PlanarRelativeTorque
Actuator torque: +tau on the body at frame a, -tau on the body at frame b (drives a joint).
📝Syntax
Block type: PlanarRelativeTorque
📥Input Arguments
Parameter Description
physical pins 2 undirected physical pin(s); 0 signal input(s).
📤Output Arguments
Parameter Description
signal ports 0 signal output(s) (sensor readings).
📄Description

Actuator torque: +tau on the body at frame a, -tau on the body at frame b (drives a joint).

Module nflow_blocks
Library Planar (acausal)
Type PlanarRelativeTorque
Label PlanarRelativeTorque
Solver Lowered to planarMechanicalIsland. Reference solver dae (differential-algebraic); the fixed-step loop and the native explicit solvers (ode1/ode4/ode45) are also supported (a jointed multibody island requires dae).

Implementation Sources

Manifestmodules/nflow_blocks/libraries/acausal_planar/library.json
{
  "id": "builtin.acausal_planar",
  "title": "Planar (acausal)",
  "version": "1.0.0",
  "format": "nflow-2",
  "metadata": {
    "author": "Allan CORNET",
    "tool": "Nelson nflow"
  },
  "comment": "Planar 2-D multibody blocks (frame connectors); lower to planarMechanicalIsland.",
  "license": "LGPL-3.0",
  "builtin": true,
  "renderModule": false,
  "blocks": [
    {
      "type": "PlanarWorld",
      "label": "PlanarWorld",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "frame",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "gravity": 9.81
      },
      "icon": "PlanarWorld.svg",
      "render": {
        "type": "image",
        "src": "PlanarWorld.svg"
      },
      "help": "Inertial world with uniform gravity (down = -y); provides a fixed frame at the origin."
    },
    {
      "type": "PlanarFixed",
      "label": "PlanarFixed",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "frame",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "x": 0,
        "y": 0
      },
      "icon": "PlanarFixed.svg",
      "render": {
        "type": "image",
        "src": "PlanarFixed.svg"
      },
      "help": "Frame rigidly fixed at the world point (x, y)."
    },
    {
      "type": "PlanarBody",
      "label": "PlanarBody",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "com",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "m": 1,
        "I": 1,
        "x0": 0,
        "y0": 0,
        "phi0": 0,
        "vx0": 0,
        "vy0": 0,
        "w0": 0
      },
      "icon": "PlanarBody.svg",
      "render": {
        "type": "image",
        "src": "PlanarBody.svg"
      },
      "help": "Rigid body: mass m, central inertia I; six states (xc, yc, phi, vx, vy, w). Named frames are body-fixed offsets from the COM."
    },
    {
      "type": "PlanarPointMass",
      "label": "PlanarPointMass",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "com",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "m": 1,
        "x0": 0,
        "y0": 0,
        "vx0": 0,
        "vy0": 0
      },
      "icon": "PlanarPointMass.svg",
      "render": {
        "type": "image",
        "src": "PlanarPointMass.svg"
      },
      "help": "Point mass (no orientation): four states (xc, yc, vx, vy); attach joints at its point."
    },
    {
      "type": "PlanarRevolute",
      "label": "PlanarRevolute",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        },
        {
          "name": "b",
          "x": 90,
          "y": 35,
          "side": "right",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {},
      "icon": "PlanarRevolute.svg",
      "render": {
        "type": "image",
        "src": "PlanarRevolute.svg"
      },
      "help": "Revolute (pin) joint: frames a and b share position, free relative rotation."
    },
    {
      "type": "PlanarPrismatic",
      "label": "PlanarPrismatic",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        },
        {
          "name": "b",
          "x": 90,
          "y": 35,
          "side": "right",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "dx": 1,
        "dy": 0
      },
      "icon": "PlanarPrismatic.svg",
      "render": {
        "type": "image",
        "src": "PlanarPrismatic.svg"
      },
      "help": "Prismatic joint: frame b slides along the world axis (dx, dy) through frame a, relative rotation locked."
    },
    {
      "type": "PlanarDistance",
      "label": "PlanarDistance",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        },
        {
          "name": "b",
          "x": 90,
          "y": 35,
          "side": "right",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "length": 1
      },
      "icon": "PlanarDistance.svg",
      "render": {
        "type": "image",
        "src": "PlanarDistance.svg"
      },
      "help": "Rigid rod: holds a fixed distance L between the points at frames a and b."
    },
    {
      "type": "PlanarRollingWheel",
      "label": "PlanarRollingWheel",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "dx": 1,
        "dy": 0,
        "px": 0,
        "py": 0,
        "radius": 1
      },
      "icon": "PlanarRollingWheel.svg",
      "render": {
        "type": "image",
        "src": "PlanarRollingWheel.svg"
      },
      "help": "Wheel at frame a rolls without slipping on the fixed surface line (px,py)+(dx,dy), staying at height radius."
    },
    {
      "type": "PlanarPositionSensor",
      "label": "PlanarPositionSensor",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [
        {
          "x": 45,
          "y": 70,
          "side": "bottom",
          "name": "out"
        }
      ],
      "defaultParams": {
        "axis": "x"
      },
      "icon": "PlanarPositionSensor.svg",
      "render": {
        "type": "image",
        "src": "PlanarPositionSensor.svg"
      },
      "help": "Absolute position of the frame-a point along the chosen axis (x, y) or the body angle (phi)."
    },
    {
      "type": "PlanarVelocitySensor",
      "label": "PlanarVelocitySensor",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [
