control_toolbox::RateLimiter< T > Class Template Reference

Public Member Functions
	RateLimiter (T min_value=std::numeric_limits< T >::quiet_NaN(), T max_value=std::numeric_limits< T >::quiet_NaN(), T min_first_derivative_neg=std::numeric_limits< T >::quiet_NaN(), T max_first_derivative_pos=std::numeric_limits< T >::quiet_NaN(), T min_first_derivative_pos=std::numeric_limits< T >::quiet_NaN(), T max_first_derivative_neg=std::numeric_limits< T >::quiet_NaN(), T min_second_derivative=std::numeric_limits< T >::quiet_NaN(), T max_second_derivative=std::numeric_limits< T >::quiet_NaN())
	Constructor.
T	limit (T &v, T v0, T v1, T dt)
	Limit the value and first_derivative.
T	limit_value (T &v)
	Limit the value.
T	limit_first_derivative (T &v, T v0, T dt)
	Limit the first_derivative.
T	limit_second_derivative (T &v, T v0, T v1, T dt)
	Limit the second_derivative.
void	set_params (T min_value=std::numeric_limits< T >::quiet_NaN(), T max_value=std::numeric_limits< T >::quiet_NaN(), T min_first_derivative_neg=std::numeric_limits< T >::quiet_NaN(), T max_first_derivative_pos=std::numeric_limits< T >::quiet_NaN(), T min_first_derivative_pos=std::numeric_limits< T >::quiet_NaN(), T max_first_derivative_neg=std::numeric_limits< T >::quiet_NaN(), T min_second_derivative=std::numeric_limits< T >::quiet_NaN(), T max_second_derivative=std::numeric_limits< T >::quiet_NaN())
	Set the parameters.

Constructor & Destructor Documentation

RateLimiter()

template<typename T >

control_toolbox::RateLimiter< T >::RateLimiter	(	T	min_value = std::numeric_limits<T>::quiet_NaN(),
		T	max_value = std::numeric_limits<T>::quiet_NaN(),
		T	min_first_derivative_neg = std::numeric_limits<T>::quiet_NaN(),
		T	max_first_derivative_pos = std::numeric_limits<T>::quiet_NaN(),
		T	min_first_derivative_pos = std::numeric_limits<T>::quiet_NaN(),
		T	max_first_derivative_neg = std::numeric_limits<T>::quiet_NaN(),
		T	min_second_derivative = std::numeric_limits<T>::quiet_NaN(),
		T	max_second_derivative = std::numeric_limits<T>::quiet_NaN()
	)

Constructor.

Parameters

[in]	min_value	Minimum value, e.g. [m/s], usually <= 0
[in]	max_value	Maximum value, e.g. [m/s], usually >= 0
[in]	min_first_derivative_neg	Minimum first_derivative, negative value, e.g. [m/s^2], usually <= 0
[in]	max_first_derivative_pos	Maximum first_derivative, positive value, e.g. [m/s^2], usually >= 0
[in]	min_first_derivative_pos	Asymmetric Minimum first_derivative, positive value, e.g. [m/s^2], usually <= 0
[in]	max_first_derivative_neg	Asymmetric Maximum first_derivative, negative value, e.g. [m/s^2], usually >= 0
[in]	min_second_derivative	Minimum second_derivative, e.g. [m/s^3], usually <= 0
[in]	max_second_derivative	Maximum second_derivative, e.g. [m/s^3], usually >= 0

Note

If max_* values are NAN, the respective limit is deactivated If min_* values are NAN (unspecified), defaults to -max If min_first_derivative_pos/max_first_derivative_neg values are NAN, symmetric limits are used

Disclaimer about the jerk limits: The jerk limit is only applied when accelerating or reverse_accelerating (i.e., "sign(jerk * accel) > 0"). This condition prevents oscillating closed-loop behavior, see discussion details in https://github.com/ros-controls/control_toolbox/issues/240. if you use this feature, you should perform a test to check that the behavior is really as you expect.

