Fault detection for a resistive position sensor
AssigneeSiemens Medical Solutions USA, Inc.
InventorDonald J. Bak
Life of this patent
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Abstract
Circuits for detecting faults in variable resistive position feedback sensors common in the use of motion control systems, provide a filter coupled to an output signal of the variable resistive position sensor for processing the signal to detect noise indicative of intermittent faults. A memory stores occurrences of signals from the filter. The memory can activate an alarm which indicates that a failure is detected. The circuits are particularly applicable to medical imaging systems such as SPECT, PET or MRI systems which contain a multiplicity of moving components that require accurate motion control and positioning.
Claims18
A circuit for detecting intermittent faults in a variable resistive position sensing device, comprising:
- a filter circuit for receiving a position signal of said variable resistive position sensing device and filtering said position signal to provide an output signal indicative of a fault in said variable resistive position sensing device;
- a storage device for storing output signals from said filters indicative of faults in said variable resistive position sensing device;
- wherein said filter circuit comprises a velocity sensor for providing a velocity signal;
- an integrator that receives said velocity signal from said velocity sensor and integrates said velocity signal to produce a velocity sensor position signal, and
- a difference circuit that obtains a difference between said velocity sensor position signal and said variable resistive position signal, and outputs said difference as a difference signal, wherein said difference signal is applied to a high-pass or band-pass filter to produce said output signal.
A motion control system, comprising:
- a motion controller;
- a motor;
- a variable resistive position sensor;
- a feedback loop coupled to an output of said variable resistive position sensor and providing a variable resistive position feedback signal to said motion controller;
- a filter circuit also coupled to said output of said variable resistive position sensor and filtering said variable resistive position feedback signal to produce a fault signal indicative of a fault in said variable resistive position sensor;
- a storage device for storing a fault signal from said filter circuit;
- wherein said filter circuit comprises a velocity sensor for providing a velocity signal;
- an integrator that receives said velocity signal from said velocity sensor and integrates said velocity signal to produce a velocity sensor position signal, and
- a difference circuit that obtains a difference between said velocity sensor position signal and said variable resistive position signal, and outputs said difference as a difference signal, wherein said difference signal is applied to a high-pass or band-pass filter to produce an output signal.
A medical imaging system, comprising:
- a movable mechanical component;
- a motion controller that controls motion of said movable mechanical component;
- a motor that moves said movable mechanical component in response to a signal from said controller;
- a variable resistive position sensor that determines a position of said movable mechanical component;
- a feedback loop coupled to an output of said variable resistive position sensor and providing a variable resistive position feedback signal to said motion controller;
- a filter circuit also coupled to said output of said variable resistive position sensor and filtering said variable resistive position feedback signal to produce a fault signal indicative of a fault in said variable resistive position sensor;
- and
- a storage device for storing a fault signal from said filter circuit
- wherein said filter circuit comprises a velocity sensor for providing a velocity signal;
- an integrator that receives said velocity signal from said velocity sensor and integrates said velocity signal to produce a velocity sensor position signal, and
- a difference circuit that obtains a difference between said velocity sensor position signal and said variable resistive position signal, and outputs said difference as a difference signal, wherein said difference signal is applied to a high-pass or band-pass filter to produce an output signal.
Dependencies are inferred from the claim text.