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Simbody
3.4 (development)
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Simbody
3.4 (development)
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Constrain a single mobility to have a particular speed. More...
#include <Constraint.h>
Inheritance diagram for SimTK::Constraint::ConstantSpeed:Public Member Functions | |
| ConstantSpeed (MobilizedBody &mobilizer, MobilizerUIndex whichU, Real defaultSpeed) | |
| Construct a constant speed constraint on a particular mobility of the given mobilizer. | |
| ConstantSpeed (MobilizedBody &mobilizer, Real defaultSpeed) | |
| Construct a constant speed constraint on the mobility of the given mobilizer, assuming there is only one mobility. | |
| ConstantSpeed () | |
| Default constructor creates an empty handle. | |
| MobilizedBodyIndex | getMobilizedBodyIndex () const |
| Return the index of the mobilized body to which this constant speed constraint is being applied (to one of its mobilities). | |
| MobilizerUIndex | getWhichU () const |
| Return the particular mobility whose generalized speed is controlled by this ConstantSpeed constraint. | |
| Real | getDefaultSpeed () const |
| Return the default value for the speed to be enforced. | |
| ConstantSpeed & | setDefaultSpeed (Real speed) |
| Change the default value for the speed to be enforced by this constraint. | |
| void | setSpeed (State &state, Real speed) const |
| Override the default speed with this one whose value is stored in the given State. | |
| Real | getSpeed (const State &state) const |
| Get the current value of the speed set point from the indicated State. | |
| Real | getVelocityError (const State &state) const |
| Return the amount by which the given State fails to satisfy this ConstantSpeed constraint. | |
| Real | getAccelerationError (const State &state) const |
| Return the amount by which the accelerations in the given State fail to satify the time derivative of this constraint (which must be zero). | |
| Real | getMultiplier (const State &) const |
| Get the value of the Lagrange multipler generated to satisfy this constraint. | |
Constrain a single mobility to have a particular speed.
One non-holonomic constraint equation. Some mobility u is required to be at a particular value s.
The assembly condition is the same as the run-time constraint: u must be set to s.
| SimTK::Constraint::ConstantSpeed::ConstantSpeed | ( | MobilizedBody & | mobilizer, |
| MobilizerUIndex | whichU, | ||
| Real | defaultSpeed | ||
| ) |
Construct a constant speed constraint on a particular mobility of the given mobilizer.
| SimTK::Constraint::ConstantSpeed::ConstantSpeed | ( | MobilizedBody & | mobilizer, |
| Real | defaultSpeed | ||
| ) |
Construct a constant speed constraint on the mobility of the given mobilizer, assuming there is only one mobility.
| SimTK::Constraint::ConstantSpeed::ConstantSpeed | ( | ) | [inline] |
Default constructor creates an empty handle.
Return the index of the mobilized body to which this constant speed constraint is being applied (to one of its mobilities).
This is set on construction of the ConstantSpeed constraint.
Return the particular mobility whose generalized speed is controlled by this ConstantSpeed constraint.
This is set on construction.
| Real SimTK::Constraint::ConstantSpeed::getDefaultSpeed | ( | ) | const |
Return the default value for the speed to be enforced.
This is set on construction or via setDefaultSpeed(). This is used to initialize the speed when a default State is created, but it can be overriden by changing the value in the State using setSpeed().
| ConstantSpeed& SimTK::Constraint::ConstantSpeed::setDefaultSpeed | ( | Real | speed | ) |
Change the default value for the speed to be enforced by this constraint.
This is a topological change, meaning you'll have to call realizeTopology() on the containing System and obtain a new State before you can use it. If you just want to make a runtime change in the State, see setSpeed().
| void SimTK::Constraint::ConstantSpeed::setSpeed | ( | State & | state, |
| Real | speed | ||
| ) | const |
Override the default speed with this one whose value is stored in the given State.
This invalidates the Velocity stage in the state. Don't confuse this with setDefaultSpeed() -- the value set here overrides that one.
| Real SimTK::Constraint::ConstantSpeed::getSpeed | ( | const State & | state | ) | const |
Get the current value of the speed set point from the indicated State.
This is the value currently in effect, either from the default or from a previous call to setSpeed().
| Real SimTK::Constraint::ConstantSpeed::getVelocityError | ( | const State & | state | ) | const |
Return the amount by which the given State fails to satisfy this ConstantSpeed constraint.
The state must already be realized through Stage::Velocity.
| Real SimTK::Constraint::ConstantSpeed::getAccelerationError | ( | const State & | state | ) | const |
Return the amount by which the accelerations in the given State fail to satify the time derivative of this constraint (which must be zero).
The state must already be realized through Stage::Acceleration.
| Real SimTK::Constraint::ConstantSpeed::getMultiplier | ( | const State & | ) | const |
Get the value of the Lagrange multipler generated to satisfy this constraint.
For a ConstantSpeed constraint, that is the same as the generalized force although by convention constraint multipliers have the opposite sign from applied forces. The state must already be realized through Stage::Acceleration.
1.7.6.1 
