Objects

Body types

There are three available body types.

1. DYNAMIC: can have a velocity, has a finite mass

2. KINEMATIC: can have a velocity, has an infinite mass (e.g., conveyor belt)

3. STATIC: cannot have a velocity, has an infinite mass (e.g., wall)

SingleBodyObjects can be of any type. ArticulatedSystems can only be DYNAMIC except the fixed base which can be STATIC.

You can get/set the body type using

• setBodyType(BodyType type)

• getBodyType() or getBodyType(body_index)

getBodyType() for ArticulatedSystems always returns DYNAMIC.

Name

All objects can be named. These names are used by visualizers. raisim::World has a functionality to retrieve an object by name. Here is an example.

auto sphere = world.addSphere(1,1);
sphere->setName("sphere");
std::string name = sphere->getName();
auto same_sphere = world.getObject("sphere");

Types

All objects can be specified as either a SingleBodyObject or an ArticulatedSystem.

• Articulated Systems
  • TL;DR
  • Introduction
  • Creating an instance
  • State Representation
  • Joints
  • URDF convention
  • Kinematics
  • Dynamics
  • Inverse Dynamics
  • PD Controller
  • Integration Steps
  • Get and Modify Robot Description in code
  • Apply External Forces/torques
  • Collision
  • Types of Indices
  • Closed-loop system
  • API
• Single-Body Objects
  • Supported Shapes
  • Compound
  • SingleBodyObject API (Parent class)
  • Compound API
  • Sphere API
  • Box API
  • Capsule API
  • Cylinder API
  • Ground API

API

class Object

Subclassed by raisim::ArticulatedSystem, raisim::SingleBodyObject

Public Functions

size_t getIndexInWorld() const

get the world index. raisim::World::getObjects() returns a vector of object pointers. This is method returns the index of this object in the vector.

Returns

the world index

const std::vector<Contact> &getContacts() const

get a vector of all contacts on the object.

Returns

contacts on the body

virtual void setExternalForce(size_t localIdx, const Vec<3> &force) = 0

apply forces at the Center of Mass

virtual void setExternalTorque(size_t localIdx, const Vec<3> &torque) = 0

apply torque on a body

virtual void setExternalForce(size_t localIdx, const Vec<3> &pos, const Vec<3> &force) = 0

apply force (expressed in the world frame) at specific location of the body (expressed in the body frame)

virtual void setConstraintForce(size_t localIdx, const Vec<3> &pos, const Vec<3> &force) = 0

apply spring force (expressed in the world frame) at specific location of the body (expressed in the body frame)

virtual ObjectType getObjectType() const = 0

get the object type. Possible types are SPHERE, BOX, CYLINDER, CONE, CAPSULE, MESH, HALFSPACE, COMPOUND, HEIGHTMAP, ARTICULATED_SYSTEM

Returns

the object type

inline virtual BodyType getBodyType(size_t localIdx) const

get the object body type. Available types are: DYNAMIC (movable and finite mass), STATIC (not movable and infinite mass), KINETIC (movable and infinite mass)

Returns

the body type

inline virtual BodyType getBodyType() const

get the object body type. Available types are: DYNAMIC (movable and finite mass), STATIC (not movable and infinite mass), KINETIC (movable and infinite mass).

Returns

the body type

virtual void getContactPointVel(size_t pointId, Vec<3> &vel) const = 0

get the contact point velocity in the world frame.

Parameters

• pointId – [in] the contact index. This is an index of a contact in the contact vector that you can retrieve from getContacts().

• vel – [out] the contact point velocity in the world frame

inline void setName(const std::string &name)

set the name of the object. You can retrieve an object by name using raisim::World::getObject()

Parameters

name – [in] name of the object.

inline const std::string &getName() const

get the name of the object

Returns

name of the object

inline void lockMutex()

locks object mutex. This can be used if you use raisim in a multi-threaded environment.

inline void unlockMutex()

unlock object mutex. This can be used if you use raisim in a multi-threaded environment.