Member Function Documentation

limit()

template<typename T >

T control_toolbox::RateLimiter< T >::limit	(	T &	v,
		T	v0,
		T	v1,
		T	dt
	)

Limit the value and first_derivative.

Parameters

[in,out]	v	value, e.g. [m/s]
[in]	v0	Previous value to v , e.g. [m/s]
[in]	v1	Previous value to v0, e.g. [m/s]
[in]	dt	Time step [s]

Returns

Limiting factor (1.0 if none)

limit_first_derivative()

template<typename T >

T control_toolbox::RateLimiter< T >::limit_first_derivative	(	T &	v,
		T	v0,
		T	dt
	)

Limit the first_derivative.

Parameters

[in,out]	v	value, e.g. [m/s]
[in]	v0	Previous value, e.g. [m/s]
[in]	dt	Time step [s]

Returns

Limiting factor (1.0 if none)

limit_second_derivative()

template<typename T >

T control_toolbox::RateLimiter< T >::limit_second_derivative	(	T &	v,
		T	v0,
		T	v1,
		T	dt
	)

Limit the second_derivative.

Parameters

[in,out]	v	value, e.g. [m/s]
[in]	v0	Previous value to v , e.g. [m/s]
[in]	v1	Previous value to v0, e.g. [m/s]
[in]	dt	Time step [s]

Returns

Limiting factor (1.0 if none)

See also

http://en.wikipedia.org/wiki/jerk_%28physics%29#Motion_control

Note

The jerk limit is only applied when accelerating or reverse_accelerating (i.e., "sign(jerk * accel) > 0").

limit_value()

template<typename T >

T control_toolbox::RateLimiter< T >::limit_value

(

T &

v

)

Limit the value.

Parameters

[in,out]

v

value, e.g. [m/s]

Returns

Limiting factor (1.0 if none)

set_params()

template<typename T >

void control_toolbox::RateLimiter< T >::set_params	(	T	min_value = std::numeric_limits<T>::quiet_NaN(),
		T	max_value = std::numeric_limits<T>::quiet_NaN(),
		T	min_first_derivative_neg = std::numeric_limits<T>::quiet_NaN(),
		T	max_first_derivative_pos = std::numeric_limits<T>::quiet_NaN(),
		T	min_first_derivative_pos = std::numeric_limits<T>::quiet_NaN(),
		T	max_first_derivative_neg = std::numeric_limits<T>::quiet_NaN(),
		T	min_second_derivative = std::numeric_limits<T>::quiet_NaN(),
		T	max_second_derivative = std::numeric_limits<T>::quiet_NaN()
	)

Set the parameters.

Parameters

[in]	min_value	Minimum value, e.g. [m/s], usually <= 0
[in]	max_value	Maximum value, e.g. [m/s], usually >= 0
[in]	min_first_derivative_neg	Minimum first_derivative, negative value, e.g. [m/s^2], usually <= 0
[in]	max_first_derivative_pos	Maximum first_derivative, positive value, e.g. [m/s^2], usually >= 0
[in]	min_first_derivative_pos	Asymmetric Minimum first_derivative, positive value, e.g. [m/s^2], usually <= 0
[in]	max_first_derivative_neg	Asymmetric Maximum first_derivative, negative value, e.g. [m/s^2], usually >= 0
[in]	min_second_derivative	Minimum second_derivative, e.g. [m/s^3], usually <= 0
[in]	max_second_derivative	Maximum second_derivative, e.g. [m/s^3], usually >= 0

Note

If max_* values are NAN, the respective limit is deactivated If min_* values are NAN (unspecified), defaults to -max If min_first_derivative_pos/max_first_derivative_neg values are NAN, symmetric limits are used

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The documentation for this class was generated from the following file:

• control_toolbox/include/control_toolbox/rate_limiter.hpp