Patent ID: 11867578
Assignee: SOUTHEAST UNIVERSITY
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 4:
5. A high-precision and miniaturized on-orbit calibration method for a six-dimensional force sensor of a space station manipulator, the on-orbit calibration method comprising the following steps:
step 1: calibrating a force in an X-direction, comprising the following steps:
step 11: mounting force applying devices on a fixing bracket which is in an inverted π-shape and comprises a horizontal plate, two vertical plates vertically arranged on the horizontal plate, and a calibration cavity with a U-shaped longitudinal cross section that is formed between the two vertical plates and the horizontal plate, wherein the force applying devices comprises a first force applying device, a second force applying device and a third force applying device that are to be mounted in the calibration cavity by the step 11, wherein the first force applying and the second force applying device are to be mounted on opposite sides of the two vertical plates, such that an axis of the first force applying device and an axis of the second force applying device are at a same height, and the third force applying device is to be mounted at a center of a top surface of the horizontal plate;
step 12: mounting a cubic stress block: mounting the cubic stress block on a top of the six-dimensional force sensor, and mounting a bottom portion of the six-dimensional force sensor at an end of the manipulator; driving the manipulator so that the cubic stress block extends into a calibration cavity and becomes in contact with three force applying heads of the three force applying devices; wherein, the X-direction of the six-dimensional force sensor is subjected to be parallel to an axial direction of the first force applying device, and a Z-direction of the six-dimensional force sensor is subjected to coincide with an axial direction of the third force applying device;
step 13: calibrating a force in a positive X-direction: applying multiple groups of forces on the cubic stress block by controlling the first force applying device, logging a data of a single axis force sensor in the first force applying device and a data of the six-dimensional force sensor, such that the calibration of the force in the positive X-direction is realized; wherein, a method for applying multiple groups of forces on the cubic stress block with the first force applying device is as follows: applying a preset voltage between a first electrode plate and a second electrode plate in the first force applying device, owing to a piezoelectric effect, several piezoelectric ceramic plates between the first and second electrode plates generate a preset displacement in the positive X-direction which is related with a magnitude of the voltage; since the force applying head in the first force applying device contacts the cubic stress block, the displacement in the positive X-direction is transformed into the force in the positive X-direction applied on the cubic stress block, and a magnitude of the force in the positive X-direction is related with the magnitude of the voltage; the single axis force sensor in the first force applying device detects and feeds back the applied force in the positive X-direction in real time, and the magnitude of the force in the positive X-direction is adjustable by controlling the magnitude of the voltage; and
step 14: calibrating a force in a negative X-direction: resetting the first force applying device, applying multiple groups of forces in the negative X-direction on the cubic stress block by controlling the second force applying device, logging a data of a single axis force sensor in the second force applying device and the data of the six-dimensional force sensor, such that the calibration of the force in the negative X-direction is realized;

step 2: calibrating a force in a Y-direction, comprising the following steps:
step 21: adjusting a stress direction of the cubic stress block: resetting the first force applying device and the second force applying device, turning the manipulator so that the Z-direction of the six-dimensional force sensor coincides with the axial direction of the third force applying device, and the Y-direction of the six-dimensional force sensor is parallel to the axial direction of the first force applying device; and
step 22: calibrating the force in the Y-direction: calibrating the force in the positive Y-direction by controlling the first force applying device as described in the step 13 and step 14; calibrating the force in a negative Y-direction by controlling the second force applying device;

step 3: calibrating a force in the Z-direction: resetting the first force applying device and the second force applying device, controlling the third force applying device to apply multiple groups of forces in the Z-direction on the cubic stress block while the Z-direction of the six-dimensional force sensor coincides with the axial direction of the third force applying device, logging a data of a single axis force sensor in the third force applying device and the data of the six-dimensional force sensor, such that the calibration of the force in the Z-direction is realized.