README
¶
PID Go
PID controllers for Go.
Examples
pid.Controller
A basic PID controller.
import (
"fmt"
"time"
"go.einride.tech/pid"
)
func ExampleController() {
// Create a PID controller.
c := pid.Controller{
Config: pid.ControllerConfig{
ProportionalGain: 2.0,
IntegralGain: 1.0,
DerivativeGain: 1.0,
},
}
// Update the PID controller.
c.Update(pid.ControllerInput{
ReferenceSignal: 10,
ActualSignal: 0,
SamplingInterval: 100 * time.Millisecond,
})
fmt.Printf("%+v\n", c.State)
// Reset the PID controller.
c.Reset()
fmt.Printf("%+v\n", c.State)
// Output:
// {ControlError:10 ControlErrorIntegral:1 ControlErrorDerivative:100 ControlSignal:121}
// {ControlError:0 ControlErrorIntegral:0 ControlErrorDerivative:0 ControlSignal:0}
}
pid.AntiWindupController
A PID-controller with low-pass filtering of the derivative term, feed forward term, a saturated control output and anti-windup.
pid.TrackingController
a PID-controller with low-pass filtering of the derivative term, feed forward term, anti-windup and bumpless transfer using tracking mode control.
Documentation
¶
Overview ¶
Package pid provides PID controllers for Go.
Index ¶
- type AntiWindupController
- type AntiWindupControllerConfig
- type AntiWindupControllerInput
- type AntiWindupControllerState
- type Controller
- type ControllerConfig
- type ControllerInput
- type ControllerState
- type TrackingController
- type TrackingControllerConfig
- type TrackingControllerInput
- type TrackingControllerState
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type AntiWindupController ¶
type AntiWindupController struct {
// Config for the AntiWindupController.
Config AntiWindupControllerConfig
// State of the AntiWindupController.
State AntiWindupControllerState
}
AntiWindupController implements a PID-controller with low-pass filter of the derivative term, feed forward term, a saturated control output and anti-windup.
The anti-windup mechanism uses an actuator saturation model as defined in Chapter 6 of Åström and Murray, Feedback Systems: An Introduction to Scientists and Engineers, 2008 (http://www.cds.caltech.edu/~murray/amwiki)
The ControlError, ControlErrorIntegrand, ControlErrorIntegral and ControlErrorDerivative are prevented from reaching +/- inf by clamping them to [-math.MaxFloat64, math.MaxFloat64].
func (*AntiWindupController) DischargeIntegral ¶
func (c *AntiWindupController) DischargeIntegral(dt time.Duration)
DischargeIntegral provides the ability to discharge the controller integral state over a configurable period of time.
func (*AntiWindupController) Reset ¶
func (c *AntiWindupController) Reset()
Reset the controller state.
func (*AntiWindupController) Update ¶
func (c *AntiWindupController) Update(input AntiWindupControllerInput)
Update the controller state.
type AntiWindupControllerConfig ¶
type AntiWindupControllerConfig struct {
// ProportionalGain is the P part gain.
ProportionalGain float64
// IntegralGain is the I part gain.
IntegralGain float64
// DerivativeGain is the D part gain.
DerivativeGain float64
// AntiWindUpGain is the anti-windup tracking gain.
AntiWindUpGain float64
// IntegralDischargeTimeConstant is the time constant to discharge the integral state of the PID controller (s)
IntegralDischargeTimeConstant float64
// LowPassTimeConstant is the D part low-pass filter time constant => cut-off frequency 1/LowPassTimeConstant.
LowPassTimeConstant time.Duration
// MaxOutput is the max output from the PID.
MaxOutput float64
// MinOutput is the min output from the PID.
MinOutput float64
}
AntiWindupControllerConfig contains config parameters for a AntiWindupController.
type AntiWindupControllerInput ¶
type AntiWindupControllerInput struct {
// ReferenceSignal is the reference value for the signal to control.
ReferenceSignal float64
// ActualSignal is the actual value of the signal to control.
ActualSignal float64
// FeedForwardSignal is the contribution of the feed-forward control loop in the controller output.
FeedForwardSignal float64
// SamplingInterval is the time interval elapsed since the previous call of the controller Update method.
SamplingInterval time.Duration
}
AntiWindupControllerInput holds the input parameters to an AntiWindupController.
type AntiWindupControllerState ¶
type AntiWindupControllerState struct {
// ControlError is the difference between reference and current value.
ControlError float64
// ControlErrorIntegrand is the control error integrand, which includes the anti-windup correction.
ControlErrorIntegrand float64
// ControlErrorIntegral is the control error integrand integrated over time.
ControlErrorIntegral float64
// ControlErrorDerivative is the low-pass filtered time-derivative of the control error.
ControlErrorDerivative float64
// ControlSignal is the current control signal output of the controller.
ControlSignal float64
// UnsaturatedControlSignal is the control signal before saturation.
UnsaturatedControlSignal float64
}
AntiWindupControllerState holds mutable state for a AntiWindupController.
type Controller ¶
type Controller struct {
// Config for the Controller.
Config ControllerConfig
// State of the Controller.
State ControllerState
}
Controller implements a basic PID controller.
