Segmented Cam Curve Generation for Smooth Shaft Motion

Solution Overview

Problem

Conventional cam curve generation techniques cause significant fluctuations in the speed and acceleration of driven shafts, leading to vibrations and increased motor requirements, especially when connecting different sections, which results in higher costs and equipment complexity.

Innovation Solution

A cam curve generating device that divides the application section into sub-sections where acceleration is either monotonic, constant, or zero, ensuring continuous position, speed, and acceleration at section boundaries, using a combination of boundary and division conditions to smooth the connection with out-section cam curves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a cam curve is generated to satisfy boundary conditions at the start and end of a section, then the connection to out-section cam curves is smooth, but fluctuations in speed and acceleration of the driven shaft become large

Engineering Contradiction:

Improvesmooth connection between cam curvesVSAvoidfluctuation in speed of driven shaft

Core Design Contradiction:

Stability of the object's compositionVSSpeed

Solution Approach 1:

The application section is divided into multiple sub-sections (first sub-section, second sub-section, third sub-section, etc.) where each sub-section has specific acceleration characteristics. This segmentation allows the cam curve to be constructed with controlled acceleration profiles in each segment, reducing overall fluctuations while maintaining smooth connections at boundaries.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the acceleration parameter systematically across different sub-sections. The first sub-section has acceleration that monotonously increases, the second has acceleration that monotonously decreases, and the third has constant acceleration. This parameter variation strategy controls speed fluctuations while ensuring continuous position, speed, and acceleration at section boundaries.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If a cam curve is generated to satisfy boundary conditions at the start and end of a section, then the connection to out-section cam curves is smooth, but fluctuations in acceleration of the driven shaft become large

Engineering Contradiction:

Improvesmooth connection between cam curvesVSAvoidfluctuation in acceleration of driven shaft

Core Design Contradiction:

Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The application section is divided into multiple sub-sections (first sub-section, second sub-section, third sub-section, etc.) where each sub-section has specific acceleration characteristics. This segmentation allows the cam curve to be constructed with controlled acceleration profiles in each segment, reducing overall fluctuations while maintaining smooth connections at boundaries.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the acceleration parameter systematically across different sub-sections. The first sub-section has acceleration that monotonously increases, the second has acceleration that monotonously decreases, and the third has constant acceleration. This parameter variation strategy controls speed fluctuations while ensuring continuous position, speed, and acceleration at section boundaries.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If conventional cam curve generation is used, then boundary conditions are satisfied, but large fluctuations require higher capacity motors and increase equipment complexity

Engineering Contradiction:

Improvesatisfaction of boundary conditionsVSAvoidmotor capacity and equipment complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The application section is divided into multiple sub-sections (first sub-section, second sub-section, third sub-section, etc.) where each sub-section has specific acceleration characteristics. This segmentation allows the cam curve to be constructed with controlled acceleration profiles in each segment, reducing overall fluctuations while maintaining smooth connections at boundaries.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the acceleration parameter systematically across different sub-sections. The first sub-section has acceleration that monotonously increases, the second has acceleration that monotonously decreases, and the third has constant acceleration. This parameter variation strategy controls speed fluctuations while ensuring continuous position, speed, and acceleration at section boundaries.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20230409002A1Cam curve generating device, cam curve generating method, and program

Publication Date: 2023.12.21 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

Provided is cam curve generating device that generates a cam curve that is smoothly connected to an out-section cam curve and reduces fluctuations in speed of a driven shaft and acceleration of the driven shaft. Cam curve generating device includes section divider that divides an application section into a plurality of sub-sections, and cam curve generator that generates a cam curve in the application section. The division condition includes a length and the type of each of the plurality of sub-sections. The boundary condition includes a position, speed, and acceleration of the driven shaft at each of a start and an end of the application section. Cam curve generator generates a cam curve that allows a position of the driven shaft, speed of the driven shaft, and acceleration of the driven shaft to be continuous at each of boundaries of the plurality of sub-sections.