Task Space Motion Model

Model rigid body tree motion given task-space inputs

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  • Library:

  • Robotics System Toolbox / Manipulator Algorithms

  • Task Space Motion Model Block

Description

The Task Space Motion Model block models the closed-loop task-space motion of a manipulator, specified as a rigidBodyTree object. The motion model behavior is defined using proportional-derivative (PD) control.

Ports

Input

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Homogenous transformation matrix representing the desired end effector pose, specified in meters.

6-element vector representing the desired linear and angular velocities of the end effector, specified in meters per second and radians per second.

6-by-m matrix representing external forces, specified in meters per second. m is the number of bodies in the rigidBodyTree object in the Rigid body tree parameter.

Dependencies

To enable this port, set the Show external force input parameter to on.

Output

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Joint positions output as an n-element vector in radians or meters, where n is the number of nonfixed joints in the rigidBodyTree object in the Rigid body tree parameter.

Joint velocities output as an n-element vector in radians per second or meters per second, where n is the number of nonfixed joints in the rigidBodyTree object in the Rigid body tree parameter.

Joint accelerations output as an n-element in radians per second squared or meters per second squared, where n is the number of nonfixed joints in the rigidBodyTree object in the Rigid body tree parameter.

Parameters

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Robot model, specified as a RigidBodyTree object. You can also import a robot model from an URDF (Unified Robot Description Formation) file using importrobot.

The default robot model, twoJointRigidBodyTree, is a robot with revolute joints and two degrees of freedom.

This parameter defines the body that will be used as the end effector, and for which the task space motion is defined. The property must correspond to a body name in the rigidBodyTree object of the property. Click Select body to select a body from the rigidBodyTree. If the rigidBodyTree is updated without also updating the end effector, the body with the highest index is assigned by default.

Proportional gain for proportional-derivative (PD) control, specified as a 6-by-6 matrix.

Derivative gain for proportional-derivative (PD) control, specified as a 6-by-6 matrix.

Damping ratios on each joint, specified as a scalar or n-element vector, where n is the number of nonfixed joints in the rigidBodyTree object in the Rigid body tree parameter.

Click the check-box to enable this parameter to input external forces using the FExt port.

Initial joint positions, specified as a n-element vector or scalar in radians. n is the number of nonfixed joints in the rigidBodyTree object in the Rigid body tree parameter.

Initial joint velocities, specified as a n-element vector or scalar in radians per second. n is the number of nonfixed joints in the rigidBodyTree object in the Rigid body tree parameter.

  • Interpreted execution — Simulate model using the MATLAB® interpreter. For more information, see Simulation Modes (Simulink).

  • 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.

Tunable: No

Model Examples

Follow Task Space Trajectory in Simulink

Follow Task Space Trajectory in Simulink

Use a Task Space Motion Model to follow a task space trajectory.

References

[1] Craig, John J. Introduction to Robotics: Mechanics and Control. Upper Saddle River, NJ: Pearson Education, 2005.

[2] Spong, Mark W., Seth Hutchinson, and Mathukumalli Vidyasagar. Robot Modeling and Control. Hoboken, NJ: Wiley, 2006.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

See Also

Blocks

Classes

Introduced in R2019b

Robotics System Toolbox Documentation

Support