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# Motor-Driven Arm for Box Frame Robot

IP.com Disclosure Number: IPCOM000043619D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 62K

IBM

## Related People

Robinson, JT: AUTHOR [+2]

## Abstract

The objective is to obtain maximum stiffness at lowest weight for a moving arm on a box frame robot. Fig. 1 shows the box frame robot with three linear degrees of freedom, X, Y and Z. Each arm is limited in linear travel by X, Y, Z which constitute the dimensions of a box called the work volume. It should be apparent that one consideration in the design of such a robot is to make the overall width W as close to X as possible so as to minimize material costs. The X arm, as shown in Fig. 1, must be driven by some means in the Y direction. One means is to utilize what is known as a cantilever arm in which one electric motor drives the X arm from one end. Another means consists of the X arm driven by an electric motor at each end thereof, as shown in Fig. 1.

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Motor-Driven Arm for Box Frame Robot

The objective is to obtain maximum stiffness at lowest weight for a moving arm on a box frame robot. Fig. 1 shows the box frame robot with three linear degrees of freedom, X, Y and Z. Each arm is limited in linear travel by X, Y, Z which constitute the dimensions of a box called the work volume. It should be apparent that one consideration in the design of such a robot is to make the overall width W as close to X as possible so as to minimize material costs. The X arm, as shown in Fig. 1, must be driven by some means in the Y direction. One means is to utilize what is known as a cantilever arm in which one electric motor drives the X arm from one end. Another means consists of the X arm driven by an electric motor at each end thereof, as shown in Fig. 1. It can be shown that the simply supported beam, that is, the beam driven at both ends, is 16 times stiffer than the cantilever beam. The present arrangement is a compromise driver arrangement between the one- and two-motor configuration. The motor 10 is mounted inside the X arm 12, allowing the overall width of the frame to be as close as possible to the work volume dimension in the X direction. The X arm 12 is driven from both ends, a simply supported beam, with the use of one motor 10, thereby saving the expense of a motor, tachometer, position encoder, servo amplifier, servo card components and the space taken by these components as well as the weight thereof. Thus, the X a...