Apparatus and method for computing operational-space physical quantity

An operational space physical quantity calculation method for computing a physical quantity in an operational space describing a relationship between forces and accelerations acting on a link structure including a plurality of linked rigid bodies, comprising the steps of:

• computing, using a processor, an inverse operational space inertia matrix by performing a forward dynamics calculation of the link structure, based on a kinetic model of the link structure, the performing comprising:
• calculating force information for a subset of the linked rigid bodies disposed between a terminal end of the link structure and a base point of the link structure, the force information corresponding to a force acting on the link structure;
• identifying, based on the operational space, a reference point disposed along the link structure, and
• determining an acceleration at the reference point, based on at least the computed force information;
• and
• computing, using a processor, an operational space bias acceleration based on the forward dynamics calculation.

A non-transitory computer-readable storage medium encoded with a computer program for causing a computer system to perform a method for computing a physical quantity in an operational space describing a relationship between forces acting on a link structure in which a plurality of rigid bodies are linked and accelerations, the method comprising the steps of:

• computing an inverse operational space inertia matrix by performing a forward dynamics calculation of the link structure, based on a kinetic model of the link structure, the performing comprising:
• calculating force information for a subset of the linked rigid bodies disposed between a terminal end of the link structure and a base point of the link structure, the force information corresponding to a force acting on the link structure;
• identifying, based on the operational space, a reference point disposed along the link structure, and
• determining an acceleration at the reference point, based on at least the computed force information;
• and
• computing an operational space bias acceleration based on the forward dynamics calculation.

An operational space physical quantity calculation apparatus for computing a physical quantity in an operational space describing a relationship between forces and accelerations acting on a link structure including a plurality of linked rigid bodies, the apparatus comprising:

• a forward dynamics calculating unit configured to perform a forward dynamics calculation based on a kinetic model of the link structure, the forward dynamics calculating unit being configured to:
• calculate force information for a subset of the linked rigid bodies disposed between a terminal end of the link structure and a base point of the link structure, the force information corresponding to at least one force acting on a link structure;
• and
• identify, based on the operational space, a reference point disposed along the link structure, and
• determine an acceleration at the reference point, based on at least the computed force information;
• and
• an operational space physical quantity computing unit configured to compute an inverse operational space inertia matrix and an operational space bias acceleration.