Enum MotorModel 

pub enum MotorModel {
    SpringDamper {
        frequency: Scalar,
        damping_ratio: Scalar,
    },
    ForceBased {
        stiffness: Scalar,
        damping: Scalar,
    },
    AccelerationBased {
        stiffness: Scalar,
        damping: Scalar,
    },
}

Determines how the joint motor force/torque is computed.

Different models offer trade-offs between ease of tuning and physical accuracy. The default is a SpringDamper model that provides stable, predictable behavior across different configurations.

Variants

SpringDamper

A spring-damper model using implicit Euler integration.

Unlike the other models, this is unconditionally stable: the implicit formulation naturally limits the response as frequency increases, preventing overshoot and oscillation even with aggressive parameters. This makes it easier to tune than the other models, which can become unstable with high stiffness values.

This is the recommended model for most use cases.

Parameters

• frequency: The natural frequency of the spring in Hz. Higher values create stiffer springs.
• damping_ratio: The damping ratio.
  • 0.0 = no damping (oscillates forever)
  • 1.0 = critically damped (fastest approach without overshoot)
  • > 1.0 = overdamped (slower approach without overshoot)
  • < 1.0 = underdamped (overshoots and oscillates)

Fields

frequency: Scalar

The natural frequency of the spring in Hz.

damping_ratio: Scalar

The damping ratio.

ForceBased

The motor force/torque is computed directly from the stiffness and damping parameters.

The model can be described by the following formula:

force = (stiffness * position_error) + (damping * velocity_error)

This produces physically accurate forces/torques, but requires careful tuning of the stiffness and damping parameters based on the masses of the connected bodies. High stiffness values can cause instability (overshoot, oscillation, or divergence), so parameters must be chosen appropriately for your timestep and mass configuration.

Parameters

• stiffness: The stiffness coefficient for position control. Set to zero for pure velocity control.
• damping: The damping coefficient for velocity control.

Fields

stiffness: Scalar

The stiffness coefficient for position control.

damping: Scalar

The damping coefficient for velocity control.

AccelerationBased

The motor force/torque is computed based on the acceleration required to reach the target.

The model can be described by the following formula:

acceleration = (stiffness * position_error) + (damping * velocity_error)

This automatically scales the motor force/torque based on the masses of the bodies, resulting in consistent behavior across different mass configurations. It is therefore easier to tune compared to the ForceBased model, which requires manual adjustment of stiffness and damping based on mass.

Note that high stiffness values can still cause instability. For unconditionally stable behavior, use the SpringDamper model instead.

Parameters

• stiffness: The stiffness coefficient for position control. Set to zero for pure velocity control.
• damping: The damping coefficient for velocity control.

Fields

stiffness: Scalar

The stiffness coefficient for position control.

damping: Scalar

The damping coefficient for velocity control.

Implementations

impl MotorModel

pub const DEFAULT: Self

The default motor model: a critically damped spring-damper with 5 Hz frequency.

Trait Implementations

impl Clone for MotorModel

fn clone(&self) -> MotorModel

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for MotorModel

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for MotorModel

fn default() -> Self

The default motor model: a critically damped spring-damper with 5 Hz frequency.

impl Enum for MotorModel

fn field(&self, __name_param: &str) -> Option<&dyn PartialReflect>

Returns a reference to the value of the field (in the current variant) with the given name.

fn field_at(&self, __index_param: usize) -> Option<&dyn PartialReflect>

Returns a reference to the value of the field (in the current variant) at the given index.

fn field_mut(&mut self, __name_param: &str) -> Option<&mut dyn PartialReflect>

Returns a mutable reference to the value of the field (in the current variant) with the given name.

fn field_at_mut( &mut self, __index_param: usize, ) -> Option<&mut dyn PartialReflect>

Returns a mutable reference to the value of the field (in the current variant) at the given index.

fn index_of(&self, __name_param: &str) -> Option<usize>

Returns the index of the field (in the current variant) with the given name.

fn name_at(&self, __index_param: usize) -> Option<&str>

Returns the name of the field (in the current variant) with the given index.

fn iter_fields(&self) -> VariantFieldIter<'_>

Returns an iterator over the values of the current variant’s fields.

fn field_len(&self) -> usize

Returns the number of fields in the current variant.

fn variant_name(&self) -> &str

The name of the current variant.

fn variant_index(&self) -> usize

The index of the current variant.

fn variant_type(&self) -> VariantType

The type of the current variant.

fn to_dynamic_enum(&self) -> DynamicEnum

Creates a new DynamicEnum from this enum.

fn is_variant(&self, variant_type: VariantType) -> bool

Returns true if the current variant’s type matches the given one.

