Multiple-assembly antenna positioner with eccentric shaft
Methods, systems, and devices are described for an antenna positioning apparatus, which includes a multiple-assembly positioner for adjusting a positioning angle about a positioning axis. The multiple-assembly positioner has two or more positioning assemblies that are coupled in series between a base structure and a positioning structure. Positioning assemblies can be individually selected based on various criteria, such as cost, complexity, angular range, and other performance, and be configured to work together to provide a desired range of adjustment to the positioning angle while simultaneously meeting precision requirements. In one example, a positioning assembly can include a shaft with an eccentric portion, which is rotated in order to provide the adjustment. A method is described where a first positioning assembly can be actuated to a first initial position, and then held, such that a second positioning assembly can be actuated to provide a selected antenna positioning angle.
1. A method of positioning an antenna, comprising:
providing an antenna positioning system having:
a base structure;
a positioning structure rotatably coupled to the base structure about a positioning axis to provide a positioning angle between the positioning structure and the base structure;
a first positioning assembly coupled with one of the base structure or the positioning structure, the first positioning assembly providing a first adjustment to the positioning angle;
a second positioning assembly coupled between the first positioning assembly and the other of the base structure or the positioning structure, the second positioning assembly providing a second adjustment to the positioning angle; and
a control system operable to actuate the first positioning assembly and the second positioning assembly;
actuating, by the control system, the first positioning assembly to a first position to establish a first value of the positioning angle;
holding, by the control system and over a first time period, the first positioning assembly at the first position; and
actuating, by the control system and during the first time period, the second positioning assembly to establish one or more second values of the positioning angle.
2. The method of claim 1 , wherein the actuating the second positioning assembly is based at least in part on the control system tracking a target.
3. The method of claim 1 , wherein the first adjustment to the positioning angle has a first angular range and the second adjustment to the positioning angle has a second angular range, and wherein the second angular range is less than the first angular range.
4. The method of claim 3 , further comprising:
determining, by the control system, that a difference between a target value of the one or more second values of the positioning angle and a current value of the one or more second values of the positioning angle has reached a threshold relative to a remaining range of the second angular range; and
actuating, by the control system, the first positioning assembly and the second positioning assembly to establish the target value of the positioning angle in response to the determined difference.
5. The method of claim 4 , further comprising:
unlocking, by the control system, the first positioning assembly prior to further actuating the first positioning assembly; and
locking, by the control system, the first positioning assembly after further actuating the first positioning assembly.
6. The method of claim 3 , further comprising:
determining, by the control system and during the first time period, that the second adjustment to the positioning angle has reached a threshold relative to the second angular range;
actuating, by the control system, the first positioning assembly and the second positioning assembly to establish a target value of the one or more second values of the positioning angle, wherein the first positioning assembly is actuated to a second position and the second positioning assembly is actuated to a nominal position at a beginning of a second time period to establish the target value of the positioning angle;
holding, by the control system and over the second time period, the first positioning assembly at the second position; and
actuating, by the control system and during the second time period, the second positioning assembly to establish one or more third values of the positioning angle.
7. The method of claim 1 , wherein the actuating the second positioning assembly further comprises:
dithering the second positioning assembly to provide one or more different antenna positions than the first position;
measuring antenna signal feedback information at the one or more different antenna positions; and
determining a current value of the positioning angle based at least in part on the measured antenna signal feedback information.
8. The method of claim 1 , further comprising:
detecting, by the control system, an error state of the second positioning assembly; and
actuating, by the control system, the first positioning assembly to establish at least one of the one or more second values of the positioning angle in response to detecting the error state of the second positioning assembly.
9. The method of claim 1 , further comprising:
determining, by the control system, at least one of the first position of the first positioning assembly or a position of the second positioning assembly;
calculating, by the control system, a controller gain schedule for the second positioning assembly based at least in part on the determining; and
determining, by the control system, an actuation command for the actuating, during the first time period, the second positioning assembly based at least in part on the controller gain schedule.
10. The method of claim 1 , wherein the actuating the second positioning assembly comprises:
rotating a shaft with an eccentric portion, an eccentricity of the eccentric portion providing the second adjustment to the positioning angle.
11. The method of claim 1 , wherein actuating the second positioning assembly comprises:
rotating a shaft, the shaft having a driven portion configured to rotate about a first axis, and the shaft having an eccentric portion with a circular cross-section about a second axis, the second axis being parallel to the first axis and separated from the first axis by an eccentricity distance.
12. The method of claim 1 , wherein actuating the first positioning assembly comprises:
actuating at least one of a turnbuckle, a linear rack gear, a hydraulic cylinder, a worm gear, a jack screw, or a ball screw.