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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 acceleration. More...
#include <Constraint.h>
Inheritance diagram for SimTK::Constraint::ConstantAcceleration:Public Member Functions | |
| ConstantAcceleration (MobilizedBody &mobilizer, MobilizerUIndex whichU, Real defaultAcceleration) | |
| Construct a constant acceleration constraint on a particular mobility of the given mobilizer. | |
| ConstantAcceleration (MobilizedBody &mobilizer, Real defaultAcceleration) | |
| Construct a constant acceleration constraint on the mobility of the given mobilizer, assuming there is only one mobility. | |
| ConstantAcceleration () | |
| Default constructor creates an empty handle. | |
| MobilizedBodyIndex | getMobilizedBodyIndex () const |
| Return the index of the mobilized body to which this constant acceleration constraint is being applied (to one of its mobilities). | |
| MobilizerUIndex | getWhichU () const |
| Return the particular mobility whose generalized acceleration is controlled by this ConstantAcceleration constraint. | |
| Real | getDefaultAcceleration () const |
| Return the default value for the acceleration to be enforced. | |
| ConstantAcceleration & | setDefaultAcceleration (Real accel) |
| Change the default value for the acceleration to be enforced by this constraint. | |
| void | setAcceleration (State &state, Real accel) const |
| Override the default acceleration with this one whose value is stored in the given State. | |
| Real | getAcceleration (const State &state) const |
| Get the current value of the acceleration set point from the indicated State. | |
| Real | getAccelerationError (const State &) const |
| Return the amount by which the accelerations in the given State fail to satify this constraint. | |
| 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 acceleration.
One acceleration-only constraint equation. Some generalized acceleration udot is required to be at a particular value a.
There is no assembly condition because this does not involve state variables q or u, just u's time derivative udot.
| SimTK::Constraint::ConstantAcceleration::ConstantAcceleration | ( | MobilizedBody & | mobilizer, |
| MobilizerUIndex | whichU, | ||
| Real | defaultAcceleration | ||
| ) |
Construct a constant acceleration constraint on a particular mobility of the given mobilizer.
| SimTK::Constraint::ConstantAcceleration::ConstantAcceleration | ( | MobilizedBody & | mobilizer, |
| Real | defaultAcceleration | ||
| ) |
Construct a constant acceleration constraint on the mobility of the given mobilizer, assuming there is only one mobility.
Default constructor creates an empty handle.
Return the index of the mobilized body to which this constant acceleration constraint is being applied (to one of its mobilities).
This is set on construction of the ConstantAcceleration constraint.
Return the particular mobility whose generalized acceleration is controlled by this ConstantAcceleration constraint.
This is set on construction.
Return the default value for the acceleration to be enforced.
This is set on construction or via setDefaultAcceleration(). This is used to initialize the acceleration when a default State is created, but it can be overriden by changing the value in the State using setAcceleration().
Change the default value for the acceleration 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 setAcceleration().
| void SimTK::Constraint::ConstantAcceleration::setAcceleration | ( | State & | state, |
| Real | accel | ||
| ) | const |
Override the default acceleration with this one whose value is stored in the given State.
This invalidates the Acceleration stage in the state. Don't confuse this with setDefaultAcceleration() -- the value set here overrides that one.
| Real SimTK::Constraint::ConstantAcceleration::getAcceleration | ( | const State & | state | ) | const |
Get the current value of the acceleration set point from the indicated State.
This is the value currently in effect, either from the default or from a previous call to setAcceleration().
| Real SimTK::Constraint::ConstantAcceleration::getAccelerationError | ( | const State & | ) | const |
Return the amount by which the accelerations in the given State fail to satify this constraint.
The state must already be realized through Stage::Acceleration.
| Real SimTK::Constraint::ConstantAcceleration::getMultiplier | ( | const State & | ) | const |
Get the value of the Lagrange multipler generated to satisfy this constraint.
For a ConstantAcceleration 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 
