Rotational Detent

Double-sided spring rotation lock.

blockType: Engee1DMechanical.Elements.Rotational.Detent

Path in the library:

/Physical Modeling/1D Mechanical/Brakes & Detents/Rotational/Rotational Detent

Description

Block Rotational Detent It is a two-sided spring-loaded rotation lock.

The locking rod rotates around the locking body. There are recesses or magnets on the body that create a total relative torque on the rod as it rotates. With the help of the block, you can simulate the rotation locks using the values of the maximum torque and the width of the recess, or using tabular values. The model also includes viscous damping and kinetic friction between the rod and the housing. You can set the friction to zero.

The model of the rotation lock

When the rod rotates relative to the body, the relative rotation leads to the appearance of a torque . Depending on the chosen parameterization, the torque model is determined by the maximum torque and the width of the notch, or by a table defining the relative rotation depending on the torque.

Regardless of the parameterization, if you specify multiple latches, all latches will have the same function of the relative rotation of the torque.

Parameterization by maximum torque and recess width

If you choose the parameterization of the maximum torque and the width of the recess, the unit ensures that the curve of the dependence of the torque on the angle of rotation provides continuous torque and its derivative in the locking area. The maximum torque values are in the middle between the center of the lock and the edges of the lock, as shown in the following figure.

rotational detent en

Parameterization according to the table

Using parameterization according to the table, you can set an arbitrary function of the dependence of torque on relative rotation. When creating such a feature, keep in mind the following recommendations.

conservation of energy

If you want to ensure energy conservation when using a locking device, then the total integral of the function of the dependence of the torque on the angle of rotation (area under the curve) must be zero.

The performance of modeling

To stabilize the lock simulation, discontinuities in the rotation function relative to the torque should be avoided.

Limitations

The model does not take inertia into account. If necessary, add inertia conditions from the outside to the R and C ports.
If you use parameterization based on maximum torque and recess width or parameterization according to the table, then kinetic friction does not depend on the normal force acting on the lock.

Ports

Conserving

# R — locking rod
rotational mechanics

Details

A non-directional port connected to the locking rod.

Program usage name

rod_flange

# C — locking housing
rotational mechanics

Details

A non-directional port connected to the lock housing.

Program usage name

case_flange

Parameters

Detent Characteristics

# Parameterization — parameterization of the lock
By peak torque and notch width | By table lookup

Details

Select a method for parameterizing the lock:

By peak torque and notch width — parameterization of the lock according to the value of the maximum torque and the width of the recess.
By table lookup — tabular parameterization of the dependence of torque on relative rotation.

Values	`By peak torque and notch width` \| `By table lookup`
Default value	`By peak torque and notch width`
Program usage name	`parameterization`
Evaluatable	Yes

# Peak torque — maximum torque
N*m | mN*m | lbf*ft

Details

The maximum torque generated inside the lock.

Dependencies

To use this parameter, set for the parameter Parameterization meaning By peak torque and notch width.

Units	`Nm` \| `mNm` \| `lbf*ft`
Default value	`0.25 N*m`
Program usage name	`T_peak`
Evaluatable	Yes

# Notch width — the width of the recess
deg | rad | rev | mrad

Details

The width of the area where the torque develops.

Dependencies

To use this parameter, set for the parameter Parameterization meaning By peak torque and notch width.

Units	`deg` \| `rad` \| `rev` \| `mrad`
Default value	`5.0 deg`
Program usage name	`notch_width`
Evaluatable	Yes

# Initial relative rotation — the initial angle of rotation between the rod and the housing
deg | rad | rev | mrad

Details

The angle between the rod and the body at the beginning of the simulation.

Units	`deg` \| `rad` \| `rev` \| `mrad`
Default value	`0.0 deg`
Program usage name	`delta_phi_start`
Evaluatable	Yes

# Relative rotation vector — vector of relative rotation values
deg | rad | rev | mrad

Details

A vector of relative rotation values, the elements of which correspond to a vector of torque values Torque vector. These two vectors must be the same size. The angles should be indicated in ascending order.

