Correcting a robotic surgery user interface device tracking input
A sequence of input samples that are measures of position or orientation of an input device being held by a user are received. A current output sample of a state of linear quadratic estimator, LQE, is computed that is an estimate of the position or orientation of the input device. The current output sample is computed based on i) a previously computed output sample, and ii) a velocity term. An updated output sample of the state of the LQE is computed, based on i) a previously computed output sample, and ii) a new input sample. Other embodiments are also described and claimed.
1. A method comprising:
receiving an input sequence of input samples that track a changing position or orientation of an input device of a robotic surgery system,
computing a current output sample, wherein the current output sample is computed based on i) a previously computed output sample, and ii) a velocity term that comprises a slope of a line fitted to a plurality of previously computed output samples, and
when an input sample is received, computing a new output sample based on i) a previously computed output sample, and ii) the input sample;
producing an output sequence that includes the current output sample and the new output sample; and
translating, by a feedback control system controller, the output sequence into actuator commands of a surgical robotic arm to which a surgical tool is attached so that the surgical tool mimics the changing position or orientation of the input device.
2. The method of claim 1 wherein when the input sample is received, the new output sample is computed by computing a Kalman filter gain.
3. The method of claim 1 wherein the input sequence comprises a sequence of orientation vectors, and the output sequence comprises an estimate of orientation of the input device.
4. The method of claim 1 wherein the current output sample is computed while the input sample has not been received, from a window of a plurality of previously computed output samples.
5. The method of claim 4 further comprising
wherein while the input sample has not been received, computing a next output sample based on i) another previously computed output sample, and ii) another velocity term, by
moving the window forward so that another plurality of previously computed output samples are within the window, and
fitting a line to said another plurality of previously computed output samples and taking a derivative of the line to compute said another velocity term.
6. The method of claim 4 wherein when the input sample is received the new output sample is computed using the previously computed output sample, the input sample, and not a velocity term.
7. The method of claim 1 wherein when the input sample is received the new output sample is computed using the previously computed output sample, the input sample, and not a velocity term.
8. An article of manufacture comprising a machine-readable medium having stored therein instructions that when executed by a processor of a robotic surgery system:
receive an input sequence of input samples that are measures of a changing position or orientation of an input device;
compute a current output sample based on i) a previously computed output sample, and ii) a velocity term that comprises a slope of a line fitted to a plurality of previously computed output samples;
when an input sample is received, compute a new output sample based on i) a previously computed output sample, and ii) the input sample;
produce an output sequence that includes the current output sample and the new output sample; and
translating the output sequence into actuator commands of a surgical robotic arm to which a surgical tool is attached so that the surgical tool mimics the changing position or orientation of the input device.
9. The article of manufacture of claim 8 wherein when the input sample is received, the new output sample is computed by computing a Kalman filter gain.
10. The article of manufacture of claim 8 wherein the input sequence comprises a sequence of orientation vectors, and the output sequence comprises an estimate of orientation of the input device.
11. The article of manufacture of claim 8 wherein the current output sample is computed while the input sample has not been received, from a window of a plurality of previously computed output samples.
12. The article of manufacture of claim 11 wherein the machine-readable medium has stored there further instructions that configure the processor to, while the input sample has not been received, compute a next output sample based on i) another previously computed output sample, and ii) another velocity term, by:
moving the window forward so that another plurality of previously computed output samples are within the window, and
fitting a line to said another plurality of previously computed output samples and taking a derivative of the line to compute said another velocity term.
13. The article of manufacture of claim 11 wherein when the input sample is received the new output sample is computed using the previously computed output sample, the input sample, and not a velocity term.
14. The article of manufacture of claim 8 wherein when the input sample is received the new output sample is computed using the previously computed output sample, the input sample, and not a velocity term.