arne Nordmann <anordman@cor-lab.uni-bielefeld.de>

x

Type :FLOAT32

Unit: newton

Translatory force along the x axis.

y

Type :FLOAT32

Unit: newton

Translatory force along the y axis.

z

Type :FLOAT32

Unit: newton

Translatory force along the z axis.

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message Forces {
    /**
     * Translatory force along the x axis.
     */
    // @unit(newton)
    required float x = 1;

    /**
     * Translatory force along the y axis.
     */
    // @unit(newton)
    required float y = 2;

    /**
     * Translatory force along the z axis.
     */
    // @unit(newton)
    required float z = 3;
}

Message JointTorques

class rst.dynamics.JointTorques

A sequence of joint torques of multiple joints.

Code author: Arne Nordmann <anordman@cor-lab.uni-bielefeld.de>

torques

Type :array of FLOAT32

Unit: newton-meter

TODO

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message JointTorques {

    /**
     * TODO
     */
    // @unit(newton-meter)
    repeated float torques = 1 [packed=true];

}