        {
          "x": 45,
          "y": 70,
          "side": "bottom",
          "name": "out"
        }
      ],
      "defaultParams": {
        "axis": "x"
      },
      "icon": "PlanarVelocitySensor.svg",
      "render": {
        "type": "image",
        "src": "PlanarVelocitySensor.svg"
      },
      "help": "Absolute velocity of the frame-a point along the chosen axis (x, y) or the angular velocity (omega)."
    },
    {
      "type": "PlanarAccelerationSensor",
      "label": "PlanarAccelerationSensor",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [
        {
          "x": 45,
          "y": 70,
          "side": "bottom",
          "name": "out"
        }
      ],
      "defaultParams": {
        "axis": "x"
      },
      "icon": "PlanarAccelerationSensor.svg",
      "render": {
        "type": "image",
        "src": "PlanarAccelerationSensor.svg"
      },
      "help": "Absolute acceleration of the body at frame a along the chosen axis (x, y) or the angular acceleration (alpha)."
    },
    {
      "type": "PlanarRelPositionSensor",
      "label": "PlanarRelPositionSensor",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        },
        {
          "name": "b",
          "x": 90,
          "y": 35,
          "side": "right",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [
        {
          "x": 45,
          "y": 70,
          "side": "bottom",
          "name": "out"
        }
      ],
      "defaultParams": {
        "axis": "x"
      },
      "icon": "PlanarRelPositionSensor.svg",
      "render": {
        "type": "image",
        "src": "PlanarRelPositionSensor.svg"
      },
      "help": "Relative position of the frame-a point minus the frame-b point along the chosen axis (x, y)."
    },
    {
      "type": "PlanarDistanceSensor",
      "label": "PlanarDistanceSensor",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        },
        {
          "name": "b",
          "x": 90,
          "y": 35,
          "side": "right",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [
        {
          "x": 45,
          "y": 70,
          "side": "bottom",
          "name": "out"
        }
      ],
      "defaultParams": {},
      "icon": "PlanarDistanceSensor.svg",
      "render": {
        "type": "image",
        "src": "PlanarDistanceSensor.svg"
      },
      "help": "Distance between the points at frames a and b."
    },
    {
      "type": "PlanarSpringDamper",
      "label": "PlanarSpringDamper",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        },
        {
          "name": "b",
          "x": 90,
          "y": 35,
          "side": "right",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "c": 100,
        "d": 1
      },
      "icon": "PlanarSpringDamper.svg",
      "render": {
        "type": "image",
        "src": "PlanarSpringDamper.svg"
      },
      "help": "Linear 2D spring-damper between the points at frames a and b: F = -(c dr + d dv)."
    },
    {
      "type": "PlanarSpring",
      "label": "PlanarSpring",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        },
        {
          "name": "b",
          "x": 90,
          "y": 35,
          "side": "right",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "c": 100
      },
      "icon": "PlanarSpring.svg",
      "render": {
        "type": "image",
        "src": "PlanarSpring.svg"
      },
      "help": "Linear 2D spring between the points at frames a and b: F = -c dr."
    },
    {
      "type": "PlanarDamper",
      "label": "PlanarDamper",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        },
        {
          "name": "b",
          "x": 90,
          "y": 35,
          "side": "right",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "d": 10
      },
      "icon": "PlanarDamper.svg",
      "render": {
        "type": "image",
        "src": "PlanarDamper.svg"
      },
      "help": "Linear 2D damper between the points at frames a and b: F = -d dv."
    },
    {
      "type": "PlanarForce",
      "label": "PlanarForce",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "fx": 0,
        "fy": 0
      },
      "icon": "PlanarForce.svg",
      "render": {
        "type": "image",
        "src": "PlanarForce.svg"
      },
      "help": "External world force (fx, fy) applied at the frame-a point (adds a torque when offset from the COM)."
    },
    {
      "type": "PlanarTorque",
      "label": "PlanarTorque",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "tau": 0
      },
      "icon": "PlanarTorque.svg",
      "render": {
        "type": "image",
        "src": "PlanarTorque.svg"
      },
      "help": "External torque tau applied to the body at frame a."
    },
    {
      "type": "PlanarRelativeTorque",
      "label": "PlanarRelativeTorque",
      "acausal": true,
      "domain": "planar",
      "width": 90,
      "height": 70,
      "physicalPins": [
        {
          "name": "a",
          "x": 0,
          "y": 35,
          "side": "left",
          "domain": "planar"
        },
        {
          "name": "b",
          "x": 90,
          "y": 35,
          "side": "right",
          "domain": "planar"
        }
      ],
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "tau": 0
      },
      "icon": "PlanarRelativeTorque.svg",
      "render": {
        "type": "image",
        "src": "PlanarRelativeTorque.svg"
      },
      "help": "Actuator torque: +tau on the body at frame a, -tau on the body at frame b (drives a joint)."
    }
  ]
}
Catalogmodules/nflow_blocks/functions/+NFlow/+internal/planarCatalog.m
  c{end + 1} = pl_entry('PlanarRelativeTorque', 'Forces', {'a', 'b'}, ...
    {{'tau', 0, 'N.m'}}, '', ...
    'Actuator torque: +tau on the body at frame a, -tau on the body at frame b (drives a joint).');
🔗See Also
PlanarWorldPlanarFixedPlanarBody
🕔Version History
Version Description
1.0.0 initial version
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