Joint accelerations given joint torques and states
Robotics System Toolbox / Manipulator Algorithms
The Forward Dynamics block computes joint accelerations for a robot model given a robot state that is made up of joint torques, joint states, and external forces. To get the joint accelerations, specify the robot configuration (joint positions), joint velocities, applied torques, and external forces.
Specify the robot model in the Rigid body tree parameter as a
rigidBodyTree object, and set the
Gravity property on the
object. You can also import a robot model from an URDF (Unified Robot Description
Format) file using
Config — Robot configuration
Robot configuration, specified as a vector of positions for all
nonfixed joints in the robot model, as set by the Rigid body
tree parameter. You can also generate this vector for a
complex robot using the
functions inside a Constant or MATLAB
JointVel — Joint velocities
Joint velocities, specified as a vector. The number of joint velocities is equal to the degrees of freedom (number of nonfixed joints) of the robot.
JointTorq — Joint torques
Joint torques, specified as a vector. Each element corresponds to a torque applied to a specific joint. The number of joint torques is equal to the degrees of freedom (number of nonfixed joints) of the robot.
FExt — External force matrix
External force matrix, specified as a 6-by-n
matrix, where n is the number of bodies in the robot
model. The matrix contains nonzero values in the rows corresponding to
specific bodies. Each row is a vector of applied forces and torques that
act as a wrench for that specific body. Generate this matrix using
externalForce with a
MATLAB Function block.
JointAccel — Joint accelerations
Joint accelerations, returned as a vector. The number of joint accelerations is equal to the degrees of freedom of the robot.
Rigid body tree — Robot model
twoJointRigidBodyTree (default) |
Robot model, specified as a
rigidBodyTree object. You
can also import a robot model from an URDF (Unified Robot Description
Format) file using
The default robot model,
twoJointRigidBodyTree, is a
robot with revolute joints and two degrees of freedom.
Simulate using — Type of simulation to run
Interpreted execution (default) |
Interpreted execution— Simulate model using the MATLAB® interpreter. This option shortens startup time but has a slower simulation speed than
Code generation. In this mode, you can debug the source code of the block.
Code generation— Simulate model using generated C code. The first time you run a simulation, Simulink® generates C code for the block. The C code is reused for subsequent simulations, as long as the model does not change. This option requires additional startup time, but the speed of the subsequent simulations is comparable to
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
Introduced in R2018a
- Inverse Dynamics | Get Jacobian | Gravity Torque | Joint Space Mass Matrix | Velocity Product Torque | Get Transform