Motion Profile Generator for Time-Optimal Trajectory Control

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Solution Overview

Problem

Conventional motion control systems face challenges with trapezoidal and S-curve profiles, including excessive system jerk, risk of overshooting, and inefficiency due to abrupt transitions and symmetrical acceleration/deceleration limitations.

Innovation Solution

A profile generator that calculates constraint-based, time-optimal motion profiles using ST-curve profiles with continuous jerk references, supporting asymmetric acceleration and deceleration, and optimizing calculations by skipping unnecessary segments and aligning with controller sample times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If trapezoidal motion profile is used, then point-to-point motion speed is improved, but system jerk becomes excessive and accuracy deteriorates

Engineering Contradiction:

Improvepoint-to-point motion speedVSAvoidsystem jerk

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent applies S-curve motion profiles that replace the sharp corners of trapezoidal velocity curves with curved transitions. By using continuous acceleration and deceleration phases that follow S-shaped curves, the system eliminates abrupt jerk changes while maintaining high motion speeds, thus resolving the contradiction between speed and jerk reduction

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent implements dynamic motion profiles that continuously adjust acceleration and deceleration rates based on real-time system state. By making the motion profile adaptive rather than static, the system can optimize for both speed and smoothness, reducing jerk while maintaining fast point-to-point motion

Inventive Principle:

Principle #15Dynamics

2Speed

If trapezoidal motion profile is used, then point-to-point motion speed is improved, but positioning accuracy deteriorates due to overshooting

Engineering Contradiction:

Improvepoint-to-point motion speedVSAvoidpositioning accuracy

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The S-curve motion profiles with continuous acceleration and deceleration phases prevent the abrupt velocity changes that cause overshooting in trapezoidal profiles. The curved transitions allow the system to smoothly approach and settle at the target position, maintaining both high speed and high positioning accuracy

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent incorporates feedback mechanisms that monitor system position and velocity in real-time, allowing the controller to adjust the motion profile dynamically. This feedback enables the system to correct for potential overshooting before it occurs, ensuring accurate positioning while maintaining fast motion

Inventive Principle:

Principle #23Feedback

3Object-generated harmful factors

If S-curve motion profile is used, then system jerk is reduced and accuracy is improved, but motion time increases

Engineering Contradiction:

Improvesystem jerkVSAvoidmotion time

Core Design Contradiction:

Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The patent implements optimized S-curve profiles that dynamically adjust the duration and shape of acceleration and deceleration phases. By making the profile adaptive, the system achieves smooth transitions with reduced jerk while minimizing the total motion time, thus resolving the contradiction between smoothness and speed

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent varies key motion parameters such as maximum acceleration, jerk limits, and profile shape factors to optimize performance. By adjusting these parameters based on the specific application requirements, the system achieves both smooth motion (reduced jerk) and fast response (reduced motion time)

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If symmetrical acceleration and deceleration is used, then control simplicity is improved, but adaptability deteriorates

Engineering Contradiction:

Improvecontrol simplicityVSAvoidacceleration and deceleration flexibility

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent explicitly supports asymmetric acceleration and deceleration profiles, allowing different maximum rates for acceleration and deceleration phases. This asymmetry enables the system to be optimized for specific application requirements (e.g., faster acceleration for positioning, slower deceleration for precision stopping) while maintaining the simplicity of predefined motion profiles

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS9041337B2Motion profile generator

Publication Date: 2015.05.26 DANFOSS POWER ELECTRONICS AS

AI summary

Systems and methods are provided for generating a constraint-based, time-optimal motion profile for controlling the trajectory of a point-to-point move in a motion control system. A profile generator can calculate an ST-curve motion profile that includes a jerk reference that varies continuously over time for at least one of the motion profile segments, thereby producing a smooth, time-optimal trajectory. The profile generator can create the motion profile to conform to a set of motion constraints provided by the user. The profile generator also supports calculation of time-optimal motion profiles having segments that align to the sample time of the motion control system. In some embodiments, the profile generator can efficiently generate the motion profile by performing reference calculations only for those segments that will be used in the final motion profile for a given point-to-point move.