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Automated Pitch Rotation Measurement

IP.com Disclosure Number: IPCOM000050599D
Original Publication Date: 1982-Nov-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Balboni, FH: AUTHOR [+3]

Abstract

Pitch rotation is the angular movement of the gripper form a suspended vertical position to a horizontal position, or vice versa, as shown in Fig. 1. The proposed test tool provided excellent pitch measurement resolution as a function of gravitational force. A 16-bit absolute position rotary encoder and weight assembly having rotation about a horizontal line or axis is used to measure accuracy and repeatability. This rotary test method facilitates automation. The automation is achieved by feeding the digital output from the encoder to the computer.

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Automated Pitch Rotation Measurement

Pitch rotation is the angular movement of the gripper form a suspended vertical position to a horizontal position, or vice versa, as shown in Fig. 1. The proposed test tool provided excellent pitch measurement resolution as a function of gravitational force. A 16-bit absolute position rotary encoder and weight assembly having rotation about a horizontal line or axis is used to measure accuracy and repeatability. This rotary test method facilitates automation. The automation is achieved by feeding the digital output from the encoder to the computer.

A bracket 10, attached to the end of the arm effector 12, allows positioning of the rotary encoder 1C axis parallel to, and ideally in line with, the pitch motor's 16 rotational axis. The encoder axis ia aligned with the pitch motor axis to eliminate any offset that would introduce oscillation on the suspended weight 18, thus the axis rotates, with no translation involved, as depicted in Fig. 2.

A weight 18 is fixed to, and suspended from, the encoder 14 shaft 15. Gravity acts to keep the weight suspended vertically. To overcome the inherent resistance of the encoder 14 (friction), an offsetting starting torque is required. This torque determines the amount of weight 18 to be suspended from the encoder shaft 15, and the length of the arm 20 between the encoder 14 axis and the weight 18. The resolution achievable is a function of starting torque which, as mentioned, determines the le...