System for capturing movements of an articulated structure
AssigneesMovea, Commissariat A L'energie Atomique Et Aux Energies Alternatives
InventorPierre Grenet
Life of this patent
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Abstract
A system for capturing the movements of a body having substantially rigid segments articulated together includes attitude units fastened onto the segments of the body, the units each including at least one accelerometer and one magnetometer, and a reduced number of gyroscopes. The system also includes a pseudo-static state detection module and a module for calculating pseudo-static angles. When all segments are detected in a pseudo-static state, the state vector is provided by the module for calculating pseudo-static angles. When a segment is detected in a dynamic state, the state vector is provided at the output of a Kalman filter.
Claims18
A system for capturing movements of a structure including at least N substantially rigid segments articulately connected with said structure, said system including:
- a set of N accelerometers with at least one measurement axis, each of said N accelerometers being substantially rigidly connected to one of said N segments,
- a set of P second sensors capable of returning one direction of a fixed reference frame, each substantially rigidly connected to a segment,
- a set of Q third sensors capable of returning a measurement representative of an angular velocity, each substantially rigidly connected to a segment,
- a module for communicating the outputs of the N accelerometers, P second sensors and Q third sensors with a computer processing module;
- said processing module including a state observer,
- said system further including:
- a pseudo-static state detection module for detecting a pseudo-static state of each of the segments of said structure,
- a pseudo-static orientation calculation module for calculating a pseudo-static orientation of the segments in a pseudo-static state,
- a state observer module configured for replacing outputs of a prediction function of the state observer with outputs of the pseudo-static orientation calculation module for the segments for which a detection condition at the output of the pseudo-static state detection module condition is true
- wherein the number Q is less than the number N and the number P.
A method for capturing movements of a structure including at least N substantially rigid segments articulately connected with said structure, said method including:
- a step of acquiring measurements from N accelerometers with at least one measurement axis, said accelerometers being substantially rigidly connected to said segments,
- a step of acquiring measurements from P second sensors configured to return a direction of a fixed reference frame, each substantially rigidly connected to a segment,
- a step of acquiring measurements from Q third sensors configured to return a measurement representative of an angular velocity, each substantially rigidly connected to a segment, and
- a step of communicating outputs of the N accelerometers, the P second sensors and the Q third sensors to a computer processing step comprising:
- a step of detecting a pseudo-static state of each of the segments of said structure,
- a step of calculating a pseudo-static orientation of the segments in a pseudo-static state, and
- if at least one output of the step of detecting a pseudo-static condition is false, a step of replacing outputs of a prediction function of a state observer which receives as input the outputs of the N accelerometers, the P second sensors and the Q third sensors, Q being less than the number N and the number P, with the outputs of the step of calculating the pseudo-static orientation for the segments for which the detection condition at an output of the pseudo-static state detection module is true.
Dependencies are inferred from the claim text.