U-Shaped Base Joint Arm Robot for High-Speed Precision

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Solution Overview

Problem

Conventional articulated-arm robots face limitations in achieving high movement speeds and positioning accuracy while maintaining a compact design, making them unsuitable for tasks requiring rapid movement of small components and limited access in industrial settings.

Innovation Solution

The articulated-arm robot design features a U-shaped base with a fork-like mounting of the first robot arm and a traction mechanism-free drive for the first axis of rotation, combined with a second drive motor positioned in the dead space to minimize moving mass and maximize working space, utilizing a gear system and a two-stage toothed belt drive for high dynamic movement and positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional articulated arm robots are used, then they can perform basic picking and placing tasks, but they cannot achieve high movement speeds combined with high positioning precision

Engineering Contradiction:
Improvemovement speedVSAvoidpositioning precision
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The robot arm is divided into multiple segments (first robot arm and second robot arm) with distinct drive mechanisms. The first robot arm uses a direct-drive motor for high-speed movement, while the second robot arm uses a traction mechanism for precise positioning, allowing each segment to be optimized for its specific function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The robot employs dynamic control where the first robot arm operates at high speeds for rapid repositioning, and the second robot arm provides fine positioning control. The control system dynamically coordinates both arms to achieve high overall speed while maintaining positioning precision through the combined action of the two segments.

Inventive Principle:
Principle #15Dynamics

2Speed

If delta robots are used for high-speed movement, then they can quickly move working platforms, but their design requires large space and cannot access confined areas

Engineering Contradiction:
Improvemovement speedVSAvoidspace requirement
Core Design Contradiction:
SpeedVSArea of stationary object

Solution Approach 1:

The robot transitions from the parallel architecture of delta robots to a serial SCARA architecture, changing the dimensional arrangement of the robot arms. This allows the robot to achieve high speeds while having a compact footprint that can access confined spaces, as the arms move in a vertical plane rather than requiring a large horizontal workspace.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The robot changes its architectural parameters from a parallel delta structure to a serial SCARA structure with parallel axes. This parameter change enables the robot to maintain high movement speeds while reducing the space requirement, allowing it to operate in confined areas where delta robots cannot fit.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If drive motors are arranged on the base for the first robot arm, then the drive is simple, but it increases the moving mass and reduces working space

Engineering Contradiction:
Improvedrive complexityVSAvoidmoving mass
Core Design Contradiction:
Device complexityVSWeight of moving object

Solution Approach 1:

The second drive motor and traction mechanism are extracted from the base and relocated to the first robot arm. This extraction reduces the moving mass on the base, increases the working space around the base, and allows the second robot arm to be driven independently without adding weight to the moving components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The drive system is reorganized from a horizontal arrangement on the base to a vertical arrangement where the second drive motor is positioned above the first robot arm. This dimensional change allows both motors to be arranged one behind the other, minimizing the footprint on the base while maintaining drive functionality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Area of moving object

If the second drive motor is arranged in the dead space area, then working space is maximized, but the drive mechanism becomes more complex

Engineering Contradiction:
Improveworking spaceVSAvoiddrive complexity
Core Design Contradiction:
Area of moving objectVSDevice complexity

Solution Approach 1:

The second drive motor and traction mechanism are nested within or mounted on the first robot arm structure. This nesting allows the second drive motor to be positioned in the dead space area without significantly increasing the overall robot volume, while the compact arrangement minimizes the added complexity of the drive mechanism.

Inventive Principle:
Principle #7Nested doll (Nesting)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enables high-speed, precise movement with reduced space requirements, allowing the robot to handle small components effectively and access confined areas, enhancing its versatility in industrial applications.

Implementation Method 1

a first drive motor, arranged concentrically to the first axis of rotation, for driving the first robot arm and the second robot arm around the first axis of rotation without any traction mechanism

Methodology Applied
Scientific EffectDirect drive mechanism:

Implementation Method 2

The first drive motor is coupled to a gear, for example a so-called harmonic drive gear, a planetary gear or an eccentric gear

Methodology Applied
Scientific EffectGear transmission: Gear

Implementation Method 3

a second drive motor with a two-stage traction mechanism transmission for moving the second robot arm around the second axis of rotation

Methodology Applied
Scientific EffectTraction mechanism:

Implementation Method 4

Chains, belts, in particular toothed belts, but also ropes or belts, in particular steel belts, can be used as traction means. The traction drive is particularly preferably designed as a two-stage toothed belt drive.

Methodology Applied
Scientific EffectBelt drive:

Implementation Method 5

The fork-like mounting of the first robot arm achieved by the U-shaped structure of the base, in conjunction with the traction mechanism-free drive of the first axis of rotation caused by the first drive motor, results in a high structural rigidity of the mounting of the first robot arm

Methodology Applied
Scientific EffectStructural rigidity:

Implementation Method 6

Articulated arm robots as described above belong to the SCARA robots, which are used to move a tool attached to the free end of the second robot arm in different directions in order to carry out specific tasks with it

Methodology Applied
Scientific EffectSCARA mechanism:

Data Source

PatentEP2321097B1Joint arm robot with u shaped base
Publication Date: 2012.05.23 STAUBLI FAVERGES SA
  • EP2321097B1 patent drawingFigure 1
  • EP2321097B1 patent drawingFigure 2
  • EP2321097B1 patent drawingFigure 3

AI summary

The invention relates to a joint arm robot (10) comprising a base (12), a first robot arm (14) disposed at the base pivotable about a first rotation axis (A) and a second robot arm (16) disposed at the first robot arm (14) pivotable about a second rotation axis (B), wherein the first rotation axis (A) and the second rotation axis (B) are at least approximately parallel to one another, and a first drive motor (24) for moving the first robot arm (14) and the second robot arm (16) about the first rotation axis (A), and a second drive motor (30) for moving the second robot arm (16) about the second rotation axis (B). To improve the dynamic behavior while at the same time maintaining positional accuracy, the base (12) has a U-shaped structure (19) with an upper shoulder (20) and a lower shoulder (22) for pivotable mounting of the first robot arm (14), the first drive motor (24) and the second drive motor (30) are fastened to the base (12) and disposed one behind the other relative to the first robot arm (14) and finally the first drive motor (24) causes a non-traction driving about the first rotation axis (A), whereas the second drive motor (30) acts on the second robot arm (16) by way of a traction gear having a transmission ratio in the range of 1:1 to 30:1.