Dependencies

To use this parameter, set for the parameter Parameterization meaning By table lookup.

Units	`deg` \| `rad` \| `rev` \| `mrad`
Default value	`[-5.0, -4.0, -3.0, -1.0, 1.0, 3.0, 4.0, 5.0] deg`
Program usage name	`delta_phi_vector`
Evaluatable	Yes

# Torque vector — vector of torques
N*m | mN*m | lbf*ft

Details

A vector of torque values, the elements of which correspond to a vector of relative rotations Relative rotation vector.

Dependencies

To use this parameter, set for the parameter Parameterization meaning By table lookup.

Units	`Nm` \| `mNm` \| `lbf*ft`
Default value	`[0.0, 0.0, -0.25, -0.1, 0.1, 0.25, 0.0, 0.0] N*m`
Program usage name	`T_vector`
Evaluatable	Yes

# Interpolation method — the interpolation method
Linear | Smooth

Details

An interpolation method for approximating the output value when the input value is between two consecutive points in the table. Set as:

Linear – select this value for the lowest computational cost.
Smooth – select this option to get a continuous curve with continuous first-order derivatives.

Dependencies

To use this parameter, set for the parameter Parameterization meaning By table lookup.

Values	`Linear` \| `Smooth`
Default value	`Linear`
Program usage name	`interpolation_method`
Evaluatable	Yes

Spacing

# Detent spacing — the method of setting the distance between the clamps
Regularly spaced | By angle vector

Details

The method of setting the distance between the clamps:

Regularly spaced – the distances between the clamps are the same.
By angle vector — the distances between the clamps can be different and are set by the user.

Values	`Regularly spaced` \| `By angle vector`
Default value	`Regularly spaced`
Program usage name	`spacing_parameterization`
Evaluatable	Yes

# Number of detents — number of retainers

Details

Specify the number of identical clips with the same interval between them. The value must be greater than or equal to `1'.

In this case, the retainers are evenly spaced in the range from -180 to +180 degrees, with the center of one retainer at `0' degrees. Non-integer values are rounded to the nearest integer.

Dependencies

To use this parameter, set for the parameter Detent spacing meaning Regularly spaced.

Default value	`1`
Program usage name	`detents_count`
Evaluatable	Yes

# Vector of detent centers — vector of fixation centers
deg | rad | rev | mrad

Details

The vector of the positions of the centers of the identical clamps in the form of a vector of angles. These values should be in the range from -180 to +180 degrees. The minimum distance between the latches should be greater than the parameter value. Notch width.

Units	`deg` \| `rad` \| `rev` \| `mrad`
Default value	`[-40.0, 0.0, 30.0, 85.0] deg`
Program usage name	`position_vector`
Evaluatable	Yes

Friction

# Viscous friction coefficient — coefficient of viscous friction
N*m/(rad/s) | ft*lbf/(rad/s)

Details

The coefficient of viscous friction at the contact of the rod with the body. The value must be greater than or equal to `0'.

Units	`Nm/(rad/s)` \| `ftlbf/(rad/s)`
Default value	`0.1 N*m/(rad/s)`
Program usage name	`viscous_coefficient`
Evaluatable	Yes

# Friction to peak torque ratio — coefficient of kinetic friction

Details

The coefficient of kinetic friction at the contact of the rod with the body. The value must be greater than or equal to `0'.

Kinetic friction is defined as the product of the coefficient of kinetic friction and the maximum torque.

Default value	`0.01`
Program usage name	`friction_to_peak_torque_ratio`
Evaluatable	Yes

# Friction velocity threshold — threshold value of the friction velocity
rpm | deg/s | rad/s

Details

The relative angular velocity required to achieve maximum kinetic friction in the retainer. The value must be greater than `0'.

Units	`rpm` \| `deg/s` \| `rad/s`
Default value	`10.0 rpm`
Program usage name	`w_friction_threshold`
Evaluatable	Yes