SlewRateLimiter

class wpimath.filter.SlewRateLimiter(*args, **kwargs)

Bases: pybind11_object

A class that limits the rate of change of an input value. Useful for implementing voltage, setpoint, and/or output ramps. A slew-rate limit is most appropriate when the quantity being controlled is a velocity or a voltage; when controlling a position, consider using a TrapezoidProfile instead.

@see TrapezoidProfile

Overloaded function.

  1. __init__(self: wpimath.filter._filter.SlewRateLimiter, positiveRateLimit: wpimath.units.units_per_second, negativeRateLimit: wpimath.units.units_per_second, initialValue: float = 0.0) -> None

Creates a new SlewRateLimiter with the given positive and negative rate limits and initial value.

Parameters:

  • positiveRateLimit – The rate-of-change limit in the positive direction, in units per second. This is expected to be positive.

  • negativeRateLimit – The rate-of-change limit in the negative direction, in units per second. This is expected to be negative.

  • initialValue – The initial value of the input.

  1. __init__(self: wpimath.filter._filter.SlewRateLimiter, rateLimit: wpimath.units.units_per_second) -> None

Creates a new SlewRateLimiter with the given positive rate limit and negative rate limit of -rateLimit.

Parameters:

rateLimit – The rate-of-change limit.

calculate(input: float) → float

Filters the input to limit its slew rate.

Parameters:

input – The input value whose slew rate is to be limited.

Returns:

The filtered value, which will not change faster than the slew rate.

lastValue() → float

Returns the value last calculated by the SlewRateLimiter.

Returns:

The last value.

reset(value: float) → None

Resets the slew rate limiter to the specified value; ignores the rate limit when doing so.

Parameters:

value – The value to reset to.