fn variant_path(&self) -> String

Returns the full path to the current variant.

fn get_represented_enum_info(&self) -> Option<&'static EnumInfo>

Will return None if TypeInfo is not available.

impl FromReflect for MotorModel

fn from_reflect(__param0: &dyn PartialReflect) -> Option<Self>

Constructs a concrete instance of Self from a reflected value.

fn take_from_reflect( reflect: Box<dyn PartialReflect>, ) -> Result<Self, Box<dyn PartialReflect>>

Attempts to downcast the given value to Self using, constructing the value using from_reflect if that fails.

impl GetTypeRegistration for MotorModel

fn get_type_registration() -> TypeRegistration

Returns the default TypeRegistration for this type.

fn register_type_dependencies(registry: &mut TypeRegistry)

Registers other types needed by this type.

impl PartialEq for MotorModel

fn eq(&self, other: &MotorModel) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialReflect for MotorModel

fn get_represented_type_info(&self) -> Option<&'static TypeInfo>

Returns the TypeInfo of the type represented by this value.

fn try_apply( &mut self, __value_param: &dyn PartialReflect, ) -> Result<(), ApplyError>

Tries to apply a reflected value to this value.

fn reflect_kind(&self) -> ReflectKind

Returns a zero-sized enumeration of “kinds” of type.

fn reflect_ref(&self) -> ReflectRef<'_>

Returns an immutable enumeration of “kinds” of type.

fn reflect_mut(&mut self) -> ReflectMut<'_>

Returns a mutable enumeration of “kinds” of type.

fn reflect_owned(self: Box<Self>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type.

fn try_into_reflect( self: Box<Self>, ) -> Result<Box<dyn Reflect>, Box<dyn PartialReflect>>

Attempts to cast this type to a boxed, fully-reflected value.

fn try_as_reflect(&self) -> Option<&dyn Reflect>

Attempts to cast this type to a fully-reflected value.

fn try_as_reflect_mut(&mut self) -> Option<&mut dyn Reflect>

Attempts to cast this type to a mutable, fully-reflected value.

fn into_partial_reflect(self: Box<Self>) -> Box<dyn PartialReflect>

Casts this type to a boxed, reflected value.

fn as_partial_reflect(&self) -> &dyn PartialReflect

Casts this type to a reflected value.

fn as_partial_reflect_mut(&mut self) -> &mut dyn PartialReflect

Casts this type to a mutable, reflected value.

fn reflect_hash(&self) -> Option<u64>

Returns a hash of the value (which includes the type).

fn reflect_partial_eq(&self, value: &dyn PartialReflect) -> Option<bool>

Returns a “partial equality” comparison result.

fn debug(&self, f: &mut Formatter<'_>) -> Result

Debug formatter for the value.

fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError>

Attempts to clone Self using reflection.

fn apply(&mut self, value: &(dyn PartialReflect + 'static))

Applies a reflected value to this value.

fn to_dynamic(&self) -> Box<dyn PartialReflect>

Converts this reflected value into its dynamic representation based on its kind.

fn reflect_clone_and_take<T>(&self) -> Result<T, ReflectCloneError>

where T: 'static, Self: Sized + TypePath,

For a type implementing PartialReflect, combines reflect_clone and take in a useful fashion, automatically constructing an appropriate ReflectCloneError if the downcast fails.

fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type.

impl Reflect for MotorModel

fn into_any(self: Box<Self>) -> Box<dyn Any>

Returns the value as a Box<dyn Any>.

fn as_any(&self) -> &dyn Any

Returns the value as a &dyn Any.

fn as_any_mut(&mut self) -> &mut dyn Any

Returns the value as a &mut dyn Any.

fn into_reflect(self: Box<Self>) -> Box<dyn Reflect>

Casts this type to a boxed, fully-reflected value.

fn as_reflect(&self) -> &dyn Reflect

Casts this type to a fully-reflected value.

fn as_reflect_mut(&mut self) -> &mut dyn Reflect

Casts this type to a mutable, fully-reflected value.

fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>

Performs a type-checked assignment of a reflected value to this value.

impl TypePath for MotorModel

fn type_path() -> &'static str

Returns the fully qualified path of the underlying type.

fn short_type_path() -> &'static str

Returns a short, pretty-print enabled path to the type.

fn type_ident() -> Option<&'static str>

Returns the name of the type, or None if it is anonymous.

fn crate_name() -> Option<&'static str>

Returns the name of the crate the type is in, or None if it is anonymous.

fn module_path() -> Option<&'static str>

Returns the path to the module the type is in, or None if it is anonymous.

impl Typed for MotorModel

fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.

impl Copy for MotorModel

impl StructuralPartialEq for MotorModel