Point on Surface Constraint

Kinematic constraint between frame origin and 2-D surface

Since R2021a

Libraries:
Simscape / Multibody / Constraints

Description

The Point on Surface Constraint block confines a point to a 2-D surface. The frame attached to the point has five degrees of freedom (three rotational and two translational). This animation shows an example of using the Point on Surface Constraint block to constrain one vertex of a brick to a plane. The vertex translates and rotates on the plane. Note that the gravity is in the -Z direction, and there is no contact between the brick and plane.

The Point on Surface Constraint block has two ports: F and B. Port F is a frame port whose origin corresponds to the point. Port B is a geometry port that you connect to the geometry of a 2-D surface. Currently, the Point on Surface Constraint block supports only the Infinite Plane block.

You can use this block to sense the constraint forces and torques between the point and 2-D surface. The forces and torques are resolved in either the base or follower frame, based on the setting of the Resolution Frame parameter.

Ports

Geometry

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Geometry port associated with the constraint surface specified by blocks like the Infinite Plane block.

Frame

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Follower frame whose origin is confined to the 2-D surface connected to the port B of the Point on Surface Constraint block. The origin of the follower frame moves on the 2-D surface and has five degrees of freedom (three rotational and two translational).

Output

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Constraint force that acts between the point and surface, returned as a vector. See Measure Joint Constraint Forces for more information. If you set the Resolution Frame parameter to Base, the sensed force is with respect to the reference frame of the surface that connects to port B.

Dependencies

To enable this port, under Constraint Force/Torque Sensing, select Force Vector.

Constraint torque that acts between the point and surface, returned as a vector. See Force and Torque Sensing for more information. If you set the Resolution Frame parameter to Base, the sensed torque is with respect to the reference frame of the surface that connects to the port B.

Dependencies

To enable this port, under Constraint Force/Torque Sensing, select Torque Vector.

Parameters

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Direction in which to measure the constraint force and torque. Reversing this direction changes the sign of the measurements. See Force and Torque Measurement Direction for more information.

Frame used to resolve the measured vector quantities. See Selecting a Measurement Frame for more information.

Select this parameter to expose the port f, which outputs the constraint force vector between B and F frames.

Select this parameter to expose the port t, which outputs the constraint torque vector between B and F frames.

Version History

Introduced in R2021a