Example ¶
package main
import (
"fmt"
"time"
"go.einride.tech/pid"
)
func main() {
// Create a PID controller.
c := pid.Controller{
Config: pid.ControllerConfig{
ProportionalGain: 2.0,
IntegralGain: 1.0,
DerivativeGain: 1.0,
},
}
// Update the PID controller.
c.Update(pid.ControllerInput{
ReferenceSignal: 10,
ActualSignal: 0,
SamplingInterval: 100 * time.Millisecond,
})
fmt.Printf("%+v\n", c.State)
// Reset the PID controller.
c.Reset()
fmt.Printf("%+v\n", c.State)
}
Output: {ControlError:10 ControlErrorIntegral:1 ControlErrorDerivative:100 ControlSignal:121} {ControlError:0 ControlErrorIntegral:0 ControlErrorDerivative:0 ControlSignal:0}
func (*Controller) Update ¶
func (c *Controller) Update(input ControllerInput)
Update the controller state.
type ControllerConfig ¶
type ControllerConfig struct {
// ProportionalGain determines ratio of output response to error signal.
ProportionalGain float64
// IntegralGain determines previous error's affect on output.
IntegralGain float64
// DerivativeGain decreases the sensitivity to large reference changes.
DerivativeGain float64
}
ControllerConfig contains configurable parameters for a Controller.
type ControllerInput ¶
type ControllerInput struct {
// ReferenceSignal is the reference value for the signal to control.
ReferenceSignal float64
// ActualSignal is the actual value of the signal to control.
ActualSignal float64
// SamplingInterval is the time interval elapsed since the previous call of the controller Update method.
SamplingInterval time.Duration
}
ControllerInput holds the input parameters to a Controller.
type ControllerState ¶
type ControllerState struct {
// ControlError is the difference between reference and current value.
ControlError float64
// ControlErrorIntegral is the integrated control error over time.
ControlErrorIntegral float64
// ControlErrorDerivative is the rate of change of the control error.
ControlErrorDerivative float64
// ControlSignal is the current control signal output of the controller.
ControlSignal float64
}
ControllerState holds mutable state for a Controller.
type TrackingController ¶
type TrackingController struct {
// Config for the TrackingController.
Config TrackingControllerConfig
// State of the TrackingController.
State TrackingControllerState
}
TrackingController implements a PID-controller with low-pass filter of the derivative term, feed forward term, anti-windup and bumpless transfer using tracking mode control.
The anti-windup and bumpless transfer mechanisms use a tracking mode as defined in Chapter 6 of Åström and Murray, Feedback Systems: An Introduction to Scientists and Engineers, 2008 (http://www.cds.caltech.edu/~murray/amwiki)
The ControlError, ControlErrorIntegrand, ControlErrorIntegral and ControlErrorDerivative are prevented from reaching +/- inf by clamping them to [-math.MaxFloat64, math.MaxFloat64].
func (*TrackingController) DischargeIntegral ¶
func (c *TrackingController) DischargeIntegral(dt time.Duration)
DischargeIntegral provides the ability to discharge the controller integral state over a configurable period of time.
func (*TrackingController) Update ¶
func (c *TrackingController) Update(input TrackingControllerInput)
Update the controller state.
type TrackingControllerConfig ¶
type TrackingControllerConfig struct {
// ProportionalGain is the P part gain.
ProportionalGain float64
// IntegralGain is the I part gain.
IntegralGain float64
// DerivativeGain is the D part gain.
DerivativeGain float64
// AntiWindUpGain is the anti-windup tracking gain.
AntiWindUpGain float64
// IntegralDischargeTimeConstant is the time constant to discharge the integral state of the PID controller (s)
IntegralDischargeTimeConstant float64
// LowPassTimeConstant is the D part low-pass filter time constant => cut-off frequency 1/LowPassTimeConstant.
LowPassTimeConstant time.Duration
// MaxOutput is the max output from the PID.
MaxOutput float64
// MinOutput is the min output from the PID.
MinOutput float64
}
TrackingControllerConfig contains configurable parameters for a TrackingController.
type TrackingControllerInput ¶
type TrackingControllerInput struct {
// ReferenceSignal is the reference value for the signal to control.
ReferenceSignal float64
// ActualSignal is the actual value of the signal to control.
ActualSignal float64
// FeedForwardSignal is the contribution of the feed-forward control loop in the controller output.
FeedForwardSignal float64
// AppliedControlSignal is the actual control command applied by the actuator.
AppliedControlSignal float64
// SamplingInterval is the time interval elapsed since the previous call of the controller Update method.
SamplingInterval time.Duration
}
TrackingControllerInput holds the input parameters to a TrackingController.
type TrackingControllerState ¶
type TrackingControllerState struct {
// ControlError is the difference between reference and current value.
ControlError float64
// ControlErrorIntegrand is the integrated control error over time.
ControlErrorIntegrand float64
// ControlErrorIntegral is the control error integrand integrated over time.
ControlErrorIntegral float64
// ControlErrorDerivative is the low-pass filtered time-derivative of the control error.
ControlErrorDerivative float64
// ControlSignal is the current control signal output of the controller.
ControlSignal float64
// UnsaturatedControlSignal is the control signal before saturation used for tracking the
// actual control signal for bumpless transfer or compensation of un-modeled saturations.
UnsaturatedControlSignal float64
}
TrackingControllerState holds the mutable state a TrackingController.