System Concept

Describes a dynamical system that is compatible with most of our tools for design and analysis. More...

Collaboration diagram for System Concept:

Classes
class	CascadeSystem< System1, System2 >
	CascadeSystem<System1,System2> More...
class	FeedbackSystem< System1, System2 >
	FeedbackSystem<System1,System2> More...
class	AffineSystem< StateVec, InputVec, OutputVec >
	AffineSystem<StateVector, InputVector, OutputVector> More...
class	PDControlSystem< System >
	PDControlSystem<System> More...
class	BotVisualizer< RobotStateVector >
	BotVisualizer<RobotStateVector> More...
class	RigidBodySystem
	Implements the System concept by wrapping the RigidBodyTree algorithms with additional sensors and actuators/forces. More...

Functions
template<typename System >
std::size_t	getNumStates (const System &sys)
	getNumStates() More...
template<typename System >
std::size_t	getNumInputs (const System &sys)
	getNumInputs() More...
template<typename System >
std::size_t	getNumOutputs (const System &sys)
	getNumOutputs() More...
template<typename Scalar , typename System >
System::template StateVector< Scalar >	createStateVector (const System &sys)
	Create a new, uninitialized state vector for the system. More...

Detailed Description

Describes a dynamical system that is compatible with most of our tools for design and analysis.

Every model of this concept must implement
X::StateVector	type for the internal state of the system, which models the Vector<ScalarType> concept
X::InputVector	type for the input to the system, which models the Vector<ScalarType> concept
X::OutputVector	type for the output from the system, which models the Vector<ScalarType> concept
template <ScalarType> StateVector<ScalarType> X::dynamics(const ScalarType& *t, const StateVector<ScalarType>& x, const InputVector<ScalarType>& u)	\( \dot{x} = \text{dynamics}(t, x, u) \)
template <ScalarType> OutputVector<ScalarType> X::output(const ScalarType& t, const StateVector<ScalarType>& x, const InputVector<ScalarType>& u)	\( y = \text{output}(t, x, u) \)
bool isTimeVarying()	should return false if output() and dynamics() methods do not depend on time. Default: true
bool isDirectFeedthrough()	should return false if output() does not depend directly on the input u. Default: true
size_t getNumStates()	only required if the state vector is dynamically-sized
size_t getNumInputs()	only required if the input vector is dynamically-sized
size_t getNumOutputs()	only required if the output vector is dynamically-sized

(always try to label your methods with const if possible)

todo: dynamics and output should be implemented as Drake::Function(s) with input-output relationships defined. then we would no longer specify isTimeVarying and isDirectFeedthrough (we could extract them from the input-output relationship)

todo: move xdot and y to be arguments instead of return values, to be consistent with Drake::Function.

Coming soon. Support for:

• deterministic discrete update
• input limits
• state constraints (must also allow for slack variables)
• zero-crossings (to inform the tools of discontinuities in the dynamics)

Function Documentation

System::template StateVector< Scalar > createStateVector

(

const System &

sys

)

Create a new, uninitialized state vector for the system.

Implemented concepts:

System Concept

Returns

a new, uninitialized state vector for the system.

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std::size_t Drake::getNumInputs

(

const System &

sys

)

getNumInputs()

Retrieve the size of the input vector

Implemented concepts:

System Concept

Return values

RowsAtCompileTime

or the result of getNumInputs() for dynamically sized vectors

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std::size_t Drake::getNumOutputs

(

const System &

sys

)

getNumOutputs()

Retrieve the size of the output vector

Implemented concepts:

System Concept

Return values

RowsAtCompileTime

or the result of getNumOutputs() for dynamically sized vectors

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std::size_t Drake::getNumStates

(

const System &

sys

)

getNumStates()

Retrieve the size of the state vector

Implemented concepts:

System Concept

Return values

RowsAtCompileTime

or the result of getNumStates() for dynamically sized vectors

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