Position-based step control algorithm for a motion control system
AssigneeNational Instruments Corporation
InventorKiran Sreekantham
Life of this patent
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Abstract
A motion control interface device includes an FPGA configured to implement a step generation algorithm that generates step control signals for a motion device. The signals are not determined based directly on time, but instead are determined from the position of the motion device. More particularly, the step generation algorithm operates to keep track of a position fraction based on the position. The position fraction is incremented (or decremented) at each clock tick of the FPGA. The algorithm generates rising edge signals when the position fraction crosses a particular threshold value, referred to as the rising edge threshold value. Similarly, the algorithm signals direction changes when the position fraction crosses a threshold referred to as the direction change threshold value.
Claims18
A motion control system comprising:
- a motion control device;
- and
- a motion control interface device, wherein the motion control interface device includes an FPGA (Field-programmable Gate Array), wherein the FPGA, independent of processors, is configured to implement a step generation algorithm for controlling the motion control device, wherein the FPGA is configured to:
- determine a fraction value representing a position of the motion control device;
- compare the fraction value to a first threshold value;
- cause the motion control device to perform a step if the fraction value has crossed the first threshold value;
- compare the fraction value to a second threshold value;
- and
- cause the motion control device to change direction along a motion axis if the fraction value has crossed the second threshold value.
A method comprising:
- configuring an FPGA (Field-programmable Gate Array) of a motion control interface device to perform a step generation algorithm for controlling a motion control device without utilizing another processor, wherein the step generation algorithm operates to:
- determine a fraction value representing a position of the motion control device;
- compare the fraction value to a first threshold value;
- cause the motion control device to perform a step if the fraction value has crossed the first threshold value;
- compare the fraction value to a second threshold value;
- and
- cause the motion control device to change direction along a motion axis if the fraction value has crossed the second threshold value.
A non-transitory computer-readable memory medium storing program instructions executable by a computer system to cause the computer system to:
- configure an FPGA (Field-programmable Gate Array) of a motion control interface device to perform a step generation algorithm for controlling a motion control device independent of processors, wherein the step generation algorithm operates to:
- determine a fraction value representing a position of the motion control device;
- compare the fraction value to a first threshold value;
- cause the motion control device to perform a step if the fraction value has crossed the first threshold value;
- compare the fraction value to a second threshold value;
- and
- cause the motion control device to change direction along a motion axis if the fraction value has crossed the second threshold value.
Dependencies are inferred from the claim text.